CN109916747B - Fire and impact real-time coupling test method for building structural member - Google Patents
Fire and impact real-time coupling test method for building structural member Download PDFInfo
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- CN109916747B CN109916747B CN201910242343.1A CN201910242343A CN109916747B CN 109916747 B CN109916747 B CN 109916747B CN 201910242343 A CN201910242343 A CN 201910242343A CN 109916747 B CN109916747 B CN 109916747B
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Abstract
The invention discloses a fire and impact real-time coupling test method for building structural members, which adopts a coupling test system, wherein the coupling test system comprises a restraint system, a heating system, an impact system and a control and data acquisition system; the constraint system provides boundary conditions on two sides of the component and applies preload; the heating system drives the high-temperature furnace to control and feed back the heating process; the impact system controls and feeds back the height of the drop hammer, the position of the furnace body is judged and fed back, and the drop hammer is released; the control and data acquisition system is used for data acquisition and coordinating the restraint, temperature rise and impact systems. The method can realize real-time coupling of fire and impact, truly simulate the process that the engineering generates fire and the building structural member such as the steel pipe concrete column bears the impact or the explosion causes actual collapse, and accurately evaluate the impact bearing capacity of the building structural member under the fire condition; the test process is carried out in a full-automatic mode, accidental errors are avoided, and the authenticity, accuracy and reliability of test results are high.
Description
Technical Field
The invention relates to the field of building structure member performance detection, in particular to a test method for real-time coupling of fire and impact of a building structure member.
Background
Impact and fire coupled structural safety studies have had extensive research background and urgent research needs. The impact resistance of the building structural member at high temperature not only considers the fire resistance, but also is an important parameter for measuring the safety and reliability of the building structural member in fire, and is an important reference index for designing and manufacturing the building structural member.
Tests of coupling of the two types of loads have not been reported so far, due to the distinct nature of the two types of loads (impact is a dynamic load, the loading ends within a few milliseconds; fire is a quasi-static load, the loading usually takes tens of minutes or more). For example, in the case of a fire, a reasonable and accurate evaluation means is not available for the working condition or the capability of the steel pipe concrete column to bear impact or explosion.
Disclosure of Invention
Aiming at the technical problems, the invention provides a fire and impact real-time coupling test method for a building structural member, which can truly simulate the process that a project is in fire and the building structural member is subjected to actual collapse caused by impact or explosion, and accurately evaluate the impact bearing capacity of the building structural member under the fire condition.
The technical solution adopted by the invention is as follows:
a real-time coupling test method for fire and impact of a building structural member adopts a real-time coupling test system, wherein the test system comprises a restraint system, a heating system, an impact system and a control and data acquisition system;
the restraint system comprises a fixed end, a sliding adjustable base, a loading assembly and a first hydraulic assembly, wherein one end of a test piece is connected with the fixed end, the other end of the test piece is connected with the sliding adjustable base, and the sliding adjustable base is connected with the first hydraulic assembly for applying axial pressure through the loading assembly;
the temperature rising system comprises a high-temperature furnace for rising the temperature of a test piece and a traction assembly for driving the high-temperature furnace to move back and forth, the high-temperature furnace is cuboid and comprises a front door plate, a rear plate, an upper plate, a lower plate, an end cover plate I and an end cover plate II, the upper plate, the lower plate, the rear plate and the end cover plate II are connected together to form a fixed part, a notch for embedding the test piece is formed in the end cover plate II, the top edge of the front door plate is hinged with one edge of the upper plate through a hinge, the front door plate and the end cover plate are connected to form a movable part, and the movable part can be opened and closed;
a front door panel opening motor and a fixed pulley I are arranged at the top of the upper plate, a rotating shaft of the front door panel opening motor is connected with one end of a steel wire rope, and the other end of the steel wire rope is connected with the lower part of the front door panel after bypassing the fixed pulley I;
the inner sides of the front door plate, the rear plate, the upper plate and the lower plate are all provided with heat insulation cotton, and the inner sides of the heat insulation cotton are all provided with heating belts which are connected with the control switch;
the traction assembly comprises a second hydraulic assembly, the second hydraulic assembly comprises a second double-acting jack, a second hydraulic pump station and an oil pipe, the second double-acting jack is connected with the second hydraulic pump station through the oil pipe, the double-acting jack is horizontally arranged, a cylinder body of the double-acting jack is connected with a rigid side plate arranged on the rear side of the high-temperature furnace, the end part of a piston rod of the double-acting jack is connected with a rear plate of the high-temperature furnace, and the high-temperature furnace is driven to horizontally move through the double-acting jack; a furnace body support is arranged at the bottom of a lower plate block of the high-temperature furnace, a sliding rail is arranged below the furnace body support, and rollers capable of moving back and forth along the sliding rail are arranged at bottom feet of the furnace body support;
the impact system is positioned above a test piece fixed by the restraint system and comprises a drop hammer, the top of the drop hammer is adsorbed with an electrified electromagnet, the upper end of the electromagnet is connected with one end of a steel strand, the other end of the steel strand is connected with a lifting motor after passing around a fixed pulley II, and the electromagnet is also connected with an electric wire; rigid channel steel for guiding the drop hammer is vertically arranged on two sides of the drop hammer;
