Educational Application of the AutoDyn7 (CADyna) Program in Advanced Dynamics Course at the Pusan National University in Korea

2005 ◽  
Author(s):  
Wan-Suk Yoo ◽  
Sung-Soo Kim ◽  
Kwang-Suk Kim ◽  
Jeong-Hyun Sohn
Keyword(s):  
Multibody Dynamics ◽  
General Purpose ◽  
Graphic User Interface ◽  
Flexible Bodies ◽  
User Input ◽  
Velocity Transformation ◽  
National University ◽  
Open Inventor ◽  
Systematic Formulation ◽  
Velocity Transformation Technique

In this study, general purpose multibody dynamics codes AutoDyn7 (AUTOmobile DYNamics in G7) and CADyna (the NT version of the AutoDyn7) are introduced for the application to education in multibody dynamics. In the Auto-Dyn7 program, an efficient and systematic formulation for rigid and flexible bodies is derived using the velocity transformation technique. The Rapid-App for GUI (Graphic User Interface) builder and the Open Inventor for 3D graphic library have been employed to develop these programs in Silicon Graphics workstation. Several special purpose modules of the AutoDyn7 program are introduced to analyze vehicle dynamic characteristics. The NT version of the AutoDyn7, named CADyna, is also developed. The pre-processor for user input is developed with Visual C++ and the post-processor is developed with OpenGL and TeeChart for animation and graph.

A Systematic Formulation for Dynamics of Flexible Multi-Body Systems Using the Velocity Transformation Technique

1993 ◽  
Vol 207 (4) ◽  
pp. 231-238 ◽  
Author(s):  
B H Lee ◽  
W S Yoo ◽  
B M Kwak
Keyword(s):  
Equations Of Motion ◽  
Normal Modes ◽  
Coordinate Space ◽  
Euler Parameters ◽  
Transformation Technique ◽  
Element Analysis ◽  
Velocity Transformation ◽  
Systematic Formulation ◽  
Multi Body ◽  
Velocity Transformation Technique

An efficient and systematic formulation for dynamics of spatial multi-body systems with flexible bodies is presented using the velocity transformation technique. The Cartesian variables are expressed in terms of the relative and elastic variables. Using the resulting kinemtic relationships, the velocity and acceleration transformation equations are derived and used to transform the equations of motion from the Cartesian coordinate space to the relative coordinate space. In order to reduce the number of elastic coordinates, elastic deformations are represented by the vibration normal modes obtained from the finite element analysis. The Euler parameters are used as the rotational coordinates since they are convenient for algebraic manipulation and have no singular condition. The formulation is illustrated by means of two numerical examples.

A General Purpose Formulation for Nonsmooth Dynamics With Finite Rotations: Application to the Woodpecker Toy

2020 ◽  
Vol 16 (3) ◽  
Author(s):  
Alejandro Cosimo ◽  
Federico J. Cavalieri ◽  
Javier Galvez ◽  
Alberto Cardona ◽  
Olivier Brüls
Keyword(s):  
Finite Element ◽  
Multibody Dynamics ◽  
Equations Of Motion ◽  
Horizontal Displacement ◽  
General Purpose ◽  
Nonsmooth Dynamics ◽  
Unilateral Constraints ◽  
Simulation Code ◽  
Frictional Contacts ◽  
Large Rotations

Abstract The aim of this work is to extend the finite element multibody dynamics approach to problems involving frictional contacts and impacts. The nonsmooth generalized-α (NSGA) scheme is adopted, which imposes bilateral and unilateral constraints both at position and velocity levels avoiding drift phenomena. This scheme can be implemented in a general purpose simulation code with limited modifications of pre-existing elements. The study of the woodpecker toy dynamics sets up a good example to show the capabilities of the NSGA scheme within the context of a general finite element framework. This example has already been studied by many authors who generally adopted a model with a minimal set of coordinates and small rotations. It is shown that good results are obtained using a general purpose finite element code for multibody dynamics, in which the equations of motion are assembled automatically and large rotations are easily taken into account. In addition, comparing results between different models of the woodpecker toy, the importance of modeling large rotations and the horizontal displacement of the woodpecker's sleeve is emphasized.

