RADIOSS_LINEAR_DYNAMICS.pptVIP

Agenda Theoretical introduction Dynamic Systems Linear X Non-linear Models Static X Dynamic Models Structural Dynamics Damping Eigen Value and Vector simulation Modal FRF – Frequency Response Function Modal Direct Transient Response Modal Direct Acoustic Analysis Acoustic Cavity Mesh NV Director NVH Post Processing Theoretical introduction Dynamic Systems A dynamical system concept can be described like mathematical representation of a point that has time dependent position on the space, this dependence can be described per a system of differential equations. Theoretical introduction Given a known load in time and space obtain the structure response in time and space or, obtain displacement, velocity acceleration of a loaded structure Theoretical introduction Dynamic Systems These systems that the classical mechanics studies can be classified in 2 different classes: Linear Dynamics Nonlinear Dynamics Theoretical introduction Static X Dynamic Models To help on understand what a dynamic system is it is interesting to compare it with a static system. There are two basic aspects that make the dynamic systems differ from static system: The loads are applied as a function of time. F t The responses are time dependent. X t Theoretical introduction Structural Dynamics Analysis Theoretical introduction Damping Any real structure will dissipate energy in general from friction and this can be modeled mathematically as a force synchronous with the velocity of the object but opposite in direction to it. Thus, for a simple mechanical damper, the force F may be related to the velocity v by where c is the viscous damping coefficient, given in units of Theoretical introduction Damping Theoretical introduction Damper Effects on System behavior Chapter 2: Modal Analysis Modal Analysis Definitions frequency modes or natural frequencies Modal Analysis Natural Frequency Eigenvalue Modal Analysis Mode Shape Eigenvector Modal Analysis Why Modal Anal