基于近场动力学的超高韧性水泥基复合材料动态失效的多尺度模拟及验证

Peridynamics (PD) is a recently developed theory in solid mechanics that employs a nonlocal model of force interaction, and replace the partial differential equations by an integral operator that sums up internal forces separated by finite distances. Peridynamics offers some advantage compared with FEM-based models, but the PD model for dynamic failure of Engineered Cementitious Composites (ECC) is still scarce. In this proposal, a multi-scale PD model will be built to describe the heterogeneous long-range and short-range interactions between materials points in ECC based on theoretical analysis and experimental observations, and which can also describe the macro-scale mechanical behavior of ECC. The proposed multi-scale PD model will correlate the parameters in PD constitutive models with the key characterized meso-scope material constants to analyze the quantitative deformation as well as the dynamic damage accumulation and failure process of ECC and its structures. The proposed numerical model will be validated through meso-test, fatigue and impact tests to investigate the inner system between the macro-scope mechanical behavior and the dynamic failure. It will enrich the existed mechanics theory of inhomogeneous materials and shed the new light on the development of ECC and the multi-phase composites.

近场动力学（Peridynamics，PD）是一种新兴的基于非局部作用思想数值计算方法，在分析材料与结构的动态断裂问题方面与其他数值计算方法相比有很大的优势，但目前还缺乏基于该理论的超高韧性水泥基复合材料（ECC）动态失效多尺度模型。本项目针对ECC，运用PD方法，构建既考虑ECC细观非均质、多相特征以及同/异相组分间的长、短程作用和界面效应，又能反映其宏观力学特性的宏细观多尺度PD分析模型，分析PD模型参数与非均质材料细观结构特征参数之间的内在联系，实现ECC动态破坏行为的全过程模拟，并结合相关微观、疲劳及冲击载荷试验，分析材料宏观力学特性与动态破坏的内在机制。成果将丰富现有非均质材料的力学理论，为高性能水泥基复合材料及类似多相复合材料的研发提供科学依据。

本项目以绿色环保和建筑资源回收再利用为目标，使用再生砖粉、再生混凝土粉和再生玻璃粉三种建筑再生微粉分别用于取代ECC中的细骨料和部分水泥，以制备生态型ECC。本项目系统研究了分别采用再生砖粉、再生混凝土粉、再生组合微粉（再生砖粉和再生混凝土粉按1：1比例混合而成）取代ECC材料中的细骨料石英砂，以及再生玻璃粉部分取代水泥所得多种类型生态型ECC基本力学性能以及微粉种类、掺量等对于ECC拉伸行为和基本力学性能的影响，结果表明在组合微分全取代石英砂的情况下，玻璃微粉取代水泥不超过30%时，所制备生态型ECC的各项力学性能指标均能满足要求。.本项目基于PD方法构建了考纤维影响的ECC材料的半离散模型，为了消除PD方法中的表面效应，基于能量等效构建了分析ECC粘结结构的界面模型，采用所构建模型分别研究了多种ECC和梯度ECC结构在冲击载荷、冲切载荷、双轴载荷、冲切等多种载荷作用下的动态失效和裂纹扩展行为，讨论了纤维掺量、缺陷尺寸及位置等对ECC结构破坏行为的影响。结果表明所构建的模型在分析ECC结构动态破坏行为方面是有效的，相比与其他数值分析方法有一定的优势。