Global instabilities of pyramidal trusses

Authors

DOI:

https://doi.org/10.5540/tcam.2026.027.e01852

Keywords:

multiple bifurcation, snap-through, pyramidal trusses

Abstract

This paper presents an exact analytical study of global instabilities in pyramidal trusses under large displacements. Using the stationarity of total potential energy and Green-Lagrange strain, non-linear equilibrium equations are derived for a 3-bar isostatic truss. The tangent stiffness matrix yields 6 critical points: 2 limit points and 2 double bifurcation points. Multiple bifurcation is shown to occur universally for α > 45◦, independent of bar count m ≥ 3 and alignment. Closed-form expressions for primary and secondary paths, validated via eigenvalue analysis, establish a generalized buckling threshold with direct implications for lightweight lattice design.

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Published

2026-03-26

How to Cite

Silva, W. T. M., Barrozo, G., & Portela, A. (2026). Global instabilities of pyramidal trusses. Trends in Computational and Applied Mathematics, 27(1), e01852. https://doi.org/10.5540/tcam.2026.027.e01852

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Section

Original Article