the control and data acquisition system comprises a signal line, a first load sensor, a second load sensor, a first distance meter, a second distance meter, a first thermocouple, a second thermocouple, infrared pair tubes, a speed meter, an acceleration sensor, a high-speed camera and a displacement meter;
the first load sensor and the displacement meter are both arranged on the loading assembly and are respectively used for measuring the axial pressure and the displacement of the test piece; the second distance meter is arranged on the upper plate and used for measuring the height of the drop hammer; the thermocouple I and the thermocouple II are both arranged in the high-temperature furnace and are in contact with a test piece, and the thermocouple I and the thermocouple II are both connected with a signal wire, wherein the thermocouple I is used for measuring the temperature in a hearth, and the thermocouple II is used for measuring the temperature on the surface of the test piece; the distance measuring instrument I is arranged on the rear plate of the high-temperature furnace and used for measuring the distance between the rear plate and the rigid side plate of the high-temperature furnace when the high-temperature furnace is withdrawn; the infrared pair transistors comprise a transmitting end and a receiving end which are matched with each other, the transmitting end of each infrared pair transistor is arranged at the bottom of the rigid channel steel, the receiving ends of the infrared pair transistors are arranged on the outer sides of an upper plate and a front door plate of the high-temperature furnace, and the infrared pair transistors are used for monitoring whether the high-temperature furnace is withdrawn in place before the drop hammer is released; the speed measuring instrument is arranged on the inner side of the lower part of the rigid channel steel and is used for measuring the speed before the drop hammer impacts the test piece; the second load sensor is arranged at the bottom of the drop hammer and used for measuring the impact force in the impact process of the drop hammer; the acceleration sensor is arranged at the top of the drop hammer and used for measuring the acceleration of the drop hammer in the process of impacting the test piece, calculating the impact force reversely according to the acceleration and comparing and correcting the impact force measured by the load sensor II;
the test method comprises the following steps:
firstly, starting a test, inputting a target axial force, a target temperature and a target impact speed through a control and data acquisition system, and calculating the height of a drop hammer according to the impact speed;
secondly, fixing two ends of a test piece to be tested with the fixed end and the sliding adjustable base respectively;
thirdly, a front door plate opening motor is started, and the front door plate opening motor pulls the front door plate through a steel wire rope to enable the front door plate to be opened upwards;
fourthly, opening a second hydraulic assembly, pushing the high-temperature furnace to slide to the side of the test piece along the sliding rail through a second double-acting jack, and feeding back the distance between the rear plate and the rigid side plate of the high-temperature furnace in real time through a first distance meter; after the furnace body reaches a target position, a test piece is just placed in a gap of a second end cover plate of the high-temperature furnace, a first thermocouple and a second thermocouple are arranged, and then a front door plate opening motor is used for controlling the front door plate to be placed downwards and closed;
fifthly, controlling the electromagnet to be in a power-on state, enabling the top of the drop hammer to be adsorbed to the powered electromagnet, starting a lifting motor, lifting the drop hammer to a target height through a steel strand by the lifting motor, and measuring and feeding back the height of the drop hammer through a distance meter II;
sixthly, applying axial force to the test piece to a target value through the first hydraulic assembly, then starting a control switch, heating the high-temperature furnace through a heating belt, measuring and feeding back the temperature in the hearth through the first thermocouple, and measuring and feeding back the temperature on the surface of the test piece through the second thermocouple;
seventhly, after the high-temperature furnace is heated to the target temperature and is kept warm for a certain time, the front door plate is opened upwards through the front door plate opening motor again, then the high-temperature furnace is controlled to be withdrawn through the second hydraulic assembly, meanwhile, the control switch is closed, and the heating belt stops heating;
eighthly, monitoring whether the high-temperature furnace is withdrawn in place or not through the infrared pair tubes, and controlling the electromagnet to be powered off and releasing the drop hammer after the high-temperature furnace is determined to be withdrawn in place;
ninth, measuring the speed before the drop hammer impacts the test piece through a speed measuring instrument, measuring the impact force in the impact process through a load sensor II, measuring the acceleration in the impact process of the drop hammer on the test piece through an acceleration sensor, calculating the impact force reversely according to the acceleration, and comparing and correcting the impact force with the impact force measured by the load sensor II; recording and displaying image information of an impact process in real time through a high-speed camera;
and step ten, collecting and storing data through a control and data collection system, removing the drop hammer, removing the test piece and finishing the test.
The invention can realize real-time coupling of fire and impact by cooperative work of the restraint system, the temperature rise system, the impact system and the control and data acquisition system, truly simulate the process that the engineering generates fire and the building structural member bears the actual collapse caused by impact or explosion, and fill the blank of the test.
The high-temperature furnace can be coupled with the impact system in real time, namely the impact test is completed immediately after the high-temperature furnace is heated to reach a preset value and is removed, so that the temperature reduction phenomenon caused by too long exposure is prevented. The high-temperature furnace can realize uniform heating and non-uniform heating (such as only upper heating, only lower heating, temperature gradient change along span and the like) through the arrangement of the heating belts or the selective starting of the heating belts so as to adapt to the actual requirements of different projects.
The control and data acquisition system can control the heating temperature, the applied axial force and the lifting height in a centralized manner, can realize real-time coupling of fire and impact, is carried out in a full-automatic manner in the test process, avoids accidental errors, and has high authenticity, accuracy and reliability of test results.
