On the reliabilities of mechanical parts and systems with experiments on mono-component systems

Reliability experiments of large sample size (n = 50, 100) were carried out on gearboxes and steel wire in order to verify the models of three-parameter Weibull distribution and Boolean system theory. Using the mechanical parts of gear couple and steel wire, systems consisting of same parts were built called mono-component system. The fatigue life data is entered in the three-parameter Weibull distribution graph to acquire the failure probability of component and system. Boolean system theory of reliability is applied to calculate the system reliability based on the the failure probability of component. The results demonstrate: The three-parameter Weibull distribution describes the failure data well but the region of early failure (0 - 5%) has a large scatter. System reliability calculated from the component reliability using Boolean model has a good correspondence of the mean value and variance to-the test data of gearbox and also shows obvious deviation in the region of early failure (0 - 5%). The result of system consisting of mono-component of steel wire gives a good result about System reliability.