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

随着纤维基材料和产业用纺织品在重型领域的应用不断扩大，纤维材料在快速应变下的力学性能问题逐渐成为焦点。这种应变在防弹纺织品中很常见，但也发生在暴露于冲击应变的纤维增强复合材料（纤维增强塑料复合材料，纺织混凝土）中。纯高性能纤维材料，特别是玻璃纤维（GF）、碳纤维（CF）和芳族聚酰胺（AR）长丝纱线的现有拉伸强度特性主要涉及静态和准静态载荷下的行为，因为没有可靠的测试台和方法可用于短期动态应变下的测试，这些测试台和方法设计用于满足高应变速度下此类样品的特殊要求。该项目的目的是以可靠和可重复的方式开发一种测试方法，用于测试浸渍和非浸渍高性能长丝纱在纤维纵向方向上的膨胀率相关长丝纱强度和刚度，特别是GF，CF和AR长丝纱。在ITM使用现有的跌落试验台构思的测试方法进一步发展了纺织高性能长丝纱线的要求以及相应的更高测试速度和高达100 s-1的膨胀率。在此基础上，开发了一个特殊的测试站，用于分析1000 s-1的进一步膨胀率范围，该测试站基于旋转驱动器，并根据这些特殊要求进行定制，包括进一步开发和集成力和距离测量技术。将为高性能长丝纱在拉伸应变下的膨胀率相关的机械材料性能的分析描述奠定基础，基于威布尔强度分布。此外，膨胀率相关的材料参数的拉伸强度，刚度和能量吸收能力进行了系统的确定和描述的解析本构方程。这些测试是纺织高性能材料在短期动态冲击应变下的局部和整体力学行为建模的重要基础，特别是对于组件设计中必不可少的失效情况，以便为有根据的，以冲击为导向的开发创造决定性的先决条件，高弹性高性能纤维材料和结构的建模和仿真以及随之而来的应用可能性。

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.