Soroushian A., Farjoodi J., Mehrazin H.

Though sometimes negligible, the true behavior of all structural systems is involved in nonlinear dynamics. In our modern engineering world, the design of complicated structural systems necessitates a thorough knowledge about the behavior and meanwhile the capability of providing economical and reliable structural designs. Because of these and the fact that for complicated structural systems, engineering practice cannot provide reliable judgments, the nonlinear dynamic behavior is gradually being considered in the design codes. Considering bilinear behavior and concepts such as ductility in seismic structural designs are good evidences. With these considerations, it seems a good idea to have a measure for comparing different nonlinear dynamic behavior of structural systems (a nonlinearity measure will cause a better interpretation of expressions such as “highly nonlinear, true nonlinear, weakly nonlinear, etc.). The authors have presented a simple method to measure the nonlinearity of dynamic piece-wisely linear structural models (also reported partially in the prestigious ICSV11). In their further studies, the authors recognized that the developed measure can not consider the effect of the temporal location of behavior changes. Overcoming this deficiency is the objective of this study. In brief, it is attempted to arrive at a more precise, yet simple, measure for the nonlinear behavior of piece-wisely linear structural dynamic models. To arrive at this objective, the authors have enhanced their previously suggested measure in view of the existing literature, the effects of nonlinearity on dynamic behavior, and the theoretical definition of nonlinearity. Numerical studies demonstrate the efficacy of the new measure. Some References 1. Soroushian, A. and Farjoodi, J. and Mehrazin, H. (2004), 'A nonlinearity measure for piece-wisely linear structural dynamics', Proceedings of the 11th Int. Congress on Sound and Vibration (ICSV11), St. Petersburg, July. 2. Babitsky, V.I., and Krupenin, V.L. (2001), Vibration of Strongly Nonlinear Discontinuous Systems, Springer, Germany.