基于高温树脂传递模塑工艺的碳纤维/聚酰亚胺复合材料连接环制备与验证

根据连接环的结构特点，结合复合材料的力学特性及成型工艺要求设计了一种隔热/承载一体的碳纤维增强聚酰亚胺复合材料连接环，采用高温树脂传递模塑成型（RTM）整体成型工艺制备了复合材料连接环样件。超声检测结果显示，连接环内部质量良好。常温静强试验结果表明，在150%使用载荷下，连接环能保持良好的结构完整性，其最大应变仅为-491.0 με，满足常温静强度设计要求。520℃严酷热载荷下的静热联合试验结果显示，连接环在118%使用载荷下发生根部连接螺钉断裂失效，连接环本体未出现明显残余变形和损伤，满足热强度设计要求。有限元分析结果显示，常温条件下复合材料连接环的应力危险点出现在孔边，破坏方式主要为孔边的挤压破坏和层间剪切失效，高温条件下复合材料连接环失效位置主要出现在其外侧隔热层及螺栓孔处，对结构承载能力影响较小。

Preparation and evaluation of carbon fiber/polyimide composite attaching collars based on high temperature resin transfer mould process

A carbon fiber/polyimide composite attaching collar was designed and manufactured by high temperature Resin Transfer Mould (RTM) process according to the structural characteristics of attaching collars and the mechanical properties and forming process requirements of composite materials. The ultrasonic inspection results showed the good internal quality of the composite attaching collar. The static strength test conducted at room temperature showed that the maximum strain of the composite attaching collar is -491.0 με, indicating that the composite attaching collar maintains structural integrity under 150% ot the design load and meets the static strength design requirements. The thermo-static mechanical coupling test results at the maximum service temperature of 520 ℃ revealed that the attaching collar failed under the limit load of 118% due to the rapture of the screws at the root. The finite element analysis showed that the maximum stress of the composite attaching collar at room temperature occurred at the edge of the holes, and the primary failure mode was crushing and interlaminar shear failure around the holes. In comparison, the primary damage of the composite attaching collar at high temperature appeared at the outer thermal protection layer and the holes, which has minor influence on the structure bearing.