Fall 2003

  Volume II: Experimental Verification of Nonlinear Dynamic Analyses

Fahriba Manju

Experimental works are performed on the dynamic response of structural models subjected to ground vibrations and the results are verified with predictions from computer programs using nonlinear dynamic analysis. The experimental facilities developed in the Structural Mechanics and Strength of Materials Lab at UAP are used for this purpose.

A 3-DOF dynamic system is created by a model 3-storied structure made of springs (as columns) and timber plates (as slabs). The mass, damping and nonlinear stiffness properties of the structure are measured from static loading arrangement and free decay test. Arrangements for ground shaking are made from simple combinations of pulley.

Variations of the displacements are recorded with time. Several experimental situations are simulated when the structural model is subjected to harmonic ground vibration of constant amplitudes but different frequencies (30, 70, 110 rpm). For parametric studies, different lab arrangements are also created by changing the mass and observing the resulting modifications to the structural behavior. Moreover, the numerical analyses are carried out in the time domain using linear as well as nonlinear dynamic models.