### Senior Scientist

Department of Mechanical Engineering

University of Wisconsin-Madison

4150ME Mech. Engineering Building

1513 University Avenue

Madison, WI 53706-1572

Email: serban@wisc.edu

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## Research

**Research Interests: **Computational dynamics, Scientific computing and parallel computing, Computational geometry, Sensitivity analysis for dynamical systems, Mathematical software

**Application Areas of Interests: **Ground vehicle mobility simulation, Terramechanics, Autonomous vehicle simulation, Virtual reality and virtual prototyping, Fluid-solid interaction, Granular dynamics

**Selected current and past projects**

Chrono::Vehicle for modeling, simulation, and visualization of ground vehicles

Co-simulation for vehicle-terrain interaction

Quantum-assisted machine learning for vehicle mobility studies

## Software

Project Chrono: Open source, high-performance C++ library for multiphysics and multibody dynamics simulations.

SaP::GPU: Sparse Linear System Solver on the GPU.

Sundials: SUite of Nonlinear and DIfferential/ALgebraic equation Solvers.

## Journal Publications

- J.L. Escalona, S. Goyal, R. Serban, and W-C Tai, “Special Issue: Selected papers from 2021 IDETC-CIE MSNDC conference,” Guest Editorial, ASME Journal of Computational and Nonlinear Dynamics, 17(5), p. 050301-1, 2022.
- S. Benatti, A. Young, A. Elmquist, J. Taves, A. Tasora, R. Serban, and D. Negrut, “End-to-end learning for off-road terrain navigation using the Chrono open-source simulation platform,” Multibody System Dynamics, https://doi.org/10.1007/s11044-022-09816-1, 2022.
- W. Hu, J. Zhou, R. Serban, D. Negrut, “Using an SPH-based continuum representation of granular terrain to simulate VIPER rover mobility,” ASME Journal of Computational and Nonlinear Dynamics, submitted, 2021.
- W. Hu, A. Zhou, S. Chandler, D. Apostolopoulos, K. Kamrin, R. Serban, and D. Negrut, “Traction control design for off-road mobility using an SPH-DAE co-simulation framework,” Multibody System Dynamics, Special Issue on Co-simulation in MSD, https://doi.org/10.1007/s11044-022-09815-2, 2022.
- A. Young, J. Taves, A. Elmquist, R. Serban, D. Negrut, S. Benatti, and A. Tasora, “Enabling artificial intelligence studies in off-road mobility through physics-based simulation of multi-agent scenarios,” ASME Journal of Computational and Nonlinear Dynamics, 17(5), p. 051001, 2022.
- F.F. Foldager, L.J. Munkholm, O. Balling, R. Serban, D. Negrut, R.J. Heck, and O. Green, “Modeling soil aggregate fracture using the discrete element method,” Soil and Tillage Research, 218, p.105295, 2022.
- L. Fang, R. Zhang, C. Vanden Heuvel, R. Serban, and D. Negrut, “Chrono::GPU: An Opensource Simulation Package for Granular Dynamic using the Discrete Element Method,” Processes, 9(10), pp. 1813, doi:10.3390/pr9101813, 2021.
- A. Elmquist, R. Serban, and D. Negrut, “A Sensor Simulation Framework for Training and Testing Robots and Autonomous Vehicles,” ASME Journal of Autonomous Vehicles and Systems, 1(2):021001, doi:10.1115/1.4050080, 2021.
- M. Rakhsha, C. Kelly, N. Olsen, R. Serban, and D. Negrut, “Multibody dynamics vs. fluid dynamics: two perspectives on the dynamics of granular flows,” ASME Journal of Computational and Nonlinear Dynamics, 15(9), 091009, https://doi.org/10.1115/1.4047237, 2020.
