In this paper a versatile and easy to use approximate procedure was used for the estimation of mode I stress intensity factors in case of multiple surface cracks in a three dimensional elastic body, subjected to remote uniaxial tensile loading. The mentioned method uses known solutions for either 2D or 3D configurations containing only one crack, and takes into consideration the interaction effect between cracks. This procedure, which is based on the principle of superposition, was applied on a configuration with three coplanar semi-elliptical cracks embedded in three dimensional elastic body, subjected to remote uniaxial tensile loading. All cracks are located in the same plane at the same distances, in the middle of the body and the applied stress is perpendicular to the cracks plane. For the verification purposes, the stress intensity factors solutions were obtained by using finite element method based computer program. The conducted analysis showed that approximate method is, above all, fast and efficient tool for stress intensity factors assessment even in the case of 3D configurations with multiple site damage. The comparison between results also showed the significance of accurate calculation of stress intensity factors, in order to provide a better understanding and prediction of 3D multiple cracks propagation.

In this paper a numerical investigation of replacement implant for partial hip arthroplasty is presented. The long-term stability of hip implants depends, among other things, on the loads acting across the joint. Forces occurring in vivo can be much greater than the recommended test values, because a typical gait cycle generates forces up to 6–7 times the body weight in the hip joint. A finite element analysis (FEA) was performed using 3-dimensional models to examine the mechanical behaviour of the femoral component at forces ranging from 2.5 to 6.3 kN. This implant design was chosen for numerical analysis because stress concentration in femoral component lead to implant fracture. Results show that the force magnitudes acting on the implant are of interest, and that they can cause implant stress field changes and implant stability problems, which can lead to implant failure

Purpose: This paper aims to present the methodology to determine Archard’s wear coefficient. By applying this coefficient into the numerical simulation of wear, it is possible to predict wear without long lasting and usually expensive experiments. Design/methodology/approach: To determine necessary particles of Archard’s equation and calculate wear coefficient K, an experimental investigation is proposed. Afterwards, the wear simulation is executed in FEM software ANSYS 18.1. Analytical method is offered to determine worn volume for cylinder-in-cylinder contact, based on “inclination” of inner cylinder. Findings: Comparing the value of Archard’s coefficient obtained by this experimental investigation with the values from the literature for the similar materials, high correlation is noted. Furthermore, numerically calculated contact pressure is confirmed with analytical method. Trend of pressure decrease due to wearing process, as well as due to increase of contact surface is observed. Practical implications: Since the prediction of the wear is closely related to the life cycle assessment of bearings, and the machines in general, it has significant practical importance for designers. Originality/value: Determination of Archard’s coefficient is usually performed by conventional pin-on-disk tribometers. This methodology offers a different approach for the determination of Archard’s wear coefficient for cylinder-in-cylinder contact, which is convenient for shaft-sliding bearing contact.