@misc{WeiserRoelligArndtetal.2008, author = {Weiser, Martin and R{\"o}llig, Mathias and Arndt, Ralf and Erdmann, Bodo}, title = {Development and test of a numerical model for pulse thermography in civil engineering}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-10980}, number = {08-45}, year = {2008}, abstract = {Pulse thermography of concrete structures is used in civil engineering for detecting voids, honeycombing and delamination. The physical situation is readily modeled by Fourier's law. Despite the simplicity of the PDE structure, quantitatively realistic numerical 3D simulation faces two major obstacles. First, the short heating pulse induces a thin boundary layer at the heated surface which encapsulates all information and therefore has to be resolved faithfully. Even with adaptive mesh refinement techniques, obtaining useful accuracies requires an unsatisfactorily fine discretization. Second, bulk material parameters and boundary conditions are barely known exactly. We address both issues by a semi-analytic reformulation of the heat transport problem and by parameter identification. Numerical results are compared with measurements of test specimens.}, language = {en} } @misc{FranzoneDeuflhardErdmannetal.2005, author = {Franzone, Piero Colli and Deuflhard, Peter and Erdmann, Bodo and Lang, Jens and Pavarino, Luca Franco}, title = {Adaptivity in Space and Time for Reaction-Diffusion Systems in Electrocardiology}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-8649}, number = {05-30}, year = {2005}, abstract = {Adaptive numerical methods in space and time are introduced and studied for multiscale cardiac reaction-diffusion models in three dimensions. The evolution of a complete heartbeat, from the excitation to the recovery phase, is simulated with both the anisotropic Bidomain and Monodomain models, coupled with either a variant of the simple FitzHugh-Nagumo model or the more complex phase-I Luo-Rudy ionic model. The simulations are performed with the {\sc kardos} library, that employs adaptive finite elements in space and adaptive linearly implicit methods in time. The numerical results show that this adaptive method successfully solves these complex cardiac reaction-diffusion models on three-dimensional domains of moderate sizes. By automatically adapting the spatial meshes and time steps to the proper scales in each phase of the heartbeat, the method accurately resolves the evolution of the intra- and extra-cellular potentials, gating variables and ion concentrations during the excitation, plateau and recovery phases.}, language = {en} } @misc{WeiserDeuflhardErdmann2004, author = {Weiser, Martin and Deuflhard, Peter and Erdmann, Bodo}, title = {Affine conjugate adaptive Newton methods for nonlinear elastomechanics}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-7768}, number = {04-01}, year = {2004}, abstract = {The paper extends affine conjugate Newton methods from convex to nonconvex minimization, with particular emphasis on PDE problems originating from compressible hyperelasticity. Based on well-known schemes from finite dimensional nonlinear optimization, three different algorithmic variants are worked out in a function space setting, which permits an adaptive multilevel finite element implementation. These algorithms are tested on two well-known 3D test problems and a real-life example from surgical operation planning.}, language = {en} } @article{HellmichKoberErdmann2008, author = {Hellmich, Christian and Kober, Cornelia and Erdmann, Bodo}, title = {Micromechanics-based conversion of CT data into anisotropic elasticity tensors, applied to FE simulations of a mandible}, volume = {36}, journal = {Annals of Biomedical Engineering}, number = {1}, doi = {10.1007/s10439-007-9393-8}, pages = {108 -- 122}, year = {2008}, language = {en} } @inproceedings{ErdmannKoberLangetal.2002, author = {Erdmann, Bodo and Kober, C. and Lang, Jens and Deuflhard, Peter and Zeilhofer, J. and Sader, Robert}, title = {Efficient and Reliable Finite Element Methods for Simulation of the Human Mandible}, booktitle = {proceedings of 9th Workshop on The Finite Element Method in Biomedical Engineering, Biomechanics and Related Fields}, address = {Ulm, Germany}, year = {2002}, language = {en} } @article{ErdmannLjubijankicNytschGeusen2007, author = {Erdmann, Bodo and Ljubijankic, M. and Nytsch-Geusen, C.