Behavioral analysis of steel I-beams under repeated dynamic loads: Impact of various impactor head types

The dynamic loadings to which the structural element is repeatedly exposed cause more damage due to the fatigue effect. In this article, the damage cases formed under the effect of the impact load acting on the weak axis of I-section steel beams under repeated impact loads are investigated and the effect of the geometric shape of the falling weight on the element behavior is evaluated by experimental and numerical methods. A 2000 mm long IPE160 section simply supported beam is subjected to impact load in the weak axis direction. The 100 kg impact load is applied from a height of 2200 mm with a hammer head having three different geometric shapes (rectangular, circular and triangular). Three-dimensional finite element models of the 6 experimental studies were analyzed using Abaqus Explicit software. In order to determine the effect of the geometric shape of the falling weight on the beam behavior under the effect of repeated load; five parameters such as displacement, acceleration, support reaction, stress distribution and plastic strain were investigated. The displacement, acceleration and support reaction formed in the beams were numerically investigated by means of finite element models and compared with the experimental results. The results obtained showed that the maximum deflection and acceleration occurred in the beams hit by the triangle-headed impact crusher. In addition, the largest plastic deformation and stress distribution were observed in the tests performed using triangle-headed impact crushers. In the series I (rectangular), II (circular), III (triangular) test series, the displacement value increased by 44%, 79% and 100%, respectively, compared to the first impact. It is seen that the 2nd degree effects play an important role in the increase of the damage level in the second impacts. It was determined that the maximum reaction force tended to increase from Series I to Series III. This shows that reducing the contact area of the falling weight significantly increases the reaction forces. • The increase in midpoint displacement can be seen as a result of decreasing the contact area of the impactor. • The accelerations generated by the impact energy increased more than twice at a second impact, according to the first impact. • The decrease in the contact surface of the hammer head increased the shear damage. • Applying the load to the exact center point of the element span provided a symmetric distribution of both deformation and stress.