Preferably, the fixed end comprises a fixed end lower base, a fixed end upper top cover and a first clamp, the fixed end lower base is fixed on a first rigid support through a high-strength bolt, the first rigid support comprises a bottom plate, a top plate and a vertical support plate connected between the bottom plate and the top plate, and a plurality of strip-shaped grooves used for adjusting the positions of the fixed ends are parallelly formed in the top plate; the upper part of the first clamp is embedded in an upper top cover of the fixed end, the lower part of the first clamp is embedded in a lower base of the fixed end, the upper top cover and the lower base are connected through a high-strength bolt, and one end of a test piece is clamped in the first clamp;
the sliding adjustable base comprises a sliding end lower base, a sliding end upper top cover, a clamp II, two sliding grooves and a steel bar, the sliding end lower base is provided with a through hole, the two sliding grooves are respectively arranged on two sides of the sliding end lower base, the middle parts of the sliding grooves are hollowed and fixed on a second rigid support through high-strength bolts, and the steel bar penetrates through the sliding end lower base and the two sliding grooves; the upper part of the second clamp is embedded into the upper top cover, the lower part of the second clamp is embedded into the lower base, the upper top cover is connected with the lower base through a high-strength bolt, and the other end of the test piece is clamped in the second clamp;
the loading assembly comprises two channel steels, a spring, an H-shaped steel and a protective cover plate, wherein one part of the H-shaped steel is connected with the sliding adjustable base through a high-strength bolt; the two channel steels are respectively called a first channel steel and a second channel steel, and the spring is in contact with the H-shaped steel through the first channel steel and the first load sensor;
the hydraulic assembly I comprises a first double-acting jack, an oil pipe and a first hydraulic pump station, a cylinder body of the first double-acting jack is connected with a second rigid support through a high-strength bolt, the end part of a piston rod of the first double-acting jack is in contact with a second channel steel, and the first double-acting jack is connected with a first hydraulic pump station through the oil pipe.
By adopting the structural design, in the real-time coupling test process of axial pressure, fire and impact, the axial force is applied to the test piece through the circular spring with moderate rigidity, so that a considerable compression amount can be realized under the condition of the same axial force, the 'vacancy' caused by the movement of the sliding end can be ensured to be supplemented in time, and the 'derailment' between the spring and the sliding end is ensured to be avoided when the displacement of the sliding end is overlarge.
Preferably, the rigid channel steel is vertically arranged, the two vertically arranged rigid channel steels are symmetrically distributed, a guide rail is welded on each rigid channel steel, the guide rails are arranged along the length direction of the rigid channel steels, and guide grooves matched with the guide rails are arranged on two sides of the drop hammer. By adopting the structure, the invention can play a better guiding role on the drop hammer, ensure that the drop hammer can vertically and positively impact a test piece and reduce the test error.
Preferably, the sliding groove is provided with a fixing hole, the second rigid support is provided with a plurality of strip-shaped grooves, the size of the hole of the fixing hole is consistent with the width of each strip-shaped groove, and the sliding groove can be fixed at different positions of the second rigid support as required.
When the working condition of coupling shaft pressure, fire and impact in real time is made for a building structural member (one end is sliding and the other end is fixed), four bolt holes at the lower part of the sliding end are released; when the working condition that fire and impact are coupled in real time is adopted for building structural members (two ends are fixed), the lower part of the sliding end is fixed on the rigid support by four high-strength bolts, so that the test base can be ensured to adapt to different test working conditions.
The groove is in a long strip shape, so that the fixed position of the base can be conveniently adjusted, and errors caused by asymmetry of the left side and the right side of the device can be compensated, and the system errors of the testing device can be further reduced.
The invention can flexibly realize whether axial force is applied or not through the base of the device, thereby being simultaneously suitable for the test requirements of beams (without axial force) and columns (with axial force) in structural engineering. When the column is tested, the phenomenon of weakening of the axial force corresponding to gradual collapse of the column due to impact can be accurately simulated due to the action of the spring device.
Preferably, the first rigid support and the second rigid support are fixed on the rigid bottom plate through a plurality of ground anchors, so that the stability of the test system can be further improved, and the test system is convenient to disassemble.
The beneficial technical effects of the invention are as follows:
the real-time coupling of fire and impact can be realized through the cooperative work of the restraint system, the heating system, the impact system and the control and data acquisition system, the process that the building structural member such as a steel pipe concrete column bears the impact or the explosion causes actual collapse when a fire disaster occurs in a project is truly simulated, and the impact bearing capacity of the building structural member under the fire disaster condition is accurately evaluated; the test process is carried out in a full-automatic mode, accidental errors are avoided, and the authenticity, accuracy and reliability of test results are high.
The base at the lower part of the sliding end can be fixed on the second rigid support through the high-strength bolt, so that the test working condition that the two ends are fixed is realized, the reflection of the building structural member subjected to impact load under the condition of fire disaster is truly reflected, and various test working conditions can be realized.
The invention has simple and compact integral structure and simple and convenient test operation.
Drawings
The invention will be further described with reference to the following detailed description and drawings:
FIG. 1 is a flow chart of a coupling test method of the present invention;
FIG. 2 is a schematic diagram of the overall configuration of a coupling test system according to the method of the present invention;
FIG. 3 is a schematic structural diagram of a temperature raising system in the coupling test system according to the present invention;
FIG. 4 is another angular view of FIG. 3;
FIG. 5 is a schematic view of the structural principle of a high temperature furnace in the temperature raising system of the present invention;
FIG. 6 is a schematic diagram of the configuration of the impulse system of the coupling test system of the present invention;
FIG. 7 is a schematic structural diagram of a restraint system in the coupling test system of the present invention;
FIG. 8 is a schematic view of a fastening end of the restraint system of the present invention;
FIG. 9 is a schematic view of a sliding adjustable mount of the restraint system of the present invention;
FIG. 10 is a schematic diagram of the loading assembly and hydraulic assembly of the restraint system of the present invention.
