Fatigue life prediction of engineering structures under multivariable random loading using structural model

The article describes the case of multivariable random loading, which occurs when the caterpillar suspension component acts as a set of loads of independent random processes. In the danger zone details of the changes in the components of the stress tensor are independent random processes. As an example of parts operating at such a loading the author discusses tracked vehicle road arm. Presently, there are no standard techniques for the estimation of fatigue life under random multivariable loading currently available. The article describes the method of estimating the fatigue life for this type of load, based on the calculation of microplastic deformation. It uses a structural model of the material, based on the description of the deformation diagram of dependence by Ramberg-Osgood. To identify the model of accumulation of damage conventional mechanical and fatigue characteristics of the material were used. Accounting for natural dispersion of fatigue characteristics allowed to get the result as a function of the probability of failure-free operation. The validity of the approach is confirmed by comparing the calculation results with the experimental data. The practical application of the technique is illustrated by the example of predicting the durability and reliability of heavily loaded parts of the high-speed caterpillar vehicle. (C) 2015 The Authors. Published by Elsevier Ltd.