Fatigue property test method for wallboard lap joint structure

Abstract

The invention relates to a fatigue property test method for a wallboard lap joint structure. The fatigue property test method is characterized by comprising the following steps of: installing a test piece in a triaxial bending-limitation clamp; clamping two ends of the test piece by using an upper chuck and a lower chuck of a tester, wherein the centering line of the two chucks is overlapped with the central line of the two ends of the test piece; then prestretching a connection piece twice; continuing to load a sine waveform with a frequency of 5 Hz, wherein the peak value of the load is 0.3[P]n; and reducing the frequency by 1 Hz every 1,000-3,000 times so as to acquire the length a of a crack at each time and a corresponding load cycle number N. The fatigue property test method has the beneficial effects that a fatigue crack extension test for the wallboard lap joint structure with longitudinal load can be carried out; a good test effect is achieved during actual use; and furthermore, any obvious vibration or deformation can be avoided, bending deformation can be eliminated effectively, axial load transmission and deformation cannot be influenced and the effectiveness of test data is guaranteed.

Description

technical field [0001] The invention relates to a fatigue performance test method of a typical wall-board lap joint structure, and particularly provides a set of fixture devices for the fatigue test of the wall-board lap joint structure and a generalized fatigue notch coefficient model. Background technique [0002] There are a large number of structural connectors in aerospace structures. Many important load-bearing components are connected to other structures by fasteners such as bolts and rivets. The test and calculation of connectors are affected by many factors, such as the connection form (lap joint or butt joint, single shear or double shear, etc.), the geometric dimensions of the connection (row distance, end distance, ratio of side distance to aperture, etc.), fasteners The type and size of the load, the type of load (static load, dynamic load or fatigue load), direction, ambient temperature, humidity, medium) and other factors. The fatigue performance analysis of...

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Problems solved by technology

[0003] However, the stress analysis of the connectors, especially the local detailed stress analysis, due to the uniqueness of the structural form of the connectors, the simultaneous contact and plastic deformation is a complex nonlinear process, which makes the calculation error very large, so that the structural analysis and Great inconvenience by design, life estimates are more spread out

For the influence of different stress states caused by the thickness of the specimen, in the process of life estimation, the local stress-strain method is used to deal with the modified Neuber method and linear interpolation method, resulting in prediction deviation

Using a three-dimensional contact model to calculate the stress severity factor of a certain part is more accurate, but it often requires a lot of calculation for large-scale connector analysis

However, the method of using two-dimensional nail elements to simulate fasteners can easily calculate the stress severity coefficient of the hole, but the influence of thickness and load is not taken into account, and the accuracy is not high enough.

The difference in fatigue life of materials with different thicknesses cannot be predicted by fatigue life, which is one of the major defects in existing life prediction methods

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