Effect of material and geometric stochasticity in attaining design objective functions for trapezoidal laminated composite plates

Abstract

Laminated composite plate structures have numerous applications in construction, aerospace, military, and automotive industries. These materials with high specific strength are being used by the engineers on a very big scale and understanding the limitations of these classes of products is extremely important for confident use. In fact, the aspects of behavior study must include application specific requirements like introducing stiffeners, increasing thickness and cutouts. Hence, an accurate understanding of their structural behavior is required in terms of deflection, stresses, frequency, failure characteristics etc. This paper highlights the stochastic effects in laminated composite trapezoidal plates to satisfy both dynamic and serviceability based objective function involving the free vibration behavior and maximum deflection under uniformly distributed load respectively. The study considers relevant plate properties as random without changing the plan area which is generally encountered in many industrial and engineering situations. Monte Carlo simulation is carried out in investigating the stochastic effects of material and geometric properties on the objective function. A positive linear trend is found to exist between the coefficients of variation of both the desired frequency and deflection with the input variables, whose slope increases as randomness of input variables increases. The probability of failure in reaching both the desired frequency and deflection is shown to be heavily dependent on the combined variation of material and geometry. The paper establishes that randomness in geometry has a more pronounced effect compared to that of material.