John Jomo MSc Reseach Assistant Room: 3161 Email: Diese E-Mail-Adresse ist vor Spambots geschützt! Zur Anzeige muss JavaScript eingeschaltet sein! Tel: +49 89 289-25064 Fax: +49 89 289-25051

Research

• Simulation in applied mechanics

Journal Papers



• Jomo, J.; de Prenter, F.; Elhaddad, M.; D'Angella, D.; Verhoosel, C.; Kollmannsberger, S.; Kirschke, J.; Nübel, V.; van Brummelen, H.; Rank, E. Robust and parallel scalable iterative solutions for large-scale finite cell analyses
  Finite Elements in Analysis and Design - Status: Accepted for publication, 2019
  DOI: 10.1016/j.finel.2019.01.009
  
  
  
  
  
  
  
• Özcan, A.; Kollmannsberger, S.; Jomo, J; De Lorenzis, L.; Rank, E. Residual stresses in metal deposition modeling: discretizations of higher order
  Computers and Mathematics with Applications, 2018 - Status: Postprint / reviewed
  
  
  
  
  
  
  
• Jomo, J.; Zander, N.; Elhaddad, M.; Özcan, A.; Kollmannsberger, S.; Mundani, R-P.; Rank, E. Parallelization of the multi-level hp-adaptive finite cell method
  Computers and Mathematics with Applications 74 (1), pp. 126-142, Elsevier, 2017
  DOI: 10.1016/j.camwa.2017.01.004 - Status: Verlagsversion / published
  
  
  
  
  
  
  

Submitted preprints

Conference Papers

• Jomo, J.; Patel, N.; Kudela, L.; Kopp, P.; Ertl, C.; Kollmannsberger, S.; Allalen, M.; Mundani, R-P.; Rank, E. Enabling efficient numerical simulations using the finite cell method on massively parallel systems
  In: Environmental Informatics Techniques and Trends, Adjunct Proceedings of the 32nd EnviroInfo conference, Garching, Germany, 2018
  
  
  
  
  
  
  

Conference Talks

• Jomo J., Carraturo M., Hug. L, Kollmannsberger S., Mundani R. P., Rank E. Numerical simulation of coupled problems in the context of the parallel hp-adaptive finite cell method
  In: VIII International Conference on Coupled Problems in Science and Engineering, Sitges, Spain, 2019
  
  
  
  
  
  
  
• Korshunova N., Jomo J., Reznik D., Kollmannsberger S., Rank E. From CT-Scans to material characterization: mechanical behavior of micro-porous metal structures
  In: High-Order Finite Element and Isogeometric Methods, 2019
  
  
  
  
  
  
  
• Korshunova, N., Jomo, J., Reznik, D., Kollmannsberger, S., Rank, E. Material characterization of additively manufactured complex steel components
  In: Simulation for Additive Manufacturing (Sim-AM 2019), 2019
  
  
  
  
  
  
  
• Jomo J., Korshunova N., Carraturo M., Kollmannsberger S., Mundani R. P., Rank E. A parallel immersed finite element framework for numerical computations of metal additive manufacturing processes and products
  In: II International Conference on Simulation for Additive Manufacturing, Pavia, Italy, 2019
  
  
  
  
  
  
  
• Korshunova, N., Jomo, J., Reznik, D., Kollmannsberger, S., Düster, A., Rank, E. Show abstract From images to material characterization of additively manufactured micro-architectured structures
  In: 13th World Congress in Computational Mechanics, 2018
  
  
  
  Recent developments in additive manufacturing have provided a unique possibility to create complex structures with porosity on a micro and meso-structural levels. Such designs can outperform conventional materials in specific industrial applications, e.g. turbine blades with a transpiration cooling. However, the high flexibility of the input parameters for the 3D printers, such as the laser diameter, hatch distance etc., challenges a reliable estimation of the mechanical behaviour of the final parts. Moreover, a high variation of porosity in all of the material directions limits the application of analytical bounds based on the void fraction ratio. Numerical homogenization is an efficient and robust alternative to perform non-desctructive evaluation of the material characteristics based on high resolution 3D images of produced specimens. The conventional Finite Element Method applied to numerical homogenization leads to a labor intensive meshing procedure to extract the representative volume elements that makes it impractial from the industrial point of view. Furthermore, non-symmetric micro-architectured structures make it difficult to apply correct boundary conditions for the solution of the microstructural boundary value problem. To address these issues, in the scope of the presented work the Finite Cell Method is employed in combination with the window method. A road map is presented for the automatized numerical computation of the homogenized elasticity tensor of additively manufactured steel structures using 3D images. The computational results are verified with the direct finite-cell computation of a given produced specimen. Validation of the proposed model is performed comparing the numerical results with the results stemming from experimental tests.
  
