Vehicle structure random vibration fatigue life calculation method considering welding residual stress

Abstract

The invention discloses a vehicle structure random vibration fatigue life calculation method considering welding residual stress, and belongs to the field of welding structure fatigue life calculation. The objective of the invention is to accurately calculate the random vibration fatigue life of a welding structure by considering the influence of welding residual stress on fatigue damage. The principle is that a time domain pavement irregularity calculation method is established based on an inverse Fourier transform method, and random pavement irregularity excitation power spectral density isdetermined; a thermoelastic-plastic theory and an ellipsoid heat source model are combined to carry out numerical simulation on the residual stress of the welded structure, excitation power spectral density is applied to the mechanical structure, random vibration analysis is performed and a structural stress power spectrum is calculated; and a stress amplitude probability density function is calculated according to the structure stress power spectrum, and the fatigue life of the vehicle structure is solved under the action of the random load according to the S-N curve of the weld joint. The method has the advantages that the initial welding residual stress and the working stress of the vehicle structure can be coupled, and the service life calculation precision under the weld random vibration load is improved.

Description

technical field [0001] The invention relates to a random vibration fatigue life calculation method of a vehicle structure considering welding residual stress, belonging to the field of fatigue life calculation of welded structures. Background technique [0002] Welding is one of the commonly used connection methods for vehicle structures. However, the welding process itself will have inconsistent recrystallization rates due to the existence of temperature gradients during the forming process, resulting in residual stress when the weld is cooled and formed, which greatly weakens the fatigue performance of the weld. [0003] At present, relevant scholars have carried out random vibration fatigue life prediction research of welded structures. The PCB solder joint random vibration fatigue life prediction method and system (public number: 105022860A) invented by Zhou Bin of the Fifth Electronics Research Institute of the Ministry of Industry and Information Technology, based on t...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problems of low prediction accuracy and low calculation efficiency existing in the fatigue life calculation method of vehicle welded structures, and to overcome the defects described in the background technology, the present invention provides a calculation method for random vibration fatigue life of vehicle structures considering welding residual stress, The inventive method comprises the following steps:

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