CN110553917A - Test system and test method for multidirectional stretching of waterproof material - Google Patents
Test system and test method for multidirectional stretching of waterproof material Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
- G01N3/10—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces generated by pneumatic or hydraulic pressure
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0001—Type of application of the stress
- G01N2203/0003—Steady
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0019—Compressive
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/003—Generation of the force
- G01N2203/0042—Pneumatic or hydraulic means
- G01N2203/0044—Pneumatic means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
- G01N2203/0075—Strain-stress relations or elastic constants
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/025—Geometry of the test
- G01N2203/0258—Non axial, i.e. the forces not being applied along an axis of symmetry of the specimen
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/026—Specifications of the specimen
- G01N2203/0262—Shape of the specimen
- G01N2203/0278—Thin specimens
- G01N2203/0282—Two dimensional, e.g. tapes, webs, sheets, strips, disks or membranes
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/0658—Indicating or recording means; Sensing means using acoustic or ultrasonic detectors
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0676—Force, weight, load, energy, speed or acceleration
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0682—Spatial dimension, e.g. length, area, angle
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Abstract
the invention discloses a test system and a test method for multidirectional stretching of a waterproof material, and the test system and the test method comprise a sample anchoring device, a pressurizing and adjusting device, a three-dimensional scanner, a thickness measuring instrument and a data processing device; the sample anchoring device comprises a cylinder and a flange plate arranged on the cylinder; the pressurizing and adjusting device comprises a pressure providing unit and an air pressure adjusting unit; the three-dimensional scanner is used for scanning the deformed outline of the sample to be measured under the initial and different air pressures to obtain the deformation outline equation under the initial and different air pressures; the thickness measuring instrument is used for measuring the thickness of the deformation top expansion highest position of the sample to be measured under the initial and different air pressures; and the data processing device obtains a stress-strain curve based on the distance between the mark points of the sample to be measured, the distance between the point of the top expansion highest position of the sample to be measured and the point closest to the top expansion highest position, the profile equation and the thickness. The invention realizes the measurement of the stress strain of the sample in the whole process from the beginning of deformation to the final failure and destruction.
Description
Technical Field
the invention belongs to the technical field of waterproof material mechanical testing, and particularly relates to a test system and a test method for multidirectional stretching of a waterproof material.
Background
The waterproof material is required to be laid on a cushion layer in actual engineering due to low elasticity modulus of the waterproof material. Under the action of external force, the cushion layer structure is deformed, and the waterproof material laid on the cushion layer is deformed accordingly. Most of the waterproof materials deformed in engineering are in a bidirectional stretching state. Therefore, the multidirectional tensile property of the waterproof material is related to the safety of the whole anti-seepage structure.
The existing waterproof material biaxial tension experimental equipment mainly comprises a traditional plane cross sample biaxial tension test, and the mechanical property of the test is obtained by stretching a cross sample through two orthogonal tension machines. The method is simple and visual, but the central test area is difficult to damage due to the problem of stress concentration, and meanwhile, the yield of the waterproof material according to the designed stress path is difficult to realize in the stretching process.
The other waterproof material biaxial tension test device is a cylindrical device, a prepared cylindrical sample is filled with liquid or gas with certain pressure to realize bulging of the sample, the upper circular cover and the lower circular cover and the bottom of the cylinder are stretched while the liquid/gas is filled, and finally biaxial tension of the sample is realized. The method can realize the yield of the central area of the sample, and the stress strain can be accurately measured, but the deformation of the method in the air inflation direction is controlled by the stress in the experimental process, the upper part and the lower part of the stretched cylinder are controlled by the strain, and the stress path is difficult to accurately reproduce the deformation of the waterproof material after the bidirectional stress in the conventional engineering. Meanwhile, the material in the test process can be distorted, so that the stress strain of the material is difficult to load as required.
The waterproof material is stretched in two directions and has the following two difficulties: 1 the strain of the waterproof material under biaxial tension is often over 100%, and conventional tests are difficult to cause the waterproof material to generate such huge strain in a test area. The 2 waterproof material test tends to begin yielding in the most complex stressed area, which is often not the central test area of the test specimen under test. At present, the conventional liquid swelling test is generally used for qualitative judgment of materials, and the deep research based on the liquid swelling test also usually assumes that the tested materials are isotropic and uniform. The sample is assumed to be a standard regular sphere after being deformed by pressure. Then, due to the limitation of materials and test equipment, the actual liquid expansion test basically keeps a regular sphere shape in the initial stage, the test sample is prone to be distorted along with the increase of pressure, and the assumption based on the regular sphere shape brings non-negligible errors. Therefore, a test instrument needs to be developed, the problem that the designated area of the test center of the sample is subjected to yield failure in the test process is solved, and meanwhile, the sample can be accurately analyzed by the instrument and a matched test method.
