Optimal design based on probability approach and fracture mechanics

This paper deals with the statistical fracture mechanical method for the optimal design of forest machine components. The problem of optimal design includes the choice of the objective function and independent design variables and establishment of the system limits. The objective function is determined as the mean total cost that includes the initial cost and the cost of failure according to the failure probability. A quasi-brittle fracture occurs under the influence of the stationary random process of loading. Analytical equations of reliability function estimation are obtained. The algorithm of the random search method includes an interval reduction with regard to zone and functional constraints. The approach to the optimal design problem solution can be applied to obtain optimal geometrical sizes and permissible limit defect values of machine components.