Abstract
Modern requirements on constructions impose that proper design strategies must be adopted in order to obtain a robust structure: in this sense, consequence-based design focuses the attention on the structural response to damage. The behavior of statically indeterminate structural systems under damage is nonlinear because the load paths intertwine each other, even if each component behaves linearly. The paper aims both to highlight the behavior of a metallic truss under progressive damage and to define a possible strategy for designing a truss that is able to sustain damage acting at random on one of its elements. Structural complexity is used as a leading parameter. Following the results of a parametric analysis, it emerges that, as much as the Normalized Structural Complexity Index increases, the efficacy of the load paths is spread such that the impact of random damage decreases, making the approach feasible.
1. Introduction
The modern requirements in structural design impose that a structure has to be robust. Many definition of structural robustness have been formulated. ISO (1998) considers the possibility of a structure not to be damaged to an extent disproportionate to the original cause. The Eurocode proposes a similar idea, considering the ability of the structure to withstand events, instead of being damaged (CEN, 2006). The American General Services Administration proposal relates to the concept of the resistance to damage without premature and/or brittle failure (ARA, 2003). The Joint Committee on Structural Safety’s document proposes an approach based on risk at a damage state (JCSS, 2011). Many authors have dealt with the concept of robustness proposing various properties that define a structure as robust (Agarwal and England, 2008; Biondini et al., 2008a; Bontempi et al., 2007; Starossek and Haberland, 2011; Val et al., 2006). Vrouwenvelder (2008) states that a robust structure should not be too sensitive to local damage, whatever the source of damage.
6. Conclusions
In summary, the study of the response of a truss structure to damage has been performed. The elastic energy was used as a measure for assessing the effects of progressive damage. In order to better evaluate the overall response, the average measure of the increment of deformation work was considered through the parameter M. In addition, the relationship between the value of the Normalized Structural Complexity Index and M was investigated. The former parameter is a measure of the efficacy of the load paths across the structure. A truss cantilever made of eight nodes and 15 rods was used throughout the calculations,