In the figure: 1. a restraint system; 2. a temperature raising system; 3. an impact system; 4. a control and data acquisition system;
1-1, test piece; 1-2, rigidly supporting a first; 1-3, rigid support II; 1-4, fixed end; 1-5, sliding the adjustable base; 1-6, loading the component; 1-7, a first hydraulic assembly; 1-8, a fixed end lower base; 1-9, fixing end upper top cover; 1-10, a sliding end lower base; 1-11, a sliding end upper top cover; 1-12, a first clamp; 1-13 and a second clamp; 1-14, a spring; 1-15, a first double-acting jack; 1-16, a hydraulic pump station I; 1-17, a groove; 1-18, sliding groove; 1-19, steel bar; 1-20 parts of H-shaped steel; 1-21, channel steel; 1-22, a protective cover plate; 1-23, high-strength bolts;
2-1, high-temperature furnace; 2-2, a hydraulic assembly II; 2-3, a sliding track; 2-4, a furnace body bracket; 2-5, front door plate; 2-6, back plate; 2-7, an upper plate; 2-8, lower plate block; 2-9, a first end cover plate; 2-10 parts of end cover plate II; 2-11, rigid side plates; 2-12, a double-acting jack II; 2-13, a hydraulic pump station II; 2-14, oil pipe; 2-15, controlling a switch; 2-16, starting a motor of a front door panel; 2-17 and a hinge; 2-18, steel wire rope; 2-19, a fixed pulley I;
3-1, dropping hammer;
4-1, signal lines; 4-2, a load sensor I; 4-3, a second distance meter; 4-4, thermocouple I; 4-5, a second thermocouple; 4-6, a first distance meter; 4-7, infrared geminate transistor receiving ends; 4-8, infrared geminate transistors transmitting ends; 4-9, a velocimeter; 4-10, an acceleration sensor; 4-11 and a second load sensor; 4-12, high speed camera; 4-13, displacement meter.
Detailed Description
With the attached drawings, the test method is based on a coupling test system, and the coupling test system comprises a restraint system 1, a heating system 2, an impact system 3 and a control and data acquisition system 4.
The restraint system 1 comprises fixed ends 1-4, sliding adjustable bases 1-5, loading assemblies 1-6 and hydraulic assemblies 1-7, one end of a test piece 1-1 is connected with the fixed ends, the other end of the test piece is connected with the sliding adjustable bases, and the sliding adjustable bases are connected with the hydraulic assemblies 1-7 for applying axial pressure through the loading assemblies 1-6.
The heating system 2 comprises a high-temperature furnace 2-1 for heating a test piece and a traction assembly for driving the high-temperature furnace to move back and forth, the high-temperature furnace 2-1 is cuboid and comprises a front door plate 2-5, a rear plate 2-6, an upper plate 2-7, a lower plate 2-8, an end cover plate I2-9 and an end cover plate II 2-10, the upper plate, the lower plate, the rear plate and the end cover plate II are connected together to form a fixed part, a notch for embedding the test piece is formed in the end cover plate II, the top edge of the front door plate is hinged to one side of the upper plate 2-7 through a hinge 2-17, the front door plate and the end cover plate are connected to form a movable part, and the movable part can be opened and closed relative to the fixed. The top of the upper plate is provided with a front door plate opening motor 2-16 and a fixed pulley 2-19, a rotating shaft of the front door plate opening motor is connected with one end of a steel wire rope 2-18, and the other end of the steel wire rope 2-18 is connected with the lower part of the front door plate after bypassing the fixed pulley. The inner sides of the front door plate, the rear plate, the upper plate and the lower plate are all provided with heat insulation cotton, the inner sides of the heat insulation cotton are all provided with heating belts, and the heating belts are connected with the control switch. The heating belt can be selected from commercial products, and preferably consists of a plurality of high-temperature ceramic heating sheets which are connected. In the four heating belts, the heating temperature of each heating belt can be freely adjusted according to the test requirements.
The traction assembly comprises a second hydraulic assembly 2-2, the second hydraulic assembly comprises a second double-acting jack 2-12, a second hydraulic pump station 2-13 and an oil pipe 2-14, the second double-acting jack is connected with the second hydraulic pump station through the oil pipe, the double-acting jack is horizontally arranged, a cylinder body of the double-acting jack is connected with a rigid side plate arranged on the rear side of the high-temperature furnace, the end part of a piston rod of the double-acting jack is connected with a rear plate of the high-temperature furnace, and the high-temperature furnace is driven to horizontally move through the double-acting jack. The bottom of the lower plate block of the high-temperature furnace is provided with a furnace body support 2-4, a sliding track 2-3 is arranged below the furnace body support, and the bottom foot of the furnace body support is provided with a roller capable of moving back and forth along the sliding track.
The impact system is located above a test piece fixed by the restraint system and comprises a drop hammer 3-1, the top of the drop hammer is adsorbed to an electrified electromagnet, the upper end of the electromagnet is connected with one end of a steel strand, and the other end of the steel strand is connected with a lifting motor after bypassing the fixed pulley II. The electromagnet is further connected with an electric wire, and the other end of the electric wire can be connected with an electric wire containing device. And rigid channel steel for guiding the drop hammer is vertically arranged on two sides of the drop hammer.
