克令吊基座的局部加强结构优化设计研究(续)

采用结构有限元方法,对某型克令吊底部加强结构的小肘板结构进行了不同方案的优化分析及计算,依据其结构特点,在前期工作的基础上,对小肘板的软硬度设计优化方案进行了具体的结构强度分析和比较,为以后克令吊底部加强结构的优化设计分析工作提供进一步的参考。     

A ductile tearing assessment diagram for cracked circular-hollow-section joints under reversed loadings

This paper proposes a ductile tearing assessment diagram (TAD) to predict the load resistance to the crack extension relationship during the stable tearing process of the circular-hollow-section (CHS) joints under the reversed in-plane bending actions. The tearing assessment diagram utilizes the envelope of the load-deformation curve from the fracture test under reversed loadings to build the connection among the fracture resistance, load resistance and crack extension. To verify the proposed approach, this study performs fracture experiments, imposing the reversed in-plane bending on the CHS X-joints, made of Q345 steel, with a surface crack near the weld toe. The experimental investigation reveals the effect of the reversed loading on the fracture resistance and validates the TAD-based assessment for tubular joints. Meanwhile, this study performs the cyclic fracture test on the single-edge-notched-tension [SE(T)] specimen made of Q345 steel and derives the TAD from the experimental record of the SE(T) specimen. The specimen-based assessment successfully predicts the load versus crack extension relation for the reported joints under reversed loadings. The study provides a basic framework to predict the joint response under reversed loadings by integrating the material fracture characteristics.