Disclosure of Invention
the invention aims to provide a test device capable of realizing bidirectional stretching of a waterproof material under different stress paths and a matched mechanical property analysis method.
in order to achieve the above object, an aspect of the present invention provides a test system for multi-directional stretching of a waterproof material, the test system comprising: the device comprises a sample anchoring device, a pressurizing and adjusting device, a three-dimensional scanner, a thickness measuring instrument and a data processing device;
the specimen anchoring device includes: the air cylinder and the flange plate are arranged on the air cylinder; the device is used for fixing a sample to be tested;
the pressurizing and regulating device comprises: the air pressure adjusting device comprises a pressure providing unit and an air pressure adjusting unit, wherein the pressure providing unit is communicated with the air pressure adjusting unit, and the air pressure adjusting unit is communicated with the air cylinder; the device is used for providing deformation air pressure for a sample to be tested;
The three-dimensional scanner is used for scanning the deformed outline of the sample to be tested under the initial and different air pressures so as to obtain the deformed outline equations of the sample to be tested under the initial and different air pressures;
the thickness measuring instrument is used for measuring the thickness of the deformation top expansion highest position of the sample to be measured under the initial and different air pressures;
The data processing device carries out data processing on the basis of the distance between a central mark point of the sample to be tested and a mark point closest to the central mark point, the distance between a point of a top expansion highest position of the sample to be tested after deformation under different air pressures and a point closest to the top expansion highest position, the deformation profile equations of the sample to be tested under initial and different air pressures, and the thicknesses of the deformation top expansion highest positions of the sample to be tested under initial and different air pressures, so that the stress and strain values of the sample to be tested under different air pressures are obtained, and further the stress-strain curve of the sample to be tested is obtained.
In another aspect of the present invention, a test method for multi-directional stretching of a waterproof material is provided, and the test method is performed by using the test system, and includes:
(1) Marking a sample to be detected;
(2) Fixing the sample to be measured in the sample anchoring device, measuring the distance between a central mark point of the sample to be measured and a mark point closest to the central mark point, scanning the initial profile of the sample to be measured by using the three-dimensional scanner to obtain the initial profile equation of the sample to be measured, and measuring the initial thickness of the sample to be measured by using a thickness measuring instrument;
(3) Providing initial deformation air pressure of the sample by using a pressurizing and adjusting device, and scanning the deformed outline of the sample to be detected by using the three-dimensional scanner after the sample to be detected is deformed stably so as to obtain a deformed outline equation of the sample to be detected; measuring the distance between the point of the highest deformation top expansion position and the point closest to the highest deformation top expansion position; measuring the thickness of the highest position of the deformation top expansion by using a thickness measuring instrument;
(4) Adjusting an air pressure adjusting unit, increasing air pressure, and repeating the measurement in the step (3) after the deformation of the sample to be measured is stable to obtain the measurement data in the step (3);
(5) repeating the step (4) until the sample to be detected is completely damaged;
(6) Based on the distance between the central mark point of the sample to be detected and the mark point closest to the central mark point, the distance between the point of the top expansion highest position of the sample to be detected after deformation under different air pressures and the point closest to the top expansion highest position, the deformation profile equations of the sample to be detected under initial and different air pressures and the thicknesses of the deformation top expansion highest positions of the sample to be detected under initial and different air pressures, data processing is carried out by using a data processing device, the stress and strain values of the sample to be detected under different air pressures are obtained, and then the stress-strain curve of the sample to be detected is obtained.
the technical scheme of the invention has the following beneficial effects:
(1) according to the invention, through improving the measurement means and the calculation means of the traditional inflatable experiment, the stress strain of the sample in the whole process from the deformation start to the final failure and damage is measured, and the problem that the stress strain of the sample in the whole process of the failure is difficult to accurately measure in the traditional experiment is solved.
(2) The method of the invention has strong applicability to non-uniform, non-linear and anisotropic materials, and solves the problem of large experimental error of the materials in the traditional method.
additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
the above and other objects, features and advantages of the present invention will become more apparent by describing in more detail exemplary embodiments thereof with reference to the attached drawings, in which like reference numerals generally represent like parts throughout.
