Experimental and numerical investigations of laminated, fibre reininforced plastics under crash loading

碰撞载荷下层压纤维增强塑料的实验和数值研究

• 批准号: 404502442
• 负责人: Professor Dr.-Ing. Christian Hopmann
• 金额: --
• 依托单位: Institut für Kunststoffverarbeitung (IKV) in Industrie und Handwerk an der RWTH Aachen
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/404502442?language=en
• 关键词: Experimental; numerical; investigations; laminated; fibre

The dimensioning of carbon fibre reinforced plastics (CFRP) can achieve a high accuracy based on quasi-static material properties and material models for static loads. The use of CFRP in crash relevant applications requires the consideration of the strain rate dependency of the mechanical properties, which is particularly pronounced for polymer matrices. Known strain rate effects are for example the embrittlement and hardening at impact loading. Goal of the project is the generation of new findings in damage mechanisms and evolution in unidirectional reinforced CFRP (UD-CFRP) laminates under impact loading and their numerical representation on components scale. Additionally, the development of robust testing methods and an RVE serve the needs for reliable scientific results concerning strain rate dependent material properties.In this project, adequate test methods will be developed, which enable a reliable determination of the mechanical properties of UD-CFRP at crash relevant strain rates. The material behaviour under highly dynamic loading will be modelled and understood on this basis using a multiscale modelling approach.The input parameters for the material models will be determined from highly dynamic tests with neat resin und unidirectional reinforced specimens in the entire relevant strain rate spectrum. An existing drop weight tower will be used for this purpose, which requires the development of fixtures, specimen geometries and the adaptation of suitable measurement instrumentations.A representative volume element (RVE) incorporating fibre, matrix and the interface will be used to investigate the material behaviour on the micro scale. This RVE provides on the one hand knowledge in strain rate effects and, on the other hand, its suitability for the numerical generation of mechanical properties will be investigated. Furthermore, a continuum mechanical description of UD-CFRP is aspired to represent the strain rate dependent, anisotropic material behaviour on the meso scale. The representation of plasticity and damage evolution is a key aspect here. Based on this, a macro model will be set up, which uses the mentioned continuum mechanical model. Investigations of the delamination behaviour of laminates under impact loading are used to develop a finite element formulation, which includes multiple laminate layers and also the consideration of delamination effects in a single element. A validation of the macro model will be performed with numerical and experimental investigations of a demonstrator part.

碳纤维增强塑料（CFRP）的尺寸标注可以基于准静态材料特性和静态载荷的材料模型实现高精度。CFRP在碰撞相关应用中的使用需要考虑机械性能的应变率依赖性，这对于聚合物基体尤其明显。已知的应变率效应是例如在冲击载荷下的脆化和硬化。该项目的目标是在冲击载荷下单向增强CFRP（UD-CFRP）层合板的损伤机制和演变及其在组件尺度上的数值表示产生新的发现。此外，稳健的测试方法和RVE的发展服务于对应变率相关材料性能的可靠科学结果的需求。在本项目中，将开发适当的测试方法，从而能够可靠地确定UD-CFRP在碰撞相关应变率下的机械性能。在此基础上，采用多尺度建模方法，对材料在高动态载荷下的行为进行建模和理解。材料模型的输入参数将通过在整个相关应变率谱中对纯树脂和单向增强试样进行高动态测试来确定。现有的落锤塔将用于此目的，这需要开发夹具，试样的几何形状和合适的测量仪器的适应。一个代表性的体积元（RVE）包括纤维，基质和界面将被用来研究微观尺度上的材料行为。该RVE一方面提供了应变率效应方面的知识，另一方面，将研究其对力学性能数值生成的适用性。此外，一个连续的力学描述UD-CFRP渴望代表应变率相关的，各向异性材料的细观尺度上的行为。塑性和损伤演化的表示是这里的一个关键方面。在此基础上，建立了一个宏观模型，该模型采用上述连续介质力学模型。研究了冲击载荷作用下层合板的脱层行为，建立了一种有限元公式，它包括多层合板，并在单个单元中考虑了脱层效应。验证的宏观模型将进行数值和实验研究的演示部分。