STUDY ON RELIABILITY MODELING OF A HYDRAULIC EXCAVATOR SYSTEM

The failure patterns of a well-known brand of a hydraulic excavator sy stem used in different environments were modelled adequately with an N HPP (non-homogeneous Poisson process) having time-dependent log-linear peril rate functions. Using the fitted model, the reliability of the excavator system was estimated in different environments (cement plant , coal mine, iron ore mine, etc.). The system reliability was found to be very poor during the initial phase of operation and gradually impr oved with an increase in cumulative operating hours regardless of chan ge in environment. Notwithstanding this general trend, the system reli ability differed significantly in different environments for any given duration of operation and was particularly very poor in cement plants . With the help of the FMEA technique, high risk prone failure modes o f the excavator system of the given model were identified and appropri ate corrective measures were initiated. The failure patterns of the mo dified excavator system changed regardless of environment, so much so that an HPP (homogeneous Poisson process) model with constant peril ra te could be fitted adequately to characterize the failure pattern of t he system. The system reliability improved considerably in the initial phase of operation since start-up.