弹塑性层合膜结构的屈诱多态失稳力学行为研究

The wrinkle-induced delamination is the major failure mode of laminated membrane structures under compression. The challenge in the theoretical analysis is how to elucidate accurately the polymorphic instability and the coupled effects of post-wrinkled modes. The study is focused on the polymorphic buckling behavior of laminated membrane structures under compression. The theoretical and experimental studies are performed on three key contents, the interactive buckling, the wrinkle-induced plastic ratching, and the wrinkle-induced delamination. Firstly, the interactive buckling control equations of elastic laminated membrane structure are established to analyze the post-wrinkled bifurcation, and to elucidate the interactive mechanism between the wrinkles and the other instability modes. Secondly, an elastoplastic buckling model of laminated membrane structure under cyclic compression is established to determine the critical conditions of surface wrinkling and plastic ratching. Based on this theoretical model, the post-wrinkled analysis is performed to track the post-wrinkled polymorphic instability modes and to elucidate the interactive effects on the wrinkles. Thirdly, the control equations of wrinkle-induced delamination of laminated membrane structure are established to search the post-wrinkled bifurcation path and the critical delamination condition. Based on this mechanical model, the nonlinear analysis is performed to understand the delamination growth and its interactive effects on the polymorphic instability modes. Finally, the polymorphic instability of laminated membrane structure is experimentally tested which is also used to verify the validation of proposed theoretical models. The tested results combined with the simulated results to deeply elucidate the polymorphic instability mechanism in the end. Several possible novel achievements will be obtained from the theoretical and experimental studies on the polymorphic instability mechanism of laminated membrane structures. These studies and results will provide a significant support to consolidate the stability theory of membrane structures.

屈诱分层鼓包是层合膜结构承压的主要失效模式，屈后失稳模式的多态化及其耦联性是理论分析中的难点。本项目主要开展层合膜结构屈诱多态失稳力学行为的理论和试验研究，重点解决相关失稳、屈诱棘轮和屈诱分层三个核心问题。首先，建立层合膜结构弹性相关失稳力学理论模型，分析屈后多级分叉力学行为，阐释褶皱演化及其与其他失稳模式的耦联机制；然后，建立弹塑性层合膜结构的失稳力学理论模型，判定褶皱与棘轮产生条件，分析屈后多态失稳模式转变、演化及其与褶皱的耦联性；之后，建立弹塑性层合膜结构屈诱分层力学理论模型，确立屈后多态失稳与分层的判定条件，分析分层的扩展演化及其与多态失稳模式的耦联关系；最后，进行层合膜结构屈诱多态失稳力学行为的试验测试，验证理论分析的可靠性，联合数值分析揭示屈后多态失稳模式的耦联机制。本项目拟在屈后多态失稳耦联机制的理论与试验分析方法方面取得创新性成果，为丰富薄膜结构稳定性基础理论研究奠定基础。

屈诱分层鼓包是层合膜结构承压的主要失效模式，屈后失稳模式的多态化及其耦联性是理论分析中的难点。本项目主要开展了层合膜结构屈诱多态失稳力学行为的理论和试验研究，重点解决了相关失稳、屈诱棘轮和屈诱分层三个核心问题。首先，对于层合膜结构的弹性相关失稳问题，建立了同时考虑局部褶皱与整体失稳的层合膜结构相关屈曲控制力学模型，确立了相关屈曲控制方程的数值求解方法；分析得到了局部与整体屈曲的临界条件，追踪得到了屈后多级分叉点与分叉平衡路径；分析得到了屈后褶皱演化及其与整体失稳的耦联机制；研究评估了基底各向异性以及双向应力条件对结构相关失稳行为的影响。然后，针对弹塑性层合膜结构的屈诱棘轮问题，建立了层合膜结构弹塑性失稳控制方程，确定了屈曲方程的数值求解方法；建立了弹塑性层合膜结构褶皱与塑性棘轮产生的条件；研究得到了弹塑性层合膜结构的压诱皱曲特性，分析了循环加载下弹塑性层合膜结构的棘轮行为；揭示了弹塑性层合膜结构屈诱多态失稳模式转变、演化与耦联机制。之后，针对弹塑性层合膜结构的屈诱分层问题，建立了弹塑性层合膜结构屈诱分层力学理论模型，确立了方程的数值求解方法；确立了屈后多级分叉与分层的判定条件；得到了预制分层对结构相关失稳行为的影响规律；揭示了屈后分层的扩展演化及其与多态失稳模式的耦联机制。研究成果发表在JMPS和IJSS等SCI检索刊物共24篇，学术会议文章12篇。授权国家发明专利9项。相关成果整理出版专著2部。本项目拟在多模式耦合失稳的理论方法方面取得创新性成果，为丰富薄膜结构稳定性基础理论研究奠定基础。