Failure rate calculating method of components based on the load-strength interference model

The failure fate model of components based on the load-strength interference model is proposed, and the relationship between the failure rate of components and time in different cases is studied. The existing failure rate calculation methods of components are analyzed, and it is pointed out that these methods for calculating the failure rate of products are all based on the statistic analysis of fail data and can not reflect the relationship between the failure rate and the factors. Then, the failure rate model capable of embodying the effect of load and strength and its degradation is developed with the time-dependent load-strength interference. The results show that for the different combinations of load and strength, the failure rate curves of components are different and have the whole or partial characteristic of bathtub-shaped curve. The method proposed can present the relationship between the failure rate of components and the parameters of load and strength, and it can be used to calculate the failure rate of components accurately as long as the parameters of load, strength and the rule of strength degradation are known. Hence, it is more applicable for the reliability design and the lifecycle management of components.