Chains of rigid bodies and their numerical simulation by local frame methods

Abstract The dynamic environment of embarqued structures such as radars or more generally electronic equipments consists of impacts, sine and large power spectrum excitations. Under these real conditions and amongst different kinds of isolation, the passive damper with nonlinear parameters can provide good performances. This paper is concerned with the dynamic behavior of rigid bodies on highly nonlinear mounts. The numerical simulation and the experiment carried out, show that the load-deflection behavior of the dampers have to be slightly ajusted with respect to impact vibrations to obtain a well designed behavior.

Download Full-text

Numerical Simulation of Multibody Systems With Time Dependant Structure

14th Biennial Conference on Mechanical Vibration and Noise: Dynamics and Vibration of Time-Varying Systems and Structures ◽

10.1115/detc1993-0103 ◽

1993 ◽

Author(s):

Pierre Joli ◽

Madeleine Pascal ◽

René Gibert

Keyword(s):

Numerical Simulation ◽

Multibody Systems ◽

Computational Algorithm ◽

Rigid Bodies ◽

Three Dimensions ◽

Integration Step ◽

General Systems ◽

Articulated Systems ◽

Jump Velocity ◽

Assembly Tasks

Abstract Current dynamic simulation programs are able to calculate the continuous motions of articulated systems or more general systems of rigid bodies in the absence of contact between members of the system or between the system and its environment. Some are able to simulate the effects of isolated contacts and impacts but none are able to simulate the motion with unrestricted multiple concurrent contacts. However, in special robotic programs such as robots performing assembly tasks or walking, it would be very interesting to simulate appropriate commands before implementing them on the robots. This paper develops intrinsic problems of collision to produce an efficient computational algorithm. This algorithm handles the detection of collision in three dimensions, the reduction of the integration step in order to avoid interpenetration between the bodies before impact, the jump velocity caused by a new collision and indicator magnitudes which determine the addition or deletion of constraints.

Download Full-text

A Semi-Discrete Approach for the Numerical Simulation of Freestanding Blocks

Computational Modeling of Masonry Structures Using the Discrete Element Method - Advances in Civil and Industrial Engineering ◽

10.4018/978-1-5225-0231-9.ch016 ◽

2016 ◽

pp. 416-439

Author(s):

Fernando Peña

Keyword(s):

Differential Equation ◽

Numerical Simulation ◽

Numerical Modeling ◽

Discrete Model ◽

Mathematical Formulation ◽

Equation Of Motion ◽

Rigid Bodies ◽

The Body ◽

Discrete Approach ◽

Rocking Motion

This chapter addresses the numerical modeling of freestanding rigid blocks by means of a semi-discrete approach. The pure rocking motion of single rigid bodies can be easily studied with the differential equation of motion, which can be solved by numerical integration or by linearization. However, when we deal with sliding and jumping motion of rigid bodies, the mathematical formulation becomes quite complex. In order to overcome this complexity, a Semi-Discrete Model (SMD) is proposed for the study of rocking motion of rigid bodies, in which the rigid body is considered as a mass element supported by springs and dashpots, in the spirit of deformable contacts between rigid blocks. The SMD can detect separation and sliding of the body; however, initial base contacts do not change, keeping a relative continuity between the body and its base. Extensive numerical simulations have been carried out in order to validate the proposed approach.

Download Full-text

On the Numerical Simulation of Incompressible Viscous Fluid Flow around Moving Rigid Bodies of Elliptical Shape

Numerical Simulations of Incompressible Flows ◽

10.1142/9789812796837_0011 ◽

2003 ◽

pp. 179-202

Author(s):

Roland Glowinski ◽

L. Hector Juárez ◽

Tsorng-Whay Pan

Keyword(s):

Numerical Simulation ◽

Fluid Flow ◽

Viscous Fluid ◽

Rigid Bodies ◽

Incompressible Viscous Fluid ◽

Viscous Fluid Flow ◽

Elliptical Shape

Download Full-text

Multibody Analysis of a Human and Inverted-Pendulum Vehicle With and Without a Handle–Hand Constraint

Volume 7B: 9th International Conference on Multibody Systems, Nonlinear Dynamics, and Control ◽

10.1115/detc2013-12047 ◽

2013 ◽

Author(s):

Chihiro Nakagawa ◽

Shunsuke Arakawa ◽

Atsuhiko Shintani ◽

Tomohiro Ito

Keyword(s):

Numerical Simulation ◽

Multibody Dynamics ◽

Inverted Pendulum ◽

Coupling Model ◽

Dynamic Interaction ◽

Rigid Bodies ◽

Gravity Center ◽

Basic Study

An inverted-pendulum vehicle is controlled by the movement of the user’s gravity center; however, detailed dynamic interaction between the vehicle and a user has not been clarified. In a previous basic study, we investigated the relationships between the user and vehicle in the case that the handle and hand are not constrained [3]. In the present study, we constructed a model that constrains the hand and handle, and simulated the situation of the vehicle accelerating. The coupling model was built using multibody dynamics. The vehicle was expressed by three rigid bodies and a user by eight rigid bodies. In the numerical simulation, it was found that the vehicle accelerates more quickly when there is a constraint linking the handle and hand. This is because the force imparted by the user’s hand, resulting in inclination of the vehicle in the traveling direction, is easily transmitted to the vehicle through the handle.

Download Full-text