Machining-induced temperature field in CFRP materials (TFC)

CFRP 材料中加工引起的温度场 (TFC)

• 批准号: 461768523
• 负责人: Professor Dr. Wolfgang Hintze
• 金额: --
• 依托单位: Institut für Produktionsmanagement und -technik
• 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/461768523?language=en
• 关键词: Machining; induced; temperature; field; CFRP

Due to their remarkable specific strength and stiffness, carbon fiber reinforced plastics (CFRP) are increasingly used for highly loaded lightweight structures, e.g. in the aerospace industry. By suitable arrangement of unidirectional (UD) fiber layers, the fibers can be optimally adapted to the effective load directions. After the original near-net forming process, it is usually necessary to machine the components to meet the precision requirements. Often, milling is used for this step. Workpiece loads associated with machining carry the risk of damaging the functional surfaces mechanically and thermally which may lead to high costs due to repair or scrap.The heat generated during machining, its distribution within the part and the resulting thermal damage are, amongst other factors, dependent on the fiber orientation with respect to the feed direction. In preliminary research, an analytical model for the calculation of the temperature field within orthotropic workpieces for arbitrary fiber orientations was developed. In this model, the (effective) heat source width and the heat flux are of primary importance. Currently, those parameters are difficult to assess, but could be identified for exemplary individual cases from experiments in this research.The objective of this research proposal is to fundamentally investigate the dependence of the thermal process parameters heat source width and heat flux on tool and material properties as well as on the cutting conditions. For this purpose, the existing machining center for cutting of CFRP is enhanced with the necessary measuring equipment for thermomechanical process characterization. Based on experimentally identified features, empirical correlations are deduced and described by a comprehensive model. Thus, the model-based simulation of the temperature field and thermal damage in the heat-affected zone of UD-CFRP workpieces is established as a function of the relevant input parameters.The model established for UD-CFRP is empirically expanded within this project and thereby delivers scientifically relevant findings on cause-effect relationships of thermal damages in machining. It is expected to be of high value for industrial practice, as the model-based simulation of UD-CFRP systems reveals process limits when machining CFRP made of non-crimped fabrics (NCF). The portability to NCF-CFRP as well as the implementation of neglected effects, e.g. the heat transfer at the part surface, will be further investigated in the second funding phase.

碳纤维增强塑料(CFRP)由于其显著的比强度和比刚度，越来越多地被用于高载荷的轻质结构，例如在航空航天工业中。通过合理地布置单向(UD)纤维层，可以使纤维最佳地适应有效载荷方向。在原始的近净成形工艺后，通常需要对零件进行加工以满足精度要求。通常，这一步要用到铣削。与加工相关的工件载荷具有机械和热损坏功能表面的风险，这可能会导致因修复或擦伤而导致的高成本。加工过程中产生的热量、其在零件内的分布以及由此产生的热损坏等因素取决于纤维相对于进给方向的取向。在初步研究中，建立了任意纤维取向的正交各向异性工件内部温度场计算的解析模型。在该模型中，(有效)热源宽度和热流密度是首要因素。目前，这些参数很难评估，但可以从本研究的实验中识别出典型的个例。本研究的目的是从根本上调查热加工参数热源宽度和热流密度与刀具和材料性能以及切割条件的关系。为此，对现有的碳纤维切割加工中心进行了改进，配备了必要的热机械工艺表征测量设备。基于实验识别的特征，推导出经验关联，并用一个综合模型来描述。因此，建立了基于模型的UD-CFRP热影响区温度场和热损伤的仿真模型，作为相关输入参数的函数，对UD-CFRP所建立的模型进行了经验性扩展，从而对加工过程中热损伤的因果关系提供了科学的相关结果。由于UD-CFRP系统的基于模型的仿真揭示了加工非卷曲织物(NCF)制成的CFRP时的工艺限制，因此有望在工业实践中具有很高的价值。在第二个供资阶段，将进一步研究NCF-CFRP的可移植性以及忽略的影响的实施，例如零件表面的热传递。