Modeling Controlled Articulated Flexible Systems Using Assumed Modes: Part II — Numerical Investigation

2001 ◽  
Author(s):  
Theodore G. Mordfin ◽  
Sivakumar S. K. Tadikonda
Keyword(s):  
Multibody Dynamics ◽  
Dynamic Systems ◽  
Flexible Multibody Dynamics ◽  
Companion Paper ◽  
Parameter Variation ◽  
Flexible Bodies ◽  
Simulation Efficiency ◽  
Multibody Dynamic ◽  
Flexible Multibody ◽  
Assumed Mode

Abstract Guidelines are sought for generating component body models for use in controlled, articulated, flexible multibody dynamics system simulations. In support of this effort, exact truth models and linearized large-articulation models are developed in a companion paper. The purpose of the truth models is to aid in evaluating the use of various types of component body assumed modes in the large-articulation models. The assumed mode models are analytically evaluated from the perspectives of both structural dynamics and multibody dynamics. In this paper, component body assumed modes are tested in a linearized large-articulation model. The numerical behavior of the model and its performance in the presence of parameter variation is investigated and explained. The results show that high accuracy, high simulation efficiency, and numerical robustness cannot be simultaneously achieved. However, in many cases, satisfactory levels of all three are achievable. Guidelines are proposed for modeling the flexible bodies in controlled-articulation flexible multibody dynamic systems.

COMPARATIVE ANALYSIS OF THE CONTENT OF THE TARAS SHEVCHENKO NATIONAL UNIVERSITY OF KYIV’S LINGUISTIC EDUCATIONAL MUSEUM EXPOSITION WITH SIMILAR INSTITUTIONS IN THE WORLD

2019 ◽  
pp. 26-32
Author(s):  
A. М. Bocharnikova
Keyword(s):  
Comparative Analysis ◽  
The Netherlands ◽  
General Purpose ◽  
The Internet ◽  
National Museum ◽  
Structural Elements ◽  
The Past ◽  
The Us ◽  
The World ◽  
National University

The article contains information on all general-purpose linguistic museums that are currently functioning in the world, functioned in the past, or are at the project stage. In cases where this is possible, the structure of museum’s exposition is examined. Criteria that have played a key role in the division of museums’ content into structural elements are defined. The accuracy of exposition authors’ compliance of their approaches has also been analyzed. The first linguistic museum in the world that opened its doors to visitors was Taras Shevchenko university of Kyiv’s Linguistic Educational Museum founded in 1992 by the order of the university’s rector. During next sixteen years it was world’s only linguistic museum till the year 2008 when National Museum of Language in the US was opened. In 2013 a new linguistic museum named Mundolingua was established in Paris. After 2014 when the museum in USA was closed and till now it continues to be the only linguistic museum in the world except Linguistic Educational Museum in Ukraine that is functioning. At present times there are several big projects of establishing a comprehensive linguistic museum in different countries. Among them is Planet Word in Washington, Museum der Sprachen der Welt in Berlin, Museum of Language in London. The work upon these projects is in progress and hasn’t reached the stage of completeness. There are also two websites available on the Internet that have the name of museum but does not contain any traces of the exposition content. These are the website of the above mentioned National Museum of Language and Taalmuseum in the Netherlands. Both of these websites are portals for announcements concerning exhibitions, lectures and meetings in different places that are somehow referred to language topics. In this article the structure of the museums content has also been analyzed. Linguistic Educational Museum in Kyiv was established for academic purposes therefore its content has the same structure as the Introductory Linguistics course. At the same time it reveals the principles of the museum exposition author’s Doctor of Science thesis named the Metatheory of Linguisics.

