船体结构有限元建模中实体单元与板壳单元连接技术

Discussion and Verification of Shell-Solid Element Connection Mode in Ship Finite Element Model

船体有限元模型普遍采用板壳(shell)单元离散,而某些大厚度局部结构形状复杂,需采用实体(solid)单元模拟。在Patran软件中,对这2种单元进行简单的节点耦合会出现自由度不匹配的问题,进而导致求解错误,故对这2种单元的连接技术进行研究尤为必要。对变厚度对接平板进行全solid单元建模计算,通过与文献结果相对比,验证数值模拟的正确性;引入复合单元法、MPC-RSCCON和MPC-Rigid3种连接技术,在不同载荷作用下对比分析结构响应;对各连接技术中的相关控制参数进行敏感性分析。结果表明,3种方法在特定条件下均能较好地实现有限元模型中shell单元与solid单元的合理连接,其中MPC-Rigid的精度更高、操作更为方便,建议在船体结构有限元建模中采用MPC-Rigid进行shell单元与solid单元的连接。

Shell element is widely used to discretize the finite element model of ship hull.However,some local structures with large thickness have complex shapes,which need to be simulated by solid elements.In Patran software,simple node coupling of the two elements will lead to the problem of degree of freedom mismatch,and then the solution error will occur.Therefore,it is necessary to study the connection technology of the two elements.The full solid element modeling calculation is carried out for the butt joint plate with variable thickness,and the correctness of the numerical simulation is verified by comparing with the results in the literature.Composite element method,MPC-RSCCON and MPC-Rigid are introduced to analyze and compare the structural response under different loads.The sensitivity analysis of the relevant control parameters in each connection technology is carried out.The results show that all of the three methods can achieve the reasonable connection of shell element and solid element in finite element model under specific conditions.Among them,MPC-Rigid is more accurate and easier to operate,and thus MPC-Rigid is suggested to be used to connect shell element and solid element in finite element modeling of hull structure.