- R. Serban and A. Recuero, “Sensitivity Analysis for Hybrid Systems and Systems With Memory,” ASME Journal of Computational and Nonlinear Dynamics, 14(9), 091006-091006-10, doi:10.1115/1.4044028, 2019.
- R. Serban, A. Recuero, P. Jayakumar, and D. Negrut, “An integrated framework for high-performance, high-fidelity simulation of ground vehicle-tire-terrain interaction,” International Journal on Vehicle Performance, 5(3), pp. 233-259, doi: 10.1504/IJVP.2019.100698, 2019.
- M. Rakhsha, A. Pazouki, R. Serban, D. Negrut, “Using a half-implicit integration scheme for the SPH-based solution of fluid-solid interaction problems,” Comp. Meth. Appl. Mech. Eng., 345, pp. 100-122, 2019.
- R. Serban, Y. Wang, K.K. Choi, P. Jayakumar, “(Guest Editorial) Special Issue: Sensitivity Analysis and Uncertainty Quantification,” ASME Journal of Computational and Nonlinear Dynamics, 14(2), 020301, doi:10.1115/1.4042262, 2019.
- R. Serban, M. Taylor, D. Negrut, and A. Tasora, “Chrono::Vehicle – Template-based Ground Vehicle Modeling and Simulation,” International Journal on Vehicle Performance, 5(1), pp. 18-39, doi: 10.1504/IJVP.2019.097096, 2019.
- A. Tasora, D. Magnoni, D. Negrut, R. Serban and P. Jayakumar, “Deformable soil with adaptive level of detail for tracked and wheeled vehicles,” International Journal on Vehicle Performance, 5(1), pp. 60-76, doi:10.1504/IJVP.2019.097098, 2019.
- A. Pazouki, M. Kwarta, K. Williams, W. Likos, R. Serban. D. Negrut, and P. Jayakumar, “Compliant contact versus rigid contact: A comparison in the context of granular dynamics,” Physical Review E, 96(4), 2017.
- D. Negrut, R. Serban, and A. Tasora, “Posing Multibody Dynamics with Friction and Contact as a Differential Complementarity Problem,” ASME Journal of Computational and Nonlinear Dynamics, 13(1):014503-014503-6. doi:10.1115/1.4037415, 2017.
- A. Li, R. Serban, and D. Negrut, “Analysis of a Splitting Approach for the Parallel Solution of Linear Systems on GPU Cards,” SIAM J. Sci. Comp., 39(3), pp. C215-C237, 2017.
- A. Recuero, R. Serban, B. Peterson, H. Sugiyama, P. Jayakumar, D. Negrut, “A High-fidelity Approach for Vehicle Mobility Simulation: Nonlinear Finite Element Tires Operating on Granular Material,” J. Terramechanics, 72, pp. 39-54, 2017.
- J. Fleischmann, R. Serban, and D. Negrut, “On the Importance of Displacement History in Soft-Body Contact Models,” ASME Journal of Computational and Nonlinear Dynamics, 11(4):044502-044502-5, doi:10.1115/1.4031197, 2015.
- R. Serban, D. Melanz, A. Li, I. Stanciulescu, P. Jayakumar, D. Negrut, “A GPU-based preconditioned Newton-Krylov solver for flexible multibody dynamics,” Intl. J. Num. Meth. Eng., 102(9), pp. 1585–1604, doi:10.1002/nme.4876, 2015.
- A. Pazouki, R. Serban, and D. Negrut, “A high performance computing approach to the simulation of fluid-solid interaction problems with rigid and flexible bodies,” Archive of Mechanical Engineering. Volume 61, Issue 2, Pages 227—251, ISSN (Online) 2300-262X, doi:10.2478/meceng-2014-0014, August 2014.
- D. Negrut, R. Serban, H. Mazhar, T. Heyn, “Parallel Computing in Multibody System Dynamics: Why, When and How,” ASME Journal of Computational and Nonlinear Dynamics, doi:10.1115/1.4027313, 9(4):041007-041007-12, 2014.
- B. Simeon, R. Serban and L.R. Petzold, “A Model of Macroscale Deformation and Microvibration in Skeletal Muscle Tissue,” M2AN, 43, pp. 805–823, 2009.
