INPUT FORCES ESTIMATION OF BEAM STRUCTURES BY AN INVERSE METHOD

An on-line recursive inverse method to estimate the input forces of beam structures is presented. The inverse method is based on the Kalman filter and a recursive least-squares algorithm. The filter models the system dynamics in a linear set of state equations. The state equations of the beam structures were constructed using the finite element method. The practicability and accuracy of the estimation method were examined with numerical simulations from which the input forces of a cantilever beam with a lumped mass on the free end were estimated from the output responses. In the numerical experiments, the cantilever beam was subjected to five types of input forces, i.e., sinusoidal, triangular impulse, rectangular impulse, a series of impulses and random. The simulation results show that the inverse method has an excellent performance to estimate the input forces of beam structural systems from the noisy measurements.

[1]  D. Williams,et al.  Dynamic loads in aeroplanes under given impulsive loads with particular reference to landing and gust loads on a large flying boat , 1945 .

[2]  H. R. Yoshimura,et al.  Force Reconstruction for Impact Tests , 1991 .

[3]  Cheng-Hung Huang.  AN INVERSE NON-LINEAR FORCE VIBRATION PROBLEM OF ESTIMATING THE EXTERNAL FORCES IN A DAMPED SYSTEM WITH TIME-DEPENDENT SYSTEM PARAMETERS , 2001 .

[4]  Li-Wei Fong,et al.  AN INPUT ESTIMATION APPROACH TO ON-LINE TWO-DIMENSIONAL INVERSE HEAT CONDUCTION PROBLEMS , 1996 .

[5]  James F. Doyle,et al.  Force identification from dynamic responses of a bimaterial beam , 1993 .

[6]  James F. Doyle,et al.  Further developments in determining the dynamic contact law , 1984 .

[7]  James F. Doyle,et al.  Determining the contact force during the transverse impact of plates , 1987 .

[8]  Jennifer E. Michaels,et al.  The inverse source problem for an oblique force on an elastic plate , 1985 .

[9]  Chao-Shih Liu,et al.  A study of an inverse method for the estimation of impulsive loads , 1998, Int. J. Syst. Sci..

[10]  C. D. Johnson.  Identification of Unknown, Time-Varying Forces/Moments in Dynamics and Vibration Problems Using a New Approach To Deconvolution , 1998 .

[11]  J. F. Doyle,et al.  Impact force identification from wave propagation responses , 1996 .

[12]  Noboru Kikuchi.  Finite Element Methods in Mechanics , 1986 .

[13]  Chih-Kao Ma,et al.  Input forces estimation of a cantilever beam , 2000 .

[14]  J. F. Doyle.  A wavelet deconvolution method for impact force identification , 1997 .