Energy redistribution patterns in damaged elastic frames

Abstract

Frames structures are systems made of connected elements and are widely diffused in civil and industrial engineering. Like other structural types, they can suffer damages. Element removal can cause the collapse of the whole structure. Alternate load path is a strategy to prevent collapse through the redistribution of the forces to the safe elements. Although this approach is largely adopted in the design of robust structures, the knowledge on how the redistribution mechanism act is still limited. To understand the mechanisms that raise, the strain energy in each structural component is considered as indicator. Two dimensionless quantities, i.e., beam-to-column flexural stiffnesses and transposed-to-proper column inertia are found to be the two relevant terms that rule the patterns of strain energy on the damaged frame. A relationship between the patterns, the increment of energy and the two dimensionless quantities is found, providing interesting insights into the behavior of such statically indeterminate structure. The results can be used for new approaches to robustness-oriented structural design.