带圆孔的薄壁管多轴向低周疲劳性能的判据

在40Cr钢制成的带圆孔的薄壁管上进行拉-扭双向的低周疲劳试验,并用弹塑性有限元方法分析试件圆孔区域应力和应变分布。通过对以前的多轴向疲劳准则的分析研究,根据薄壁管拉-扭双向疲劳的试验和理论分析的结果,提出了一个新的多轴向应力疲劳的判据。它可以比较好地预测疲劳起裂寿命和裂纹位置。     

缺口对GH33A合金在复杂应力条件下力学行为的影响——高温合金力学冶金(11)

本文研究了缺口对GH33A合金在高温低周疲劳及劳疲/蠕变交互作用下的力学行为。结果表明:缺口使GH33A合金低周疲劳寿命缩短,其缩短的程度随缺口尖锐程度的增加而加剧。低周疲劳高应力时,保载时间的作用引入了蠕变分量,促使低周疲劳寿命Nf降低。在低周疲劳固定最大应力,改变最小应力而造成蠕变/疲劳交互作用情况下,其断裂寿命在一定条件下具有最大值,断裂机制可由纯疲劳断裂逐步转化为纯蠕变断裂,其程度主要决定于蠕变应力(或疲劳应力)分量所占比例的大小。     

Mg、Zr对GH33A合金高温疲劳以及静、动态蠕变行为的影响

本文研究了含Mg、Zr与不含Mg、Zr两种GH33A合金的高温疲劳和静、动态蠕变行为。结果表明,微量元素Mg、Zr对提高疲劳性能不显著,也不能改善疲劳缺口敏感性。缺口疲劳性能取决于缺口的几何参数Kt与λ,材料的光滑疲劳极限和平均晶粒尺寸微量元素Mg、Zr的良好作用主要表现在静态蠕变条件下,充分发展和延长了蠕变第Ⅱ和第Ⅲ阶段,增加蠕变断裂延伸率,并大大提高断裂寿命。这种良好作用在恒载且迭加有疲劳交变应力的动态蠕变条件下仍然保持。     

自动控制理论实验仪测试软件的实现

基于虚拟仪器技术,开发了自动控制理论实验仪,更新了自动控制理论课程的实验手段,有效地提高了实验效率,增强了教学效果。该文论述实验仪测试软件的设计,包括其体系结构、主要内容、特点。     

纺粘热轧非织造布透水性能的研究

聚酯纺粘热轧非织造布被广泛用作塑料排水板滤膜,纺粘热轧的工艺参数对滤膜的性能有很大影响。测试和分析了纺丝速度、轧点面积和轧辊压力对纺粘热轧滤膜透水率的影响。结果说明,随着纺丝速度、轧点面积和轧辊压力的增加,纺粘热轧滤膜的透水率均减小。     

球墨铸铁微观组织形成的数值模拟

基于结晶动力学理论,建立了球墨铸铁凝固过程各阶段微观组织形成形核和长大的数学模型;根据该结晶动力学模型,编制了球铁微观组织形成模拟软件FTStructure．该软件可以预测球铁凝固过程中各相的形成以及固态转变中铁素体和珠光体的形成,并进而预测铸态力学性能．模拟了阶梯形试块的冷却曲线、微观组织和布氏硬度．模拟与实测结果符合较好．     

40Cr调质齿轮弯曲强度可靠性试验研究

论述了40Cr钢调质齿轮轮齿弯曲疲劳强度可靠性的试验研究.试验是在4个应力水平（每个应力水平的样本不少于6个）上进行的.在试验数据基础上,拟合出R-S-N曲线及方程.最终获得40Cr钢调质齿轮轮齿在不同可靠度时的弯,弯曲疲劳强度值.     

Correction to: A note on the three methods of item analysis

Behaviormetrika - In the original publication of the article, Appendix A was published incorrectly.     

One universal method of complex system reliability,maintainability, supportability,testability quotas design and trade-off based on improved flower pollination algorithm

For modern complex system, quality has become a serious and difficult problem that restricts the generation of combat effectiveness. Withal, based on domestic and foreign research and analysis, this paper puts forward a trade-off method for complex system reliability, maintainability, supportability, testability (RMST) design, which is suitable for product design stage. First, aiming at the uncertain problem of complex system constrained optimization, the good-point set population initialization, Deb feasibility comparison method and ε constraint method are integrated into the flower pollination algorithm, to construct the algorithm for RMST quotas design and trade-off. Second, taking the typical series-parallel repairable system as an example, one general model for complex system RMST quotas design and trade-off based on effectiveness is constructed. Finally, take an unmanned nuclear radiation detection system as a typical case, to verify its feasibility, advantages, and disadvantages.