Analysis of the correlation between fatigue behavior of remote laser cut fiber reinforced composites and process parameters

纤维增强塑料（FRP）由于其突出的质量比强度和刚度，为轻量化设计提供了很大的潜力。作为加工工具的激光作为一种无力和无接触的热方法是无磨损的，并且将远程加工应用于FRP材料提供了高加工速度。由于过去的资助期间，广泛的知识是在静态和循环机械载荷下的远程激光切割玻璃钢的行为。对开孔试样的准静态拉伸试验表明，采用适当的加工参数进行远程激光束切割，可以获得比铣削更高的静态强度。加工方法和材料性能之间的这种相互作用可以通过基于有限元法的数值模型来解释，该模型是在该项目中开发的。拟议的继续项目的目的是对远程激光切割工艺对FRP机械性能的影响进行后续扩展。特别地，将提供实验和数值证明，切割轮廓的几何形状影响激光切割过程并因此影响基质汽化区（MVZ）的扩展，以及通过应力集中的出现影响机械性能。由于MVZ本身对结构性质也有影响，因此出现了复杂的工艺-结构-性质关系，这有待研究。为了对这些关系进行一致性分析，将扩展第一项目阶段提供的数值过程和结构模型，以便全面了解和模拟损伤发展。在继续项目的范围内，重点是将以前的结果和调查结果转移到与应用相关的层压板和载荷上。此外，远程激光切割试样的老化导致机械疲劳敏感性增加和容许准静态最大应力降低的假设有待研究。

Fiber-reinforced plastics (FRP) offer a high potential for lightweight designs due to their outstanding mass-specific strengths and stiffnesses. The laser as a processing tool is wear-free as a force- and contact-free thermal method, and the application of the remote process to FRP materials offers high processing speeds. As a result of the past funding period, extensive knowledge is available on the behavior of remote laser-cut FRP under static and cyclic mechanical loadings. Quasi-static tensile tests on open-hole specimens have shown that remote laser beam cutting with appropriate processing parameters leads to higher static strengths than milling. This interaction between the processing method and the material properties could be explained by a numerical model based on the finite element method, which was developed in the project. The aim of the proposed continuation project is the consequent extension of the investigations on the influence of the remote laser cutting process on the mechanical properties of FRP. In particular, the experimental and numerical proof is to be provided that the geometry of the cutting contour influences both the laser cutting process and thus the expansion of the matrix vaporization zone (MVZ), as well as the mechanical properties by the occurrence of stress concentrations. Since the MVZ itself also has a proven influence on the structural properties, complex process-structure-property relationships arise, which are to be investigated. For the consistent analysis of these relationships, the numerical process and structural models provided in the first project phase are to be extended in such a way that the damage development can be comprehensively understood and simulated. Within the scope of the continuation project, the focus is on the transfer of the previous results and findings on remote laser beam cutting of FRP to application-relevant laminates and loads. Furthermore, the assumption that aging of remote laser cut specimens leads to an increased mechanical fatigue sensitivity and a reduction of the tolerated quasi-static maximum stress is to be investigated.