FIG. 1 shows a schematic diagram of the inflatable stretching solution according to the present invention.
FIG. 2 shows a schematic diagram of a test system for multidirectional stretching of a water repellent material according to one embodiment of the present invention.
FIG. 3 shows a schematic view of a specimen anchoring device of a waterproof material multi-directional tensile testing system according to one embodiment of the present invention.
Fig. 4 shows a schematic view of a specimen anchoring device and a three-dimensional scanner of a waterproof material multi-directional tensile testing system according to an embodiment of the present invention.
Description of reference numerals:
1. pressure providing unit 2, air pressure adjusting unit 3, air cylinder 4, sample to be measured 5, three-dimensional scanner 6, thickness measuring instrument 7 and flange plate
Detailed Description
Preferred embodiments of the present invention will be described in more detail below. While the following describes preferred embodiments of the present invention, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
one aspect of the present invention provides a test system for multi-directional stretching of a waterproof material, the test system comprising: the device comprises a sample anchoring device, a pressurizing and adjusting device, a three-dimensional scanner, a thickness measuring instrument and a data processing device;
The specimen anchoring device includes: the air cylinder and the flange plate are arranged on the air cylinder; the device is used for fixing a sample to be tested;
The pressurizing and regulating device comprises: the air pressure adjusting device comprises a pressure providing unit and an air pressure adjusting unit, wherein the pressure providing unit is communicated with the air pressure adjusting unit, and the air pressure adjusting unit is communicated with the air cylinder; the device is used for providing deformation air pressure for a sample to be tested;
The three-dimensional scanner is used for scanning the deformed outline of the sample to be tested under the initial and different air pressures so as to obtain the deformed outline equations of the sample to be tested under the initial and different air pressures;
The thickness measuring instrument is used for measuring the thickness of the deformation top expansion highest position of the sample to be measured under the initial and different air pressures;
The data processing device carries out data processing on the basis of the distance between a central mark point of the sample to be tested and a mark point closest to the central mark point, the distance between a point of a top expansion highest position of the sample to be tested after deformation under different air pressures and a point closest to the top expansion highest position, the deformation profile equations of the sample to be tested under initial and different air pressures, and the thicknesses of the deformation top expansion highest positions of the sample to be tested under initial and different air pressures, so that the stress and strain values of the sample to be tested under different air pressures are obtained, and further the stress-strain curve of the sample to be tested is obtained.
in this, the sample anchor comprises right circular ring flange and supporting cylinder, and waterproof material sample passes through the ring flange to be fixed on the cylinder in the experiment, and pressurization and adjusting device connect the cylinder, through adjusting different atmospheric pressure in the experiment, realizes the tensile of experiment under different stress size.
In the invention, the air pressure required in the test process can be adjusted at any time through the air pressure adjusting unit.
According to the invention, preferably, the flange is arranged above the air outlet of the air cylinder, and the air cylinder is fixedly connected with the flange.
In the invention, the cylinder and the flange are fixedly connected through bolts. During testing, the film to be tested is placed between the cylinder and the flange plate, the film to be tested completely covers the air outlet of the cylinder, and the film to be tested is fixed on the cylinder through the flange plate.
in the invention, the three-dimensional scanner can be a three-dimensional scanner commonly used in the field, during measurement, a sample to be measured is placed in the scanning radius of the three-dimensional scanner to carry out three-dimensional scanning to obtain the initial profile conformation of the sample to be measured after deformation under different air pressures, a plurality of profile points are selected based on the obtained profile conformation, and a corresponding profile equation is obtained through fitting.
according to the present invention, preferably, the pressure providing unit is communicated with an air pressure adjusting unit through a pipeline, and the air pressure adjusting unit is communicated with the cylinder side wall through a pipeline.
In the invention, during testing, gas enters the cylinder through the side wall of the cylinder, and after the gas in the cylinder is fully filled, the film to be tested covered on the cylinder is enabled to be bulged upwards under the action of pressure along with the continuous introduction of the gas, so that the film to be tested is deformed.
in the invention, preferably, the inner cavity of the cylinder is cylindrical, and the flange is in a perfect circle shape.
In the invention, the air pressure adjusting unit is a pressure adjusting valve.
According to the present invention, preferably, the pressure providing unit is an air compressor.
according to the present invention, preferably, the thickness measuring instrument is an ultrasonic thickness gauge.
