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Experimental and virtual analysis of draping effect and of their impact on the structural mechanical behaviour of composite components

悬垂效应及其对复合材料部件结构力学行为影响的实验和虚拟分析

基本信息

批准号：
287275762
负责人：
Professor Dr.-Ing. Maik Gude
金额：
--
依托单位：
Institut für Leichtbau und Kunststofftechnik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/287275762?language=en
关键词：
Experimental virtual analysis draping effect

项目摘要

The mass of load-carrying structural components can be considerably reduced by using high-performance fibre reinforced plastics. This material class, however, is not yet well-established for safety-relevant medium- and high-volume applications, since the real material behaviour is not sufficiently predictable. One reason is the considerable discrepancy between the real material behaviour, which is significantly influenced by process control, and the idealising assumptions of the available models for structural simulation. Depending on the complexity of the geometry of the component, the fibre architecture is very inhomogeneous and includes varying fibre orientations, varying fibre volume contents and local draping effects like overlaps, gaps and undulations. Only if those draping effects are diagnosed by experiments and are suitably considered in structural simulation, it will be possible to reliably construct complexly shaped composite components.Hence, objectives of the project are the development of methods to precisely detect draping effects in unidirectionally reinforced composites, the formulation of material models to describe the material impact of those draping effects, and the development of a continuous virtual process chain. Using the example of unidirectional non-crimped carbon fibre/epoxy resin composites, the draping effects arising from the preforming process will be specifically considered for construction. Firstly, experimental investigations are conducted to examine how discontinuities develop during draping and how they affect the properties of the composite. Based on that, the impact of those imperfections on the structural mechanical behaviour is investigated and quantified, partly by means of in-situ computer tomography. In order to consider draping effects in the frame of a CAE chain, they need to be detected by draping simulation. Therefore, draping simulations are conducted and experimentally validated using the example of a generic demonstrator component. For structural mechanical analysis of draping effects, simulation models at meso level will be developed and validated to discretely represent the fibre architecture of the non-crimped fabric including all relevant draping effects. Based on both the experimental investigations and the numerical studies at meso level, homogenised material models at macro level will be developed. These macro mechanical models shall describe the deformation and damage behaviour of the inhomogeneous material with sufficient accuracy, including draping effects. The final objective of the project is to properly represent the identified draping effects as well as their structural mechanical impact within a completed CAE chain. Such a continuous process and structural simulation chain promises great advantages for the design of composite components with non-crimp fabrics and, consequently, also an improved exploitation of the lightweight potential of high-performance composite materials.

通过使用高性能的纤维增强塑料，承载结构部件的质量可以大大降低。然而，由于真实的材料行为不能充分预测，因此该材料类别尚未完全确定用于安全相关的中容量和大容量应用。原因之一是真实的材料行为之间的相当大的差异，这是显着的过程控制的影响，和理想化的假设结构模拟模型。取决于部件几何形状的复杂性，纤维结构非常不均匀，包括不同的纤维取向、不同的纤维体积含量和局部悬垂效应，如重叠、间隙和起伏。只有通过实验诊断出这些悬垂效应，并在结构模拟中加以适当考虑，才有可能可靠地构建复杂形状的复合材料部件。因此，本项目的目标是开发精确检测单向增强复合材料中悬垂效应的方法，制定描述这些悬垂效应对材料影响的材料模型，以及开发连续的虚拟过程链。以单向非卷曲碳纤维/环氧树脂复合材料为例，在施工中将特别考虑预成型过程中产生的悬垂效应。首先，进行实验研究，以研究如何不连续性发展过程中的悬垂性，以及它们如何影响的复合材料的性能。在此基础上，这些缺陷对结构力学行为的影响进行了研究和量化，部分是通过原位计算机断层扫描。为了在CAE链的框架中考虑悬垂效果，需要通过悬垂模拟来检测悬垂效果。因此，悬垂模拟进行和实验验证使用的通用演示器组件的例子。对于悬垂效应的结构力学分析，将开发和验证中观层面的模拟模型，以离散地表示非卷曲织物的纤维结构，包括所有相关的悬垂效应。基于实验研究和细观水平的数值研究，将开发宏观水平的均匀化材料模型。这些宏观力学模型应足够精确地描述非均匀材料的变形和损坏行为，包括悬垂效应。该项目的最终目标是在一个完整的CAE链中正确地表示已识别的悬垂效应及其结构机械影响。这样一个连续的过程和结构模拟链的承诺，具有非卷曲织物的复合材料部件的设计，因此，也提高了开发的高性能复合材料的轻量化潜力的巨大优势。