Nonlinear vibration equations for loudspeaker revolution shells

Nonlinear discretization vibration equations are derived for loudspeaker revolution shells. The nature modes of loudspeaker revolution shells are chosen to discretize the continuous body according to the virtual work principle. Geometric nonlinearities are accounted for by utilizing the strain-displacement relation of the Sanders nonlinear shell theory. The coefficients of the equations are determined by the finite element method. The equations show that the axisymmetric mode is driven directly, whereas the asymmetric modes are excited by the axisymmetric mode through a parametric excitation. The equations can be used to analyze the subharmonic distortion, harmonic distortion and intermodulation distortion caused by the loudspeaker shell nonlinearity.