层压复合材料分层扩展分析的虚拟裂纹闭合技术及其应用

Virtual crack closure technique for delamination growth analysis of laminated composites and its application

提出一种基于虚拟裂纹闭合技术的界面元模型,用以模拟复合材料的分层破坏和预测结构的承载能力。界面元被嵌入在模型分层扩展路径上,计算结构的能量释放率,结合幂指数破坏准则,模拟复合材料的分层扩展。对由于裂尖单元长度不同所带来的分析误差进行了适当的修正,以降低网格粗细变化所带来的不利影响。为了检验该界面元的可靠性,分别将其应用于对双悬臂梁(DCB)模型、端边切口(ENF)模型和混合模式弯曲(MMB)模型的分层扩展分析中。计算结果与解析解基本吻合,从而验证了采用该界面元模拟复合材料分层破坏的可行性。用该方法对3个含有不同初始损伤复合材料T型接头的界面拉脱分层破坏进行数值模拟,计算结果与试验数据吻合良好。

An interface element model based on the virtual crack closure technique（VCCT） was introduced to study the 2D delamination growth problem and predict the loading capacity of laminated composites.The interface elements were embedded along the potential crack path in advance to calculate the strain energy release rate and simulate the delamination growth of laminated composites in conjunction with the power law fracture criteria.The numerical errors induced by the different lengths of the elements at the crack tip had been corrected to minimize the negative effect of change in mesh density on numerical results.The double cantilever beam（DCB）,end notch flexure（NEF） and mixed mode bending（MMB） models were taken to validate this approach.The results of the FE simulation agree well with the analytical solutions.It confirms that the approach is reliable and feasible for modeling the delamination growth in laminated composites.Three composite T-joints with different flaws were numerically simulated with the interface elements.Excellent agreement was found between the numerical results and the experimental data.