Reliability Evaluation And Analysis Of Liquefied Natural Gas Sensor

With the development of energy industries, such as the coal industry and the petrochemical industry, the types and applications of explosive and toxic gas have been increased, so that all kinds of gas sensor also came into being and are widely used. People have to pay more attention to the reliability of gas sensor for the quality problems appeared during the long-term use.In this dissertation, the Liquefied Natural Gas sensor was taken as the object. At first, did an FMECA(Failure Mode Effecting and Criticality) and FTA(Failure Tree Analysis) to gas sensor and found out that the heating wire, cooled heat pump piece and carrier materials are the weakness part of the whole gas sensor. According to the classic working environments, deeply analyzed the failure mechanism of gas sensor's typical failure modes, such as failure of platinum wire, alumina carrier and catalyst deactivation, and educed the failure physics equation. Secondly, according to the weak link of gas sensor, temperature, vibration, impact and voltage were chosen as the enhancement stress, the stress profiles were designed, and a test project of reliability enhancement testing and failure analysis was presented. Thirdly, statistically analyzed the reliability enhancement test data, and then the estimated the unknown parameter of the life-stress equation. Convert the enhancement test data to normal environment through environment factor. In the case of small samples, the sensor's supposed life distribution was verified under the introduction of the maximum entropy theory and considering the affect of many factors. The reliability indices of gas sensor under the normal stress level were estimated according to the sensor's life distribution.Eventually, gave a conclusion to the reliability research content of gas sensor which has been carried out, and proposed the further reliability research content, and the research direction of this Foundation project.