Development of failure criteria of thin shells and fabrics based on multiscale modeling and peridynamic

近年来，由高强度、轻质纤维制成的平纹编织织物已用于各种工程应用中，软防弹衣、飞机机身屏障）到高性能柔性系统（例如，降落伞、气囊和帆）。特别是，具有极高强度重量比的织物材料，如Kevlar和Zylon，正在迅速成为弹道冲击和穿透技术的支柱。织物的机械性能主要取决于其底层的微观结构，而微观结构又由单组分纱线的材料性能和织物编织的几何形状决定。在这项工作中，申请人将继续开发多尺度模型来预测织物材料的失效和损伤机制。在安全应用中使用的织物的故障将具有灾难性的结果。申请人先前表明，多尺度方法适用于分析织物材料中的变形和应力。多尺度模型提供了底层微观结构的详细应力状态，在织物由机织纱线制成的情况下。这项工作的结果将允许设计基于织物的更安全，更轻的系统。建立材料和结构力学行为的理论模型具有重要意义。从工程的角度来看，理论模型可以让设计师更好地理解发生的重要现象。因为理论模型使用数学作为一种语言，它不受物理限制。使用数学模型允许设计者测量实验中无法测量的量。数学模型允许寻求对设计的优化的鲁棒过程。此外，理论研究的成本很小，因为理论模型的发展将随后仅使用计算机进行数值模拟。当理论和数值研究达到成熟时，应与实验研究相结合。实验研究的成本显着降低，因为大部分的分析已经进行了数值计算。

In recent years, plain woven fabric made of high strength, lightweight fiber has been utilized in a variety of engineering applications ranging from ballistic shields (e.g., soft body armor, aircraft fuselage barriers) to high-performance flexible systems (e.g., parachutes, airbags and sails). In particular, fabric materials with extremely high strength-to-weight ratio, such as Kevlar and Zylon, are rapidly becoming mainstays in ballistic impact and penetration technologies. The mechanical properties of fabric depend crucially on the underlying microstructure, which is determined by the material properties of single constituent yarns and the geometry of the fabric weaving. In this work, the applicant will continue to develop a multi-scale model to predict the failure and damage mechanism of fabric materials. A failure of fabric used in safety applications will have catastrophic results. It was previously shown by the applicant that the multi-scale approach is applicable for analyzing deformation and stresses in fabric material. The multi-scale model provides a detailed stress state of the underlaying microstructure which in the case of fabric is made of woven yarns. The results of this work will allow to design a safer and lighter systems based on fabrics. The development of a theoretical model for mechanical behavior of materials and structure has significant importance. From the engineering point of view a theoretical model allows a designer a better understanding of the important phenomena taking place. Since a theoretical model use mathematics as a language which is free of physical limitation. Using a mathematical model permits the designer to measure quantities which cannot be measured in experiment. A mathematical model permits robust process of seeking optimization to the design. Moreover, the cost of theoretical investigation in small, since the development of a theoretical model will be followed by numerical simulations using only computers. When the theoretical and numerical studies reach maturity it should be integrated into experimental study. The cost of the experiment research is significantly reduced since large portion of the analysis was already performed numerically.