CONSISTENT FINITE-ELEMENT DISCRETIZATION OF DISTRIBUTED RANDOM LOADS

A convenient consistent-load finite element (FE) formulation is propos ed for the discretization of distributed random excitations. The rando m excitation field is approximated by interpolating its nodal values i n terms of the element shape functions. Spatial correlations of the ra ndom distributed excitation and equivalent loads on rotational degrees of freedom are taken into account by this consistent-load approach. T he computational cost is considerably less than the most rigorous FE f ormulation which involves double area integration and double summation over pairs of elements, and yet this new approach gives comparable ac curacy. The equivalent excitational power spectral density matrix gene rated by this approach can be used to compute structural responses by means of frequency domain techniques. Applications to beam and plate s tructures subjected to random pressure loads are given. Response resul ts obtained using the present approach are observed to give better acc uracy than the lumped-load approximation procedures. Furthermore, the method is well suited to implementation in existing FE codes.