基于Workbench的主起落架车架前轮叉应力分析及结构优化设计

针对某型飞机主起落架车架前轮叉根部多次出现疲劳裂纹,前轮叉作为主起落架车架的关键件,其性能优劣严重影响起落架的安全性。利用ANSYS Workbench仿真软件对其结构进行应力分析,得到其薄弱部位,利用拓扑优化和多参数优化相结合的方法对其结构进行优化和对比分析。分析得到的薄弱部位与实际使用情况相吻合,优化后的结构合理,受力明显改善,质量比优化之前减少了17.3%。     

Constitutive behavior and microstructural evolution in hot deformed 2297 Al-Li alloy

The microstructural evolution mechanism and constitutive behavior of 2297 Al-Li alloy were studied via thermal compression test with the constant strain rates of 0.001–1 s⁻¹ and the deformation temperatures ranging from 623 to 773 K. To verify the predictable ability of diverse constitutive models under different stress states, the hot compression experiments with stress triaxiality varying from −0.33 to 0.46 were conducted. The microstructures of the deformed specimens under diverse deformation conditions are probed to reveal the mechanism of hot deformation behavior. The experimental results indicate that the work-hardening and dynamic softening are competitive during the hot compression process, and the dynamic softening is more obvious under low deformation temperature and high strain rate. The microstructural analysis manifests that the dynamic recovery gets predominant at high deformation temperature to produce fine grains. Meanwhile, the dynamic recrystallization becomes more dominant as the strain rate decreases, which is sensitive to the stress triaxiality. In addition, both the modified Johnson-Cook model and strain-compensated Arrhenius-type function are suitable for describing the flow behavior of 2297 alloy, while the latter reveals a more accurate prediction. However, the predictability of the two kinds of models is worsened with the transformation of stress triaxiality, and the validity of the Arrhenius-type model is restricted by high stress triaxiality.     

矿井提升机主轴应力分析

本文将实际的三维问题有效地简化为平面问题,采用有限元程序SAP5P,计算六种工况下,主轴突变截面处的应力,并对计算结果进行分析和图形处理.     

ARJ21复杂双曲面长桁零件弯扭复合冷成型方法

通过对零件几何特征和计算机辅助软件的分析，在掌握零件变化规律的基础上，确定了零件的成型方法，以及实验确定成型过程中各参数值。     

陶瓷材料小裂纹的生长与聚合

对陶瓷材料小裂纹的生长与聚合规律进行了试验研究。结果表明由Ｖｉｋｅｒｓ压痕法引入的单个小裂纹的裂纹扩展速率（ｄａ／ｄｔ）随裂尖应力强度因子的增大呈先降后升的Ｖ形特征。理论分析和数据处理均表明这种特征是由压痕法引入的残余应力场的影响所致。试验结果还表明多个小裂纹的生长与聚合规律也与残余应力场密切相关。文中提出的叠加残余应力场模型很好地解释了上述试验结果     

HTPB推进剂动态力学响应常温段松驰转变物理本质

用动态粘弹谱仪和动态力学热分析仪（ＤＭＡ－７）研究了ＨＴＰＢ推进剂、预应变老化的ＨＴＰＢ推进剂以及ＨＴＰＢ聚氨酯胶片在－１００－１００℃范围内的动态力学松驰现象，并用扫描电镜观察了所测材料的形貌。     

螺旋弹簧应力松弛实验研究

对导弹弹体及发动机中常用的压缩螺旋弹簧进行了应力松弛实验研究,得到了这种弹簧在常温下长期贮存中的应力松弛方程,为导弹武器系统的质量评判和延寿提供了可靠的实验依据。     

斜喷管收敛段壳体三维应力场的有限元法计算

对固体火箭发动机斜喷管收敛段壳体应力场采用有限元法进行了分析和计算。提出了该方法的力学模型，基本公式，基本方法和算例。具有理论意义和工程应用价值。     

间隙连接对胶接接头应力分布和强度的影响

运用弹塑性有限元法结合实验研究了连续和间隙连接的单搭接接头应力分布规律，并考虑了胶瘤的影响。结果表明，在相当大间隙长度范围内和适当的间隙位置条件下，间隙连接接头并没有大幅度地减小其承载能力，相反其有效搭接区域剪切强度呈明显升高趋势；胶层应力峰值仍然发生在搭接末端；胶瘤承担了相当大的载荷作用；过大的间隙长度以及不当的间隙位置会导致胶层靠近间隙端应力集中明显加剧，成为新的高应力区，可能导致接头破坏模式的改变。实验结果与数值分析结果很好地吻合。