Spatial Dynamics of Deformable Multibody Systems With Variable Kinematic Structure: Part 2—Velocity Transformation

1990 ◽  
Vol 112 (2) ◽  
pp. 160-167 ◽  
Author(s):  
C. W. Chang ◽  
A. A. Shabana
Keyword(s):  
Multibody Systems ◽  
Robot Manipulator ◽  
Spatial Dynamics ◽  
Dynamic Equations ◽  
Velocity Transformation ◽  
Joint Forces ◽  
Joint Coordinates ◽  
Deformable Bodies ◽  
Spatial System ◽  
Velocity Transformation Technique

In Part 1 of these two companion papers, the spatial system kinematic and dynamic equations are developed using the Cartesian and elastic coordinates in order to maintain the generality of the formulation. This allows introducing general forcing functions and adding and/or deleting kinematic constraints. In control applications, however, it is desirable to determine the joint forces associated with the joint variables. On the other hand the use of the joint coordinates to formulate the dynamic equations leads to a complex recursive formulation based on loop closure equations. In this paper a velocity transformation technique applicable to spatial multibody systems that consist of interconnected rigid and deformable bodies is developed. The Cartesian variables are expressed in terms of the joint and elastic variables. The resulting kinematic relationships are then employed to determine the joint forces associated with the joint variables. A spatial robot manipulator that manipulates an object is presented as a numerical example to exemplify the development presented in this paper.

Real-Time Explicit Flexible Multibody Dynamics Solver With Application to Virtual-Reality Based E-Learning

2011 ◽  
Author(s):  
Tamer M. Wasfy ◽  
Hatem M. Wasfy ◽  
Jeanne M. Peters
Keyword(s):  
Virtual Reality ◽  
Finite Elements ◽  
Rigid Body ◽  
Real Time ◽  
Multibody Dynamics ◽  
Flexible Multibody Dynamics ◽  
Rigid Bodies ◽  
Flexible Bodies ◽  
Joint Contact ◽  
E Learning

A flexible multibody dynamics explicit time-integration parallel solver suitable for real-time virtual-reality applications is presented. The hierarchical “scene-graph” representation of the model used for display and user-interaction with the model is also used in the solver. The multibody system includes rigid bodies, flexible bodies, joints, frictional contact constraints, actuators and prescribed motion constraints. The rigid bodies rotational equations of motion are written in a body-fixed frame with the total rigid body rotation matrix updated each time step using incremental rotations. Flexible bodies are modeled using total-Lagrangian spring, truss, beam and hexahedral finite elements. The motion of the elements is referred to a global inertial Cartesian reference frame. A penalty technique is used to impose joint/contact constraints. An asperity-based friction model is used to model joint/contact friction. A bounding box binary tree contact search algorithm is used to allow fast contact detection between finite elements and other elements as well as general triangular/quadrilateral rigid-body surfaces. The real-time solver is used to model virtual-reality based experiments (including mass-spring systems, pendulums, pulley-rope-mass systems, billiards, air-hockey and a solar system) for a freshman university physics e-learning course.

An Open Code for the Dynamic Simulation of Multibody Systems

2004 ◽  
Author(s):  
Pietro Fanghella ◽  
Carlo Galletti ◽  
Giorgio Torre
Keyword(s):  
Control Systems ◽  
Multibody Systems ◽  
Object Oriented ◽  
General Purpose ◽  
External Control ◽  
Common Environment ◽  
Flexible Bodies ◽  
Kinematic Chains ◽  
Dynamic Simulator ◽  
User Friendly

The paper presents several features of a dynamic simulator for multibody systems. Its main characteristics are the following: it can deal with mechanisms with open and closed kinematic chains, allows definitions of rigid and flexible bodies, permits definitions of complex non-standard dynamic actions by a powerful and well-known general-purpose simulation package, and provides links to user-friendly interfaces for result displaying and interfacing with external control systems. In order to perform all these actions, a common environment based on Matlab has been established. The software is implemented using the Matlab object-oriented language. The first part of the paper provides a basic discussion of the mathematical approach followed to model multibody systems, then the actual software implementation is described. The designed software architecture is open and allows great model generality; moreover, the software can be optimized and tailored to specific multibody models in order to obtain good computational efficiency. Integration aspects in Simulink and VRML environments are analyzed.

