Engineering Seminar Series
Pierre Jehel, Ph.D., M.Sc., M.Eng.
Assistant Professor
Ecole Centrale Paris, France

On using Rayleigh damping models in computational time history seismic analysis of inelastic structures

Abstract

In the computational seismic inelastic time history analysis (ITHA) of structures, part of the imparted seismic energy is absorbed by the inelastic structural model and Rayleigh damping is commonly used as an additional energy dissipation source. It has been acknowledged that, in ITHA, Rayleigh damping models have to be carefully designed to avoid unintended consequences as, for instance, the appearance of large damping ratios for some vibration modes. The main purpose of this talk is to present a method to design optimal Rayleigh damping models in the sense that it provides the best control possible on the time history of the damping ratios throughout ITHA
Issues likely to be encountered using such damping models will be recalled. How the modal damping ratios change with the level of structural damage will be explicitly shown. Then, upper and lower bounds for the damping ratios in a given frequency range will be calculated. Here and there during the talk, depending on time constraints, we will step back and adopt broader viewpoints on modeling damping in ITHA. In a probabilistic setting, we will illustrate how sensitive to the Rayleigh damping model some engineering demand parameters can be. In a probabilistic setting, we will illustrate how sensitive to the Rayleigh damping model some engineering demand parameters can be. Also, in an attempt to find more rational alternatives to using Rayleigh damping, we will allude to how explicitly accounting for material heterogeneity in the structural model can convey damping effects at the structural level..

About Prof. Jehel

Dr. Jehel received his Engineering Degree in Civil Engineering from Ecole Specialedes Travaux Publics (ESTP) in Paris, France in 2005. He holds M.Sc. (2006) and Ph.D.(2009) degrees in Mechanics and Civil Engineering from Ecole Normale Superieure (ENS) Cachan, France. His research interests have been focused on developing computational structural and material models for the simulation of inelastic civil engineering structures in seismic loading (finite element method, enhanced beam kinematics, concrete behavior laws, Rayleigh damping models). He has recently oriented his research toward the vibrant and challenging field of uncertainty quantification in structural seismic risk analysis and, to this purpose; he is currently developing probabilistic structural inelastic computational models. Since November 2012, he is supported by a Marie Curie International Outgoing Fellowship within the 7th European Community Framework Program and develops his research activities in the Department of Civil Engineering and Engineering Mechanics at Columbia University in the city of New York.

Date

Monday, December 2nd, 2013

Time

02:00 pm EST

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