对TC2钛合金焊接接头进行硬度测试以及拉伸、疲劳对比试验，并观察全部疲劳断口，分析焊接接头光滑试样的疲劳性能与影响因素。结果表明，焊缝区的硬度最高，约高于母材50HV，塑性较差，焊缝中的微观焊接缺陷是不可避免的，是影响焊接接头疲劳寿命的主要因素；热影响区的硬度较低，塑性较好，其拉伸强度是焊接接头部位的最薄弱区，但却有较好的疲劳性能。在99%可靠度的前提下，焊接接头的疲劳寿命约为母材寿命的46%。

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Common cause failure (CCF) is analyzed as a manifestation of the probabilistic characteristics of component failure rate:probability stemming from stochastic environment load. CCF revolved concepts, such as 'root cause' and 'coupling mechanism' are interpreted mathematically from the viewpoint of random environment load bringing about failure dependency. Opinions about 'inherent CCF' and 'additional CCF', 'absolute CCF' and 'relative CCF' are presented and discussed. An easy-to-use CCF model is developed through multi-dimension environment load-component strength interference analysis and knowledge based parameter discretization. Owing to its strict statistical foundation, such a model has the ability of estimating component failure rate:probability and common cause failure rates: probabilities consistently, dealing with low redundancy system CCF and high redundancy system CCF uniformly, and predicting high multiplicity failure rate:probability based on low multiplicity failure data satisfactorily.

Metal strain gauges need to be designed differently from strain gauges made from silicon. In this paper equations are derived that allow us to calculate the resistance change of metal strain gauges as a function of the position on a thick diaphragm, a thin membrane and a disc simply supported at the rim. The results of finite element calculations presented reveal that large deviations from these equations occur for strain gauges on thin membranes made of soft materials.

In order to demonstrate the role of multi-crack growth:coalescence in the leak-before-break concept, Monte Carlo method is applied to simulate multiple crack growth:coalescence behavior which are quite common to component vulnerable zone such as weld. For the multi-crack behavior simulation, typical component vulnerable zone is postulated to have randomly distributed initial cracks. The parameters such as crack number, crack location and crack length are all treated as random variables. The crack distribution parameters are assumed according to generic knowledge available. For single crack situation, the crack size with detectable leak and the critical crack size with unstable propagation are cited from literature. For the multi-crack situation, an equivalent crack-opening area is used to identify the detectable leak. The simulation results show that, for LBB concept related components, the existence of multiple cracks might lead to much shorter leak-free time and much shorter allowable response time compared with those in single crack situation.