The control and data acquisition system comprises a signal line 4-1, a load sensor I4-2, a distance meter II 4-3, a thermocouple I4-4, a thermocouple II 4-5, a distance meter I4-6, infrared geminate transistors (an infrared geminate transistor receiving end 4-7 and an infrared geminate transistor transmitting end 4-8), a speedometer 4-9, an acceleration sensor 4-10, a load sensor II 4-11, a high-speed camera 4-12 and a displacement meter 4-13. The first load sensor and the displacement meter are both arranged on the loading assembly and are respectively used for measuring the axial pressure and the displacement of the test piece. And the second distance meter is arranged on the upper plate and used for measuring the height of the drop hammer. The thermocouple I and the thermocouple II are both arranged in the high-temperature furnace and are in contact with a test piece, the thermocouple I and the thermocouple II are both connected with a signal wire, the thermocouple I is used for measuring the temperature in the hearth, and the thermocouple II is used for measuring the temperature on the surface of the test piece. And the distance meter I is arranged on the rear plate of the high-temperature furnace and used for measuring the distance between the rear plate and the rigid side plate of the high-temperature furnace when the high-temperature furnace is withdrawn. The infrared geminate transistors comprise a transmitting end and a receiving end which are matched, the transmitting end of each infrared geminate transistor is arranged at the bottom of the rigid channel steel, the receiving ends of the infrared geminate transistors are arranged on the outer sides of an upper plate and a front door plate of the high-temperature furnace, and the infrared geminate transistors are used for monitoring whether the high-temperature furnace is withdrawn in place before the drop hammer is released. When the infrared pair tube receiving end 4-7 can receive the signal sent by the infrared pair tube transmitting end 4-8, the high-temperature furnace is not withdrawn to the right position; otherwise, when the signal is not received, the high-temperature furnace is withdrawn, and the drop hammer can be released. The speedometer is arranged on the inner side of the lower part of the rigid channel steel and is used for measuring the speed of the drop hammer before impacting the test piece. And the second load sensor is arranged at the bottom of the drop hammer and used for measuring the impact force in the impact process of the drop hammer. The acceleration sensor is arranged at the top of the drop hammer and used for measuring the acceleration of the drop hammer in the process of impacting the test piece, and the impact force is inversely calculated according to the acceleration sensor and compared and corrected with the impact force measured by the load sensor II.
The test method comprises the following steps:
firstly, starting a test, inputting a target axial force, a target temperature and a target impact speed through a control and data acquisition system, and calculating the height of a drop hammer according to the impact speed;
secondly, fixing two ends of a test piece to be tested with the fixed end and the sliding adjustable base respectively;
thirdly, a front door plate opening motor is started, and the front door plate opening motor pulls the front door plate through a steel wire rope to enable the front door plate to be opened upwards;
fourthly, opening a second hydraulic assembly, pushing the high-temperature furnace to slide to the side of the test piece along the sliding rail through a second double-acting jack, and feeding back the distance between the rear plate and the rigid side plate of the high-temperature furnace in real time through a first distance meter; after the furnace body reaches a target position, a test piece is just placed in a gap of a second end cover plate of the high-temperature furnace, a first thermocouple and a second thermocouple are arranged, and then a front door plate opening motor is used for controlling the front door plate to be placed downwards and closed;
fifthly, controlling the electromagnet to be in a power-on state, enabling the top of the drop hammer to be adsorbed to the powered electromagnet, starting a lifting motor, lifting the drop hammer to a target height through a steel strand by the lifting motor, and measuring and feeding back the height of the drop hammer through a distance meter II;
sixthly, applying axial force to the test piece to a target value through the first hydraulic assembly, then starting a control switch, heating the high-temperature furnace through a heating belt, measuring and feeding back the temperature in the hearth through the first thermocouple, and measuring and feeding back the temperature on the surface of the test piece through the second thermocouple;
seventhly, after the high-temperature furnace is heated to the target temperature and is kept warm for a certain time, the front door plate is opened upwards through the front door plate opening motor again, then the high-temperature furnace is controlled to be withdrawn through the second hydraulic assembly, meanwhile, the control switch is closed, and the heating belt stops heating;
eighthly, monitoring whether the high-temperature furnace is withdrawn in place or not through the infrared pair tubes, and controlling the electromagnet to be powered off and releasing the drop hammer after the high-temperature furnace is determined to be withdrawn in place;
ninth, measuring the speed before the drop hammer impacts the test piece through a speed measuring instrument, measuring the impact force in the impact process through a load sensor II, measuring the acceleration in the impact process of the drop hammer on the test piece through an acceleration sensor, calculating the impact force reversely according to the acceleration, and comparing and correcting the impact force with the impact force measured by the load sensor II; recording and displaying image information of an impact process in real time through a high-speed camera;
and step ten, collecting and storing data through a control and data collection system, removing the drop hammer, removing the test piece and finishing the test.
The invention can realize real-time coupling of fire and impact by cooperative work of the restraint system, the temperature rise system, the impact system and the control and data acquisition system, truly simulate the process that the engineering generates fire and the building structural member bears the actual collapse caused by impact or explosion, and fill the blank of the test.
The control and data acquisition system can control the heating temperature, the applied axial force and the lifting height in a centralized manner, can realize real-time coupling of fire and impact, is carried out in a full-automatic manner in the test process, avoids accidental errors, and has high authenticity, accuracy and reliability of test results.
As a further design of the invention, the fixed end comprises a fixed end lower base 1-8, a fixed end upper top cover 1-9 and a clamp I1-12, and the fixed end lower base is fixed on the rigid support I1-2 through a high-strength bolt. The rigid support comprises a bottom plate, a top plate and a vertical supporting plate connected between the bottom plate and the top plate, and a plurality of strip-shaped grooves used for adjusting the positions of the fixed ends are formed in the top plate in parallel. The upper portion of anchor clamps I is embedded in stiff end upper portion top cap, and the lower part of anchor clamps I is embedded in stiff end lower part base, and upper portion top cap and lower part base pass through high strength bolt connection, and the one end centre gripping of test piece is in anchor clamps I.
The sliding adjustable base comprises a sliding end lower base 1-10, a sliding end upper top cover 1-11, a clamp II 1-13, two sliding grooves 1-18 and a steel bar 1-19. The sliding end lower part base is provided with a through hole, the two sliding grooves are respectively arranged on two sides of the sliding end lower part base, the middle parts of the sliding grooves are hollowed out and fixed on the second rigid support through high-strength bolts, and the steel bar penetrates through the sliding end lower part base and the two sliding grooves. The upper portion of anchor clamps two is embedded in the upper portion top cap, and the lower part of anchor clamps two is embedded in the lower part base, and upper portion top cap and lower part base pass through high strength bolt and connect, and the other end centre gripping of test piece is in anchor clamps two.
