含大开口复合材料结构损伤与渐进失效的近场动力学模拟及其验证

Existence of large cutout in load bearing composite structure is generally to satisfy functional requirements. Damage and progressive failure issues due to the presence of large cutout are difficulties and major concerns in the research of this kind of structure. In this project, a nonlocal, meshfree type state based Peridynamic(PD) laminate theory will be investigated and applied to simulate the process from damage propagation to final failure of composite laminate with large cutout. Nonordinary state based Peridynamic theory will be developed to build its relationship with classical damage theory/criteria. To improve the computation efficiency, a combined techique of parallel computation, modular modeling and method of PD-FEM coupling will be developed. To further verify the accuracy and completeness of PD code, experiments on composite laminate with cutouts of various kinds of shapes, sizes are to be carried out under different loading conditions, experimental results will be the foundation of correction of micromodulus of PD bonds, and will be the support of criterion of effective damage propagation. Outcomes of the project will provide theoretical basis and numerical simulation platform for analysis and recurrence of damage propagation in composite laminate structure with large cutout, and promote the capability of PD in analyzing practical structures in engineering field.

大开口在承力复合材料结构中因功能需要而存在。由大开口引起的损伤和渐进失效问题是该类结构的研究难点和热点。本项目将采用非局部无网格形式的态型近场动力学复合材料层合板理论（PDLT）来模拟含大开口复合材料结构损伤扩展至失效的全过程。利用非常规形式的PD理论建立与传统损伤理论之间的联系，应用不同形式的复合材料本构模型，进一步揭示大开口在复合材料结构失效模式中的影响规律。为提高计算效率，通过并行加速、模块化建模及PD与有限元方法耦合相结合的方式进行对比计算。为了验证程序的准确性与完整性，进行不同载荷、开口形状、尺寸复材结构试验，试验结果既为PD模型中键常数的修正依据，也是模拟损伤扩展路径有效性的判据。本项目得以完成，将会为分析和重现该类结构的损伤扩展过程提供理论依据和数值模拟平台，有效提高近场动力学理论的工程实用性。

本项目主要利用近场动力学理论（Peridynamics，PD）进行含开口复合材料结构的损伤和失效研究。在理论研究方面，建立了全新的面基型非常规态PD理论，不仅具备传统非常规态型PD理论全部的理论优势，还能有效避免零能模式问题；针对复合材料平面外弯扭变形特征，建立了Kirchhoff板复合材料PD理论；此外，建立了复合材料格子型PD理论，能同时兼顾数值精度与计算效率两大优势。在算法研究中，建立了复合材料单层物质点模型与有限元和PD耦合模型，单层物质点模型用单层PD物质点表征多层复合材料的力学特征，能有效提升数值模型的计算效率；有限元和PD耦合模型只包含极少数PD物质点，而且能根据转换准则自适应生成PD区域，避免了推断损伤区域带来的数值误差问题。对含开口复合材料结构，主要研究了不同开口形式对失效模式的影响，并进一步研究了含冲击缺陷复合材料结构的损伤模式。本项目得以完成，在一定程度上推动了PD理论和数值算法的发展，并为复合材料工程应用提供了理论依据。