基于动态显式分析的复合材料盒段失效模拟

Failure simulation of composite box based on dynamic explicit finite element analysis

为了研究复合材料结构失效过程并为强度设计提供分析依据,对结构进行失效模拟。在静态隐式分析中,材料的失效和破坏常常导致严重的不收敛。针对复合材料多墙盒段结构,采用动态显式分析方法对弯曲载荷工况进行了试验模拟。壁板和墙均采用层壳元,在上壁板中面嵌入一层体元模拟层间失效,利用用户自定义材料(VUMAT)的方法对材料性能进行连续衰减,并进行渐进式失效分析。分析表明,动态显式分析避免了不收敛问题,能比较准确地模拟复合材料盒段的失效过程,无论是应变、屈曲载荷、破坏载荷,还是破坏形式,分析结果均与试验结果吻合较好,屈曲载荷、破坏载荷的预测值与试验结果误差在7%以内。表明本文方法可以满足工程设计和分析要求。

In order to investigate the mechanism of composite failure so as to provide analysis basis for strength designing, structure failure simulation is necessary. In the process of static general failure analysis, material decay often causes severe convergence problems. Dynamic explicit analysis can well model material breakage. In this paper, the mechanical response of multi-wall box under bending load case is simulated using dynamic explicit analysis method. Panel and wall are modeled with shell element. A solid geometry is introduced to the half-thickness of the up-panel to simulate inter-laminar damage. The VUMAT subroutine is adopted to degrade material stiffness consecutively while damage occurred. It is shown that dynamic explicit analysis can well simulate the damage process of the box. Analysis results including strain, buckling load, failure load and collapse mode are in good agreement with test results. The errors of predicted buckling load and failure load are within 7%, which shows the method is satisfactory to engineering design.