  
  
• de Prenter, F.; Jomo, J.; Elhaddad, M.; D'Angella, D.; Kollmannsberger, S.; Verhoosel, C.; van Brummelen, H.; Rank, E. Preconditioned iterative solvers for the multi-level hp-adaptive finite cell method
  In: 6th European Conference on Computational Mechanics, Glasgow, United Kingdom, 2018
  
  
  
  
  
  
  
• Kollmannsberger, S.; Özcan, A.; Carraturo, M.; Kopp, P.; Jomo, J.; Rank, E. Additive Manufacturing
  In: Advanced School on Immersed Methods, Eindhoven, Netherlands, 2017
  
  
  
  
  
  
  
• Özcan A.; Kollmannsberger S.; Jomo J.; Rank E. Thermo-elastoplastic simulation of selective laser melting processes with multi-level hp-adaptive finite cell method
  In: XIV International Conference on Computational Plasticity , 2017
  
  
  
  
  
  
  
• Jomo, J.; Zander, N.; Elhaddad, M.; Özcan, A.; Kollmannsberger, S.; Mundani, R-P.; Rank, E. A parallel approach for the multi-level hp-daptive finite cell method
  In: Siam Conference on Computational Science and Engineering 2017, SIAM, 2017
  
  
  
  
  
  
  
• Prenter F. d., Verhoosel C., Jomo J., Kollmannsberger S., van Brummelen H., Rank E. Preconditioned iterative solvers for finite cell discretizations
  In: eXtended Discretization MethodS X-DMS 2017, 2017
  
  
  
  
  
  
  
• Özcan, A.; Kollmannsberger, S.; Jomo, J.; Rank, E. Numerical Simulation of Selective Laser Melting Processes with Multi-Level hp-Adaptive Finite Cell Method
  In: 10th International Conference on Advanced Computational Engineering and Experimenting, Split, Croatia, 2016
  
  
  
  
  
  
  
• Jomo, J.; Zander, N.; Elhaddad, M.; Özcan, A.; Kollmannsberger, S.; Mundani, R-P.; Rank, E. Parallelization of the multi-level hp-adaptive finite cell method
  In: 5th European Seminar on Computing, Pilsen, Czech Republic, 2016
  
  
  
  
  
  
  
• Elhaddad, M.; Zander, N.; Jomo, J.; Kollmannsberger, S.; Kirschke, J. S.; Ruess, M.; Rank, E. Show abstract Adaptive discretizations for bone-implant systems using the finite cell method
  In: Engineering Mechanics Institute Conference 2016, Nashville, TN, USA, 2016
  
  
  
  In recent years, the finite element method has been increasingly used to study the biomechanics of bone-implant systems. Patient-specific models need to consider the individual geometry for every case. Typically, geometric models of the bone are reconstructed from medical images --- most commonly CT scans . Following segmentation, a finite element mesh has to be generated. This can be a simple voxel-based mesh, where a predefined number of voxels constitute one finite element in a grid that matches the voxel model. Alternatively, geometry-conforming meshing procedures can be used to generate an unstructured mesh. To this end, the surface points are extracted from the voxel model and converted to a solid model, which is then meshed into an unstructured grid. Similarly, the geometry of the implant is usually reconstructed from medical images, or provided by Computer-Aided-Design (CAD) models, and then incorporated in the finite element mesh. The adequate treatment of the bone-implant interface demands the spatial refinement of the finite element mesh at the interface for an accurate solution. For voxel-based finite elements, a very fine resolution is already necessary to resolve the implant's geometry. This leads to an extremely high number of degrees of freedom, as the whole grid has to be refined. On the other hand, geometry-conforming finite elements need more pre-processing (converting the bone's voxel model to a solid model), and complex meshing procedures to resolve geometries of the bone and the implant with graded refinement of the mesh towards the interface. In this contribution, we will use the finite cell method (FCM) in conjunction with a hierarchical refinement scheme to model a vertebral fixation system. The FCM discretization completely circumvents the mesh generation procedure, as the geometry is resolved on the integration level. Here, the flexibility of FCM in dealing with different types of geometric representations is demonstrated: the bone's geometry is represented by the voxel model from a CT-scan, whereas the implant's geometry is directly described by a CAD solid model. Both representations are directly used in the FCM framework, thereby substantially reducing the pre-processing effort. Furthermore, the hierarchical refinement scheme yields a higher accuracy at the bone-implant interface by adaptively refining the FCM grid.
  
  
  

Supervised theses

• Filomeno, Giovanni Matrix-Free Conjugate Gradient for the Finite Cell Method
  Master's thesis, Technische Universität München, 2017
  
  
  
  
  
  
  
• Abdelaleim, O. Implementation of Plastic Material Models in Finite Cell Method with Multi-level hp-adaptivity
  Master's thesis, Technische Universität München, 2016
  
  
  
  
  
  
  

Courses

• Introduction to Programming in C++ (Winter Term 15/16)
• Computation in Engineering I (Winter Term 15/16)
• Computation in Engineering II (Summer Term 16)
• Computation in Engineering I (Winter Term 16/17)
• Computation in Engineering II (Summer Term 17)