Advantages and limitations of multi-degree-of-freedom models to simulate impact behaviour of concrete structures

摘要

The present contribution deals with the behaviour of reinforced concrete beams under impact load.rnMoreover, the paper is intended as a discussion of advantages and limitations of different numericalrnmodels according to the degree of complexity. Two types of models are used. On the one hand, arnsimplified approach is presented, consisting of a three-degree-of-freedom model that reproduces thernresponse of simply supported reinforced concrete beams subjected to an impact load at the midspan.rnThe three degrees of freedom represent: 1) the contact between the beam and the projectile, 2) thernflexural behaviour of the beam, and 3) the development of a critical shear crack. Nonlinearrnbehaviour and damping are introduced into the three degrees of freedom. On the other hand, arncomprehensive finite element model (Ansys LS-Dyna) has been used, which includes a concreterndamage model with strain rate effect. It is discussed how the failure mode and the main physicalrnbehaviour are reproduced, comparing advantages and disadvantages regarding the reproduction ofrnnonlinearities or strain rate effects, as well computational time required to perform parametricrnanalyses.