Title page for ETD etd-08252008-162620


Type of Document Dissertation
Author Engelstad, Stephen Philip
URN etd-08252008-162620
Title Nonlinear probabilistic finite element modeling of composite shells
Degree PhD
Department Engineering Mechanics
Advisory Committee
Advisor Name Title
Reddy, Junuthula N. Committee Chair
Cramer, Mark S. Committee Member
Frederick, Daniel Committee Member
Johnson, Eric R. Committee Member
Singh, Mahendra P. Committee Member
Keywords
  • Composite materials
Date of Defense 1990-11-05
Availability restricted
Abstract

A probabilistic finite element analysis procedure for laminated composite shells has been developed. A total Lagrangian finite element formulation, employing a degenerated 3-D laminated composite shell element with the full Green-Lagrange strains and first-order shear deformable kinematics, forms the modeling foundation. The first-order second-moment technique for probabilistic finite element analysis of random fields is employed and results are presented in the form of mean and variance of the structural response. The effects of material nonlinearity are included through the use of a rate-independent anisotropic plasticity formulation with the macroscopic point of view. Both ply-level and micromechanics-level random variables can be selected, the latter by means of the Aboudi micromechanics model. A number of sample problems are solved to verify the accuracy of the procedures developed and to quantify the variability of certain material type/structure combinations. Experimental data is compared in many cases, and the Monte Carlo simulation method is used to check the probabilistic results. In general, the procedure is quite effective in modeling the mean and variance response of the linear and nonlinear behavior of laminated composite shells.

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