In the invention, a measuring probe of the ultrasonic thickness gauge is placed on a measured point for measurement, and the thickness of the deformation top expansion highest position of a sample to be measured under initial and different air pressures is obtained.
In another aspect of the present invention, a test method for multi-directional stretching of a waterproof material is provided, and the test method is performed by using the test system, and includes:
(1) marking a sample to be detected;
(2) Fixing the sample to be measured in the sample anchoring device, measuring the distance between a central mark point of the sample to be measured and a mark point closest to the central mark point, scanning the initial profile of the sample to be measured by using the three-dimensional scanner to obtain the initial profile equation of the sample to be measured, and measuring the initial thickness of the sample to be measured by using a thickness measuring instrument;
(3) Providing initial deformation air pressure of the sample by using a pressurizing and adjusting device, and scanning the deformed outline of the sample to be detected by using the three-dimensional scanner after the sample to be detected is deformed stably so as to obtain a deformed outline equation of the sample to be detected; measuring the distance between the point of the highest deformation top expansion position and the point closest to the highest deformation top expansion position; measuring the thickness of the highest position of the deformation top expansion by using a thickness measuring instrument;
(4) Adjusting an air pressure adjusting unit, increasing air pressure, and repeating the measurement in the step (3) after the deformation of the sample to be measured is stable to obtain the measurement data in the step (3);
(5) repeating the step (4) until the sample to be detected is completely damaged;
(6) based on the distance between the central mark point of the sample to be detected and the mark point closest to the central mark point, the distance between the point of the top expansion highest position of the sample to be detected after deformation under different air pressures and the point closest to the top expansion highest position, the deformation profile equations of the sample to be detected under initial and different air pressures and the thicknesses of the deformation top expansion highest positions of the sample to be detected under initial and different air pressures, data processing is carried out by using a data processing device, the stress and strain values of the sample to be detected under different air pressures are obtained, and then the stress-strain curve of the sample to be detected is obtained.
in the invention, different deformation air pressures correspond to different deformation profiles and further correspond to different deformation profile equations, different stress and strain values can be obtained based on the different deformation profile equations, and a stress-strain curve is drawn based on the different stress-strain values.
In the invention, a three-dimensional scanner is used for scanning to obtain the initial profile and the deformed profile of the sample to be detected, a plurality of profile points are selected based on the obtained profile conformation, and a corresponding profile equation is obtained through fitting.
The main improvement of the invention lies in abandoning the original spherical jacking assumption, adopting a digital measurement method, solving the profile equation of the deformed sample and combining the thickness accurately measured by an ultrasonic thickness gauge, and accurately solving the stress of the sample. Thereby the test method is suitable for nonlinear and non-uniform high molecular materials.
in the invention, in the step (4), repeating the measurement in the step (3) to obtain the measurement data in the step (3) means that the three-dimensional scanner is used for scanning the deformed outline of the sample to be measured to obtain a deformation outline equation of the sample to be measured; measuring the distance between the point of the highest position of the deformation top expansion and the point closest to the highest position of the deformation top expansion; and measuring the thickness of the highest position of the deformation top expansion by using a thickness measuring instrument.
According to the present invention, preferably, step (1) is to mark a central mark point and a plurality of optional mark points on the surface of the sample to be measured.
in the invention, a plurality of marking points marked on the surface of the sample to be measured can cover the whole surface of the sample to be measured.
in the invention, in the step (2), the sample to be tested is fixed between the cylinder and the flange.
according to the present invention, in the step (3), the initial deformation gas pressure of the sample is preferably 1 to 10kpa, more preferably 1 to 5kpa, and further preferably 1 to 2 kpa;
In the step (4), the air pressure is increased by 1 to 10kpa, preferably 1 to 5kpa, and more preferably 1 to 2kpa at a time.
According to the invention, preferably, in the step (3) and the step (4), after the sample to be measured deforms and stabilizes, the sample to be measured stands still for 2-3min, and then data measurement is carried out.