Simulation of Multibody Dynamics in Autocad

1996 ◽  
Author(s):  
Shih-Tin Lin ◽  
Jhy-Hong Lin
Keyword(s):  
Dynamic Analysis ◽  
Multibody Dynamics ◽  
Variational Formulation ◽  
Input Data ◽  
Multibody System ◽  
Robot Manipulators ◽  
Mechanical Systems ◽  
General Purpose ◽  
User Friendly

Abstract A general purpose multibody dynamics algorithm is written and merged into AutoCAD. This merger creates a user friendly environment for the simulation of multibody mechanical systems such as robot manipulators. Users can prepare input data of the dynamic code easily after creating an AutoCAD drawing of the multibody system. After the dynamic analysis is complete, the results can be easily used to produce animation slides in AutoCAD. The multibody dynamics algorithm uses a recursive variational formulation. This formulation has been proven to be computationally more efficient.

Efficient Coupling of Absolute Nodal Coordinate Formulation Flexible Bodies With an Existing Multibody Dynamics Code

2012 ◽  
Author(s):  
Jeff Liu ◽  
Abdel-Nasser A. Mohamed
Keyword(s):  
Multibody Dynamics ◽  
Absolute Nodal Coordinate Formulation ◽  
Sparse Matrix ◽  
Equations Of Motion ◽  
Matrix Solution ◽  
State Equations ◽  
Combined System ◽  
Flexible Bodies ◽  
Absolute Nodal Coordinate ◽  
Efficient Coupling

A couple of issues are identified in the process to embed absolute nodal coordinate formulation (ANCF) flexible bodies in an existing multibody dynamics code. (1) The generalized coordinates of ANCF must be solved together with those of the rest of the mechanism in a combined system of the equations of motion. (2) The various constraints, joints, and forces elements supported in the multibody dynamics code must be extended to the ANCF flexible bodies without major code restructuring. This paper describes two novel techniques that were devised to solve these issues. The first is the idea of interface triad. We will demonstrate how to construct the interface triad such that all exiting constraints, joints, and forces elements are automatically supported. The second idea is to represent the equations of motion of the ANCF body as a user-defined subroutine element representing a set of implicit general state equations subroutine (GSESUB). By treating each ANCF body modularly as a user-defined subroutine, not only all existing integration options of its host solver, e.g., HHT or DAE index-1, 2, and 3, etc., are automatically supported, but also the existing features such as parallel computing and sparse matrix solution of the existing multibody dynamics software are supported with minimum programming. Numerical examples are presented to demonstrate the efficiency and the success of these two techniques.

Recursive Linearization of Multibody Dynamics and Application to Control Design

1994 ◽  
Vol 116 (2) ◽  
pp. 445-451 ◽  
Author(s):  
Tsung-Chieh Lin ◽  
K. Harold Yae
Keyword(s):  
Multibody Dynamics ◽  
Equations Of Motion ◽  
Control Design ◽  
Numerical Differentiation ◽  
Difficult Problem ◽  
General Purpose ◽  
Computational Method ◽  
Computational Error ◽  
Dynamics Modeling ◽  
Analytical Approximations

The nonlinear equations of motion in multibody dynamics pose a difficult problem in linear control design. It is therefore desirable to have linearization capability in conjunction with a general-purpose multibody dynamics modeling technique. A new computational method for linearization is obtained by applying a series of first-order analytical approximations to the recursive kinematic relationships. The method has proved to be computationally more efficient. It has also turned out to be more accurate because the analytical perturbation requires matrix and vector operations by circumventing numerical differentiation and other associated numerical operations that may accumulate computational error.

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