- R. Serban, “A parallel computational model for sensitivity analysis in optimization for robustness,” Opt. Meth. Soft., 24(1), pp. 105–121, 2009.
- R. Serban, C. Homescu, L.R. Petzold, “The effect of problem perturbations on nonlinear dynamical systems and their reduced order models,” SIAM J. Sci. Comp., 29(6), pp. 2621–2643, 2007.
- C. Homescu, L.R. Petzold, and R. Serban, “Error Estimation for Reduced-Order Models of Dynamical Systems,” SIAM Review., 49(2), pp. 277–299, 2007.
- L.R. Petzold, Y. Cao, S. Li, and R. Serban, “Sensitivity analysis of differential-algebraic equations and partial differential equations,” Comp. Chem. Eng., 30, pp. 1553–1559, 2006.
- A.C. Hindmarsh, P.N. Brown, K.E. Grant, S.L. Lee, R. Serban, D. Shumaker, and C.S. Woodward, “SUNDIALS: Suite of Nonlinear and Differential/Algebraic Equation Solvers,” ACM Trans. Math. Soft., 31, pp. 363–396, 2005.
- C. Homescu, L.R. Petzold, and R. Serban, “Error Estimation for Reduced-Order Models of Dynamical Systems,” SIAM J. Num. An., 43(4), pp. 1693–1714, 2005.
- R. Serban, S. Li, and L. Petzold, “Adaptive Algorithms for Optimal Control of Time-Dependent Partial Differential-Algebraic Equation Systems,” Int. J. Num. Meth. Eng., 57, pp. 1457–1469, 2003.
- Y. Cao, S. Li, L. R. Petzold, and R. Serban, “Adjoint Sensitivity Analysis for Differential-Algebraic Equations: The Adjoint DAE System and its Numerical Solution,” SIAM J. Sci. Comp., 24(3), pp. 1076–1089, 2003.
- R. Serban and L.R. Petzold, “Efficient Computation of Sensitivities for Ordinary Differential Equation Boundary Value Problems,” SIAM J. Num. An., 40(1), pp. 220–232, 2002.
- R. Serban, W.S. Koon, M. Lo, J. Marsden, L.R. Petzold, S.D. Ross, and R. Wilson, “Halo Orbit Mission Correction Maneuvers Using Optimal Control,” Automatica, 38(4), pp. 571—583, 2002.
- R. Serban and L.R. Petzold, “COOPT – A Software Package for Optimal Control of Large-Scale Differential-Algebraic Equation Systems,” J. Math. Comp. Sim., 56(2), pp. 187—203, 2001.
- R. Serban and J.S. Freeman, “Identification and Identifiability of Unknown Parameters in Multibody Dynamic Systems,” Multibody System Dynamics, 5(4), pp. 335—350, 2001.
- R. Serban and E.J. Haug, “Globally Independent Coordinates for Real-Time Vehicle System Simulation,” J. Mech. Design, 122(4), pp. 575-582, 2000.
- L.L. Raja, R.J. Kee, R. Serban, and L.R. Petzold, “Computational Algorithm for Dynamic Optimization of Chemical Vapor Deposition Processes in Stagnation Flow Reactors,” J. Electrochemical Soc., 147(7), pp. 2718—2726, 2000.
- E.J. Haug, D. Negrut, R. Serban, and D. Solis, “Numerical Methods for High Speed Vehicle Dynamic Simulation,” Mech. Struct. Mach., 27(4), pp. 507–533, 1999.
- R. Serban and E.J. Haug, “Kinematic and Kinetic Derivatives in Multibody System Analysis,” Mech. Struct. Mach., 26(2), pp. 145–173, 1998.
- R. Serban, D. Negrut, F.A. Potra, and E.J. Haug, “A Topology Based Approach for Exploiting Sparsity in Multibody Dynamics in Cartesian Formulation,” Mech. Struct. Mach., 25(3), pp. 379–396, 1997.
- D. Negrut, R. Serban, and F.A. Potra, “A Topology Based Approach for Exploiting Sparsity in Multibody Dynamics. Joint Formulation,” Mechanics of Structures and Machines, 25(2), pp. 221-241, 1997.
- E.J. Haug, D. Coroian, and R. Serban, “Variable-Fidelity Differential-Algebraic Equation Model Correlation,” Mech. Struct. Mach., 25(1), pp. 61—85, 1997.

