Abstract： A new parameter called exponential strain energy density sum parameter, which reflects
the stability characteristic of structural working state, is proposed based on the strain energy
density of structure for analyzing the seismic responses of single-layer reticulated shell
structures. Firstly, contour graphs and curves for various responses of single-layer reticulated
shell are plotted, exhibiting that the existing parameters are incapable of completely describing
the entire working performance of structure, and particularly in the elastic-plastic working
stage, the existing parameters cannot reflect the stable and exact working characteristics of
structures due to external loads. Secondly, it is attempted to sum up the exponential strain
energy density of all elements to obtain a new parameter. By investigating the changing feature of
the new parameter with seismic intensity when the structure is working in elastic or elastic-
plastic stage, it is found that the new parameter can reflect the stability characteristic of
structural working state, the transition characteristic of structure from working state to failure
state, and the instability characteristic of structure in failure state. Finally, according to the
investigated working characteristics and the maximum nodal displacements of single-layer
reticulated shell structures, the grading and division indices for seismic damage of the
structures are proposed, which can be referred when conducting in-depth seismic analysis of shell
structure and improving the corresponding design codes.
