Weld seam fatigue life calculation method based on total strain energy density

Abstract

The invention discloses a weld seam fatigue life calculation method based on total strain energy density. The method mainly comprises the steps that 1, the weld-seam total strain energy density, a life function equation and a fatigue strength coefficient, a fatigue strength index, a cyclic strengthening coefficient and a cyclic strain hardening index which are needed by half-cycle life stress and a strain function equation are acquired through a welded joint fatigue test; 2, the weld seam structure is simulated through a shell unit module, the stress-strain response of the weld seam structure under the cyclic load action is calculated through a multi-load step method, and a stress-strain hysteretic curve is output; 3, the total strain energy density is calculated according to the stress-strain response, and the hot point fatigue life and a damage value of a weld toe of the weld seam are calculated by combining the energy density with the life function equation. According to the method, contribution of elastic-plastic stress and strain to the fatigue damage is comprehensively taken into account, scalar quantities are taken as damage parameters, the position and direction problems related to vectors are effectively avoided, the calculation precision is improved, and the time is saved.

Description

technical field [0001] The invention relates to a calculation method for weld seam fatigue life based on total strain energy density, which belongs to the field of weld seam fatigue life calculation. Background technique [0002] As an efficient manufacturing process, welding is widely used in mechanical equipment manufacturing. However, in actual use, due to repeated loads and fatigue during use, weld fatigue cracking often occurs, and the cracking position often occurs at the weld toe, so the research on fatigue damage analysis of welded structures is based on its Research on fatigue life calculation of key position welds. [0003] The calculation of weld fatigue life in the actual structure depends on the fatigue test and numerical simulation of the material specimen. However, the component fatigue test period is long, and it is impossible to load the actual complex load, which is more likely to cause waste of resources. Therefore, through the simulation technology The ...

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Problems solved by technology

[0004] In order to solve the problems of low prediction accuracy and calculation efficiency existing in the existing weld fatigue life calculation method, and overcome the defects described in the background technology, the present invention provides a weld fatigue life calculation method based on the total strain energy density. The present invention The method includes the following steps:

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