Mesoscopic damage analysis of braided composites using mesh-superposition techniques for static failure and impact loading

使用静态失效和冲击载荷的网格叠加技术对编织复合材料进行细观损伤分析

• 批准号: 463336942
• 负责人: Professor Dr.-Ing. Peter Middendorf
• 金额: --
• 依托单位: Institut für Flugzeugbau (IFB)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/463336942?language=en
• 关键词: Mesoscopic; damage; analysis; braided; composites

Braiding is an economical and fast manufacturing method to produce continuous textile preforms. Via variations in the braiding angle and braiding pattern it is possible to obtain architectures that can be optimally suited for applied loadings. In addition, braided composites have excellent damage tolerance in which damage propagation is influenced by the yarn architecture. For an accurate analysis of these damage processes it is essential to account for geometric complexity of the architecture and the various fibre or yarn, matrix and yarn-matrix interface failure mechanisms that can occur. To date this has not been possible, and most damage models use a homogenised approach that approximates damage. In particular, impact modelling of dynamic problems is challenging since detailed modelling of the architecture and the necessary computing capacities has so far made this type of simulation impractical.To overcome these limitations, this proposal will investigate mesh superposition techniques to discretely model the yarn and matrix phases, with kinematic coupling to combine the two constituents. This approach greatly reduces the model sizes and the degrees of freedom necessary for a practical solution. One drawback of the method is superposition of yarn and matrix volumes causing duplication of stiffness. This must be accounted for to obtain an equivalent stress distribution compared to a conventional model. For damage modelling and damage propagation this is necessary throughout the runtime of the numerical simulation. Furthermore, previous modelling techniques cannot be used without adaption for the mesh superposition technique to model damage or delamination for static failure or impact loading.This research proposal investigates new methods to predict damage modelling at the mesoscopic scale of braided composites for both static failure and impact loading. Furthermore, existing finite element-based modelling methods and well validated composites damage models will be applied, with new research focussed on combining these models with the new mesh superposition technique. As a result, the occurring damage mechanisms are no longer homogenised, but can be captured separately and holistically, which leads to a higher forecast quality and better material understanding than with previous modelling approaches. In the proposed study, a load case optimized braided architecture will be derived, which is validated for different load cases from static non-symmetrical shear and open-hole tension to impact and compression-after-impact tests. This method is not only limited to braided structures and will be applicable to other woven textile composites and advance current capabilities to model geometrically complex components under static failure and impact loading.

编织是生产连续纺织预制件的一种经济、快速的制造方法。通过改变编织角和编织模式，可以获得最适合所施加载荷的结构。此外，编织复合材料具有良好的损伤容限，损伤传播受纱线结构的影响。为了准确分析这些损伤过程，必须考虑体系结构的几何复杂性以及可能发生的各种纤维或纱线、基质和纱线-基质界面失效机制。到目前为止，这是不可能的，大多数损伤模型使用接近损伤的均质化方法。特别是，动态问题的冲击建模是具有挑战性的，因为到目前为止，对体系结构和必要的计算能力的详细建模使这种类型的模拟变得不实用。为了克服这些限制，本提案将研究网格叠加技术，以离散地建模纱线和基质相，并通过运动学耦合来结合这两个组成部分。这种方法大大减少了实际解决方案所需的模型尺寸和自由度。该方法的一个缺点是纱线和基质体积的叠加导致刚度重复。必须考虑这一点，以获得与传统模型相比的等效应力分布。对于损伤建模和损伤传播，这在整个数值模拟运行时都是必需的。此外，如果不采用网格叠加技术来模拟静态破坏或冲击载荷下的损伤或分层，则无法使用先前的建模技术。本研究计划探索新的方法来预测编织复合材料在静态破坏和冲击载荷下的细观损伤模型。此外，将应用现有的基于有限元的建模方法和经过良好验证的复合材料损伤模型，新的研究重点是将这些模型与新的网格叠加技术相结合。因此，发生的损伤机制不再是同质化的，而是可以单独和整体地捕获，这导致了比以前的建模方法更高的预测质量和更好的材料理解。在所提出的研究中，将推导出一种载荷工况优化编织结构，该结构在从静态非对称剪切和开孔拉伸到冲击和冲击后压缩试验的不同载荷工况下得到验证。这种方法不仅限于编织结构，还将适用于其他机织纺织复合材料，并提高了现有的模拟几何复杂部件在静态破坏和冲击载荷下的能力。