Abstract

This paper puts forward a new method to predict the bearing strength of single bolt joint based on characteristic length method (CLM) and progressive damage model (PDM). Instead of performing the whole campaign of PDM-based CLM on whole structure of joint, the characteristic length and stress distribution of the sub-laminates obtained by dividing the original laminate are used. Stress gradient along the thickness, which is caused by the secondary bending effect of single-lap joint, can be taken into consideration. 3D progressive damage models are established for obtaining the bearing response of sub-laminate with emphasis on fiber kinking theory, where an interpolation algorithm is adopted to find the kinking plane and corresponding kinking angle. Both numerical models and experiments are utilized to verify our scripts of new method. It is concluded that the bending effect can be successfully considered and the proposed method shows advantages for the structural design of mechanically joints.

• Highlights

• A new method is put forward by dividing the original laminate into sub-laminates to account for secondary bending effect.

• A progressive damage model based characteristic length method is employed to predict failure of each sub-laminate.

• The kink band theory is used for the interpretation of the mechanism of fiber compressive damage and a zero-thickness cohesive method is used for interlaminar damage.

• An interpolation algorithm is adopted to find the kinking plane while a graphic method is used to obtain the kinking angle.

摘要

提出了一种基于特征长度法（CLM）和渐进损伤模型（PDM）的单螺栓接头承载强度预测新方法。不是对接头的整个结构执行基于 PDM 的 CLM 的整个运动，而是使用通过分割原始层压板获得的子层压板的特征长度和应力分布。可以考虑由单搭接接头的二次弯曲效应引起的沿厚度方向的应力梯度。建立3D渐进损伤模型以获得子层压板的承载响应，强调纤维扭结理论，其中采用插值算法找到扭结平面和相应的扭结角度。数值模型和实验都用于验证我们的新方法脚本。

• 强调

• 提出了一种新的方法，将原始层板划分为子层板，以解决二次弯曲效应。

• 采用基于渐进损伤模型的特征长度方法来预测每个子层压板的失效。

• 扭结带理论用于解释纤维压缩损伤的机理，零厚度内聚法用于层间损伤。

• 采用插值算法寻找扭结平面，采用图解法获得扭结角。