Sharif Digital Repository

In the present paper, a steering knuckle of a passenger car that serves as a highly critical component from the safety point of view, is considered to evaluate accuracy some of categories of the multiaxial fatigue criteria, through comparing their predictions with the experimental results. This component is subjected to the highest road- and steering-induced random and non-proportional loads that are exerted on several points of the component. The mechanical properties and fatigue strengths are determined experimentally and the fatigue life assessment tests are performed by the authors. Quantometric analyses and scanning electron microscope (SEM) have been employed to detect the failure... 

Optimal trajectory and muscle forces of a human-like musculoskeletal arm are predicted for planar point-to-point movements using optimal control theory. The central nervous system (CNS) is modeled as an optimal controller that performs a reaching motion to final states via minimization of an objective function. For the CNS strategy, a cubic function of muscles stresses is considered as an appropriate objective function that minimizes muscles fatigue. A two-DOF nonlinear musculoskeletal planar arm model with four states and six muscle actuators is used for the evaluation of the proposed optimal strategy. The nonlinear variational formulation of the corresponding optimal control problem is... 

In this paper seven different multiaxial fatigue criteria based on stress, strain and energy were employed to estimate the fatigue lives of double shear lap joint specimens of aluminum 2024-T3 with bolt clamped and interference fitted-bolt clamped fastener holes. Detailed finite element (FE) simulations were conducted to obtain the stress and strain distributions in the joint to be used to as basic data in estimating the fatigue lives using multiaxial fatigue criteria. The estimated lives were compared with available experimental fatigue test results to investigate the capability of the criteria in predicting the fatigue lives. The results showed that the accuracy of life estimation for any...