Dynamic Analysis of Folded Low Shells by Using Finite Element Analysis

Aims: This work is devoted to the development of a finite element algorithm for solving problem in forced vibrations of folded low shells.

Methodology: The differential equations for harmonic analysis are obtained from the Lagrange variational principle. Description of the dynamic behavior is made by the structure discretization into a system of curvilinear iso-parametric finite elements used in modal analysis. The method is implemented by a calculation code on a square-plane folded shell model withnumber of crease edges in both directions k=l=3.

Results: Displacement amplitudesare obtained by decomposition into vibration eigenforms. The maximum values of dynamic stresses are determined taking into account the shell's support conditions.The results of the harmonic analysis show thatimprovement in frequency characteristics and reduction of stresses in the folded shell depend on the constructive and internal damping of the structureand the increase in the number of fold edges k and l in both directions for examplebecause this contributes to decrease in the forced vibration amplitudes.