Investigação experimental e numérica sobre o fenômeno de impacto em barras

Abstract

In building`s columns design, the NBR 6118:2014 gives no indications about the procedure for column design subjected to impact loads. On the other hand, the NBR 7188:2013 standard, referring to bridges design, recommends the use of some impact coefficients without considering the mass and speed of the vehicle. In this context, this undergraduate final work looks for an experimental and numerical research about the phenomenon of impact in bars. In the experimental test carried out, a steel ball was launched in free fall, from different heights, in a steel bar set in a fixed support. This situation was reproduced computationally in the ANSYS Autodyn® software, using the finite element method, focusing on displacements. When comparing the experimental tests and the numerical tests, it could be seen that there was a good convergence between the presented results. By means of these results, it was based on the determination of the impact coefficient, which is given by the ratio between the equivalent static force and the static force given by the force weight. The coefficient of impact seeks to multiply the static loads to reproduce the displacement due to the action of the dynamic analysis. With the coefficients found, an abacus was elaborated according to the velocity and masses of the object of impact. Therefore, the method to discovery the dynamic impact coefficients, for being validated, could be used for application in several projects and allows the simplification of numerical calculations.