复合推进剂线粘弹本构方程的细观力学分析(Ⅰ)球形颗粒增强效应分析

从基体和微粒本构关系出发, 应用Ｅｓｈｅｌｂｙ 等效夹杂理论及宏观平均理论的分析方法, 确定复合体的本构关系, 从细观层次揭示弹性微粒对粘弹基体的增强效应。     

三体随动跟踪式重力卫星姿态与无拖曳控制方法

采用非接触洛伦兹力执行器代替微推进系统,提出一种“质量块—载荷舱—平台舱”三体随动跟踪式重力卫星总体架构,避免传统低低跟踪重力场测量卫星设计中的质心波动与执行机构带来的动力学不确定性影响。其次,建立了该架构下的卫星姿轨耦合动力学模型,并在此基础上针对动力学非线性耦合项的影响,构建了一种基于带宽参数化自适应补偿的复合自抗扰控制方法,提升姿态与无拖曳控制性能。最后,采用数学仿真验证了所提出的重力卫星总体架构及其控制方法的有效性。仿真结果表明,该方法有效提升了系统的频域性能。     

复合固体推进剂拉伸/压缩性能对比研究(英文)

为了获得药柱受压状态的模量参数,开展了推进剂压缩性能的探索测试。参照拉伸标准试件,进行了压缩试件尺寸的设计与调试,通过不同高度试件的测试结果及破坏形貌分析,确定了试件尺寸。在此基础上进行了不同应变下的推进剂拉/压对比测试。相同应变率下,压缩模量较拉伸模量高,压缩模量随压缩速度的变化规律与拉伸模量一致,随着速度的提高,模量随之提高。     

气动加热下金属蜂窝板热响应特性数值模拟

提出一种计算非稳态气动加热下金属蜂窝板内辐射导热耦合换热数值计算方法。将金 属蜂窝夹芯板作为三层平板结构,建立沿厚度方向一维传热控制方程,采用Monte
Carlo方法求解蜂窝腔内辐射换热,有限体积法求解蜂窝板内耦合换热,考虑蜂窝金属与空 气热物性随温度变化,对某结构的正六角形蜂窝板在模拟气动加热条件下两表面温度响应进 行了数值预测,数值预测结果与文献中的实验结果对比表明该方法能够准确模拟蜂窝夹心板 内传热过程;对采用Swann & Pittman当量导热系数经验公式进行蜂窝非稳态表面温度响应 计算可靠性进行了验证,结果表明该公式在计算非稳态气动加热下蜂窝表面温度时存在较大 误差,给出的热面温度过高,冷面温度过低,两表面温差最大相对误差高达140％。     

复合材料夹芯板的屈曲分析

本文考虑到了横向剪切的作用，通过应用最小势能原理和能量变分方法建立了复合材料夹芯板的稳定性控制方程，在位移场的表达式中，将横向和纵向位移对z进行泰勒展开，并且保留了前四项，在使得横向剪力满足在上下表面为零的条件下，选用了同一阶剪切理论相同的参数，即引入参考曲面的法线转角φx,φy，避免了引入横向剪力修正系数。给出了满足不同边界条件的基本项，采用了Galerkin方法，对稳定性方程求解，在对控制方程线性化以后，通过计算系数矩阵的最小广义特征值来获得了屈曲载荷，并且将屈曲载荷计算与文献做了对比，分析了夹芯板的几何尺寸，纤维铺设方式以及边界条件对屈曲载荷的影响。     

考虑平整性要求的板壳自适应结构静变形控制

基于四节点压电复合材料层合板单元和相应有限分析方法，利用结构位移对电压的灵敏度，对以压电材料为作动器的板壳自适应结构，进行了考虑平整性要求的静力变形控制。根据控制目标和约束限制，由数学规划问题确定结构承载时作动器所需的控制电压，最后以数值算例给出了仿真结果，以验证所提出方法的有效性。     

Optimization Design System for Composite Structures Based on Grid Technology

To solve the topology optimization of complicated multi-objective continuous/discrete design variables in aircmit structure design, a Parallel Pareto Genetic Algorithm （PPGA） is presented based on grid platform in this paper. In the algorithm, the commercial finite element analysis （FEA） software is integrated as the calculating tool for analyzing the objective functions and the filter of Pareto solution set based on weight information is introduced to deal with the relationships among all objectives. Grid technology is utilized in PPGA to realize the distributed computations and the user interface is developed to realize the job submission and job management locally/remotely. Taking the aero-elastic tailoring of a composite wing for optimization as an example, a set of Pareto solutions are obtained for the decision-maker. The numerical results show that the aileron reversal problem can be solved by adding the limited skin weight in this system. The algorithm can be used to solve complicated topology optimization for composite structures in engineering and the computation efficiency can be improved greatly by using the grid platform that aggregates numerous idle resources.     

Carbon nanotube protected composite laminate subjected to lightning strike: Interlaminar film distribution investigation

A kind of interlaminar film with carbon nanotubes inserted into polyether ketone with cardo was used for lightning strike protection of composite laminates. The distribution of the interlaminar film was investigated by experimental and numerical methods. Artificial lightning strike tests were conducted for 12-film carbon nanotube and traditional surface silver coating protected specimens. Then corresponding finite element models (FEMs) were established to analyze the lightning strike effect and validated by the experimental results. Based on the FEMs, the number, distribution and thickness of interlaminar film were investigated in order to obtain equivalent protection effect with the traditional surface silver coating. The results show that only the first two layers were damaged for the surface silver coating protected specimen, while 5 layers were ablated for the 12-film protected specimen. Lightning strike damage area of the laminate protected with 5-film carbon nanotube is almost the same as that of the laminate protected with 12-film carbon nanotube. Compared with traditional surface silver coating protection, one film protection with thickness of 360 μm can make the laminate to obtain equivalent damage depth, 54.8% smaller damage area and 58% less additional weight. And reparability of the laminate is better than that of the laminate protected with 5 interlaminar films.     

复合材料加筋壁板多点冲击损伤和高周剪切疲劳试验

为研究多点冲击损伤和高周剪切疲劳对复合材料加筋壁板损伤演化、屈曲行为及破坏模式的影响,制作了9块相同构型的复合材料加筋壁板,设计了冲击试验、高周剪切疲劳试验和剩余剪切强度试验。在多点冲击和高周剪切疲劳试验过程中,使用超声C扫描系统监测了损伤区域。C扫描图像表明损伤区域的长度和宽度随着循环次数的增加而增加。与无预制损伤试验件相比,多点冲击损伤和高周剪切疲劳试验件的平均破坏载荷下降了约50%。冲击或疲劳形成的初始损伤对破坏模式产生影响,冲击疲劳试验件出现了局部蒙皮屈曲变形,破坏裂纹非常接近冲击点。      

电动通用飞机复合材料结构设计及验证技术

为了设计和制造出重量轻、工艺简单且经济实惠的电动通用飞机,提出了一种新型的复合材料结构设计和验证方法。对飞机的载荷传递进行了理论分析,采用CATIA对飞机结构进行建模,并使用PATRAN/NASTRAN进行了强度计算,根据计算结果,优化了复合材料铺层设计,采用二维图纸的形式快速完成发图。对所采用复合材料的组件和整机进行了一系列的力学试验验证,形成了一套适合轻型飞机的结构快速试验验证方法。根据不同类型零部件的特点采用不同的制造工艺,使生产成本和周期得到有效控制。设计结果、试验数据的有效性和工艺质量的可靠性已经在锐翔RX1E电动双座飞机上得到了证实,该飞机的各项性能满足设计指标要求。