Numerical simulation to reliability analysis of fault-tolerant repairable system

In the traditional method for the reliability analysis of fault-tolerant system, the system structure is described by means of binary decision diagram (BDD) and Markov process, and then the reliability indexes are calculated. However, as the size of system augments, the size of state space will increase exponentially. Additionally, Markov approach requires that the failure and repair time of the components obey an exponential distribution. In this study, by combining dynamic fault tree (DFT) and numerical simulation based on the minimal sequence cut set (MSCS), a new method to evaluate reliability of fault-tolerant system with repairable components is proposed. The method presented does not depend on Markov model, so that it can effectively solve the problem of the state-space combination explosion. Moreover, it is suitable for systems whose failure and repair time obey an arbitrary distribution. Therefore, our method is more flexible than the traditional method. At last, an example is given to verify the method.     

冲击荷载进行桥梁模态试验的研究

桥梁模态中多通过天然脉动作为激励力,但是很多情况下由于脉动信号的不可控制性而导致试验结果较差,而将力锤的脉冲激励应用到实际桥梁测试中可得到理想的试验结果。分析了不同试验方法在桥梁中使用的特点,对不同激励方法得到的试验效果进行比较,指出在不同情况下使用不同试验方法的效果和限制。介绍了力锤具有能量集中的优点,且其频率范围符合桥梁的特性。最后通过实例介绍力锤激励的方法,并通过试验得到较好的桥梁竖向动力特性。     

小水面双体船结构优化分析

分析某型号小水线面双体船在2种航态下的结构强度问题,并在此基础上实现该船体结构的优化,以达到提高结构总体性能,减小结构重量并降低结构重心之目的.在研究中,根据 CCS 规范计算双体船结构的外载荷,并用有限元法进行结构强度分析.最后,通过集成多学科优化平台,以遗传算法为搜索策略,同时对2种航态下的船体结构进行优化.数值计算表明,优化结果具有可行性,可为现实设计提供参考.