Abstract
This paper describes vibration analysis using finite element method for elastic frames with a panel connected by nonlinear concentrated springs under impact load. The restoring force of the spring has cubic nonlinearity and linear hysterisis damping. Finite element for the nonlinear spring is expressed and is connected to the elastic frames with the panel modeled by linear solid finite elements in consideration of complex modulus of elasticity. Further, the discretized equations in physical coordinate are transformed into the nonlinear ordinary coupled equations using normal coordinate corresponding to linear natural modes. This transformation yields computation efficiency. Influences of vibration damping and rigidity of the frame are clarified on the nonlinear impact responses.
