Study of Crashworthiness of Light Aircraft Fuselage Structures: A Numerical and Experimental Investigation

摘要

A combined analytical and experimental program was undertaken to study the crashworthiness of light aircraft fuselage structures. In the analytical study, a self-consistent system of equations was developed using the finite element method. These equations were linearized (in terms of displacements and angular velocities) and extended to include material nonlinearities. Rib and curved plate elements which include all rigid-body modes were also derived utilizing a matrix formulation to provide ease in programming. The system of equations was then solved using an implicit Newmark-Beta method with the Frontal Solver routine, that avoids inverting the matrices at every time step. This technique requires smaller computer storage than a banded storage method and has other implicit advantages such as stability and accuracy. In addition, a pendulum gantry crash facility was designed and constructed to test scale model stiffened aluminum fuselage structures in a simulated free-flight impact mode. Tests were carried out and dynamic measurements were made of selected g-loads (accelerations) and component strains.