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Multi-scale mechanical modelling of braided composites including process induced defects

编织复合材料的多尺度力学建模，包括过程引起的缺陷

基本信息

批准号：
323019910
负责人：
Professor Dr.-Ing. Thomas Gries
金额：
--
依托单位：
Institut für Textiltechnik (ITA)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/323019910?language=en
关键词：
Multi scale mechanical modelling braided

项目摘要

In this project proposal a methodology for multi-scale FEM simulation of braided composites, with defects, will be developed and used to obtain homogenised composites damage models for industrial macro-scale analysis. For materials characterisation a detailed manufacture and test program will be undertaken to characterise a wide range of braid mechanical properties. Defects in braids, in particular fibre damage and architecture irregularities always occur and a variety of braids with different machine settings will be produced to create such defects, which will then be quantified using scanning and computer tomography. Therefore ITA has recently developed an online laser scanning sensor. Furthermore ITA has a wide range of process knowledge as far as the correlation between machine settings and the appearance of braiding defects is concerned. After the infusion, coupon preparation and mechanical testing for stiffness, damage and failure will be undertaken. Digital image correlation techniques will be used to identify and measure variations in surface damage, with cyclic loading to measure damage and plasticity evolution. New models will then be incorporated in the process simulation of the braided preforms to produce numerical models of braids that contain defects. These will be compared to test measurements for validation. IFB have recently de-veloped a novel approach to extract 3D representative volume elements (RVE) from process simulation results which have shown potential for stiffness and damage/failure modelling. These capabilities will be extended here to include the process induced defects and will be supported by FE micromechanical analysis for failure prediction of impregnated yarns. Finally, the work will be used to calibrate homogenised composites damage models in com-mercial FE codes and validated against a test program of coupons and a demonstrator struc-ture. The main new results of this research will be new knowledge of defects generated dur-ing processing of braids. Which will be quantified, and used in prediction of real (imperfect) braid mechanical properties. The work will make use of and link, analysis techniques across all scales from micro- to meso- and finally macro-analysis. Finally, the research will provide important new knowledge of damage/failure of braids under complex loading and make a critical evaluation of current homogenised composites damage models used in commercial FE codes, with suggestions for future improvements.

在该项目提案中，将开发一种对有缺陷的编织复合材料进行多尺度有限元模拟的方法，并用于获得用于工业宏观尺度分析的均质复合材料损伤模型。对于材料表征，将采取详细的制造和测试计划来表征各种编织物的机械性能。编织物中的缺陷，特别是纤维损坏和结构不规则性总是会发生，并且将生产具有不同机器设置的各种编织物以产生此类缺陷，然后使用扫描和计算机断层扫描对这些缺陷进行量化。因此ITA最近开发了一种在线激光扫描传感器。此外，就机器设置与编织缺陷外观之间的相关性而言，ITA 拥有广泛的工艺知识。输注后，将进行优惠券准备和硬度、损坏和失效的机械测试。数字图像相关技术将用于识别和测量表面损伤的变化，并通过循环加载来测量损伤和塑性演变。然后，新模型将被纳入编织预成型件的过程模拟中，以生成包含缺陷的编织物的数值模型。这些将与测试测量结果进行比较以进行验证。 IFB 最近开发了一种从过程模拟结果中提取 3D 代表性体积元素 (RVE) 的新方法，该方法显示了刚度和损伤/故障建模的潜力。这些功能将在此扩展，包括工艺引起的缺陷，并将得到有限元微机械分析的支持，用于浸渍纱线的故障预测。最后，这项工作将用于校准商业有限元代码中的均质复合材料损伤模型，并根据优惠券测试程序和演示结构进行验证。这项研究的主要新成果将是对编织物加工过程中产生的缺陷的新认识。它将被量化，并用于预测真实（不完美）的编织物机械性能。这项工作将利用和链接从微观到中观以及最后宏观分析的所有尺度的分析技术。最后，该研究将提供复杂载荷下编织物损坏/失效的重要新知识，并对商业有限元代码中当前使用的均质复合材料损坏模型进行批判性评估，并为未来的改进提出建议。