TY - JOUR A1 - Otto, Peter A1 - De Lorenzis, L. A1 - Unger, Jörg F. T1 - Coupling a NURBS contact interface with a higher order finite element discretization for contact problems using the mortar method JF - Computational Mechanics N2 - In this paper, a contact problem between two bodies, discretized by finite elements, is solved by adding an auxiliary NURBS layer between the bodies. The advantages of a smooth contact formulation in a NURBS approach are combined with simple mesh generation procedures for the bodies discretized with finite elements. Mesh tying conditions are used to couple the NURBS layer with the finite element discretization. The NURBS layer is the master side for contact and mesh tying. Mesh tying is enforced either using pointwise or mortar type approaches. Frictionless 2D and 3D contact problems are considered using small deformations. The contact problem is discretized with the mortar method and a penalty approach is used to enforce the contact constraints. A robust element-based quadrature is applied for mortar tying and contact discretizations, thus avoiding computationally expensive Segmentation. KW - Contact mechanics KW - Isogeometric analysis KW - Mortar methods KW - Spectral element method PY - 2018 DO - https://doi.org/10.1007/s00466-018-1645-y SN - 0178-7675 SN - 1432-0924 VL - 63 IS - 6 SP - 1203 EP - 1222 PB - Springer AN - OPUS4-46800 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Otto, Peter A1 - De Lorenzis, L. A1 - Unger, Jörg F. T1 - A regularized model for impact in explicit dynamics applied to the split Hopkinson pressure bar JF - Computational Mechanics N2 - In the numerical simulation of Impact phenomena, artificial oscillations can occur due to an instantaneous change of velocity in the contact area. In this paper, a nonlinear penalty regularization is used to avoid these oscillations. Aparticular focus is the investigation of higher order methods in space and time to increase the computational efficiency. The spatial discretization is realized by higher order spectral element methods that are characterized by a diagonal mass matrix. The time integration scheme is based on half-explicit Runge–Kutta scheme of fourth order. For the conditionally stable scheme, the critical time step is influenced by the penalty regularization. A framework is presented to adjust the penalty stiffness and the time step for a specific mesh to avoid oscillations. The methods presented in this paper are applied to 1D-simulations of a split Hopkinson pressure bar, which is commonly used for the investigation of materials under dynamic loading. KW - Penalty regularization KW - Spectral element method KW - Differential–algebraic equations KW - Split Hopkinson pressure bar KW - Dynamic contact PY - 2016 DO - https://doi.org/10.1007/s00466-016-1311-1 SP - 1 EP - 15 PB - Springer-Verlag CY - Berlin Heidelberg AN - OPUS4-36967 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -