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Engine downsizing is the use of a smaller engine in a vehicle that provides the power of a larger one. It is the result of car manufacturers attempting to provide more efficient vehicles by adding modern technologies, for instance, turbochargers, direct injection and variable camshaft. The smaller engine is also lighter and provides torque and power with similar performance to a much larger engine. However, the downsizing technique may lead to undesirable vibration effects on the driveline, such as structural damaging, vibration fatigue failure and extra noise. All these issues are related to natural frequencies investigation and they are often determined through the finite element method together with experimental tests during the product development phase. This work presents the finite element method limitation for natural frequencies determination of automotive components and a possible solution for the issue.

Traditional propeller shafts using universal joints have been replaced by sophisticated and complex solutions that not only reduce weight, but also increase the performance of such systems in modern automotive vehicles. Due to its complexity that nowadays even may combine plastic and metallic components, traditional analytical models reach their limits to support engineers during their design phase. Particularly, in the case of their analysis under vibration, it becomes critical, as the life time of a propeller shaft and its components (bushes and joints) have to work far away from their natural frequency values. Analytical solutions seem not to be helpful anymore, when one need to reach a mostly precise value of a natural frequency of complex shafts. Although the FEM analysis nowadays is so far highly developed, they are still no responding to the increasingly demand for high accurate results in a short period of development time.