Based on the conservation law and bending theory, a technique to determine complicated stress intensity factors on three-dimensional components is proposed, A series of closed form expressions of stress intensity factor are derived for cracked shells under different loads, such as bending, tension. The method requires the geometric relationship between multiple singular stress fields from the crack section, and the relationship between the stress at different crack tips can be estimated. In the expression of the stress intensity factor K, K is proportional to the stress σ at the crack tip, and we can get the supplementary equation of between different stress fields K according to the ratio of the stress at the crack tip, then use the J-integral method to calculate the stress intensity factors of different stress fields. In order to verify the feasibility of this method, a cracked R-fluted shells model was constructed. Under the action of the bending moment, the corner crack propagation is simulated through the reserved corner crack, and two crack tips with different stress fields are generated during the simulation. The research result indicates that the proposed method is effective for cracked R-fluted shells, and has universal applicability for solving complex stress intensity factors on three-dimensional components.

基于守恒定律和弯曲理论，提出了一种确定三维构件上复杂应力强度因子的方法，推导出了受弯曲、受拉等不同载荷作用下开裂壳应力强度因子的一系列闭式表达式。该方法需要裂纹截面的多个奇异应力场之间的几何关系，可以估计不同裂纹尖端的应力之间的关系。在应力强度因子K的表达式中，K与裂纹尖端的应力σ成正比，根据裂纹尖端应力的比值，可以得到不同应力场K之间的补充方程，然后用J-积分法计算不同应力场的应力强度因子。为验证该方法的可行性，建立了裂纹R型槽壳模型。在弯矩作用下，通过预留角裂纹模拟角裂纹扩展，在模拟过程中产生两个应力场不同的裂纹尖端。研究结果表明，该方法对裂纹R型槽壳有效，对求解三维构件上的复杂应力强度因子具有普遍适用性。