## Book chapters

- “A Connected Autonomous Vehicle Emulator for testing multi-agent, conventional/autonomous mixed-vehicle traffic scenarios,” D. Negrut, A. Elmquist, D. Hatch, P. Ramanathan, R. Serban, ACIER:AMS, John Michopoulos editor, 2019.
- “Chrono: An Open Source Multi-Physics Dynamics Engine,” A. Tasora, R. Serban, H. Mazhar, A. Pazouki, D. Melanz, J. Fleischmann, M. Taylor, H. Sugiyama, and D. Negrut, Springer’s Lecture Notes in Computer Science, Tomas Kozubek editor, 2016.
- “Unified Memory in CUDA 6: A Brief Overview, ” D. Negrut, R. Serban, A. Li, A. Seidl, Dr. Dobb’s Journal, September 2014.
- “A Lagrangian-Lagrangian framework for the simulation of rigid and deformable bodies in fluid,” A. Pazouki, R. Serban, and D. Negrut, Multibody Dynamics: Computational Methods and Applications, Springer, ISBN: 9783319072593, 2014.
- “SUNDIALS Equation Solvers,” A.C. Hindmarsh and R. Serban, Scholarpedia, pp. 10676, 2007.
- “Sensitivity Analysis and Design Optimization of Differential-Algebraic Equation Systems,” L.R. Petzold, R. Serban, S. Li, S. Raha, and Y. Cao, Computational Aspects of Nonlinear Structural Systems with Large Rigid Body Motion, J.A.C. Ambrosio and M. Kleiber Eds., NATO SCI Comp. Syst., 179, IOS Press, pp. 153–168, 2001.

PhD thesis

- “Dynamic and Sensitivity Analysis of Mutibody Systems”

Mechanical Engineering, University of Iowa, Iowa City IA

Advisor: Edward J. Haug

## Conference Papers

- R. Serban, J. Taves, Z. Zhou, “Real-time simulation of ground vehicles on deformable terrain,” Proc. ASME 2022 IDETC/CIE, August 14-17, 2022, St. Louis, USA.
- S. Benatti, C. Schwarz, A. Young, A. Elmquist, R. Serban, and D. Negrut, “A Geographically Distributed Simulation Framework for the Analysis of Mixed Traffic Scenarios Involving Conventional and Autonomous Vehicles ,” WCX SAE World Congress Experience, April 5-7, 2022, Detroit, USA.
- S. Benatti, A. Elmquist, J. Taves, A. Young, C. Schwarz, R. Serban, and D. Negrut, “Using Chrono-enabled human-in-the-loop simulation to capture the interplay between conventional and autonomous vehicle operation,” MD2021, Intl. Conference on Machine Design, Sept. 9-10, 2021, Univ. of Porto, Portugal.
- W. Hu, J. Zhou, R. Serban, D. Negrut, “Using an SPH-based continuum representation of granular terrain to simulate the rover mobility,” Proc. ASME 2021 IDETC/CIE, virtual/online.
- A. Young, J. Taves, A. Elmquist, R. Serban, D. Negrut, S. Benatti, and A. Tasora, “Enabling artificial intelligence studies in off-road mobility through physics-based simulation of multi-agent scenarios,” Proc. ASME 2021 IDETC/CIE, virtual/online.
- J. Taves, A. Elmquist, A.Young, R. Serban, and D. Negrut, “Synchrono: A scalable, physics-based simulation platform for testing groups of autonomous vehicles and/or robots,” International Conference on Intelligent Robots and Systems (IROS), 2020.
- D. Negrut, R. Serban, A. Elmquist, J. Taves, A. Young, A. Tasora, and S. Benatti, “Enabling artificial intelligence studies in off-road mobility through physics-based simulation of multi-agent scenarios,” 2020 NDIA Ground Vehicle Systems Engineering and Technology Symposium, August 7-9, 2020, Novi, MI.

