TORSIONAL OSCILLATIONS OF ENGINE WITH INTERNAL COMBUSTION

1. Melisa Velic, Federation of Bosnia and Herzegovina , Bosnia and Herzegovina

In practice is often encountered that most mechanical systems are exposed to a variable periodic load. Consequently the presence of oscillations in a large number of devices and machines is expected and cannot be avoided. Oscillating at specific, critical regimes, can cause very high additional loads, and in some cases can lead to mechanical failure. Therefore, one should pay special attention to the study of oscillatory movement.

In this paper we made a calculation of parameters which are important for torsional oscillations by creating an equivalent system of crankshaft. Stiffness of the crankshaft is determined by using finite element method and CATIA software package. After selecting desired load in the form of torque and after making finite element analysis, we calculated rigidity of the element by analyzing angle of crankshaft rotation of individual points. After that we compared calculated value of stiffness with value we got by using empirical formulae and got very good results.

As the actuating torque consists of momentum of gases and momentum of inertial forces that do not have harmonic character we made Fourier analysis to obtain the amplitude of oscillation of individual discs of equivalent systems. Second form of oscillation is considered, because it is positioned in the working range of engine. The results obtained are shown in a form of diagrams.

Key words: torsional oscillations, crankshaft, stiffness, rigidity.

Tematska oblast: Mehanika i konstrukcije

Uvodni rad: Da

Datum: 29.12.2010.

Br. otvaranja: 945

11th International Conference on Accomplishments in Mechanical and Industrial Engineering


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