While dynamic fracture in MM was initially captured quite naturally by separation of nodes, ,, ,, ,, the authors in reference, for example found that such an approach might lead to numerical fracture. These authors reported finite element simulations underpredict the impact resistance of concrete. For example, the authors in reference 39 accurately predicted the penetration depth and residual impact velocities compared to the experiments done by the authors in reference 40. MM have also been used to model impact events. An overview and computer implementation aspects of meshfree methods (MM) is discussed in reference 38. Meshfree or meshless methods are good alternatives to FEM, ,, ,, ,, ,, , as they can model large deformation and perforations without additional techniques and much loss of accuracy. Often, element-deletion methods were exploited in order to allow for large deformations and complete perforations. Many studies are baed on finite element analysis, ,, ,, ,. In reference 15, the authors extended their scalar damage model for isotropic damage to anisotropic damage by introducing a vectorial damage.Īnother important ingredient to model the impact resistance of concrete is the computational method.
This dynamic damage variable depends on previous damage increments and the associated damage rates. It employs a dynamic damage variable that delays the damage evolution in order to take the strain-rate effect into account. In this work, we employ a constitutive model proposed in reference 14. Coupled damage-plasticity models were proposed for instance in references, ,,. A quasi-continuum plasticity approach capturing the dynamic buckling strength of sandwich structures was proposed by Rabczuk et al. In reference 5, the authors extended the famous Johnson-Cook (JC) model to concrete materials the JC model accounts for strain rate and temperature effects and also plastic deformations. Popular constitutive models based on damage mechanics include the work in references,. For high dynamic loading it is important to accurately capture the material response under extreme pressure loading and the so-called strain rate effect. Besides computational methods, constitutive models are an important ingredient of any mechanical model. Computational modelling of concrete under impact loading remains one of the key challenges in civil engineering.
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