Spectral element approach to wave propagation in uncertain beam structures

This paper presents a study on the uncertainty in material parameters of wave propagation responses in metallic beam structures. Special effort is made to quantify the effect of uncertainty in the wave propagation responses at high frequencies. Both the modulus of elasticity and the density are considered uncertain. The analysis is performed using a Monte Carlo simulation (MCS) under the spectral finite element method (SEM). The randomness in the material properties is characterized by three different distributions, the normal, Weibull and extreme value distributions. Their effect on wave propagation in beams is investigated. The numerical study shows that the CPU time taken for MCS under SEM is about 48 times less than for MCS under a conventional one-dimensional finite element environment for 50 kHz loading. The numerical results presented investigate effects of material uncertainties on high frequency modes. A study is performed on the usage of different beam theories and their uncertain responses due to dynamic impulse load. These studies show that even for a small coefficient of variation, significant changes in the above parameters are noticed. A number of interesting results are presented, showing the true effects of uncertainty response due to dynamic impulse load.

Keywords

MCS, SEM, normal distribution, Weibull distribution, extreme value distribution, wavenumber, group speeds

Milestones

Received: 28 July 2009

Revised: 1 January 2010

Accepted: 14 January 2010

Published: 8 November 2010

Authors

V. Ajith
Department of Aerospace Engineering Indian Institute of Science Bangalore 560012 India

S. Gopalakrishnan
Department of Aerospace Engineering Indian Institute of Science Bangalore 560012 India
http://www.aero.iisc.ernet.in/krishnan

Vol. 5, No. 4, 2010

V. Ajith and S. Gopalakrishnan

Abstract

Keywords

Milestones

Authors