DETERMINATION OF STIFFNESS PROPERTIES OF A HETEROGENEOUS BEAM BY ITS DYNAMICAL CHARACTERISTICS
In this study the statement and the solution of the inverse problem of identifying the unknown variable stiflhess properties of the heterogeneous beam by its known dynamical characteristics is given.Modem technology allows to measure the vibrodisplacement of the certain points of the constructions in the process of free of forced vibrations.Further computer processing of the measurement data gives the functional dependence of the displacement of some points in time.These functions are considered as dynamical characteristics of the beam and give more information than classical frequences and amplitude data.Given the function of displacement in time of the middle cross-section of the beam in two different experiments,each consisting of exciting free longitudinal vibrations in the beam and finding its dynamical characteristic in the middle cross-section,its possible to determine one of the stiffness properties function (Youngs module or density) if the other property function is known. In order to solve the inverse problem (determining properties by dynamical characteristics),the direct problem is solved first (determining dynamical characteristics of the heterogeneous beam by its properties).Its well known that currently no exact solution exists for direct problem as well as inverse problem.The approximate direct problem solution presented in this work is based on the ideas of the asymptotic method of phase integrals-Wentzel-Kramers-Brillouin and Louivelle-Steklovs method. Applying the inverse pseudo-solution approach to the stated inverse problem,the problem is converted into minimization problem,where minimization functional is the difference between the direct problem solution and known dynamical characteristics functions.Due to complexity of the direct problem solution,its not possible to apply the classical methods to minimize the tunctional and the Genetic Algorithms are used.A special program has been developed to implement this algorithm and has shown consistent convergence and good matching between direct problem data and inverse problem solutions (and vice versa).
V.A.Gordon YU.S.Stepanov p.N.Anokhin
Orel State Technical University,Russia
国际会议
第二届国际非均质材料力学会议(The Second International Conference on Heterogeneous Material Mechanics)
安徽黄山
英文
1381
2008-06-03（万方平台首次上网日期，不代表论文的发表时间）