A piecewise constant failure intensity model

We study repairable systems with non-monotone failure intensity. Three commonly used functions in the literature are considered, namely, power law function, exponential function, and logistic function. Their additive combinations are explored to accommodate different failure processes for practical repairable systems, such as monotone increasingdecreasing, bathtub, roller-coaster shape, etc. The shape and flexibility of these models under different parameter values are discussed. The existence and determination of maintenance planning is also explained under each possible scenario. We then illustrate the proposed models with a real world example of High Throughput Screening Automation Systems.