## Invited Talks

- Oct. 2022 “TBD,” Keynote lecture, 6th Joint ICMD / 10th ACMD, New Delhi, India, 16-20 Oct. 2022.
- Apr. 2022, “Vehicles and robots in mud and on the Moon – Challenges in vehicle mobility,” Invited presentation, Intel Tech Forum, virtual.
- Sep. 2021 “On using adjoint methods for analysis of dynamical systems,” Invited lecture, 3rd Intl. Multibody Summer Workshop & Summer School, University of Parma, Italy, 13-17 Sep. 2021.
- Jul. 2021 “Real-time deformable terrain simulation for off-road vehicles,” Invited talk, ICVE 2021, Shanghai, China, 23-26 Jul 2021.
- Sep. 2019 “Ground vehicle mobility assessment with Chrono::Vehicle,” Aarhus University, Aarhus, Denmark.
- May. 2019 “An overview of Chrono capabilities from a vehicle mobility perspective,” University of Parma, Parma, Italy.
- Apr. 2019 “Adjoint-based methods for analysis of dynamical systems,” Beijing Institute of Technology, Beijing, China.
- Apr. 2019 “Complementarity methods for large-scale non-smooth rigid body dynamics,” Beijing Institute of Technology, Beijing, China.
- Sep. 2018 “NG-NRMM Software Demonstration,” NATO Cooperative Demonstration of Technology (CDT), Houghton, MI, USA.
- Dec. 2016 “Co-simulation framework for ground vehicle – terrain interaction,” Aarhus University, Aarhus, Denmark.
- Dec. 2016 “Complementarity methods for frictional contact in large-scale granular dynamics simulations,” University of La Coruna, Spain.
- Aug. 2016 “Project Chrono: An Integrated Software Solution for Ground Vehicle Mobility,” 2016 Machine-Ground Interaction Consortium Workshop: “Next Generation Mobility Modeling and Simulation,” Novi, MI.
- Apr. 2016 “High Performance Computing in Computational Dynamics,” Multibody Dynamics Workshop 2016, University of Parma, Italy.
- Oct. 2014 “A GPU-based preconditioned Newton-Krylov solver for flexible multibody dynamics,” Dept. of Mechanical and Industrial Engineering, University of Illinois at Chicago.
- Nov. 2007 “Design and implementation of a coordinate projection integrator for ODEs with invariants,” Lindbergh Seminar Series in Mechanical Engineering, University of Wisconsin – Madison.
- Sep. 2007 “The SUNDIALS integration and sensitivity analysis solvers,” ACE Workshop on Management of Numerical Errors in Nuclear Systems Modeling, North Carolina State University, Raleigh, NC, September 2007.
- Aug. 2007 “Sensitivity analysis in SUNDIALS: Current and coming attractions,” Eight DOE ACTS Collection Workshop, Berkeley, CA, August 2007.
- Apr. 2007 “Methods and software for sensitivity analysis of dynamical systems,” Computational Modeling and Design Group Seminar, University of Wisconsin – Madison, April 2007.
- Sep. 2006 “Sensitivity Analysis for ODE and DAE systems”, NUMDIFF-11, Halle, Germany, September 2006.
- Jul. 2006 “Sensitivity Analysis for Dynamical Systems Described by ODEs and DAEs: Methods and Tools”, Simbios Seminar Series, Stanford, CA, July 2006.
- May. 2006 “Sensitivity Analysis and Uncertainty Quantification,” Chevron Research, San Ramon, CA, May 2006.
- Aug. 2005 “SUNDIALS – Suite of Nonlinear/Differential Algebraic Equation Solvers”, Sixth Workshop on the DOE ACTS Collection, Berkeley, CA, August 2005.
- May. 2005 “Sensitivity Analysis for Dynamical Systems: Methods and Tools”, Workshop on Mathematical and Computational Geoscience, Golden, CO, May 2005.
- Aug. 2004 “SUNDIALS: Suite of Nonlinear and Differential/Algebraic Equation Solvers”, Fifth Workshop on the DOE ACTS Collection, Berkeley, CA, August 2004.
- May. 2004 “Error estimation for reduced order models of dynamical systems”, Second Sandia Workshop on PDE-Constrained Optimization: Toward Real-time and Online PDE-constrained Optimization, Santa Fe, NM, May 2004.
- Dec. 2002 “Sensitivity Analysis: What, Why, and How?” Workshop on Predictability of Complex Phenomena, Santa Fe, NM, December 2002.
- Feb. 2002 “Adjoint sensitivity analysis for ODE and DAE systems”, Bay Area Scientific Computing Day 2002, Pleasanton, CA, February 2002.
- Aug. 2001 “Sensitivity Computation for Optimal Control of DAE Systems”, Sensitivity AnalysisWorkshop 2001, Livermore, CA, August 2001.
- Nov. 1999 “Control and optimization of dynamic systems with applications to halo orbit missions,” NSF-KDI/IGPP Workshop on Accurate Simulation and Modeling of Physical Systems, Institute of Geophysics and Planetary Physics, San Diego, CA, November 1999.
- Sep. 1999 “Methods and software for optimal control of dynamical systems,” Mechanical Dynamics Inc., Ann Arbor, MI, September 1999.
- Aug. 1999 “Sensitivity analysis and optimal control for large-scale dynamical systems: Applications”, Auckland Numerical Ordinary Differential Equations, Auckland, New Zealand, August 1999.
- Jul. 1999 “Globally independent coordinates for real-time vehicle simulation.” I/UCRC summer Technical Conference, Durango, CO, July 1999.

