Comparison of reliability functions of simple mixed four-element systems

The paper deals with the comparison of reliability function, mean time to failure, and hazard rate function for simple mixed systems. Simple systems are those that can be divided into a sequence of series and/or parallel subsystems. The paper compares systems consisting of four subsystems; a total of seven systems are compared. A system with four parallel arranged subsystems is also included in the paper, for which the mean time to failure has the largest value. A system with four series-arranged subsystems is also included in the paper, for which the mean time to failure has the smallest value. The MATLAB program was used for the solution.