CN115265983A - Fatigue strength storage parameter measurement test system for aircraft engine welding pipeline - Google Patents
Fatigue strength storage parameter measurement test system for aircraft engine welding pipeline Download PDFInfo
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- CN115265983A CN115265983A CN202210935624.7A CN202210935624A CN115265983A CN 115265983 A CN115265983 A CN 115265983A CN 202210935624 A CN202210935624 A CN 202210935624A CN 115265983 A CN115265983 A CN 115265983A
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- fatigue strength
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M7/00—Vibration-testing of structures; Shock-testing of structures
- G01M7/02—Vibration-testing by means of a shake table
- G01M7/025—Measuring arrangements
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Abstract
The invention provides a fatigue strength storage parameter measurement test system for an aircraft engine welding pipeline, which comprises a vibration table and a vibration table controller, wherein the vibration table controller controls the vibration table in a closed loop manner; the conduit is clamped and fixed on the vibration table, the strain gauge and/or the displacement sensor are used for measuring the conduit, and data collected by the strain gauge and/or the displacement sensor are sent to an upper computer for storage and analysis through a dynamic data collection system. The method can effectively obtain the fatigue strength reserve of the pipeline welding seam, meet the national military standard requirement and provide data support for evaluating the pipeline design rationality; the test difficulty is low, the test cost is low, and the test period is short.
Description
Technical Field
The invention relates to a fatigue strength storage parameter measurement test system for an aircraft engine welding pipeline, and belongs to the technical field of general tests.
Background
The national military standard GJB 3816-1999 general technical requirement of aircraft engine pipeline system requires the fatigue strength storage coefficient of the welding conduit assembly anti-vibration strength welding position to be designed according to the formula (1).
In the formula
σ a Fatigue limit of the welded joint in MPa.
σ v Maximum alternating stress in MPa measured at the pipe joints, fixings and fulcrums.
Obviously, σ in the above formula a And σ v Must be obtained by experimentation. Wherein σ a Measured at the tester, obtained by statistical data analysis methods, and σ v It is actually measured during the engine test run.
σ a The method is carried out according to HB/Z112-86 statistical analysis method for material fatigue test, and is obtained by adopting a lifting method. During testing, the working pipeline of the engine is used as a test piece, and the engine is installed in a fixed installation mode in a simulated mode. As the engine pipelines are used for connecting all parts, accessories and the parts and the accessories, the engine pipeline has complex structure, different shapes and sizes and more quantity, is arranged in the three-dimensional vertical surface space inside and outside the engine, and needs to adopt a triaxial vibration table to carry out tests. The triaxial vibration table is a novel product, most aero-engine product manufacturing and research units do not have the test capability, and factors such as high test cost, large technical difficulty, long test period and the like are usually not measured a That is, the evaluation of the pipeline cannot be performed according to equation (1), but rather an empirical limit value σ is given lim As a criterion, if σ is v ＜σ lim The judgment is qualified. This criterion is due to an empirical limit value σ lim Unreasonable values are taken, and the reasonability of the design can not be effectively evaluated and the faults of the engine pipeline can not be effectively controlled.
Disclosure of Invention
In order to solve the technical problems, the invention provides a fatigue strength reserve parameter measurement test system for an aircraft engine welding pipeline, which can effectively obtain the fatigue strength reserve at the pipeline welding seam, meet the national military standard requirements and provide data support for evaluating the rationality of pipeline design.
The invention is realized by the following technical scheme.
The invention provides a fatigue strength storage parameter measurement test system for an aircraft engine welding pipeline, which comprises a vibration table and a vibration table controller, wherein the vibration table controller controls the vibration table in a closed loop manner; the conduit is clamped and fixed on the vibration table, the strain gauge and/or the displacement sensor are used for measuring the conduit, and data collected by the strain gauge and/or the displacement sensor are sent to an upper computer for storage and analysis through a dynamic data collection system.
The pipe is formed by sleeving two sections of pipelines, a welding seam is arranged at the end part of the pipeline sleeved outside, and the clamping section for clamping and fixing the pipe is staggered at the welding seam and is positioned on the pipeline sleeved outside.
The guide pipe is clamped by a pressurizing block, and the pressurizing block is controlled to lift by a telescopic mechanism.
The telescopic mechanism is a bolt, and the bolt is installed on the portal clamp.
And the displacement sensor also sends the acquired data to the vibration table controller.
The strain gauges are attached to the catheter in a plurality of axial directions.
One strain gauge is respectively stuck at the position of the same section at a quarter of a circle interval.
The dynamic data acquisition system calculates the Euclidean distance of a two-dimensional space by the values of the strain gauges to obtain the alternating stress.
The invention has the beneficial effects that: the fatigue strength reserve of the pipeline welding seam can be effectively obtained, the national military standard requirements are met, and data support is provided for evaluating the pipeline design rationality; the test difficulty is low, the test cost is low, and the test period is short.
Drawings
FIG. 1 is a schematic block diagram of the system of the present invention;
FIG. 2 is a schematic view of one embodiment of the catheter of FIG. 1 being clamped;
FIG. 3 is a schematic view of the clamping principle of the welding line according to the present invention.
