The Combined Finite/Discrete Element Method in Transient Dynamics of Reinforced Concrete Structures under Blast Loading

Abstract

The research here presented has employed the newly evolved finite-discrete element method in the development of novel numerical solutions for the analysis of failure and collapse of reinforced concrete structures under hazardous blast loads. The first step to achieving this was to study the structural response, failure and collapse of individual structural elements. Thus the research in this area is taken further by using numerical solutions to study the behaviour of reinforced concrete beams to the point of failure. The results are implemented into the combined finite-discrete element method through a novel computationally efficient two noded beam element. Numerical integration across the cross section of the beam element is applied to facilitate the application of nonlinear constitutive laws for both steel and concrete for the case of multi-axial bending coupled with axial force. The accuracy of this new element is tested and validated under both static and dynamic loading situations using analytical solutions together with experiments undertaken at the University of Alberta and The Swiss Federal Institute of Technology. The proposed element has the advantage of reducing the size of the problem by fifty percent through the elimination of the rotational degrees of freedom using static condensationT. he new element,w hen coupledw ith NBS contactd etection, enables the same finite element mesh to be used for the discretised contact solutions, thus further reducing the CPU time required. When implemented into the finite-discrete element method, the proposed numerical solution also takes into account contact-impact and inertia effects. It is therefore both an accurate and CPU efficient solution to the combined finite-discrete element analysis of structural response, failure and collapse of real life structuresw hen subjectedt o hazardouslo ads as demonstratedin the thesis. T Bangash