Hollow-structure high-cycle fatigue vibration testing device and method

Abstract

The invention belongs to the technical field of testing, and relates to a hollow-structure high-cycle fatigue vibration testing device and method. The testing device comprises a testing device base, a simple supported end support plate, a simple supported end chuck bearing, a simple supported end chuck, a hinged support end chuck, a hinged support end chuck shaft, a rocker, a rocker bearing and a hinged support end support. By means of the clamping scheme of simply supporting at one end and hinged supporting at the other end, the maximum stress area of a tested piece is far away from the clamping position. The tested piece with the equal cross section and the relatively simple appearance of the cross sections can be adopted in the testing device, the stress of the checked part of the tested piece is distributed relatively simply, and the subsequent theoretical analysis is facilitated. According to the appearance scheme of the hollow-structure tested piece and the corresponding high-cycle fatigue vibration testing device, the hollow-structure high-cycle vibration tested piece is simple in structure and even in appearance. The checked part of the tested piece is far away from the clamping end, the stress state of the tested piece is relatively simple and even, and the loading process of a vibration platform is simple.

Description

technical field [0001] The invention belongs to the technical field of testing, and relates to a hollow structure high-cycle fatigue testing device and method. Background technique [0002] At present, various types of aircraft mainly use aviation turbojet engines as power devices. When this type of power device works, air is sucked in. After the air pressure is increased, fuel is injected into the high-pressure air and burned to generate high-temperature and high-pressure gas. The gas is used for direct or indirect Generate thrust. The part that increases the air pressure is called "compressor". At present, the compressor is mainly of axial flow type, which is composed of multiple similar units, each unit is one level, and consists of two sets of blades before and after, and the front set is The moving blades rotate at a high speed during work to increase the speed of inhaled air, and the latter group reduces the airflow speed and increases the pressure. In the cooperativ...

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Problems solved by technology

[0009] The existing specimen is a flat specimen with a clamping end. During the test, the specimen undergoes a bending deformation. In this test state, the maximum stress point is located at the transition fillet between the clamping end and the flat plate, that is, the maximum stress The point is located at the root of the flat plate. Because it is in the geometric change zone (there is a transition fillet), it leads to stress concentration and uneven stress distribution, which is not convenient for subsequent theoretical analysis. On the basis of the above test pieces, some schemes change the shape of the test piece, If the thickness is gradually reduced along the height direction of the test piece, or the design scheme with a larger transition fillet is adopted, the maximum stress area on the test piece can be transferred from the transition fillet area of ​​the clamping end to the plate. However, with this structure In addition, this type of structural design scheme will also lead to a large stress gradient at the assessment site

If the design of the test piece remains unchanged, but the high-order mode shape is used for the test, although this can make the maximum stress area away from the clamping end, however, this type of test is limited by the test device, such as the frequency range of the vibration table and the magnitude of the thrust. Under the excitation frequency, it is difficult to ensure that the stress level of the assessment part of the test piece reaches the order of magnitude in the test task book. In addition, when the test piece generates high-order vibration, the deformation area is irregular, which also causes the stress distribution of the test piece to be uneven.

[0010] According to the above analysis, the shortcomings of the current high-cycle fatigue test of hollow structures are: 1) the maximum stress in the test piece (that is, the assessment part) is at the clamping end; 2) there is a large stress concentration in the test part and the surrounding area; 3) Inconsistent structures in different regions; 4) It is difficult to carry out tests using high-order mode shapes

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