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Nowadays, the market trends on engine components development are focused in lower emissions, fuel consumption reduction, downsizing and higher peak combustion pressure. In this scenario, macro-profile bearing optimization plays an important rule on stresses reduction and consequently structural safety factor increasing. Thus, a structural optimization was performed to define the best crankpin profile for a given crankshaft (named U-Shape crankpin profile). This profile can be designed with emphasis on mass and friction reduction without penalties on structural and torsional stiffness results. Since there is more than one objective, it is necessary to perform a multi objective optimization that will result in a Paretto frontier, in which all design points meet the targets.

In the past few years, Finite Element Analysis (FEA) has become an almost essential engineering tool in product development. In addition to that, structural optimization, which is almost as old as the finite element method, is a widely used tool in engineering product design definition. One vastly used method is the shape optimization, which has as an objective the minimization of stress concentration on determined regions. In this work, a 6 cylinder diesel engine crankshaft was analyzed and a structural optimization was performed, more specifically at the web region. The interpretation of the shape optimization results led to a slightly modified geometry of the crankshaft, with the mass of the crankshaft throw only 0.5% higher than the original model. Also, the fatigue safety factor evaluation was performed for both reference and optimized crankshafts as a comparison criterion. The same boundary condition used in the shape optimization was employed for the fatigue factor evaluation.