According to the present invention, preferably, in step (6), the data processing includes the following data processing formula:
Wherein, F 2 represents the horizontal force of the point of the top expansion highest position after each deformation, p represents the deformation air pressure applied to the sample to be tested each time, F (x) represents the initial profile equation of the sample to be tested or the deformation profile equation of each time, x 1 represents the coordinate point of the point closest to the top expansion highest position on the profile equation of the sample to be tested after each deformation, x 2 represents the coordinate point of the top expansion highest position after each deformation on the profile equation of the sample to be tested, L t represents the distance between the point of the top expansion highest position after each deformation and the point closest to the top expansion highest position, L represents the distance between the central mark point of the sample to be tested and the mark point closest to the central mark point, σ represents the deformation stress of the sample to be tested each time, a represents the initial thickness of the sample to be tested or the thickness of the top expansion highest position after each deformation, and ε represents the strain of the sample to be tested each time.
In the invention, as shown in fig. 1, a point 2 is the highest point of the jacking expansion after deformation in a scanned image, and a point 1 is an adjacent point closest to the point 2 in the image, the sample is subjected to stress analysis, the highest point of the jacking expansion of the sample is only subjected to tensile force in the X direction, the tensile force at the point 1 can be decomposed into X, Y directions, the sample is kept still under air pressure P in the test process, and according to a mechanical balance equation, the resultant force of the force F PY of the air pressure P acting on the sample is equal to the force of the F 1 in the Y axis direction at the point 1, the force of the force F PX of the air pressure P acting on the sample plus the force of the F 1 in the X axis direction at the point 1 is equal to F 2, a function is created after function fitting is carried out on the profile of the sample after jacking expansion, and a function F (X) is created, the force of the air pressure P acting on the sample is obtained by differentiating the function F:
Wherein, F Spy is the integral of the vertical component of the deformation air pressure p applied to the sample to be tested on the sample deformation contour line each time, F Spx is the integral of the horizontal component of the deformation air pressure p applied to the sample to be tested on the sample deformation contour line each time, F 1y is the force in the vertical direction (i.e. the force in the y-axis direction) applied to the point 1, and F 1x is the force in the horizontal direction (i.e. the force in the x-axis direction) applied to the point 1.
Solving the output F 2, and solving the stress of the sample by combining the thickness of the sample (see formula (2));
equations (3) and (4) refer to strain calculation equations.
in the invention, when no pressure is applied to the sample, the obtained initial profile equation is a straight line, namely when data processing is carried out, the initial profile equation and the initial thickness of the sample to be measured can be substituted into the formula (1) to the formula (4) or can be not substituted, if substituted, the obtained F 2, stress and strain values are all 0, if not substituted, the sample is not stressed because no pressure is applied to the sample, and no strain occurs, so the stress and strain values at the moment are still all 0.
The invention is further illustrated by the following examples:
Examples
As shown in fig. 2 to 4, the present embodiment provides a test system for multi-directional stretching of a waterproof material, the test system comprising: a sample anchoring device, a pressurizing and adjusting device, a three-dimensional scanner 5, a thickness measuring instrument 6, and a data processing device (not shown); the sample anchoring device comprises a cylinder 3 and a flange 7 arranged on the cylinder 3; used for fixing a sample 4 to be tested; the pressurizing and adjusting device comprises a pressure providing unit 1 and an air pressure adjusting unit 2, wherein the pressure providing unit 1 is communicated with the air pressure adjusting unit 2 through a pipeline, and the air pressure adjusting unit 2 is communicated with the side wall of the air cylinder 3 through a pipeline; the device is used for providing deformation air pressure for a sample to be tested; the three-dimensional scanner 5 is used for scanning the deformed contours of the sample 4 to be tested under the initial and different air pressures so as to obtain the deformed contour equations of the sample to be tested under the initial and different air pressures; the thickness measuring instrument 6 is used for measuring the thickness of the deformation top expansion highest position of the sample 4 to be measured under the initial and different air pressures; the data processing device carries out data processing on the basis of the distance between a central mark point of the sample to be tested and a mark point closest to the central mark point, the distance between a point of a top expansion highest position of the sample to be tested after deformation under different air pressures and a point closest to the top expansion highest position, the deformation profile equations of the sample to be tested under initial and different air pressures, and the thicknesses of the deformation top expansion highest positions of the sample to be tested under initial and different air pressures, so that the stress and strain values of the sample to be tested under different air pressures are obtained, and further the stress-strain curve of the sample to be tested is obtained. The flange 7 is arranged above the air outlet of the air cylinder 3, and the air cylinder 3 is fixedly connected with the flange 7; the inner cavity of the cylinder is cylindrical, and the flange plate is in a perfect circle shape; the pressure providing unit 1 is an air compressor; the air pressure adjusting unit 2 is a pressure adjusting valve; the thickness measuring instrument 6 is an ultrasonic thickness measuring instrument.
