Short-term dynamic stress-strain behavior of textile high-performance materials

在纤维基材料和工业纺织品在重载领域的应用日益广泛的背景下，纤维材料在快速应变下的力学性能问题正逐渐成为人们关注的焦点。这种应变在防弹纺织品中很常见，但也出现在纤维增强材料(纤维增强塑料复合材料、纺织混凝土)暴露在冲击应变下的复合材料中。现有的纯高性能纤维材料，特别是玻璃纤维(GF)、碳纤维(CF)和芳纶(AR)长丝的拉伸强度特性主要是指在静态和准静态载荷下的行为，因为没有可靠的试验台和方法来满足这些样品在高应变速度下的特殊要求，可以在短期动态应变下进行测试。该项目的目的是开发一种测试方法，以可靠和可重复的方式测试浸渍和未浸渍的高性能长丝，特别是GF、CF和AR长丝在纤维纵向上的膨胀率相关的长丝强度和硬度。ITM设想的测试方法是利用现有的跌落试验台，考虑到纺织高性能长丝的要求以及相应更高的测试速度和高达100 S-1的膨胀率。在此基础上，开发了一个专门的试验站，用于分析S-1到1000的膨胀率范围，该试验站基于旋转传动，并根据这些特殊要求进行了定制，包括进一步开发和集成力和距离测量技术。此外，还将为基于威布尔强度分布的高性能长丝在拉伸应变下与膨胀率相关的力学材料性能的分析描述奠定基础。此外，系统地确定了与膨胀率相关的材料参数抗拉强度、刚度和吸能能力，并用解析本构方程进行了描述。这些规律是建模纺织高性能材料在短期动态冲击应变下的局部和全球力学行为的重要基础，特别是对于部件设计中必不可少的失效情况，以便为高弹性高性能纤维材料和结构的有理有据的、以冲击为导向的开发、建模和模拟以及随后的应用可能性创造决定性的先决条件。

In the context of an expansion of applications of fiber-based materials and technical textiles in heavy duty fields, the question of mechanical properties of fiber materials under fast-acting strains is gradually gaining center stage. Such strains are common in ballistic protection textiles, but also occur in composite materials with fiber reinforcements (fiber-reinforced plastic composites, textile concrete) exposed to impact strains. The existing tensile strength characteristics for pure high-performance fiber materials, particularly fiberglass (GF), carbon fiber (CF), and aramid (AR) filament yarns, refer largely to the behavior under static and quasistatic load, as no reliable test benches and methods designed to meet the special requirements of such samples under high strain velocities are available for tests under short-term dynamic strain. The aim of the project is the development of a testing method for expansion rate-dependent filament yarn strengths and stiffnesses of impregnated and non-impregnated high-performance filament yarns in the fiber longitudinal direction, especially GF, CF, and AR filament yarns, in a reliable and reproducible manner. A testing methodology conceived at ITM, using an existing drop test rig, is developed further with the requirements of textile high-performance filament yarns and the correspondingly higher testing speeds and expansion rates of up to 100 s-1 in mind. Building on the findings, a special test station for the analysis of the further expansion rate range to 1000 s-1 is developed, based on a rotary drive and customized to these special requirements and including the further development and integration of force and distance measurement technology.Additionally, the groundwork is to be laid for an analytical description of the expansion rate-dependent mechanical material properties of the high-performance filament yarns under tensile strain, based on a Weibull strength distribution. Additionally, the expansion rate-dependent material parameters tensile strength, stiffness and energy absorption capability are determined systematically and described by analytical constitutive equations. These regularities are a substantial basis for the modeling of the local and global mechanical behavior of textile high-performance materials at short-term dynamic impact strains, particularly for the failure case essential in component design, in order to create the decisive prerequisites for well-founded, impact-oriented developments, modelings and simulations of highly resilient high-performance fiber materials and structures and the consequent application possibilities.