@misc{NaveedKuehhorn, author = {Naveed, Zishan and K{\"u}hhorn, Arnold}, title = {An Isogeometric Based Study of Contact Behaviour for Rotating Structures}, series = {14th World Congress on Computational Mechanics (WCCM)-ECCOMAS Congress 2020, Virtual Conference: 11-15 January 2021}, journal = {14th World Congress on Computational Mechanics (WCCM)-ECCOMAS Congress 2020, Virtual Conference: 11-15 January 2021}, language = {en} } @misc{NaveedKuehhornKober, author = {Naveed, Zishan and K{\"u}hhorn, Arnold and Kober, Markus}, title = {Contact Behaviour of Isogeometric Analysis for Rotating Structures and its Industrial Application by Coupling to the Classical Finite Element Method}, series = {VII International Conference on Isogeometric Analysis, M{\"u}nchen, 18.-20. September 2019}, journal = {VII International Conference on Isogeometric Analysis, M{\"u}nchen, 18.-20. September 2019}, pages = {1}, abstract = {Especially for rotating structures like bearings non-smooth contact surfaces, as they appear in classical finite element modeling, lead to various problems during the analysis involving mesh interlocking and spurious oscillations in contact forces. In order to eliminate these issues, very fine meshes and additional smoothing strategies are employed in case of the finite element method (FEM). But also Non-Uniform Rational B-splines (NURBS) based isogeometric analysis (IGA) can be very useful for the contact analysis due to the inherent higher order continuity of NURBS basis functions. In this contribution, the contact behavior using classical FEA and IGA approaches is studied by means of an example of a pendulum under gravitational load. In addition, a more practical example of a coupled IGA-FEM problem with a cylindrical roller bearing is also reported in this paper. This research study of contact analysis has been carried out for the above mentioned examples using LS-DYNA and illustrates that contact surfaces of coarsely meshed geometry lock the rotation of the parts in case of classical FEM. On the contrary, when the contact surface is represented by NURBS elements it allows the rotation of the parts and effectively alleviates the contact force oscillation.}, language = {en} } @misc{NaveedKuehhornKober, author = {Naveed, Zishan and K{\"u}hhorn, Arnold and Kober, Markus}, title = {Comparative Evaluation of Isogeometric Analysis and Classical FEM with Regard to Contact Anaylsis}, series = {12th European LS-DYNA Conference 2019, 14-16 May 2019, Koblenz}, journal = {12th European LS-DYNA Conference 2019, 14-16 May 2019, Koblenz}, pages = {10}, abstract = {Isogeometric analysis represents a newly developed technique that offers the application of Computer Aided Designs (CAD) concept of Non-uniform Rational B-Splines (NURBS) tool to describe the geometry of the computational domain. The simplified transition of CAD models into the computational domain eliminates the problems arising from the geometrical discontinuities induced by the faceted approximation of the mesh. Moreover, numerical analysis directly on NURBS objects significantly reduces the design-to-analysis time compared to traditional FEA approach. In the field of contact mechanics, when finite elements are applied to geometry with curved surfaces, the result is a non-smooth geometrical representation of interface surfaces which may lead to mesh interlocking, high jumps and spurious oscillations in contact forces. To eliminate these issues, various surface smoothening strategies are to be employed in case of FEM. Isogeometric based analysis alleviates these issues without employing any additional smoothening strategy due to inherent higher order continuity of NURBS basis functions and much more accurate results are obtained compared to conventional FE approach. In the current study, LS-DYNA is used to demonstrate the capabilities and advantage of an isogeometric analysis though an example of pendulum under gravitational load. The numerical simulation results are analytically validated and the comparison of NURBS surfaces with faceted surfaces is carried out to investigate the accuracy.}, language = {en} }