Measuring device for flexural fatigue property of flexible material

A bending fatigue and measuring device technology, applied in the field of fatigue measurement, can solve problems such as unreported measurement technology, and achieve the effect of reasonable function, simple device components, and easy installation and replacement

Inactive Publication Date: 2005-03-02
DONGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Measurement techniques for symmetrical, fixed-point bending fatigue of such flexible materials have not been reported

Method used

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  • Measuring device for flexural fatigue property of flexible material
  • Measuring device for flexural fatigue property of flexible material
  • Measuring device for flexural fatigue property of flexible material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Example 1 Fixed load single fiber bending fatigue test results

[0035] The pretension is 3cN / dtex, and the fatigue life test results of aramid (Twaron2000) fibers are:

[0036] Condition Twaron 2000 (1.68dtex) fatigue life (times)

[0037] 35° 3.29cN 9655 9900 10350 9385 10022 8900 8960 9356 8800 9360

[0038] 35° 6.58cN 4630 5780 3300 4345 4160 5740 4980 3089 3015 3020

[0039] 45° 4.93cN 4145 4200 2960 3018 4042 3760 2738 3600 2710 2360

[0040] 55° 3.29cN 1540 1054 1100 1680 1530 1308 1086 2315 2185 1450

[0041] It can be seen from the above table that under a small specific stress (less than 10% of the specific stress of fiber fracture) and a small rotation angle, the fiber bending fatigue failure does not reach the conventionally used 10%. 5 Fatigue life shows that although aramid fibers have high tensile strength, they have poor resistance to bending fatigue.

Embodiment 2

[0042] Example 2 Relaxation Test of Fibers

[0043] Using the relaxation stress measurement mode, measure the relaxation characteristics of Twaron2000 (1.68dtex):

[0044] condition ε 0 =2%

[0045] Time t(h) 1 2 6 10 14 18 20 24 28 32

[0046] Stress σ(cN) 111.5 106.2 90.2 76.4 64.5 54.7 50.3 42.6 40.2 40.1

[0047] By calculation, at constant elongation ε 0 =2%, the relaxation time τ of the fiber is 23.86h. Because stress relaxation is a tensile characteristic, the fiber has better tensile fatigue resistance properties.

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PUM

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Abstract

The invention is an apparatus used for measuring flexible material flexural fatigue, with property of being consisted of crank block rack mechanism, force and displacement sensor, upper and lower cartridge, optical plummet centering system, up-and-down and rotation driving system and control circuit, program and signal collection system, finishing measurement of fixed point flexural fatigue and relaxation creep behaviour of flexible material with stationary load and stretch effectively and accurately. The index property measured are endurance failure time, endurance limit strength and limiting strain, relaxation time, sample thickness or diameter. The apparatus has simple but practical structure, convenient installation and replacement, many tunable parameters containing sample length, fixed points position and their distance, bending rotational angle and angular frequency, original load and stretch, accurate measurement, and can avoid influence of move of application point in bending, offset of sample and vibration.

Description

Technical field: [0001] The patent of the present invention relates to the fatigue measurement technology in the field of flexible materials (fibers, yarns, fabrics and membrane materials, etc.). Background technique: [0002] Fatigue refers to the failure of materials under prolonged or repeated low stress, more specifically, fatigue refers to the damage or failure of materials under repeated stress or strain, or under prolonged static stress or constant strain, Damage and failure caused by creep or relaxation of materials. The evaluation of fatigue failure and fatigue life should be considered corresponding to the given fatigue action mode, such as tension, bending, torsion, compression, or compound action. [0003] Fatigue research initially started in the field of metal materials. German A. Wohler et al. first conducted research in this area, pointed out that some metals have fatigue limits, and plotted the fatigue test results as the S-N curve of the relationship betwe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/00G01N3/20G01N19/00
Inventor 于伟东刘晓艳
Owner DONGHUA UNIV
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