The Influence of Structural Design Parameters on the Retention Force and Interference-Fit Reliability of Connecting Rod Bushings

Connecting rod bushing loosening in diesel engines is a critical failure mode that causes accelerated wear and potential catastrophic damage. This study systematically examines the effects of key structural parameters—inner diameter, wall thickness, and width—on the retention force of interference fits. Employing theoretical analysis and finite element simulation (assuming a dry friction coefficient μ = 0.2 for steel–bronze), this work predicts an optimal interference range of 0.08–0.11 mm, corresponding to a theoretical retention force of 33.61–46.25 kN. A limited experiment validated the model at lower interference levels, but the proposed range remains a model-derived prediction awaiting extensive verification. Simulation-based parametric analysis quantified the influence of each factor: retention force decreases by ~2 kN per 2 mm increase in inner diameter, increases by ~3 kN per 0.25 mm increase in wall thickness (the most significant parameter), and increases by 1.3 kN per 1 mm increase in width. These findings establish a predictive, simulation-driven design framework for guiding bushing design and assembly control in heavy-duty applications, with the explicit understanding that its core outputs are model-predicted and require experimental confirmation.