The elastic loading assembly comprises two channel steels 1-21, a spring 1-14, an H-shaped steel 1-20 and a protective cover plate 1-22, wherein one part of the H-shaped steel 1-20 is connected with a sliding adjustable base through a high-strength bolt, two ends of the spring 1-14 are respectively connected with one channel steel, the two channel steels and the spring are completely covered by the protective cover plate, the other part of the H-shaped steel is covered by the protective cover plate, and the protective cover plate is connected with a second rigid support through the high-strength bolt. The two channel steels are respectively called a first channel steel and a second channel steel, and the spring is in contact with the H-shaped steel through the first channel steel and the first load sensor. The first hydraulic assembly comprises a first double-acting jack 1-15, an oil pipe and a first hydraulic pump station 1-16, a cylinder body of the first double-acting jack is connected with a second rigid support through a high-strength bolt, the end part of a piston rod of the first double-acting jack is in contact with a second channel steel, and the first double-acting jack is connected with a first hydraulic pump station through the oil pipe.
By adopting the structural design, in the real-time coupling test process of axial pressure, fire and impact, the axial force is applied to the test piece through the circular spring with moderate rigidity, so that a considerable compression amount can be realized under the condition of the same axial force, the 'vacancy' caused by the movement of the sliding end can be ensured to be supplemented in time, and the 'derailment' between the spring and the sliding end is ensured to be avoided when the displacement of the sliding end is overlarge.
Furthermore, the rigid channel steel is vertically arranged, the two vertically arranged rigid channel steels are symmetrically distributed, a guide rail is welded on each rigid channel steel, the guide rails are arranged along the length direction of the rigid channel steels, and guide grooves matched with the guide rails are arranged on two sides of the drop hammer. By adopting the structure, the invention can play a better guiding role on the drop hammer, ensure that the drop hammer can vertically and positively impact a test piece and reduce the test error.
Furthermore, a fixing hole is formed in the sliding groove, a plurality of strip-shaped grooves 1-17 are formed in the second rigid support, the size of a hole of the fixing hole is consistent with the width of each strip-shaped groove, and the sliding groove can be fixed at different positions of the second rigid support according to needs.
When the working condition of coupling shaft pressure, fire and impact in real time is made for a building structural member (one end is sliding and the other end is fixed), four bolt holes at the lower part of the sliding end are released; when the working condition that fire and impact are coupled in real time is adopted for building structural members (two ends are fixed), the lower part of the sliding end is fixed on the rigid support by four high-strength bolts, so that the test base can be ensured to adapt to different test working conditions.
The groove is in a long strip shape, so that the fixed position of the base can be conveniently adjusted, and errors caused by asymmetry of the left side and the right side of the device can be compensated, and the system errors of the testing device can be further reduced.
The invention can flexibly realize whether axial force is applied or not through the base of the device, thereby being simultaneously suitable for the test requirements of beams (without axial force) and columns (with axial force) in structural engineering. When the column is tested, the phenomenon of weakening of the axial force corresponding to gradual collapse of the column due to impact can be accurately simulated due to the action of the spring device.
Furthermore, the first rigid support and the second rigid support are fixed on the rigid bottom plate through a plurality of ground anchors, so that the stability of the test system can be further improved, and the test system is convenient to disassemble.
The invention relates to a fire and impact real-time coupling test system for building structural members, which comprises a restraint system, a heating system, an impact system and a control system, wherein the functions and the control relationship among the systems are summarized as follows:
the function of the restraint system is primarily to provide a boundary condition on both sides of the member, applying a preload. The function of the heating system is mainly to drive the high-temperature furnace and control and feed back the heating process. The impact system mainly has the functions of controlling and feeding back the height of the drop hammer, judging and feeding back the position of the furnace body, obtaining the instruction of the control and data acquisition system and releasing the drop hammer. The control and data acquisition system mainly has the functions of controlling data acquisition, coordinating constraint, temperature rise and impact systems.
With respect to the overall sensor arrangement, the restraint system includes a load sensor integrated on the loading assembly. The temperature raising system comprises a plurality of thermocouples which are respectively arranged on the surface of the test piece and inside the furnace body; the infrared pair tubes are arranged in a row, the transmitting ends of the infrared pair tubes are arranged at the bottom of the rigid channel steel, and the receiving ends of the infrared pair tubes are arranged on a furnace body top plate and a front door plate; the distance measuring instrument is arranged on the rear plate of the furnace body; and a control door opener (a front door plate opening motor, a steel wire rope and a fixed pulley I) is arranged on the upper plate of the furnace body. The impact system includes acceleration and velocity sensors. The control and data acquisition system comprises a strain gauge, a high-speed camera, a displacement meter and the like, and coordinates the lines of the restraint, temperature rise and impact system.
During specific work, the constraint system sends out a target load instruction, and the load application process is measured and fed back. A temperature control part of the heating system sends out a target temperature instruction, and measures and feeds back a temperature signal; the braking part sends out a high-temperature furnace displacement instruction and feeds back the position of the high-temperature furnace. The impact system sends out a target impact speed instruction, sends out a drop hammer trigger command and feeds back the position of the furnace body.
The control and data acquisition system comprises a data acquisition system I and a data acquisition system II, wherein the data acquisition system I is mainly used for acquiring information such as pre-applied axial force, temperature change in the temperature rise process and the like at the beginning; and the data acquisition system II is mainly used for acquiring data such as impact force, acceleration, speed, displacement meter, high-speed camera and the like in the impact process.
