海上运货6t吊笼结构的设计研究

Study of structure design of 6t sea cage

采用基于梁壳单元组合结构和三维单元的有限元法对海上运货6 t吊笼进行了静力分析和模态分析。数值模拟研究发现原设计的由钢管、槽钢、角钢和H型钢组成的吊笼框架结构满足强度和刚度要求,但是底板变形较大,已经接近或超过底板的厚度。计算结果表明:采用壳单元计算底板的应力和变形约为采用实体单元计算结果的1.5倍;采用三维实体单元时,单元边长比从10∶1变为2.5∶1时对变形的影响相对较小,位移相对误差低于3%,但是对应力的影响较大,等效应力的相对误差高达56%。通过增加底盘的加强筋,可以降低底板变形和底盘等效应力。

The static and modal analysis for 6 t sea cage is conducted using both beam shell elements and the 3-dimensional element.Numerical results have shown that the frame of the cage,which consist of tube,angle steel and H-shaped steel,meets the requirements of strength and stiffness but the maximum displacement of the bottom plate is close to the thickness of the plate,meanwhile the results also show that the stress and deflection of bottom plate by the shell element are about 1.5 times to the those by the 3 D solid element.Parameter study shows that the edge length ratio of element influences the results directly,the relative error of displacement is less than 3% when the element edge length ratio change from 101to 2.51,however,the relative error of von Mises stress is close to 56%.Adding ribs to the chassis can help to decrease the stresses of both bottom plate and chassis.