The test system is used for testing, and the specific test method for the multidirectional stretching of the waterproof material comprises the following steps:
(1) And marking a central mark point and a plurality of optional mark points on the surface of the sample to be detected, so that the plurality of mark points marked on the surface of the sample to be detected can cover the whole surface of the sample to be detected.
(2) Fixing the sample to be tested in the sample anchoring device, measuring the distance between a central mark point of the sample to be tested and a mark point closest to the central mark point, erecting a three-dimensional scanner 5, scanning the initial contour of the sample to be tested 4 by using the three-dimensional scanner 5 to obtain the initial contour equation of the sample to be tested 4, and measuring the initial thickness of the sample to be tested 4 by using a thickness measuring instrument 6; wherein the sample 4 to be measured is fixed between the cylinder 3 and the flange 7 by using bolts.
(3) The air compressor is opened, the air pressure adjusting unit 2 is started, the initial air pressure is adjusted to be 2kpa, and the test is started: providing an initial sample deformation air pressure of 2kpa by using a pressurizing and adjusting device, standing for 2min after the sample to be detected deforms stably, and scanning the deformed outline of the sample to be detected by using the three-dimensional scanner 5 to obtain a deformation outline equation of the sample to be detected; then, measuring the distance between the point of the highest deformation top expansion position and the point closest to the highest deformation top expansion position; measuring the thickness of the highest position of the deformation top expansion by using a thickness measuring instrument 6;
(4) Adjusting the air pressure adjusting unit 2, increasing the air pressure by 2kpa, standing for 2min after the deformation of the sample to be detected is stable, and scanning the deformed outline of the sample to be detected by using the three-dimensional scanner 5 to obtain a deformation outline equation of the sample to be detected; then, measuring the distance between the point of the deformation top expansion highest position and the point closest to the top expansion highest position; measuring the thickness of the highest position of the deformation top expansion by using a thickness measuring instrument 6;
(5) repeating the step (4) until the sample to be detected is completely damaged;
(6) Based on the distance between a central mark point of the sample to be detected and a mark point closest to the central mark point, the distance between a point of a top expansion highest position of the sample to be detected after deformation under different air pressures and a point closest to the top expansion highest position, a deformation profile equation of the sample to be detected under initial and different air pressures and the thickness of the sample to be detected at the initial and different air pressures, data processing is carried out by using a data processing device to obtain the stress and strain values of the sample to be detected under different air pressures so as to obtain a stress-strain curve of the sample to be detected; wherein, the data processing comprises the following data processing formula:
Wherein, F 2 represents the horizontal force of the point of the top expansion highest position after each deformation, p represents the deformation air pressure applied to the sample to be tested each time, F (x) represents the initial profile equation of the sample to be tested or the deformation profile equation of each time, x 1 represents the coordinate point of the point closest to the top expansion highest position on the profile equation of the sample to be tested after each deformation, x 2 represents the coordinate point of the top expansion highest position after each deformation on the profile equation of the sample to be tested, L t represents the distance between the point of the top expansion highest position after each deformation and the point closest to the top expansion highest position, L represents the distance between the central mark point of the sample to be tested and the mark point closest to the central mark point, σ represents the deformation stress of the sample to be tested each time, a represents the initial thickness of the sample to be tested or the thickness of the top expansion highest position after each deformation, and ε represents the strain of the sample to be tested each time.
having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.
Claims (10)
1. a test system for multi-directional stretching of waterproof materials is characterized by comprising: the device comprises a sample anchoring device, a pressurizing and adjusting device, a three-dimensional scanner, a thickness measuring instrument and a data processing device;
The specimen anchoring device includes: the air cylinder and the flange plate are arranged on the air cylinder; the device is used for fixing a sample to be tested;
The pressurizing and regulating device comprises: the air pressure adjusting device comprises a pressure providing unit and an air pressure adjusting unit, wherein the pressure providing unit is communicated with the air pressure adjusting unit, and the air pressure adjusting unit is communicated with the air cylinder; the device is used for providing deformation air pressure for a sample to be tested;
The three-dimensional scanner is used for scanning the deformed outline of the sample to be tested under the initial and different air pressures so as to obtain the deformed outline equations of the sample to be tested under the initial and different air pressures;
the thickness measuring instrument is used for measuring the thickness of the deformation top expansion highest position of the sample to be measured under the initial and different air pressures;
the data processing device carries out data processing on the basis of the distance between a central mark point of the sample to be tested and a mark point closest to the central mark point, the distance between a point of a top expansion highest position of the sample to be tested after deformation under different air pressures and a point closest to the top expansion highest position, the deformation profile equations of the sample to be tested under initial and different air pressures, and the thicknesses of the deformation top expansion highest positions of the sample to be tested under initial and different air pressures, so that the stress and strain values of the sample to be tested under different air pressures are obtained, and further the stress-strain curve of the sample to be tested is obtained.
