Degradation Modeling of Digital Multimeter with Multiple-Performance Indices in Dynamic Marine Environment

Digital multimeter is used in marine environment to measure Direct Current Voltage (DCV), Direct Current (DC), Alternating Current Voltage (ACV), Alternating Current (AC) and Resistance (R) under different measuring ranges in the marine system. In addition, digital multimeter suffers three dynamic environmental stresses including temperature, relative humidity, and salinity. Aiming at improving prediction accuracy of digital multimeter reliability and residual lifetime, this paper focuses on degradation modeling and lifetime prediction of digital multimeter with multi-performance indices and in complex marine environment. The measurement errors of the five indices are used as the degradation signals to reflect the performance of the digital multimeter. A degradation model considering the effects of the three dynamic marine environmental stresses is proposed based on initial degradation measurement, degradation rate function and Wiener process to predict the cumulative distributions of the First Passage Time (FPT) of the five indices. Furthermore, the Copula function with the lowest AIC value is used to model the dependence structure among multiple performance indices. A case study based on measurement errors of digital multimeter and dynamic environment data for nine months is presented to illustrate the proposed method.