超低温环境下T700/环氧复合材料拉-压疲劳性能及损伤机理

项目名称： 超低温环境下T700/环氧复合材料拉-压疲劳性能及损伤机理

项目编号： No.11302036

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 刘新

作者单位： 大连理工大学

项目金额： 28万元

中文摘要： 轻质高强碳纤维增强树脂基复合材料已成为制造可重复使用飞行器上液氧燃料贮箱的理想材料选择，明确这种复合材料在超低温环境下的疲劳特性是当前亟待解决的关键问题之一。本项目拟针对T700碳纤维增强环氧树脂复合材料，采用试验和数值模拟相结合的方法，研究其在超低温环境下的疲劳特性。通过超低温（-196℃）/室温（25℃）热循环疲劳试验，研究复合材料在热疲劳过程中产生损伤的特性；在液氮温度下，对复合材料进行拉-压疲劳试验，绘制由刚度退化控制的预测复合材料超低温疲劳寿命的Sc-N疲劳曲线，并考虑温度因素对复合材料疲劳特性的影响，建立以剩余刚度为损伤参量的超低温疲劳累积损伤模型；通过研究组分材料的低温热力学性能、疲劳载荷的应力比和应力水平、铺层角度等因素对复合材料超低温疲劳损伤特性的影响，揭示复合材料的超低温疲劳损伤机理。本项目的研究将为碳纤维复合材料在超低温环境下使用的可靠性提供评估方法和理论预测模型。

中文关键词： 液氧燃料贮箱；复合材料；超低温；疲劳特性；损伤机理

英文摘要： Carbon fiber reinforced polymer-matrix composite materials(CFRP) is an ideal choice for manufacturing the liquid oxygen tank of reusable launch vehicles,as its high specific strength and specific modulus, and excellent mechanical and thermal properties. The fatigue properties of CFRP, especially at cryogenic temperature, is imorpant to the reliablity of reusable launch vehicles significantly,must be studied carefully in order to make sure the safety of vehicles. We will study the fatigue properties in cryogenic temperature condition of high performance T700/EP composite materials in this project. At first,thermal cycling fatigue test of CFRP between cryogenic temperature(-196℃) and room temperature （25℃）will be performed to research its damage characteristic in this condition. Secondly, the tesion-compression fatigue test will be carried out at liquid nitrogen temperature，and the Sc-N curve based on stiffness degradation will be obtained, from which we could predict the safe fatigue life of CFRP at cryogenic temperature. Taking account of the influence of temperature, a fatigue damage cumulative model based on stiffness degradation will be proposed in this project,and then tested and modified according to experimental data .Finally, the influence of stacking sequence and layer angle of composites laminates, and

英文关键词： liquid oxygen tank；composite materials；cryogenics；fatigue properties；damage mechanism