}, title = {Entwicklung einer Toolbox zur zwei- und dreidimensionalen instation{\"a}ren thermischen Bauteilsimulation mit KARDOS}, volume = {29}, journal = {Bauphsik}, number = {1}, pages = {33 -- 39}, year = {2007}, language = {en} } @inproceedings{ErdmannLangSeebass1997, author = {Erdmann, Bodo and Lang, Jens and Seebass, Martin}, title = {Adaptive Solutions of Nonlinear Parabolic Equations with Application to Hyperthermia Treatments}, booktitle = {CHT'97}, editor = {de Vahl Davis, G. and Leonardi, E.}, address = {Cesme, Turkey}, pages = {103 -- 110}, year = {1997}, language = {en} } @inproceedings{ErdmannLangSeebass1998, author = {Erdmann, Bodo and Lang, Jens and Seebass, Martin}, title = {Optimization of Temperature Distributions for Regional Hyperthermia based on a Nonlinear Heat Transfer Model}, volume = {858}, booktitle = {Biotransport}, editor = {Diller, K.}, pages = {36 -- 46}, year = {1998}, language = {en} } @article{ErdmannLangSeebass1999, author = {Erdmann, Bodo and Lang, Jens and Seebass, Martin}, title = {The Impact of a Nonlinear Heat Transfer Model for Temperature Control in Regional Hyperthermia}, volume = {49}, journal = {IEEE Transactions on Biomedical Engineering}, number = {9}, pages = {1129 -- 1138}, year = {1999}, language = {en} } @incollection{LangErdmannKoberetal.2003, author = {Lang, Jens and Erdmann, Bodo and Kober, Cornelia and Deuflhard, Peter and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Effiziente und zuverl{\"a}ssige Finite-Elemente-Methoden zur Simulation des menschlichen Unterkiefers}, volume = {1}, booktitle = {Berichte des IZWR - Interdisziplin{\"a}res Zentrum f{\"u}r Wissenschaftliches Rechnen}, editor = {Alt, Walter and Hermann, Martin}, publisher = {Universit{\"a}t Jena}, address = {Germany}, pages = {49 -- 57}, year = {2003}, language = {en} } @inproceedings{KoberErdmannHellmichetal.2005, author = {Kober, C. and Erdmann, Bodo and Hellmich, Christian and Geiger, M. and Sader, Robert and Zeilhofer, Hans-Florian}, title = {How does the periodontal ligament influence overall stress/strain profiles of a partially edentulous mandible?}, booktitle = {Proc. of 8th Int. Conference on Biological Mechanisms of Tooth Eruption, Resorption and Movement, Phuket, Thailand}, editor = {Davidovitch, Z. and Mah, J. and Suthanarak, S.}, address = {Harvard Society of the Advancement of Orthodontics, Boston, Massachusetts, USA}, year = {2005}, language = {en} } @inproceedings{KoberErdmannHellmichetal.2004, author = {Kober, C. and Erdmann, Bodo and Hellmich, Christian and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Anisotropic Simulation of the Human Mandible}, booktitle = {Proc. of 17th ASCE Engineering Mechanics Conference}, publisher = {Univ. of Delaware}, year = {2004}, language = {en} } @inproceedings{KoberErdmannHellmichetal.2005, author = {Kober, C. and Erdmann, Bodo and Hellmich, Christian and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Consideration of Bone Inhomogeneity and Anisotropy in Deformation Analysis of a Human Mandible}, volume = {1}, booktitle = {Proc. of BMT2005, 39th Annual Congress of the German Society of Biomedical Engineering, Nuremberg, Germany}, editor = {Boenick, U. and Bolz, A.}, publisher = {VDE}, address = {Nuremberg, Germany}, pages = {814 -- 815}, year = {2005}, language = {en} } @inproceedings{KoberErdmannHellmichetal.2005, author = {Kober, C. and Erdmann, Bodo and Hellmich, Christian and Sader, Robert and Zeilhofer, Hans-Florian}, title = {The Influence of the Periodontal Ligament on Overall Stress/Strain Profiles of a Human Mandible}, booktitle = {Proc. of 23rd CADFEM Users' Meeting, Int. Congress on FEM Technology, Biomechanics}, editor = {CADFEM GmbH, Grafing}, address = {Bonn, Germany}, pages = {1 -- 10}, year = {2005}, language = {en} } @inproceedings{KoberErdmannLangetal.2004, author = {Kober, C. and Erdmann, Bodo and Lang, Jens and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Sensitivity of the Temporomandibular Joint Capsule for the Structural Behaviour of the Human Mandible}, volume = {49-2}, booktitle = {Proc. BMT 2004}, address = {Ilmenau, Deutschland}, pages = {372 -- 373}, year = {2004}, language = {en} } @article{DeuflhardErdmannRoitzschetal.2009, author = {Deuflhard, Peter and Erdmann, Bodo and Roitzsch, Rainer and Lines, Glenn Terje}, title = {Adaptive Finite Element Simulation of Ventricular Dynamics}, volume = {12}, journal = {J. Computing and Visualization in Science}, pages = {201 -- 205}, year = {2009}, language = {en} } @inproceedings{KoberErdmannLangetal.2004, author = {Kober, C. and Erdmann, Bodo and Lang, Jens and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Adaptive Finite