Techno Press
Techno Press

Structural Engineering and Mechanics
  Volume 6, Number 6, September 1998 , pages 659-671
DOI: https://doi.org/10.12989/sem.1998.6.6.659
 


Natural frequency characteristics of composite plates with random properties
Salim S, Iyengar NGR, Yadav D

 
Abstract
    Exercise of complete control on all aspects of any manufacturing / fabrication process is very difficult, leading to uncertainties in the material properties and geometric dimensions of structural components. This is especially true for laminated composites because of the large number of parameters associated with its fabrication. When the basic parameters like elastic modulus, density and Poisson\'s ratio are random, the derived response characteristics such as deflections, natural frequencies, buckling loads, stresses and strains are also random, being functions of the basic random system parameters. In this study the basic elastic properties of a composite lamina are assumed to be independent random variables. Perturbation formulation is used to model the random parameters assuming the dispersions small compared to the mean values. The system equations are analyzed to obtain the mean and the variance of the plate natural frequencies. Several application problems of free vibration analysis of composite plates, employing the proposed method are discussed. The analysis indicates that, at times it may be important to include the effect of randomness in material properties of composite laminates.
 
Key Words
    composite laminates, material property randomness, perturbation method, natural frequencies, standard deviation of response
 
Address
Salim S, Indian Inst Technol, Dept Aerosp Engn, Kanpur 208016, Uttar Pradesh, India
Indian Inst Technol, Dept Aerosp Engn, Kanpur 208016, Uttar Pradesh, India
 

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