From Neweul to Neweul-M<Superscript>2</Superscript>: symbolical equations of motion for multibody system analysis and synthesis

The state-of-the-art for deriving symbolical equations of motion for multibody systems is reviewed. The fundamentals of formalisms based on Newton–Euler equations are presented and the recent development of a research software called Neweul-M² is highlighted. The modeling approach with commands and a graphical user interface are discussed as well as system analysis options, control design by export to Matlab/Simulink, and parameter optimization for system synthesis. The alternatives within the program using symbolic and numeric approaches are emphasized. A double pendulum is used to explain the program features and a vehicle benchmark model is presented as an example. Advanced applications include closed kinematic loops and flexible bodies.     

Multibody System Dynamics: Roots and Perspectives

The paper reviews the roots, the state-of-the-art and perspectives of multibody system dynamics. Some historical remarks show that multibody system dynamics is based on classical mechanics and its engineering applications ranging from mechanisms, gyroscopes, satellites and robots to biomechanics. The state-of-the-art in rigid multibody systems is presented with reference to textbooks and proceedings. Multibody system dynamics is characterized by algorithms or formalisms, respectively, ready for computer implementation. As a result simulation and animation are most important. The state-of-the-art in flexible multibody systems is considered in a companion review by Shabana.Future research fields in multibody dynamics are identified as standardization of data, coupling with CAD systems, parameter identification, real-time animation, contact and impact problems, extension to control and mechatronic systems, optimal system design, strength analysis and interaction with fluids. Further, there is a strong interest on multibody systems in analytical and numerical mathematics resulting in reduction methods for rigorous treatment of simple models and special integration codes for ODE and DAE representations supporting the numerical efficiency. New software engineering tools with modular approaches promise improved efficiency still required for the more demanding needs in biomechanics, robotics and vehicle dynamics.     

Sloshing cargo in silo vehicles

The driving stability of silo vehicles is significantly affected by the type of cargo that is transported and the design of the tank. Cargo motion can have both beneficial and negative aspects in terms of driving stability and braking performance. Neglecting the influence of the dynamically moving cargo in driving simulations of silo vehicles leads to significant errors in the simulation results. We propose a new method for the dynamic simulation of silo vehicles carrying granulates. The method couples Lagrangian particle methods, such as the discrete element method, and multibody systems methods using co-simulations. We demonstrate the capability of the new approach by providing simulation results of two benchmark maneuvers. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Florian Fleissner received his Dipl.-Ing. degree in Mechanical Engineering from the University of Erlangen, Germany, in 2003. He is currently working as research and teaching assistant, completing his Ph.D. in Mechanical Engineering at the Institute of Engineering and Computational Mechanics at the University of Stuttgart, Germany. Vincenzo D’Alessandro graduated in 2008 in Mechanical Engineering at the Politecnico di Milano, Italy. He is currently working as a Ph.D. candidate in Mechanical Engineering at the department of mechanical engineering at the Politecnico di Milano. Werner Schiehlen was educated as a mechanical engineer and received a Ph.D. on satellite dynamics in 1966. After working for 10 years with the Technical University Munich and spending one year with NASA in the US he was appointed full professor of mechanics with the University of Stuttgart until his retirement in 2002. He published more than 320 scientific papers in applied and computational dynamics including 7 books mostly translated in foreign languages, too. Werner Schiehlen served as President of IUTAM. Since 1997 he is Editor-in-Chief of the international journal MULTIBODY SYSTEM DYNAMICS. Peter Eberhard received his Dipl.-Ing. in Mechanical Engineering, his Dr.-Ing. and his Habilitation in Mechanics from the University of Stuttgart in Germany. In 2000 he was appointed as Professor of Mechanics and System Dynamics at the University of Erlangen-Nuremberg before he became 2002 Full Professor and Director of the Institute of Engineering and Computational Mechanics at the University of Stuttgart. In 2000 he received the Richard-von-Mises award and in 2007 an Honorary Professorship at the Nanjing University of Science and Technology, P.R. China. His research interests include multibody dynamics, contact mechanics, mechatronics, optimization and biomechanics.     

Recent developments in multibody dynamics

Multibody system dynamics is based on classical mechanics and its engineering applications originating from mechanisms, gyioscopes, satellites and robots to biomechanics Multibody system dynamics is characterized by algorithms or formalisms, respectively, ready for computer implementation As a result simulation and animation are most convenient Recent developments in multibody dynamics are identified as elastic or flexible systems, respectively, contact and impact problems, and actively controlled systems Based on the history and recent activities in multibody dynamics, recursive algorithms are introduced and methods for dynamical analysis are presented Linear and nonlinear engineering systems are analyzed by matrix methods, nonlinear dynamics approaches and simulation techniques Applications are shown from low frequency vehicles dynamics including comfort and safety requirements to high frequency structural vibrations generating noise and sound, and from controlled limit cycLes of mechanisms to penodic nonlinear oscillations of biped walkers The fields of application are steadily increasing, in particular as multibody dynamics is considered as the basis of mechatronics     

Computational aspects in multibody system dynamics

The modeling of discrete engineering and biomechanical systems is presented, kinematics and kinetics are developed with sparse matrix techniques, formalisms with minimal and maximal number of coordinates are discussed and the computational efficiency of simulations is analyzed. The animation is shown for a three-body pendulum and the overall dynamical analysis is verified qualitatively by an experiment.