基于广义混合富集元法的应力强度因子分析

ANALYSIS OF STRESS INTENSITY FACTOR BASED ON GENERALIZED MIXED ENRICHED ELEMENT METHOD

以位移元模型为基础求解裂纹尖端应力强度因子(Stress Intensity Factor,SIF)的方法众多,但是,当模型网格较稀疏时,位移元模型的刚度偏大;另外,位移元模型不方便直接引入应力边界条件,边界应力结果有失客观性。基于富集元思想,结合广义H⁃R变分原理提出了广义混合富集元列式。基于该列式的有限元模型,一方面消除了经典混合富集元法结果的震荡问题,另一方面兼顾了裂纹尖端应力参量的奇异性和应力边界条件引入的方便性。实例分析表明,利用该方法求解应力强度因子,数值结果稳定可靠且精度较高。

The stress intensity factor(SIF)have been studied by many methods based on the displacement element model.However,under sparse meshes,the displacement element models will suffer from excessive stiffness,and are difficult to introduce the stress boundary conditions directly which lacking in objectivity.The generalized mixed enriched element method is proposed based on the principle of enriched element and generalized H⁃R variational principle.This method takes the crack tip stress singularity into account,considers the introducing of stress boundary conditions,and overcomes the oscillation of the classical mixed enriched element method.Numerical examples show that the stress intensity factor obtained by this method is stable and reliable with a high degree of accuracy.