Schwingungsuntersuchungen an einer Pkw-Karosserie

(Title: Investigations into the vibrations of an automobile body)

The numerical treatment of the lower elastic vibrations of a motorcar body is presented. The displacement method has been found to be an effective technique for this calculation. When idealising the structure it is tried to show the lower boundary for the subdivision of the structure, with which satisfying results can be obtained.

The presented results show, that the calculation of the vibration characteristics of a car body is possible with relatively simple model structures. But it must be pointed out that the model structure has to be constructed considering requirements made upon the results. For the calculation of the four lower vibration modes the car body is idealised with beam and triangular elements. By this method the stiffness and mass matrices arc derived. The distributed mass is simply condensed to mass points in the nodes of the structure. Together with the stiffness matrix the mass matrix is reduced to a practical size for the final computation of the eigenvalues and cigenmodes.