Application of the lumped mass technique in dynamic analysis of a flexible L-shaped structure under moving loads

• L-shaped frame with tip mass under moving force of constant magnitude is considered.
• 2-DOF model of the frame with lumped masses and massless beams is presented.
• The concept of moving force flexibility influence coefficients is introduced.
• The validation of the results is based on the assumed-modes method.

This paper presents a lumped-mass approach for the approximate determination of the dynamic response of a flexible L-shaped structure with tip mass subjected to a moving load. The load in the form of a force of a constant magnitude moving across the top beam of the L-shaped frame with a constant speed is considered. A two degrees of freedom model is formed, which allows to avoid complex analytic postulations and finite element formulations. The incorporation of the moving load influence on the frame structure is achieved through moving force flexibility influence coefficients. By using the assumed-modes method with polynomial shape functions, the validation of the approach is given.