Reliability of manufacturing equipment in complex environments

We present two stochastic failure models for the reliability evaluation of manufacturing equipment that degrades due to its complex operating environment. The first model examines the case when the environment is a temporally nonhomogeneous continuous-time Markov chain, and the second assumes the environment is a temporally homogeneous semi-Markov process on a finite space. Derived are transform expressions for the lifetime distributions. A few examples are provided to illustrate the main results. Author to whom correspondence should be addressed.