In general, the progressive failure analysis of space truss systems ca
n only be adequately evaluated with both material and geometric nonlin
earities considered. This paper utilizes constitutive relationships to
provide the fundamental modeling of elastic and inelastic member beha
vior, coupled with a geometrically nonlinear finite element model. Mod
eled member material behavior modes include: buckling, yielding, inela
stic post-buckling, unloading, and reloading. Geometric nonlinearity i
s based on iteratively correcting the linearized updated Lagrangian sp
ace truss displacement equations. Interaction of the nonlinear loading
behavior results in structure force redistribution which can lead to
member failure, unloading, or reloading. Such behavior can lead to the
progressive failure of a space truss structure. The developed model t
races the sequence of localized buckling, yielding, and inelastic memb
er response. Results are presented to demonstrate model capabilities f
or representing the inelastic, progressive failure response of space t
russ structures.