复合材料瞬变电磁检测的模拟试验

建立了小尺度浅层瞬变电磁法检测碳纤维复合材料的计算模型.沿测线将计算模型进行简化,通过Hankel变换求取测点的瞬变电磁响应,组合所有测点的数据获得复合材料的瞬变电磁响应.结果表明:异常与试块缺陷有很好的对应关系,计算精度随测点间距的减小而增加.通过与检测试验数据的对比,分析和验证了计算模型的适用性和精度.     

开孔层压板拉伸破坏的2D渐进损伤模拟

运用渐进损伤的唯象描述方法,结合应力分析、失效判断、材料刚度退化对开孔层压板在拉伸载荷下从材料开始出现局部破坏直到整个构件失效的过程进行了基于2D有限元模型的数值模拟,模拟得到的位移栽荷曲线与文献曲线基本一致,对最终破坏载荷的预测与文献中的试验值相差-2.0%,与文献预测值相差1%,表明渐进损伤方法可以在工程上用于层压板的失效模拟和预测.     

C/ SiC 材料在国外空间光学系统上的应用

C/SiC复合材料具有高的比强度、低的热变形敏感度以及在高低温环境下的适应性,这使其成为目前最具前途的空间光学系统应用材料.本文总结了国外一些国家C/SiC的制备方法及其在空间技术上的具体应用.     

General aspects on structural integrity

This paper seeks to mark the fruitful collaborative research between scholars in the University of Southampton and Beihang University for last 25 years on structural integrity. Their efforts addressed some important issues in structural integrity such as fatigue and fracture behavior,fatigue load spectra, fatigue and fracture lifetimes, reliability-based service period, adhesively bonded composite patch repairs, Plain Woven Fabric(PWF) composites and composite artefacts.New advances in engineering approaches, experimental methods, numerical algorithms and understanding of failure mechanisms relating to structural integrity are highlighted. Probable limits(or drawbacks) are also discussed. This review provides an insight into the general aspects on structural integrity and constitutes a basis for pointers to the further works on structural integrity.     

层合复合材料高速冲击仿真研究进展

简述高强度纤维增强层合复合材料在高速冲击下的主要损伤模式和计算后的能量评估内容,介绍有限元仿真过程中不同材料模型、失效模型和刚度软化的特点,评述整体和分层两种建模方法的优缺点,提出发展趋势。     

复合材料结构用紧固件及机械连接技术

先进树脂基复合材料具有的较多优点使其在先进飞机上的使用量越来越大,但是由于材料本身结构特性的原因,使得复合材料结构在连接、装配、使用中易产生一系列问题,针对复合材料的特点及连接和使用中存在的问题,系统地阐述了复合材料结构使用的紧固件用的材料、各种结构用先进紧固件类型以及连接中需解决的具体技术问题。     

Enhanced electrothermal effect of carbon fibrous composites decorated with high conductive carbon nanotube webs

Literature has demonstrated that Carbon Nanotubes (CNTs) can greatly enhance the electrical conductivity and matrix-dominated mechanical properties of fibrous composites. However, electrothermal coupling effect of CNTs on Carbon Fiber Reinforced Plastics (CFRPs) has scarcely been considered. This work prepared and introduced thin and porous CNT webs to the surface or/and interface of a CFRP to enhance its electrothermal properties. The results show that CNT webs can enhance the transverse electrical conductivities of the CFRP by 231%−519% in a current range of 50–150 mA, when compared to the base-CFRP. Also, the surface temperature of CNT webs decorated CFRP can be improved by 20.5–32.3 °C within 3 min showing a self-heating rate of 6.8–10.8 °C/min just with an applied voltage of 20–30 V, increased by 152%−177% when compared to the base-CFRP (2.7–3.9 °C/min). Also, deicing can be finished within 4–10 min with a voltage of 18 V and an input power of 246 W/m². Moreover, the electrothermal processes nearly have no negative effect on the mechanical properties of the CFRP. The relatively low input power and short response time for deicing make the CNT webs decorated CFRP may be a potential new generation for aeronautical deicing structure.     

玻璃纤维表面偶联剂处理方法对树脂基复合材料性能的影响

采用扫描电镜、超声波探伤、浸润及力学性能测试等方法，研究玻璃纤维的不同偶联剂处理方法对纤维增强树脂基复合材料性能的影响。结果表明，使用前处理法处理的玻璃纤维对树脂的浸润性能良好，成型的树脂基复合材料耐烧蚀性能好，力学性能优异，产品质量明显提高。     

浅析复合材料框架式成型模具设计技术

对于大尺寸复合材料零件成型所用的大型框架式模具,在设计过程中需要使模型建模及更改快速化,需要详细分析模具在实际使用工况下的应力及变形、模具在固化过程中的温度分布及变形情况,并在设计过程中考虑尺寸补偿及回弹补偿,以使模具设计达到高效、精准、优化的目的;使模具结构更好地满足复材零件成型精度要求.     

铺层比例对层合板连接结构损伤特性影响分析

复合材料螺栓连接结构,其铺层比例、铺层顺序对整体结构连接效率具有重要影响.基于ABAQUS有限元软件平台,对其进行二次开发定义材料损伤退化方法,建立三维渐进损伤模型对不同铺层比例复合材料层合板螺栓连接结构的损伤扩展及破坏特性进行数值模拟分析,计算结果与验证试验结果吻合较好.分析仿真与试验结果表明:对于CCF300/BA9916Ⅱ型复合材料层合板螺栓连接结构,铺层比例对结构连接效率有重要影响,合理确定±45°层比例可以显著提高孔边应力集中区的抗挤压和抗剪切能力,有效改善连接结构的破坏模式;在±45°层比例增加到50％之后,复合材料层合板螺栓连接结构的连接强度将不再显著提高.