In the figure: 1-bolt, 2-door-shaped clamp, 3-pressurizing block, 4-conduit, 5-clamping section and 6-welding seam.
Detailed Description
The technical solution of the present invention is further described below, but the scope of the claimed invention is not limited to the described.
Example 1
As shown in figures 1 to 3, the fatigue strength storage parameter measurement test system for the aircraft engine welding pipeline comprises a vibration table and a vibration table controller, and is characterized in that: the vibration table controller controls the vibration table in a closed loop mode; the conduit 4 is clamped and fixed on the vibration table, the strain gauge and/or the displacement sensor are used for measuring the conduit 4, and data acquired by the strain gauge and/or the displacement sensor are transmitted to an upper computer for storage and analysis through a dynamic data acquisition system.
Example 2
Based on the embodiment 1, the conduit 4 is formed by sleeving two sections of pipelines, a welding seam 6 is arranged at the end part of the pipeline sleeved outside, and the clamping section 5 for clamping and fixing the conduit 4 is staggered at the welding seam 6 and is positioned on the pipeline sleeved outside.
Example 3
Based on the embodiment 1, the conduit 4 is clamped by the pressurizing block 3, and the pressurizing block 3 is controlled to lift by the telescopic mechanism.
Example 4
Based on embodiment 3, the telescopic mechanism is a bolt 1, and the bolt 1 is installed on a portal clamp 2.
Example 5
Based on embodiment 1, the displacement sensor also sends the acquired data to the vibration table controller.
Example 6
Based on example 1, the strain gauges are attached to the catheter 4 in a plurality in the axial direction.
Example 7
Based on example 6, one strain gauge was attached to each section at a distance of one quarter of a turn.
Example 8
Based on example 1, the dynamic data acquisition system calculates the euclidean distance in two dimensions for the values of the strain gauges to obtain the alternating stress.
Example 9
Based on the above embodiments, the material, diameter, wall thickness, welding process, etc. of the test pipeline are determined according to the engine pipeline design requirements, the failure occurrence rate, etc. Determining the first-order modal frequency of the pipeline, and determining the length of the cantilever of the pipeline through simulation calculation.
The clamp is designed into a door-shaped structure, has the advantages of good rigidity, convenience in installation and the like, the first-order modal frequency of the clamp is more than 10 times of that of a test pipeline, the step placing sliding and installation limiting are designed, and the design requirements of the clamp are met.
The test conduit pipe is cylindrical, in order to ensure that a clamping surface is tightly matched, the stress is uniform, the pressurizing block is designed into a symmetrical two-block structure, one surface matched with the pipeline is a cambered surface, the stress surface is a plane, the anti-moving step is designed at the force application position, the equal-length copper core rod materials are filled in the clamping section of the test conduit pipe, and the pipeline is ensured not to slide, deform and damage in the test process.
And determining the test working temperature, the diameter and the material of the test pipeline, selecting a strain gauge and an adhesive, and sticking the strain gauge on the maximum strain area of the pipeline. The error of the sensitivity coefficient of the strain gauge is not more than 2%.
The test system is an excitation system and consists of an electromagnetic vibration table (single axial direction), a power amplifier, an acceleration sensor and a control system. The frequency response range of the vibration table is not less than 2000Hz, and the thrust is not less than 20kN.
The test system is used for measuring strain and consists of a strain gauge, a laser displacement sensor, a dynamic signal acquisition system and a computer. The dynamic signal acquisition system has the functions of recording and analyzing strain, rotating speed and vibration signals and the like, the maximum sampling rate is not less than 51.2kS/s, and the system measurement error is not more than +/-1%. The measuring range of the laser displacement sensor is not less than +/-20 mm; the frequency response is not less than 2kHz; the measurement error is not more than +/-0.007 mm.
And installing a door-shaped clamp and a test conduit on the vibration table.
Setting an initial clamping torque, determining the first-order modal frequency of the test pipeline through the frequency sweep of the vibration table, setting the step length of the clamping torque, and changing the clamping torque until the first-order modal frequency is unchanged.
And exciting the test pipeline under the first-order modal frequency, selecting a maximum stress value from the test pipeline, and determining the position of a maximum stress point.
The position of an amplitude monitoring point is selected according to the mode vibration mode, the excitation energy is changed under the first-order mode frequency, a relation curve of the maximum stress value and the amplitude under different excitation energy is obtained, and the linearity of the maximum stress value and the amplitude is 99%.
Tensile strength sigma of pipe b One third of the initial stress. At a first-order modal frequency, experiments were conducted at a specified initial stress and a specified cycle base using a resonance dwell method. The test is carried out according to a lifting method, in particular to a statistical analysis method for the material fatigue test of HB/Z112-86. The valid data points were assigned 6 pairs with better than 90% confidence.
σ v The measurement of the value is carried out in the test run of the whole engine, so the measurement pipeline is an engine working pipeline, and a welding pipeline which is the same as a fatigue test material, a pipe diameter and a welding process is selected.
