A new solution is developed to model the stable postbuckling behaviour of a
truss-lattice shear panel. The mode shapes are derived through load equilibrium
conditions and are based on the load in the structural members. The load in each
member of a single-cell panel can be calculated exactly, without the need for an
iterative postbuckling path, and the method produces excellent results in initial and
advanced postbuckling. Comparisons are drawn with an alternative analytical
method and the commonplace finite element approach. A Rayleigh–Ritz method
based on a Fourier approximation to the mode shape provides the useful progression
from an unbuckled to a buckled structure giving excellent results in initial
postbuckling, although is limited for advanced postbuckling. The standard finite
element method for this problem produces accurate results but with limited detail
around the buckling load owing to the presence of an imperfection in the
shape of the initial mode, which is required to initiate the postbuckling
analysis.