Parts not described in the above modes can be realized by adopting or referring to the prior art.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (3)
1. A fire and impact real-time coupling test method for building structural members is characterized by comprising the following steps: the test method adopts a real-time coupling test system, wherein the test system comprises a restraint system, a heating system, an impact system and a control and data acquisition system;
the restraint system comprises a fixed end, a sliding adjustable base, a loading assembly and a first hydraulic assembly, wherein one end of a test piece is connected with the fixed end, the other end of the test piece is connected with the sliding adjustable base, and the sliding adjustable base is connected with the first hydraulic assembly for applying axial pressure through the loading assembly;
the temperature rising system comprises a high-temperature furnace for rising the temperature of a test piece and a traction assembly for driving the high-temperature furnace to move back and forth, the high-temperature furnace is cuboid and comprises a front door plate, a rear plate, an upper plate, a lower plate, an end cover plate I and an end cover plate II, the upper plate, the lower plate, the rear plate and the end cover plate II are connected together to form a fixed part, a notch for embedding the test piece is formed in the end cover plate II, the top edge of the front door plate is hinged with one edge of the upper plate through a hinge, the front door plate and the end cover plate are connected to form a movable part, and the movable part can be opened and closed;
a front door panel opening motor and a fixed pulley I are arranged at the top of the upper plate, a rotating shaft of the front door panel opening motor is connected with one end of a steel wire rope, and the other end of the steel wire rope is connected with the lower part of the front door panel after bypassing the fixed pulley I;
the inner sides of the front door plate, the rear plate, the upper plate and the lower plate are all provided with heat insulation cotton, and the inner sides of the heat insulation cotton are all provided with heating belts which are connected with the control switch;
the traction assembly comprises a second hydraulic assembly, the second hydraulic assembly comprises a second double-acting jack, a second hydraulic pump station and an oil pipe, the second double-acting jack is connected with the second hydraulic pump station through the oil pipe, the double-acting jack is horizontally arranged, a cylinder body of the double-acting jack is connected with a rigid side plate arranged on the rear side of the high-temperature furnace, the end part of a piston rod of the double-acting jack is connected with a rear plate of the high-temperature furnace, and the high-temperature furnace is driven to horizontally move through the double-acting jack; a furnace body support is arranged at the bottom of a lower plate block of the high-temperature furnace, a sliding rail is arranged below the furnace body support, and rollers capable of moving back and forth along the sliding rail are arranged at bottom feet of the furnace body support;
the impact system is positioned above a test piece fixed by the restraint system and comprises a drop hammer, the top of the drop hammer is adsorbed with an electrified electromagnet, the upper end of the electromagnet is connected with one end of a steel strand, the other end of the steel strand is connected with a lifting motor after passing around a fixed pulley II, and the electromagnet is also connected with an electric wire; rigid channel steel for guiding the drop hammer is vertically arranged on two sides of the drop hammer;
the control and data acquisition system comprises a signal line, a first load sensor, a second load sensor, a first distance meter, a second distance meter, a first thermocouple, a second thermocouple, infrared pair tubes, a speed meter, an acceleration sensor, a high-speed camera and a displacement meter;
the first load sensor and the displacement meter are both arranged on the loading assembly and are respectively used for measuring the axial pressure and the displacement of the test piece; the second distance meter is arranged on the upper plate and used for measuring the height of the drop hammer; the thermocouple I and the thermocouple II are both arranged in the high-temperature furnace and are in contact with a test piece, and the thermocouple I and the thermocouple II are both connected with a signal wire, wherein the thermocouple I is used for measuring the temperature in a hearth, and the thermocouple II is used for measuring the temperature on the surface of the test piece; the distance measuring instrument I is arranged on the rear plate of the high-temperature furnace and used for measuring the distance between the rear plate and the rigid side plate of the high-temperature furnace when the high-temperature furnace is withdrawn; the infrared pair transistors comprise a transmitting end and a receiving end which are matched with each other, the transmitting end of each infrared pair transistor is arranged at the bottom of the rigid channel steel, the receiving ends of the infrared pair transistors are arranged on the outer sides of an upper plate and a front door plate of the high-temperature furnace, and the infrared pair transistors are used for monitoring whether the high-temperature furnace is withdrawn in place before the drop hammer is released; the speed measuring instrument is arranged on the inner side of the lower part of the rigid channel steel and is used for measuring the speed before the drop hammer impacts the test piece; the second load sensor is arranged at the bottom of the drop hammer and used for measuring the impact force in the impact process of the drop hammer; the acceleration sensor is arranged at the top of the drop hammer and used for measuring the acceleration of the drop hammer in the process of impacting the test piece, calculating the impact force reversely according to the acceleration and comparing and correcting the impact force measured by the load sensor II;
the test method comprises the following steps:
firstly, starting a test, inputting a target axial force, a target temperature and a target impact speed through a control and data acquisition system, and calculating the height of a drop hammer according to the impact speed;
secondly, fixing two ends of a test piece to be tested with the fixed end and the sliding adjustable base respectively;
thirdly, a front door plate opening motor is started, and the front door plate opening motor pulls the front door plate through a steel wire rope to enable the front door plate to be opened upwards;
fourthly, opening a second hydraulic assembly, pushing the high-temperature furnace to slide to the side of the test piece along the sliding rail through a second double-acting jack, and feeding back the distance between the rear plate and the rigid side plate of the high-temperature furnace in real time through a first distance meter; after the furnace body reaches a target position, a test piece is just placed in a gap of a second end cover plate of the high-temperature furnace, a first thermocouple and a second thermocouple are arranged, and then a front door plate opening motor is used for controlling the front door plate to be placed downwards and closed;
fifthly, controlling the electromagnet to be in a power-on state, enabling the top of the drop hammer to be adsorbed to the powered electromagnet, starting a lifting motor, lifting the drop hammer to a target height through a steel strand by the lifting motor, and measuring and feeding back the height of the drop hammer through a distance meter II;
sixthly, applying axial force to the test piece to a target value through the first hydraulic assembly, then starting a control switch, heating the high-temperature furnace through a heating belt, measuring and feeding back the temperature in the hearth through the first thermocouple, and measuring and feeding back the temperature on the surface of the test piece through the second thermocouple;
seventhly, after the high-temperature furnace is heated to the target temperature and is kept warm for a certain time, the front door plate is opened upwards through the front door plate opening motor again, then the high-temperature furnace is controlled to be withdrawn through the second hydraulic assembly, meanwhile, the control switch is closed, and the heating belt stops heating;
eighthly, monitoring whether the high-temperature furnace is withdrawn in place or not through the infrared pair tubes, and controlling the electromagnet to be powered off and releasing the drop hammer after the high-temperature furnace is determined to be withdrawn in place;
ninth, measuring the speed before the drop hammer impacts the test piece through a speed measuring instrument, measuring the impact force in the impact process through a load sensor II, measuring the acceleration in the impact process of the drop hammer on the test piece through an acceleration sensor, calculating the impact force reversely according to the acceleration, and comparing and correcting the impact force with the impact force measured by the load sensor II; recording and displaying image information of an impact process in real time through a high-speed camera;
and step ten, collecting and storing data through a control and data collection system, removing the drop hammer, removing the test piece and finishing the test.
