SBIR-STTR Award

The objective of this Phase I research is to develop a computational procedure for predicting the life and reliability of composite structural panels subjected to complex dynamic loads from acoustic, aerodynamic, and thermal environments. The proposed research uses a nonclassical variational approach and a time domain Monte Carlo method to develop analytical equations of high accuracy and efficiency. The structural mechanical model will include modeling for transverse shear effects. The time domain Monte Carlo method will permit an examination of the effects of peak stresses and exceedances; subsequently, meaningful predictions of structural life (fatigue) can be made. Phase I research will be used to verify the synergistic combining of the nonclassical variational methods with the Monte Carlo time domain analysis. The resulting computational procedure will be used to establish the feasibility of the developing either a discretized (finite element) or numerical computer program to be completed during any Phase II effort. This research will lead to a new technology base for estimating the nonlinear response characteristics of a new generation of aircraft exposed to severe acoustic aerodynamic, and thermal environments.

The objective of the proposed Ph II research is to develop computational programs for the prediction of nonlinear flutter (aeroinelasticity) in panels made from low-temperature polymer matrix materials such as graphite/epoxy in Kevlar/polyester used in aircraft primary and secondary structures, and radomes and high-temperature capability materials for use on supersonic/hypersonic vehicles (NASP). The structural and material models, defined during Ph I research, effectively model complex phenomena including nonlinear geometry (large deformations), nonlinear material behavior (in plane and in the matrix), transverse shear,curvature in two directions of the structure, damping, and thermal heating. The aerodynamic models include extended nonlinear piston theory for supersonic/hypersonic flow with subsonic/transonic flow treated by allowing the structural/material modules to interact with full-fledged CFD codes, thus permitting state-of-the-art aerodynamic modeling to be used with high fidelity structural/material models. Of extreme importance to the Air Force is Anamet's intention to implement these numerical models on a low-cost transputer-based personal computer (TPC) system capable of performing at the rate of 20 Mips. At the option of the Air Force, the TPC can be a deliverable item as a part of Phase II effort. This would give the Air Force the capability to perform advanced state-of-the-art nonlinear flutter calculations without reliance on a mainframe computer system.