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机织织物已被用于各种工程应用，从防弹盾(例如，软体装甲、飞机机身护栏)到高性能柔性系统(例如，降落伞、安全气囊和帆)。特别是，具有极高强度重量比的织物材料，如凯夫拉和赛隆，正迅速成为弹道冲击和侵彻技术的支柱。织物的力学性能在很大程度上取决于织物的微观结构，而微观结构由单组分纱线的材料性能和织物织造的几何形状决定。在这项工作中，申请者将继续开发多尺度模型来预测织物材料的失效和损伤机理。安全应用中使用的织物发生故障将产生灾难性的后果。申请人先前已经证明，多尺度方法适用于分析织物材料的变形和应力。多尺度模型提供了衬底微观结构的详细应力状态，在织物由机织纱线组成的情况下。这项工作的结果将允许设计出更安全、更轻的基于织物的系统。建立材料和结构力学行为的理论模型具有重要意义。从工程学的角度来看，理论模型使设计者能够更好地理解正在发生的重要现象。因为理论模型使用数学作为一种不受物理限制的语言。使用数学模型允许设计者测量在实验中无法测量的量。数学模型允许对设计进行稳健的优化过程。此外，理论研究的成本很小，因为在开发理论模型之后，将只使用计算机进行数值模拟。当理论和数值研究成熟时，应将其整合到实验研究中。实验研究的成本大大降低，因为很大一部分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.