The stress-intensity factors of box beams under torsion and crack propagation under torsion or/and bending moment are discussed here. This study is motivated by a previous work [1] that derived a closed-form expression of the mode II stress-intensity factor for thin-walled beams with a centered longitudinal crack and subjected to torsion. Naturally, the way in which mode I stress-intensity factors are influenced by torsion is of interest. The influence of parameters such as crack length, crack angle, width and depth of beam, wall thickness, and stiffener size on mode I and mode II stress-intensity factors has been studied using the finite element method and represented the data in a surrogate model using two approaches: 1) a Fourier-series-based correction factor, and 2) an artificial neural network. The crack propagation is also of interest. Specifically, the crack propagation study focuses on both the limit loadings and the angle in which the initial crack growth occurs.

本文讨论了箱形梁在扭转作用下的应力-强度因子以及在扭转或/和弯矩作用下的裂纹扩展。这项研究是基于先前的工作[1]的，该工作得出了具有中心纵向裂纹并受到扭转的薄壁梁II型应力强度因子的闭式表达式。自然地，模式I应力强度因子受扭转影响的方式很有趣。使用有限元方法研究了裂纹长度，裂纹角度，梁的宽度和深度，壁厚以及加劲肋尺寸等参数对模式I和模式II应力强度因子的影响，并将其表示为替代模型中的数据使用两种方法：1）基于傅立叶级数的校正因子，以及2）人工神经网络。裂纹扩展也很重要。