Fundamental analysis of the machining process of a composite material made of concrete andCFRP with diamond grinding tools

虽然混凝土能够承受很高的压缩载荷，但它承受拉伸载荷的可能性很低。因此，在建筑构件中嵌入钢筋作为加固。为避免腐蚀，钢筋必须覆盖一层厚厚的混凝土。由于用碳纤维增强塑料（CFRP）制成的元素代替这些钢元素，有可能减少混凝土覆盖的数量。这为更薄、更轻的钢筋混凝土构件提供了机会。根据建筑行业的最新发展和现有的研究计划，可以假设CFRP增强混凝土元件的数量将在未来几年内增加，因此需要有效的切割工具用于这种复合材料。在这个研究项目中，计划对CFRP与混凝土制成的新型复合材料的加工工艺进行基础分析工作。划痕试验是了解材料去除基本机理的基本试验方法。因此，将对单个金刚石颗粒进行路径和力控制试验，以分析加工过程的基本相互依赖性。用形状确定的金刚石颗粒来估计机械载荷和发生的磨损。进一步的知识是通过对单个金刚石浸渍段进行测试获得的。在单晶粒划伤试验的基础上，计划进行路径控制和力控制试验。在调查中，CFRP钢筋混凝土切割过程中的力学和热载荷将进行分析。可以认为，高工艺温度可能导致cfrp基材料的热损伤以及段的堵塞。此外，还可以评估替代冷却策略的可行性。此外，由于CFRP的磨损和未切割纤维引起的部分横向磨损的研究特别有趣，特别是这些影响如何降低工具寿命。基于单粒划伤试验和金刚石浸渍段试验的定量和定性结果，将生成单尺度和多尺度过程模型。作为一个例子，材料和晶粒取向的依赖性及其对材料去除的影响将被分析。这些知识可用于多相材料CFRP增强混凝土加工工艺的优化。通过对单粒和多粒试验的综合分析，对材料去除的具体机制有了全面的了解。因此，这些研究为开发用于加工碳纤维增强混凝土的高效金刚石工具奠定了基础。

Although concrete is able to bear high compressive loads, its possibility to withstand tensile loads is very low. Hence, in construction elements steel bars are embedded as reinforcement. To avoid corrosion, a thick concrete covering of the steel bars is necessary. Due to the substitution of these steel elements with elements made of carbon fibre reinforced plastic (CFRP) it is possible to reduce the amount of the concrete covering. This provides the opportunity for thinner and lighter construction elements made of reinforced concrete. Regarding recent developments in the construction industry and existing research programs it can be assumed that the amount of CFRP reinforced concrete elements will increase in the next few years and therefore efficient cutting toolsfor this kind of composite material are required. Within this research program it is planned to conduct basic analysis work regarding the machining process of the new composite material madeof CFRP and concrete. Scratch tests are a fundamental testing method to understand the fundamental mechanism of material removal. Therefore path- and force-controlled tests with single diamond grains will be carried out to analyse the fundamental interdependencies of the machining process. Diamond grains with defined shape are used to estimate the mechanical loads and the occurring wear. Further knowledge is gained by conducting tests with single diamond impregnated segments. Based on the single grain scratch tests, it is planned to carry out path- and force controlled tests.Within the investigations, the mechanical and thermal load during the cutting of CFRP reinforced concrete will be analysed. It can be assumed that high process temperatures probably lead to a thermal damage of the CFRP-matrix material as well as in clogging of the segments. Furthermore, the feasibility of alternative cooling strategies can be assessed. Additionally, investigations on the lateral wear of the segments due to fraying and uncut fibres of the CFRP are of special interest, especially how these influences may reduce the tool life. Based on the quantitative and qualitative results of single grain scratch tests and diamond impregnated segment tests single- and multi-scale process models will be generated. As an example the dependency of material and grain alignment and its influence on the material removal will be analysed. This knowledge can be used for the optimisation of the machining process of the multiphase material CFRP reinforced concrete. Due to the comprehensive analysis of single and multi-grain tests a global understanding of the specific mechanisms of material removal is reached.Hence, these investigations constitute the fundamental basis for the development of efficient diamond tools for the machining of CFRP reinforced concrete.