TS-83
Considerations on the experimental studies of semiconductor sensors for combustible gas carrier and their accelerated testing
Nobutoyo TSUTSUMI*, Zimei SU**, Qian GAO**, Shigehiro YAMAMOTO** and Takeshi HASHIMOTO**
Abstract
Many kinds of semiconductor sensors are widely used in various kinds of devices and apparatuses in order to monitor and control their system. In a vessel carrying gas including materials such as LNG and LPG, an alarm system using the sensor can be utilized to prevent a gas explosion incident.
For the purpose of securing durable performance of the system, the reliability of sensors are essential. In the case of developing an accelerated testing of one failure mode, the FTA (Fault Tree Analysis) is a useful method to diagonose, and find failed mechanism, accelerated testing and reliability improving technique of the product. This paper presented the concept and procedures of developing accelerated testing.
Key Words: Sensor technology, Monitoring, Diagonosis technology, FTA(Fault Tree Analysis), Failure mode, Failure-mechanism, Design of experiment, Weibull chart, Acceleration factor, Accelerated testing
1. Introduction
In accordance with the widespread use of electronic equipment, every sensor is utilized for improving its usefulness and securing its safety.
In a vessel too, as shown in Fig.1, the use and the application of sensors get under way and will supposedly spread in the future because of its safety and coveniences during operation.
Considering the aforementioned use, the reliability and durability of sensors are essential in the designing and developing stages.
In order to achieve this purpose, the development and use of the accelerated testing with high acceleration factor and accuracy is necessary.
To find out factors affecting a failure mode, FTA is a useful and effective method.
While developing the accelerated testing to find the resistance change failure early and precisely, FTA was effectively used and acceleration factor obtained around 105 times.
This paper describes the details mentioned above and the results of the preparatory experiments to develop new accelerated testing for gas sensors using FTA.
Fig. 1 The use of sensors in a vessel
2. Suggesting the procedure for developing accelerated testing.
The fundamentals of accelerated testing are applying larger environmental stresses to the products than actualy used during normal operation, to find weakness in design before production. The important points for this are how accurately and early one can uncover the failed mechanism.
If the single failure mode is analyzed, one can place the failure mode as top event of the Fault Tree and utilize all possible information available, such as the data obtained in past experiments, process data and engineering documents.
