Non-Linear Probabilistic Modification of Miner’s Rule for Damage Accumulation

A non-linear modification to Miner’s rule for damage accumulation is proposed to reduce the scatter between experimental fatigue life and fatigue life predicted according to the original Miner’s sum. Based on P-s-n probability distribution and design s-n curves, the modification satisfies the assumption of equality between the mean damage degree (at the critical level) and fatigue life random variables, which is not covered in the original formulation. The adopted formulation shows the discrepancies between the fatigue lives predicted according to the design s-n curves and the estimated probability distribution. It also proves that it is inappropriate to apply a normal distribution to fatigue life analysis and that the model becomes non-linear only for non-normal distributions. The predictions according to the established model were compared to the predictions obtained with Miner’s rule.

Literature Review on Fatigue Life Analysis of Railway Track Incorporating Effect of Load Sequence

As the railways are the prime mode of transportation, it is extensive to concentrate on railways which increase the economic growth of the country. Considering that the railway traffic system has an enormous influence on the people, the strength reliability of those components is a very important matter related to the safety and safety of the people. As for the strength reliability, one amongst the important study themes is that the strength or fatigue characteristic of every railway component that's subject to repeated loads during use. The reason why it is necessary to consider the fatigue characteristic carefully is that fatigue is a microscopic fracture caused by the initiation and propagation of a crack due to a cyclic slip deformation of the scale of single grain, that fatigue occurs even under a stress smaller than the strength characteristic under a static load (e.g., tensile strength), which it can suddenly result in a fatal fracture without causing any macroscopic plastic deformation and also causes derailment. The literature survey carried out talks about the ideal model for studying dynamic response of railway track, linear and non-linear approaches to find the fatigue life of railway track, crack initiation and propagation, inspection interval for cracks. The literature survey carried out in this paper gives a fair idea about the research gap and thus motivates researchers to carry out future research on the gap found. Keywords: Fatigue life, shear springs, dampers, literature survey, Rain-flow counting method, non-linear damage accumulation, linear mechanics approach, head checks crack and squat crack.