Dynamic damage criterion and damage mode for single layer lattice shell

Abstract

When member buckling and joint fractures are considered in the numerical analyses of single layer lattice shells, the relationship curve between peak ground acceleration of the earthquake and the maximum nodal displacement, and the time–history curve of maximum nodal displacement, are erratic and unpredictable. Therefore, with such considerations, the current approach to determine dynamic damage of single layer lattice shells by comparing peak ground acceleration of the earthquake with critical ground acceleration derived from incremental dynamic analysis is inappropriate. An improved structure dynamic damage criterion is proposed for single layer lattice shells in this paper, which reviews the balance status of structure dynamic resistance against the earthquake action, and the structure damage time can be predicted by the occurrence of non-convergent solution to the structural nonlinear dynamic equilibrium equations in the iterative process from the mathematical point of view. Numerical examples are presented to illustrate the simplicity and practicality of the proposed criterion. This criterion serves clear physical meaning and is of considerable potential applicability in analyzing single layer lattice shell structures. Results of parametric analyses of single layer lattice shells under severe earthquake actions indicate that the structure dynamic damage is not determined by material strength failure. For single layer spherical lattice shell, it is determined by structural instability resulted from member buckling; and for single layer cylindrical lattice shell, it is determined by the combined effect of structural instability and the change of structural topology that resulted from member buckling and joint fractures respectively.