Carles Colomer Segura

VALIDATION OF A NUMERICAL AND ANALYTICAL MODEL OF IMPACTED COLUMNS BY MEANS OF SMALL-SCALE DROP WEIGHT EXPERIMENTS

The analysis of structures under extreme accidental actions such as explosion or impact has been an ongoing topic of research since the 50’s. Especially regarding the dynamic behaviour of impulsively loaded columns, many analytical and numerical models have been developed, which aim at predicting the ultimate load bearing capacity of the column and its residual level of deformation, which is directly linked to the residual capacity of the column after the impact. Nevertheless most of the existing approaches lack an appropriate consideration of membrane related resisting mechanisms, either by completely neglecting the presence of any longitudinal restraints or by assuming them as perfectly rigid. A realistic evaluation of the dynamic behaviour of the column requires therefore a more exact approach in order to consider arbitrary longitudinal connector stiffnesses. This paper presents a new analytical approach to the deformational and energetic behaviour of impacted column elements, which allows for an closed form solution of the maximum displacements under arbitrary longitudinal boundary conditions. On the other hand, a small-scale drop weigth tower has been constructed in order to validate the results of the analytical model and compare them to predictions of other numerical approaches. The test rig has been conceived to allow for longitudinal displacements of the specimen, thus allowing to measure the motion of the column both in transversal and longitudinal direction.