新能源汽车车身碳纤维复合材料/铝合金粘铆连接结构服役性能研究

The lightweight of new energy vehicle has promoted the use of aluminum alloy and carbon fiber reinforced composites, consequently the dissimilar material joint problem is widely concerned by the automotive industry. The adhesive-riveted bonding process of carbon fiber reinforced composites and aluminum alloy could effectively improve their joint strength. However, there exist several problems such as complex fatigue failure mechanism, low prediction accuracy of joint performance, difficulty of adjusting process parameters and so on, which impedes its popularization and application. In this research, the static, dynamic and fatigue mechanical tests of notched carbon fiber reinforced composite plate and carbon fiber reinforced composites/aluminum alloy adhesive-riveted joints considering the automobile service conditions are performed. Meanwhile, a constitutive model of the performance degradation of adhesive layer under environmental aging and numerical simulation models of the service performances of adhesive-riveted bonding joint are established. Then the mechanism of progressive damage failure of the adhesive-riveted joint under hygrothermal effect is studied, and the influence of hygrothermal condition on the joint properties and fatigue life of adhesive-riveted connecting structure is revealed. A process simulation model for adhesive-riveted joint of carbon fiber reinforced composites/aluminum alloy is established, and the influence of process parameters on strength and fatigue life of adhesive-riveted joint is studied, then a design optimization method for process parameters is proposed. Furthermore, the proposed strategy is verified by the application adhesive-riveted boding of new energy vehicle body carbon fiber reinforced composites/aluminum alloy parts, which provides a reasonable and scientific method for its industrialization application.

新能源汽车轻量化促进了铝合金、碳纤维复合材料的使用，但随之而来的异种材料连接问题也受到汽车行业的广泛关注。碳纤维复合材料/铝合金粘铆连接工艺可以有效地提高连接强度，但存在疲劳失效机理复杂、连接性能预测精度低、工艺参数调控困难等问题，阻碍了其推广应用。本项目通过考虑汽车服役工况的带孔碳纤维复合材料板以及碳纤维复合材料/铝合金粘铆连接的静态、动态及疲劳力学性能试验研究，建立环境老化作用下的胶层性能退化本构模型以及粘铆连接结构的服役性能数值仿真模型，研究湿热效应下粘铆连接渐进损伤失效机理，揭示湿热环境对粘铆连接性能和疲劳寿命的影响规律；建立面向车身零部件结构的碳纤维复合材料/铝合金粘铆连接的工艺仿真模型，研究连接工艺参数对粘铆连接强度和疲劳寿命的影响，提出粘铆连接工艺参数优化设计方法，并通过新能源汽车车身碳纤维复合材料/铝合金零部件粘铆连接的应用验证，为其产业化应用提供合理、科学的方法。

采用高强轻质材料是提升汽车安全、实现汽车轻量化设计的主要技术手段之一。具有低密度、高比强度、高比模量等优异性能的碳纤维复合材料和铝合金材料在新能源车辆中的应用前景广阔，但随之而来的材料连接问题也受到汽车行业的广泛关注。碳纤维复合材料与铝合金通过胶接和铆接进行组合，形成粘铆连接结构，是提高其连接性能的有效手段，但碳纤维复合材料与铝合金粘铆连接存在疲劳失效机理复杂、连接性能预测精度低、工艺调控困难等问题，阻碍了其推广应用。本项目通过考虑汽车服役工况的带孔碳纤维复合材料板以及碳纤维复合材料/铝合金粘铆连接的静态、动态及疲劳力学性能试验研究，建立了受环境老化作用下的胶层性能退化本构模型以及粘铆连接结构的服役性能数值仿真模型；研究湿热效应对粘铆连接渐进损伤失效机理，揭示了湿热环境对粘铆连接性能和疲劳寿命的影响规律；建立了面向车身零部件结构的碳纤维复合材料/铝合金粘铆连接的工艺仿真模型，研究连接工艺参数对粘铆连接强度和疲劳寿命的影响，提出了粘铆连接工艺参数优化设计方法，并通过了新能源汽车车身碳纤维复合材料/铝合金零部件粘铆连接的应用验证，为其产业化应用提供了合理方法和技术支持。