An innovative method for determining the stress concentration factor of interference fit joints and additional design recommendations

In interference fits, the difference in length between the shaft and hub leads to stress concentrations on the shaft at the locations corresponding to the ends of the hub. This creates a numerical singularity in finite element analysis and makes it hard to determine the true maximum stress. Hence, the accuracy of the stress concentration factor computed using the finite element method is uncertain. One of the primary objectives of this paper is to introduce a novel methodology to tackle numerical singularity, by adopting a concept from fracture mechanics. Subsequently, the proposed method was employed to assess the influence of geometric variables and the specific material utilized on the stress concentration factor. The parameters are the ratio of shaft outer diameter to hub outer diameter ((Formula presented.)), the ratio of hub length to shaft outer diameter ((Formula presented.)), the ratio of shaft inner diameter to outer diameter ((Formula presented.)) and the type of hub material. Then, analysis of variance tests were employed for a comprehensive understanding. The results demonstrated the efficacy of the method in addressing the numerical singularity problem through their consistency, which is a significant finding given the importance of precise determination of the stress concentration factor in predicting joint behavior and its direct implications for practical applications. Furthermore, the rigidity of the material selected for the hub, in conjunction with the utilization of hollow or solid shafts, was identified as the primary parameters influencing the stress concentration factor. When supplemented by other variables, the stress concentration factor can be manipulated on a wide scale. © 2025 Taylor & Francis Group, LLC.