Element Simulation of the Human Mandible Using a New Physiological Model of the Masticatory Muscles}, volume = {4}, booktitle = {Proc. of 75th Annual Meeting of the GAMM}, number = {1}, pages = {332 -- 333}, year = {2004}, language = {en} } @inproceedings{KoberErdmannSaderetal.2003, author = {Kober, C. and Erdmann, Bodo and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Simulation of the Human Mandible}, booktitle = {Proceedings of 10th Workshop on The Finite Element Method in Biomedical Engineering, Biomechanics and Related Fields}, address = {Ulm, Germany}, year = {2003}, language = {en} } @article{KoberErdmannSaderetal.2003, author = {Kober, C. and Erdmann, Bodo and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Belastungssimulation beim menschlichen Biss im Vergleich mit der Dichtestruktur im Unterkieferknochen}, volume = {48}, journal = {Biomedizinische Technik}, number = {Erg{\"a}nzungsband 1}, pages = {268 -- 269}, year = {2003}, language = {en} } @article{SchenklMuggenthalerHubigetal.2017, author = {Schenkl, Sebastian and Muggenthaler, Holger and Hubig, Michael and Erdmann, Bodo and Weiser, Martin and Zachow, Stefan and Heinrich, Andreas and G{\"u}ttler, Felix Victor and Teichgr{\"a}ber, Ulf and Mall, Gita}, title = {Automatic CT-based finite element model generation for temperature-based death time estimation: feasibility study and sensitivity analysis}, volume = {131}, journal = {International Journal of Legal Medicine}, number = {3}, doi = {doi:10.1007/s00414-016-1523-0}, pages = {699 -- 712}, year = {2017}, abstract = {Temperature based death time estimation is based either on simple phenomenological models of corpse cooling or on detailed physical heat transfer models. The latter are much more complex, but allow a higher accuracy of death time estimation as in principle all relevant cooling mechanisms can be taken into account. Here, a complete work flow for finite element based cooling simulation models is presented. The following steps are demonstrated on CT-phantoms: • CT-scan • Segmentation of the CT images for thermodynamically relevant features of individual geometries • Conversion of the segmentation result into a Finite Element (FE) simulation model • Computation of the model cooling curve • Calculation of the cooling time For the first time in FE-based cooling time estimation the steps from the CT image over segmentation to FE model generation are semi-automatically performed. The cooling time calculation results are compared to cooling measurements performed on the phantoms under controlled conditions. In this context, the method is validated using different CTphantoms. Some of the CT phantoms thermodynamic material parameters had to be experimentally determined via independent experiments. Moreover the impact of geometry and material parameter uncertainties on the estimated cooling time is investigated by a sensitivity analysis.}, language = {en} } @article{WeiserFreytagErdmannetal.2018, author = {Weiser, Martin and Freytag, Yvonne and Erdmann, Bodo and Hubig, Michael and Mall, Gita}, title = {Optimal Design of Experiments for Estimating the Time of Death in Forensic Medicine}, volume = {34}, journal = {Inverse Problems}, number = {12}, doi = {10.1088/1361-6420/aae7a5}, pages = {125005}, year = {2018}, abstract = {Estimation of time of death based on a single measurement of body core temperature is a standard procedure in forensic medicine. Mechanistic models using simulation of heat transport promise higher accuracy than established phenomenological models in particular in nonstandard situations, but involve many not exactly known physical parameters. Identifying both time of death and physical parameters from multiple temperature measurements is one possibility to reduce the uncertainty significantly. In this paper, we consider the inverse problem in a Bayesian setting and perform both local and sampling-based uncertainty quantification, where proper orthogonal decomposition is used as model reduction for fast solution of the forward model. Based on the local uncertainty quantification, optimal design of experiments is performed in order to minimize the uncertainty in the time of death estimate for a given number of measurements. For reasons of practicability, temperature acquisition points are selected from a set of candidates in different spatial and temporal locations. Applied to a real corpse model, a significant accuracy improvement is obtained already with a small number of measurements.}, language = {en} }