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.

基于准静态材料特性和静载荷下的材料模型，碳纤维增强塑料(CFRP)的尺寸标注可以达到很高的精度。在碰撞相关应用中使用CFRP需要考虑力学性能的应变率依赖关系，这一点对于聚合物基质尤为明显。已知的应变率效应例如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碳纤维复合材料(UD-CFRP)层合板的损伤机理和演化方面产生新的发现，并在部件尺度上进行数值表示。此外，稳健测试方法和RVE的发展满足了关于应变率相关材料性能的可靠科学结果的需要。在该项目中，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力学性能。材料在高动态载荷下的行为将在此基础上采用多尺度模拟方法进行模拟和理解。材料模型的输入参数将从整个相关应变率谱中的纯树脂和单向加筋试件的高动态试验中确定。为此，将使用现有的落锤塔，这需要开发夹具、试件几何形状和适当的测量仪器。将使用包含纤维、基质和界面的代表性体积元素(RVE)来研究材料在微观尺度上的行为。这种RVE一方面提供了应变率效应方面的知识，另一方面也将研究它在力学性能数值生成中的适用性。此外，UD-CFRP的连续介质力学描述被期望在细观尺度上描述与应变率相关的各向异性材料行为。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，利用所建立的连续介质力学模型建立了宏观模型。通过对层合板在冲击载荷作用下的分层行为的研究，建立了包括多个层合层的有限元列式，并在单个单元中考虑了分层效应。宏观模型的验证将通过对演示部件的数值和实验研究来完成。