## Service

**Professional societies**

- Vice-chair of the ASME Technical Committee on Multibody Systems and Nonlinear Dynamics (TC-MSND)
- Member of the IMSD (International Association for Multibody System Dynamics) International Steering Committee
- ASME (since 1998)
- SIAM (since 2000), member of the SIAG on Computational Science and Engineering

**Editorial board**

- Guest Editor, Special Issue on “Selected Papers from the 2021 MSNDC,” J. of Computational and Nonlinear Dynamics (2022)
- Associate Editor, J. of Computational and Nonlinear Dynamics, ASME (2019 – )
- Guest Editor, Special Issue on “Sensitivity Analysis and Uncertainty Quantification,” J. of Computational and Nonlinear Dynamics (2018)
- Associate Editor, Mathematics and Computers in Simulation, Elsevier (2007-2020)

**Conference organizer**

- 18th International Conference on Multibody Systems, Nonlinear Dynamics, and Control, ASME IDETC/CIE, St. Louis, MO, August 14-17, 2022
- 7th International Conference on Multibody System Dynamics (IMSD), Madison, WI, June 2022 (Postponed)
- 14th International Conference on Multibody Systems, Nonlinear Dynamics, and Control, ASME IDETC/CIE, Quebec City, Canada, August 26-29, 2018
- 13th International Conference on Multibody Systems, Nonlinear Dynamics, and Control, ASME IDETC/CIE, Cleveland, OH, August 6-9, 2017.

## Personal Information

**Education**

B.S, Aeronautics, Polytechnic Institute of Bucharest, Romania

Ph.D, Mechanical Engineering, University of Iowa

**Past appointments**

- (2008-2013) Senior Computational Scientist, Xulu Entertainment
- (2001-2008) Computational Scientist, Center for Applied Scientific Computing, LLNL
- (1998-2001) Postgraduate Researcher, University of California Santa Barbara

**External links**

LinkedIn

ReasearchGate

Publons

GitHub