Calculation Method of Hot Spot Stress at Weld Toe

Abstract

A method for calculating a hotspot stress at a weld toe comprises the following steps: S10: pre-processing a finite element model; S2: performing calculation according to the finite element model; S3: extracting a linear force and a linear moment of each node; S4: calculating a pulling stress, a bending stress, and a real stress at a weld toe according to the linear force and the linear moment of each node that are extracted in S3; and S5: obtaining a hotspot stress of each node at the weld toe by summing real stresses together. In S10, a built geometric model for a virtual strain gauge is divided into a strain gauge periphery and a strain gauge core block, each surface corresponding to the strain gauge core block is divided into N sub-surfaces, one linear feature is generated at a side edge of each sub-surface, and N+1 linear features in total are generated for the N sub-surfaces. The foregoing calculation method has simple steps, relatively high efficiency, and high calculation precision, greatly reduces manpower and material resources, and improves efficiency of later-stage design verification of a welding structure and design quality of the welding structure.

Description

technical field [0001] The invention relates to the calculation field, in particular to a calculation method for hot spot stress at a weld toe. Background technique [0002] In welded structures, the inherent fatigue strength of welded joints tends to be low. This is because the special manufacturing process of welding includes too many additional factors that are detrimental to the fatigue performance of the structure: discontinuous structures such as connection accessories, reinforcements, and weld geometry. These geometric discontinuities lead to discontinuities in structural stiffness. Ultimately, this can easily lead to high stress concentrations at the welded joint. The severity of stress concentration determines the fatigue strength of the welded structure. In fact, in areas of high stress concentration, due to the highly nonlinear stress gradient, it is difficult to intercept a uniform stress value with mechanical significance to assess the fatigue life of the str...

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Problems solved by technology

However, the nominal stress method also has serious limitations: 1) The fatigue failure of the welded structure is caused by the stress concentration at the welded joint, while the nominal stress method ignores the stress concentration of the welded joint

2) Due to the diversity of welded joints, the one-to-one correspondence between welded joints and S-N curves is difficult to achieve

However, before this method is implemented, the 3D geometric model of the welded structure needs to be converted into a 2D geometric model of the plate and shell. For complex steel structures, it is difficult to accurately express the 3D solid model with the 2D plate and shell model, and it takes a lot of time and labor costs. Engineering applications There are certain limitations in

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