Identification of Elastic Properties of Composite Laminates

This article is focused on application of the response surface method (RSM) for solution of structural identification problems. The approximating functions are obtained from the data of deterministic numerical experiment. The numerical experiment is performed in the sample points of experiment design. A minimal mean squared distance Latin hypercube (MMSDLH) design is used in the present paper. For building the response surfaces, a local approximation method is employed. An example of application of the response surface method and experiment design for identification of elastic properties of laminated composite material is discussed. Elastic properties of carbon/epoxy laminate are determined employing the experimentally measured eigenfrequencies of composite plates. The identification functional represents differences between experimentally measured and numerically calculated frequencies, which are dependent on variables to be identified. The identification parameters are five elastic constants of material. The elastic constants identified from vibration test have been compared with the values obtained from independent static test. Good agreement of the results is observed.     

Analysis of the sensitivity of a vibration-based procedure for structural identification

We analyze the accuracy of estimation of structural component material properties (elastic modulus, Poisson’s ratio, density, etc.) using the technique for measuring the eigenfrequencies of oscillations. The accuracy of frequency estimation using the Fourier method and its influence on the final result are evaluated. Relationships between the errors in the frequency estimation and those in the identified parameters are derived using the metamodel method. Application of the method is illustrated by the example of a shell element with a stiffening rib. __________ Translated from Problemy Prochnosti, No. 4, pp. 140–147, July–August, 2006.     

Automotive electronics

We live in a rapidly changing world where none of us is clairvoyant. Our desire, but inability, to forecast the future includes the next frontiers of high technology. This rapidly changing environment produces many new venues that drive future change. The rapid growth of automotive electronics has always had its new “frontiers.” This article addresses the practical aspects and issues