Study of the Mechanical Behavior of Low-Velocity Impact Loading in the Presence of Stress Concentrators

The aim of this article was to assess the behavior of polymer composites under low-velocity impact considering stress concentrators (two side holes at the point of impact) and determine the residual mechanical properties of these materials using FAI (Flexural After Impact). Analysis of residual properties ascertained the effects of damage and stress concentrators, assessing their individual influence in increasing the stress concentration factor (K). This analysis was conducted via tests that consider the separate effects of each case and a formulation that relates them. In addition, this paper also assessed the influence of void percentage on the impact and residual strength, developing two E-glass fiber fabric-based composites with different void percentage. The tests performed showed that impact damage increased the concentration factor of the material by 18%, but in samples tested with side holes, damage decreased residual strength by only 5%.