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载荷材料模型实现高精度。在碰撞相关应用中使用 CFRP 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。已知的应变率效应例如是冲击载荷下的脆化和硬化。该项目的目标是在单向增强 CFRP (UD-CFRP) 层压板在冲击载荷下的损伤机制和演变及其在组件规模上的数值表示方面产生新的发现。此外，稳健的测试方法和 RVE 的开发满足了有关应变率相关材料性能的可靠科学结果的需求。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 的机械性能碰撞相关应变率。在此基础上，将使用多尺度建模方法对高动态载荷下的材料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使用纯树脂和单向增强样本进行的高动态测试来确定。现有的落重塔将用于此目的，这需要开发固定装置、样品几何形状以及适应合适的测量仪器。将使用包含纤维、基体和界面的代表性体积单元 (RVE) 来研究材料微观尺度上的行为。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机械性能数值生成的适用性。此外，UD-CFRP 的连续力学描述旨在表示细观尺度上依赖于应变率的各向异性材料行为。可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，建立宏观模型，该模型采用上述连续介质力学模型。对冲击载荷下层压板分层行为的研究用于开发有限元公式，其中包括多个层压板层以及单个单元中的分层效应的考虑。宏观模型的验证将通过演示部件的数值和实验研究来进行。