2. the testing system of claim 1, wherein the flange is disposed above an air outlet of the air cylinder, and the air cylinder is fixedly connected to the flange.
3. The testing system of claim 1, wherein the pressure providing unit is in communication with an air pressure regulating unit via a conduit, the air pressure regulating unit being in communication with the cylinder sidewall via a conduit.
4. The testing system of claim 1, wherein the pressure providing unit is an air compressor.
5. the testing system of claim 1, wherein the thickness gauge is an ultrasonic thickness gauge.
6. A test method for multi-directional tensile of a waterproof material, characterized in that the test is performed by using the test system of any one of claims 1 to 5, the test method comprising:
(1) Marking a sample to be detected;
(2) fixing the sample to be measured in the sample anchoring device, measuring the distance between a central mark point of the sample to be measured and a mark point closest to the central mark point, scanning the initial profile of the sample to be measured by using the three-dimensional scanner to obtain the initial profile equation of the sample to be measured, and measuring the initial thickness of the sample to be measured by using a thickness measuring instrument;
(3) Providing initial deformation air pressure of the sample by using a pressurizing and adjusting device, and scanning the deformed outline of the sample to be detected by using the three-dimensional scanner after the sample to be detected is deformed stably so as to obtain a deformed outline equation of the sample to be detected; measuring the distance between the point of the highest deformation top expansion position and the point closest to the highest deformation top expansion position; measuring the thickness of the highest position of the deformation top expansion by using a thickness measuring instrument;
(4) adjusting an air pressure adjusting unit, increasing air pressure, and repeating the measurement in the step (3) after the deformation of the sample to be measured is stable to obtain the measurement data in the step (3);
(5) repeating the step (4) until the sample to be detected is completely damaged;
(6) Based on the distance between the central mark point of the sample to be detected and the mark point closest to the central mark point, the distance between the point of the top expansion highest position of the sample to be detected after deformation under different air pressures and the point closest to the top expansion highest position, the deformation profile equations of the sample to be detected under initial and different air pressures and the thicknesses of the deformation top expansion highest positions of the sample to be detected under initial and different air pressures, data processing is carried out by using a data processing device, the stress and strain values of the sample to be detected under different air pressures are obtained, and then the stress-strain curve of the sample to be detected is obtained.
7. The test method according to claim 6, wherein the step (1) is to mark a central mark point and a plurality of optional mark points on the surface of the sample to be tested.
8. the test method according to claim 6, wherein in the step (3), the initial deformation gas pressure of the sample is 1 to 10kpa, preferably 1 to 5kpa, further preferably 1 to 2 kpa;
in the step (4), the air pressure is increased by 1 to 10kpa, preferably 1 to 5kpa, and more preferably 1 to 2kpa at a time.
9. The test method according to claim 6, wherein in the step (3) and the step (4), after the sample to be tested is deformed and stabilized, the sample is left for 2-3min, and then data measurement is performed.
10. The test method according to claim 6, wherein in the step (6), the data processing includes a data processing formula as follows:
wherein, F 2 represents the horizontal force of the point of the top expansion highest position after each deformation, p represents the deformation air pressure applied to the sample to be tested each time, F (x) represents the initial profile equation of the sample to be tested or the deformation profile equation of each time, x 1 represents the coordinate point of the point closest to the top expansion highest position on the profile equation of the sample to be tested after each deformation, x 2 represents the coordinate point of the top expansion highest position after each deformation on the profile equation of the sample to be tested, L t represents the distance between the point of the top expansion highest position after each deformation and the point closest to the top expansion highest position, L represents the distance between the central mark point of the sample to be tested and the mark point closest to the central mark point, σ represents the deformation stress of the sample to be tested each time, a represents the initial thickness of the sample to be tested or the thickness of the top expansion highest position after each deformation, and ε represents the strain of the sample to be tested each time.
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