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采用随机有限单元法对含浅表面和深表面裂纹焊接结构的可靠性进行了计算。该方法克服了传统的确定性断裂力学在结构的安全评定中结果偏于保守的缺点。在结构可靠性计算中 ,采用自行编制的基于摄动理论的三维随机有限元程序 ,就焊接残余应力对结构可靠性的影响进行了计算 ,并讨论了断裂韧度、外载荷、裂纹尺寸三个随机变量的变异对结构可靠性的影响。计算结果表明 ,焊接残余应力对结构的可靠性有较大影响 ,无论结构中是否有残余应力 ,上述三个随机变量中 ,断裂韧度的变异对结构的可靠性影响最大 ,其次是外载荷 ,裂纹尺寸的变异对结构的可靠性影响较前两者都小。
The reliability of welded structures with shallow and deep surface cracks was calculated using the stochastic finite element method. The method overcomes the shortcomings that the traditional deterministic fracture mechanics results are conservative in structural safety assessment. In the calculation of structural reliability, a three-dimensional random finite element program based on perturbation theory, which is self-compiled, is used to calculate the influence of welding residual stress on the structural reliability. The fracture toughness, external load and crack size are discussed Effect of Variation of Random Variables on Structural Reliability. The calculated results show that the welding residual stress has a great influence on the structural reliability. Regardless of whether there is any residual stress in the structure, the variation of fracture toughness has the greatest effect on the structural reliability of the three random variables, followed by the external load, The variation of crack size has less influence on the reliability of the structure than the former two.