2. The method for testing the fire and impact real-time coupling of the building structural member according to claim 1, wherein: the fixing end comprises a fixing end lower base, a fixing end upper top cover and a first clamp, the fixing end lower base is fixed on a first rigid support through a high-strength bolt, the first rigid support comprises a bottom plate, a top plate and a vertical support plate connected between the bottom plate and the top plate, and a plurality of strip-shaped grooves used for adjusting the positions of the fixing ends are formed in the top plate in parallel; the upper part of the first clamp is embedded in an upper top cover of the fixed end, the lower part of the first clamp is embedded in a lower base of the fixed end, the upper top cover and the lower base are connected through a high-strength bolt, and one end of a test piece is clamped in the first clamp;
the sliding adjustable base comprises a sliding end lower base, a sliding end upper top cover, a clamp II, two sliding grooves and a steel bar, the sliding end lower base is provided with a through hole, the two sliding grooves are respectively arranged on two sides of the sliding end lower base, the middle parts of the sliding grooves are hollowed and fixed on a second rigid support through high-strength bolts, and the steel bar penetrates through the sliding end lower base and the two sliding grooves; the upper part of the second clamp is embedded into the upper top cover, the lower part of the second clamp is embedded into the lower base, the upper top cover is connected with the lower base through a high-strength bolt, and the other end of the test piece is clamped in the second clamp;
the loading assembly comprises two channel steels, a spring, an H-shaped steel and a protective cover plate, wherein one part of the H-shaped steel is connected with the sliding adjustable base through a high-strength bolt; the two channel steels are respectively called a first channel steel and a second channel steel, and the spring is in contact with the H-shaped steel through the first channel steel and the first load sensor;
the hydraulic assembly I comprises a first double-acting jack, an oil pipe and a first hydraulic pump station, a cylinder body of the first double-acting jack is connected with a second rigid support through a high-strength bolt, the end part of a piston rod of the first double-acting jack is in contact with a second channel steel, and the first double-acting jack is connected with a first hydraulic pump station through the oil pipe.
3. The method for testing the fire and impact real-time coupling of the building structural member according to claim 1, wherein: the rigid channel steel is vertically arranged, the two vertically arranged rigid channel steels are symmetrically distributed, a guide rail is welded on each rigid channel steel, the guide rails are arranged along the length direction of the rigid channel steels, and guide grooves matched with the guide rails are arranged on two sides of the drop hammer.
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| CN113514217B (en) * | 2021-06-04 | 2023-06-30 | 桂林理工大学 | Test device and test method for simulating impact of building structure in fire disaster |
| CN113640153B (en) * | 2021-09-14 | 2024-05-03 | 太原理工大学 | Test device for simulating fire and explosion coupling disasters of structural member |
| CN114813011B (en) * | 2022-04-25 | 2023-04-14 | 山西大学 | Test device for testing mechanical degradation behavior of material under impact and transient high-temperature coupling |
| CN116735131B (en) * | 2023-05-22 | 2024-02-06 | 石家庄铁道大学 | Device and method for simulating continuous collapse resistance of structure under explosive load |
| CN116840079B (en) * | 2023-07-04 | 2023-12-29 | 哈尔滨工业大学 | Test system and method for impact-high temperature coupling loading of metal component |
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| DE19614966C1 (en) * | 1996-04-17 | 1997-09-25 | Karlsruhe Forschzent | Testing machine for impact tests |
| JP2003228282A (en) * | 2002-02-05 | 2003-08-15 | Sekisui House Ltd | Apparatus for experiencing impact resistance strength of exterior wall |
| CN202837117U (en) * | 2012-08-28 | 2013-03-27 | 上海金玺实验室有限公司 | Pendulum bob impact testing machine capable of controlling temperature |
| CN204536137U (en) * | 2015-05-07 | 2015-08-05 | 山东建筑大学 | Fire impacts integrated test unit |
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| CN107402226B (en) * | 2017-07-24 | 2024-03-19 | 华侨大学 | Fire resistance test device and method for concrete roof of underground space structure |
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| CN109374446B (en) * | 2018-09-29 | 2019-08-09 | 长安大学 | A kind of impact test apparatus |
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