And selecting a strain gauge and an adhesive according to the working temperature, the pipe diameter and the material of the measuring pipeline. The strain gauges are attached to the vicinity of the screwed joint, the welded portion, and the mounting/fixing portion (at an interval of about 1 to 2 mm). The strain gauges are adhered along the axial direction, one strain gauge is adhered on the same section at a distance of a quarter of a circle, and one strain gauge is defined to be in a 0-degree direction, and the other strain gauge is defined to be in a 90-degree direction.
And submitting for assembly after the pasting work of the strain gauge is finished. Assembly is performed as the assembly process file and care is taken to protect the strain gauges and their leads.
The dynamic signal acquisition system records a measuring point strain signal and an engine rotating speed signal in the whole process of the engine test run, the position of the maximum alternating stress point and the corresponding engine state are determined by scanning in the slow vehicle-maximum slow pushing process (the change rate of the speed regulation rotating speed in the slow vehicle-maximum slow pushing process is generally not more than 60 r/min/s), and the engine continues to work for 2-3 min in the state.
The data analysis bandwidth is not less than 2.5 times of the maximum rotating speed frequency of the engine. And carrying out frequency domain analysis on the acquired data, and extracting the alternating stress amplitude in the corresponding engine state.
According to the measurement results, according to the formula
Calculate sigma v Value of where σ 0° And σ 90° The measurement values of two strain gauges with one quarter of circumference at the same measurement point are measured in MPa.
If the main component of the stress amplitude exists and the vibration level of the one-time rotor frequency resonance of the engine is less than 80% of the specified value, the formula is followed
Performing stress correction, wherein Vms Maximum stress, V, measured in the pipeline at one rotor frequency resonance spec For maximum permissible specified vibration level value, V, of vibration at rotor speed frequency max ms The maximum vibration value of the casing at the rotor speed is measured at the vibration measuring point on the 'vehicle-mounted' during the test run.
Finally, according to the formula
Formula (II)
And formula
The fatigue strength reserve factor, in which σ is calculated a In order to be the limit of the fatigue strength,
number of pairs of adjacent stress levels, σ i And σ i+1 A pair of data showing opposite test results (destruction and overshoot) was presented.
Claims (8)
1. The utility model provides an aeroengine welded tube way fatigue strength deposit parameter measurement test system, includes shaking table and shaking table control appearance, its characterized in that: the vibration table controller controls the vibration table in a closed loop mode; the conduit (4) is clamped and fixed on the vibration table, the strain gauge and/or the displacement sensor are used for measuring the conduit (4), and data acquired by the strain gauge and/or the displacement sensor are transmitted to an upper computer for storage and analysis through a dynamic data acquisition system.
2. The fatigue strength reserve parameter measurement test system for the aircraft engine welded pipeline according to claim 1, characterized in that: the pipe (4) is formed by sleeving two sections of pipelines, a welding seam (6) is arranged at the end part of the pipeline sleeved outside, and the clamping section (5) for clamping and fixing the pipe (4) is staggered at the welding seam (6) and is positioned on the pipeline sleeved outside.
3. The fatigue strength reserve parameter measurement test system for an aircraft engine welded pipeline according to claim 1, characterized in that: the guide pipe (4) is clamped by the pressurizing block (3), and the pressurizing block (3) is controlled to lift by the telescopic mechanism.
4. The fatigue strength reserve parameter measurement test system for the aircraft engine welded pipeline according to claim 3, characterized in that: the telescopic mechanism is a bolt (1), and the bolt (1) is installed on the portal clamp (2).
5. The fatigue strength reserve parameter measurement test system for an aircraft engine welded pipeline according to claim 1, characterized in that: and the displacement sensor also sends the acquired data to the vibration table controller.
6. The fatigue strength reserve parameter measurement test system for an aircraft engine welded pipeline according to claim 1, characterized in that: the strain gauges are adhered to the guide pipe (4) in a plurality of axial directions.
7. The fatigue strength reserve parameter measurement test system for an aircraft engine welded pipeline according to claim 6, characterized in that: one strain gauge is respectively adhered to the same section at a distance of a quarter of a circle.
8. The fatigue strength reserve parameter measurement test system for an aircraft engine welded pipeline according to claim 1, characterized in that: the dynamic data acquisition system calculates the Euclidean distance of a two-dimensional space by the values of the strain gauges to obtain the alternating stress.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210935624.7A CN115265983A (en) | 2022-08-04 | 2022-08-04 | Fatigue strength storage parameter measurement test system for aircraft engine welding pipeline |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210935624.7A CN115265983A (en) | 2022-08-04 | 2022-08-04 | Fatigue strength storage parameter measurement test system for aircraft engine welding pipeline |
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| CN115265983A true CN115265983A (en) | 2022-11-01 |
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| CN202210935624.7A Pending CN115265983A (en) | 2022-08-04 | 2022-08-04 | Fatigue strength storage parameter measurement test system for aircraft engine welding pipeline |
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| CN (1) | CN115265983A (en) |
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- 2022-08-04 CN CN202210935624.7A patent/CN115265983A/en active Pending
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