A contribution to a wedge shaped load introduction in highly stressed fiber polymer composite structures

对高应力纤维聚合物复合材料结构中楔形载荷引入的贡献

• 批准号: 163599025
• 负责人: Professor Dr.-Ing. Helmut Schürmann
• 金额: --
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/163599025?language=en
• 关键词: contribution; wedge; shaped; load; introduction

The introduction of high loads into structural elements mostly is the core problem while designing with fiber polymer composites. The reasons are as followed: On the one hand only thin thicknesses exist because of the high strength of the material. On the other hand the anisotropy of the material makes design more complex. Due to the fact that the force flow within load introduction areas often runs transverse to the fiber, the lower stiffnesses and strengths lead to an early failure. Because of assembly reasons mostly a change to another material gets necessary. That means that the different properties of two materials have to be considered.The wedge connection describes a solution for introducing concentrated loads into composite structures which is capable to bear very high loads and by its shape is closure safe and inspires confidence. A uniform load distribution within the wedge area is necessary in order to take advantage of the extremely high strengths in fiber orientation. In particular the high local pressure load within the intersection to the wedge area causes early failure by wedge fracture (fracture mode C). Consequently it defines the transferable load of the entire connection.At the chair Konstruktiver Leichtbau und Bauweisen theoretical and practical pilot tests have already been conducted. In doing so it was possible to increase the failure load of the wedge connection by the following measures:- Variation of the wedge angle, the clamp length and the wedge radius- Insertion of cores consisting of different materials- Optimisation of the wedge pattern manufacturing- Insertion of transverse inner-pliesAnother interesting variation is the wedge connection as rotation-symmetric construction. By doing so tube connections made from fiber polymer composites can be integrated within tubes.In the framework of the submitted project the measures to increase the failure load of wedges have to be put on a firm basis. The primary objective is to clearly extend and deepen the present results and finding optimised solutions. In addition an experimental validation of the wedge design has to be conducted. Furthermore it is necessary to transfer the results of the wedge connection with rectangular cross section to rotation-symmetric tube connections.The superior objective is to give rules to the design engineers working with fiber polymer composites and to make data available for the maximal load capacity of wedge connections.

高载荷引入结构构件是纤维聚合物复合材料设计中的核心问题。原因如下：一方面，由于材料的高强度，只有较薄的厚度存在。另一方面，材料的各向异性使设计更加复杂。由于加载区域内的力流经常横穿纤维，较低的刚度和强度会导致早期破坏。由于组装原因，大多数情况下需要更换另一种材料。这意味着必须考虑两种材料的不同特性。楔形连接描述了一种将集中载荷引入复合材料结构的解决方案，该方案能够承受非常高的载荷，并且其形状是闭合安全的，并激发了人们的信心。为了利用纤维取向的极高强度，楔形区内的均匀载荷分布是必要的。特别是，与楔形区交叉处的高局部压力载荷导致楔形断裂(C型断裂)的早期破坏。因此，它定义了整个连接的可传递载荷。在Konstruktiver Leichtbau and Bauweisen椅子上，已经进行了理论和实际试验。在这样做的过程中，有可能通过以下措施来增加楔形连接的破坏载荷：-改变楔形连接的角度、夹具长度和楔形半径-插入由不同材料组成的芯子-优化楔形图案制造-插入横向内板另一个有趣的变化是作为旋转对称结构的楔形连接。通过这样做，由纤维聚合物复合材料制成的管连接可以集成到管内。在提交的项目框架内，增加楔形件破坏载荷的措施必须建立在坚实的基础上。主要目标是清楚地扩展和深化目前的成果，并找到优化的解决方案。此外，还必须对楔形设计进行实验验证。此外，还需要将矩形截面楔形连接的结果转化为旋转对称的管连接，其最优目标是为从事纤维聚合物复合材料工作的设计工程师提供规则，并为楔形连接的最大承载能力提供数据。