Contact Force Models for Multibody Dynamics


Book Description

This book analyzes several compliant contact force models within the context of multibody dynamics, while also revisiting the main issues associated with fundamental contact mechanics. In particular, it presents various contact force models, from linear to nonlinear, from purely elastic to dissipative, and describes their parameters. Addressing the different numerical methods and algorithms for contact problems in multibody systems, the book describes the gross motion of multibody systems by using a two-dimensional formulation based on the absolute coordinates and employs different contact models to represent contact-impact events. Results for selected planar multibody mechanical systems are presented and utilized to discuss the main assumptions and procedures adopted throughout this work. The material provided here indicates that the prediction of the dynamic behavior of mechanical systems involving contact-impact strongly depends on the choice of contact force model. In short, the book provides a comprehensive resource for the multibody dynamics community and beyond on modeling contact forces and the dynamics of mechanical systems undergoing contact-impact events.




Kinematics and Dynamics of Multibody Systems with Imperfect Joints


Book Description

This book presents suitable methodologies for the dynamic analysis of multibody mechanical systems with joints. It contains studies and case studies of real and imperfect joints. The book is intended for researchers, engineers, and graduate students in applied and computational mechanics.




Impact & Friction Of Solids, Structures & Machines: Theory & Applications In Engineering & Science, Intl Symp


Book Description

This book deals with the dynamics of mechanical systems in presence of impact and friction. The contributors are an international group of engineers and scientists from industrial and academic institutions of more than 23 countries around the world concerned with the modeling, analysis, measurement and control of nonsmooth mechanical structures. Contact laws lead to mathematical models that are highly nonlinear and nonsmooth or discontinuous. Discontinuous and nonsmooth processes introduce problems with data processing techniques and analytical methods. Thanks to great advances in computer technology and computational analysis, as well as the introduction of new experimental devices such as the atomic-force microscope and the quartz-crystal-microbalance probe, the study of impact and friction — one of the oldest problems in physics, is now in a phase of rapid and exciting development. The growing number of research breakthroughs have promoted the development of new technologies in the description and design of systems with impact and friction models to understand nature, structures, machines, transportation systems, and other processes. A fairly comprehensive picture of these new developments is presented in this book by researchers who are giving up-to-date accounts of the present state of the field in many aspects.The book is essential for introducing readers in mechanical engineering, material science, applied mathematics, aerospace engineering, ocean engineering, biomechanics, and civil engineering to recent developments in nonsmooth mechanics. It is also useful for self-study purposes by professionals and practitioners in the field.




Applied Nonlinear Dynamics And Chaos Of Mechanical Systems With Discontinuities


Book Description

Rapid developments in nonlinear dynamics and chaos theory have led to publication of many valuable monographs and books. However, most of these texts are devoted to the classical nonlinear dynamics systems, for example the Duffing or van der Pol oscillators, and either neglect or refer only briefly to systems with motion-dependent discontinuities. In engineering practice a good part of problems is discontinuous in nature, due to either deliberate reasons such as the introduction of working clearance, and/or the finite accuracy of the manufacturing processes.The main objective of this volume is to provide a general methodology for describing, solving and analysing discontinuous systems. It is compiled from the dedicated contributions written by experts in the field of applied nonlinear dynamics and chaos.The main focus is on mechanical engineering problems where clearances, piecewise stiffness, intermittent contact, variable friction or other forms of discontinuity occur. Practical applications include vibration absorbers, percussive drilling of hard materials and dynamics of metal cutting.




Multi-body Dynamic Modeling of Multi-legged Robots


Book Description

This book describes the development of an integrated approach for generating the path and gait of realistic hexapod robotic systems. It discusses in detail locomation with straight-ahead, crab and turning motion capabilities in varying terrains, like sloping surfaces, staircases, and various user-defined rough terrains. It also presents computer simulations and validation using Virtual Prototyping (VP) tools and real-world experiments. The book also explores improving solutions by applying the developed nonlinear, constrained inverse dynamics model of the system formulated as a coupled dynamical problem based on the Newton–Euler (NE) approach and taking into account realistic environmental conditions. The approach is developed on the basis of rigid multi-body modelling and the concept that there is no change in the configuration of the system in the short time span of collisions.










Nonsmooth Mechanics


Book Description

Thank you for opening the second edition of this monograph, which is devoted to the study of a class of nonsmooth dynamical systems of the general form: ::i; = g(x,u) (0. 1) f(x, t) 2: 0 where x E JRn is the system's state vector, u E JRm is the vector of inputs, and the function f (-, . ) represents a unilateral constraint that is imposed on the state. More precisely, we shall restrict ourselves to a subclass of such systems, namely mechanical systems subject to unilateral constraints on the position, whose dynamical equations may be in a first instance written as: ii= g(q,q,u) (0. 2) f(q, t) 2: 0 where q E JRn is the vector of generalized coordinates of the system and u is an in put (or controller) that generally involves a state feedback loop, i. e. u= u(q, q, t, z), with z= Z(z, q, q, t) when the controller is a dynamic state feedback. Mechanical systems composed of rigid bodies interacting fall into this subclass. A general prop erty of systems as in (0. 1) and (0. 2) is that their solutions are nonsmooth (with respect to time): Nonsmoothness arises primarily from the occurence of impacts (or collisions, or percussions) in the dynamical behaviour, when the trajectories attain the surface f(x, t) = O. They are necessary to keep the trajectories within the subspace = {x : f(x, t) 2: O} of the system's state space.




Synthesis and Properties of Mechanically Alloyed and Nanocrystalline Materials


Book Description

ISMANAM96 Proceedings of the International Symposium on Metastable, Mechanically Alloyed and Nanocrystalline Materials (ISMANAM-96), Rome, Italy, May 1996




Energy Dissipation and Vibration Control: Modeling, Algorithm and Devices


Book Description

This book is a printed edition of the Special Issue "Energy Dissipation and Vibration Control: Modeling, Algorithm and Devices" that was published in Applied Sciences