Effect of Hourglass Control on LS-DYNA® Concrete Constitutive Models in Low Velocity Impact Simulations

The performance of reinforced concrete structural components under impact loading has received significant attention over the past decade, with high fidelity numerical simulations supplementing the available experimental test data. Several studies have evaluated the prediction of impact force and displacement time histories, as well as cracking and spalling, using a number of constitutive models in LS-DYNA. Under-integrated hexahedral elements are typically used in these analyses with hourglass control introduced to suppress hourglass modes. Prior studies have demonstrated that finite element analysis of reinforced concrete beams to impact loading is sensitive to the hourglass coefficient, however several studies have limited their basis of selection of appropriate hourglass coefficients to relative hourglass energy and comparison of model predictions with experimental measurements of displacement and force time histories. Furthermore, studies contrasting the performance of different constitutive models have routinely used a single hourglass coefficient for all models [1, 2]. This may be problematic if individual constitutive models demonstrate unique sensitivity to the hourglass control.