曲面碳/碳蜂窝制备及其均布载荷下的力学性能

Preparation of curved carbon/carbon honeycomb and its mechanical properties under uniform load

精密仪器对承载平台结构的要求不断提高,蜂窝结构由于其轻质和超高稳定性的特点而受到广泛关注。为了满足异形复合材料承载平台的需求,本文采用热压成型和树脂浸渍碳化-化学气相沉积(Chemical vapor deposition,CVD)相结合的工艺制备了不同规格曲面碳/碳蜂窝结构试样,而后根据曲面蜂窝的结构特点和服役环境,设计了均布载荷的测试方法对不同试样进行压缩试验,分析了蜂窝厚度、铺层角度、曲率半径等因素对曲面蜂窝力学性能的影响规律。结果表明:当蜂窝的径向厚度增大时,蜂窝壁屈曲程度增大,蜂窝双层壁处所受载荷增大,胶粘面开裂倾向更加显著;当蜂窝纤维取向由0°至45°转变蜂窝壁皱曲转变方式为不皱曲-韧性皱曲-塑性皱曲;当曲面蜂窝的曲率半径减小时,其破坏模式逐渐由双层壁脱粘开裂向蜂窝壁的屈曲断裂转变。本文制备的曲面碳/碳蜂窝压缩强度达到1.48 MPa,具备良好的力学性能,可以满足日益复杂化的航天结构承载需求。

With the increasing demand of precision instruments on the bearing platform structure,honeycomb structure has been widely concerned because of its light weight and ultra-high stability.In order to meet the requirements of the special-shaped composite bearing platform,this paper used the combination of hot pressing and resin impregnation carbonization and chemical vapor deposition(CVD)to prepare the curved carbon/carbon honeycomb structure samples of different specifications.Then,according to the structural characteristics of curved honeycomb and the service environment,a test method of uniform load was designed to conduct compression tests on different samples.The influences of honeycomb thickness,layering angle and curvature radius on the mechanical properties of curved honeycomb were analyzed.The results show that when the radial thickness of honeycomb increases,the bending degree of honeycomb wall increases,the load on honeycomb double-walled space increases,and the cracking tendency of adhesive surface becomes more obvious.When the orientation of honeycomb fiber changes from 0°to 45°,the bending mode of honeycomb wall changes to non-buckling,ductile buckling and plastic buckling.When the curvature radius of curved honeycomb decreases,the failure mode gradually changes from decudation cracking to buckling fracture of honeycomb wall.The curved carbon/carbon honeycomb prepared in this paper has a compressive strength of 1.48 MPa,and has good mechanical properties,which can meet the requirements of increasingly complex aerospace structures.