Three point bending fatigue testing apparatus

Abstract

The invention provides a three point bending fatigue testing apparatus, which can enrich the functions of a tensile fatigue testing machine so that the tensile fatigue testing machine can carry out three point bending fatigue tests. A rotatable clamping mechanism design is adopted; the bending fatigue tests with a negative stress ratio can be carried out effectively, the boundary conditions of a three point bending experiment can be satisfied, the experiment range is enlarged; a conventional three point clamp is optimized, the apparatus cost is reduced, and the sample positioning problem is solved. The adopted clamping structure can prevent a test piece from sliding during the long term fatigue experiment process; the upper clamping structure of the clamping structure is adjustable so as to clamp test pieces with different thicknesses; the clamping structure is composed of a roller and a trapezoidal block; the roller is in line contact with a test piece during the experiment process and is convenient to replace so as to guarantee the experiment accuracy; the trapezoidal block can prevent the interference on the test piece during the experiment process; and a load can be effectively applied on the test piece during the bending fatigue experiment process (with a negative stress ratio) through the combination of an upper press head and a lower press head.

Description

technical field [0001] The invention belongs to a device for testing the mechanical properties of a plate material, in particular to a bending fatigue test device suitable for a tensile fatigue test machine. Background technique [0002] In the actual work of many large and complex mechanical equipment, its components are often subjected to alternating bending loads. Therefore, it is very important to evaluate the fatigue performance of components through bending fatigue tests, and it can provide reference for design and manufacture. [0003] The function of the bending fatigue testing machine is single, and the requirements for the size and shape of the test piece are relatively high, and the versatility is not strong. Tensile fatigue testing machines with stronger versatility and higher precision should be used in practical engineering fields. For the bending fatigue test, an experimental device is needed to expand the function of the tensile fatigue testing machine to pe...

AI Technical Summary

Problems solved by technology

[0004] The existing three-point bending test device can only perform quasi-static bending tests, but it cannot effectively perform bending fatigue tests, and it has the following shortcomings:

When the specimen breaks suddenly, if there is no corresponding protection, it may be dangerous, and may cause secondary damage to the test fracture, which is not conducive to later analysis

Therefore, the traditional three-point bending test fixture cannot effectively perform fatigue tests

[0006] 2. The design of the traditional three-point bending test fixture cannot perform the bending fatigue test of the tension-compression cyclic load, that is, the negative stress ratio, and the scope of application is not wide

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