A Computational Model of Scapulo-Humeral-Clavicle Complex via Multibody Dynamics

2009 ◽  
Author(s):  
Shanzhong Shawn Duan ◽  
Keith M. Baumgarten
Keyword(s):  
Rigid Body ◽  
Soft Tissues ◽  
Equations Of Motion ◽  
Rigid Bodies ◽  
The Body ◽  
Constraint Forces ◽  
Upper Arm ◽  
Body Model ◽  
Rigid Body Model ◽  
Concentric Ball

The shoulder-upper arm complex has the most mobile joint in the body and is composed of three main bones: the collarbone (clavicle), the shoulder blade (scapula), and the upper arm bone (humerus). The shoulder joint is a non-concentric ball and socket joint. It differs from the hip, a highly stabilized, concentric ball and socket joint, that is constrained mostly by its osseous anatomy. Thus, the shoulder has more flexibility and less inherent stability than the hip because it is mainly stabilized by muscles, tendons, and ligaments. The relative decrease in stability of the shoulder compared to other joints puts the shoulder at increase risk of damage by disease or injury. The constraints added by muscles, tendons, and ligaments make modeling of the shoulder a challenge task. This paper presents a multi rigid body model to describe dynamical properties of the scapulo-humeral-clavicle complex. The bones are represented by rigid bodies, and the soft tissues (tendons, ligaments and muscles) are represented by springs and actuators attached to the rigid bodies. The rigid bodies are connected by ideal kinematic joints and have fixed centers of gravity. Equations of motion of the multi rigid body model are derived via Kane’s methods. Combination of springs and actuators includes independent variables for both motion and constraint forces, the sum of which determine the activation level.

Vibration Modes and Frequencies of Timoshenko Beams With Attached Rigid Bodies

1995 ◽  
Vol 62 (1) ◽  
pp. 193-199 ◽  
Author(s):  
M. W. D. White ◽  
G. R. Heppler
Keyword(s):  
Boundary Conditions ◽  
Rigid Body ◽  
Timoshenko Beam ◽  
Equations Of Motion ◽  
Frequency Equation ◽  
Rigid Bodies ◽  
The Body ◽  
Mode Shapes ◽  
Timoshenko Beams ◽  
First Moment

The equations of motion and boundary conditions for a free-free Timoshenko beam with rigid bodies attached at the endpoints are derived. The natural boundary conditions, for an end that has an attached rigid body, that include the effects of the body mass, first moment of mass, and moment of inertia are included. The frequency equation for a free-free Timoshenko beam with rigid bodies attached at its ends which includes all the effects mentioned above is presented and given in terms of the fundamental frequency equations for Timoshenko beams that have no attached rigid bodies. It is shown how any support / rigid-body condition may be easily obtained by inspection from the reported frequency equation. The mode shapes and the orthogonality condition, which include the contribution of the rigid-body masses, first moments, and moments of inertia, are also developed. Finally, the effect of the first moment of the attached rigid bodies is considered in an illustrative example.

A Family of Butterfly Flexural Joints: Q-LITF Pivots

2011 ◽  
Author(s):  
Xu Pei ◽  
Jingjun Yu ◽  
Shusheng Bi ◽  
Guanghua Zong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rigid Body ◽  
Rigid Bodies ◽  
The Other ◽  
Element Analysis ◽  
Leaf Type ◽  
Center Shift ◽  
Body Model ◽  
Rigid Body Model

The Leaf-type Isosceles-Trapezoidal Flexural (LITF) pivot consists of two compliant beams and two rigid-bodies. For a single LITF pivot, the range of motion is small while the center-shift is relatively large. The capability of performance can be improved greatly by the combination of four LITF pivots. Base on the pseudo-rigid-body model (PRBM) of a LITF pivot, a method to construct the Quadri-LITF pivots is presented by regarding a single LITF pivot (or double-LITF pivot) as a the configurable flexure module. Ten types of Q-LITF pivots are synthesized. Compared with the single LIFT pivot, the stroke becomes larger, and stiffness becomes smaller. Four of them have the increased center-shift. The other four have the decreased center-shift. One of the quadruple LITF pivots is selected as the examples to explain the proposed method. The comparison between PRBM and Finite Element Analysis (FEA) result shows the validity and effectiveness of the method.

Identifying Sets of Constraint Forces by Inspection

2013 ◽  
Vol 80 (2) ◽  
Author(s):  
Carlos M. Roithmayr ◽  
Dewey H. Hodges
Keyword(s):  
Mechanical System ◽  
Equations Of Motion ◽  
Rigid Bodies ◽  
The Body ◽  
Vector Form ◽  
Constraint Forces ◽  
Constraint Force ◽  
Symbolic Algebra ◽  
Constraint Equations ◽  
Angular Velocities

A mechanical system is often modeled as a set of particles and rigid bodies, some of which are constrained in one way or another. A concise method is proposed for identifying a set of constraint forces needed to ensure the restrictions are met. Identification consists of determining the direction of each constraint force and the point at which it must be applied, as well as the direction of the torque of each constraint force couple, together with the body on which the couple acts. This important information can be determined simply by inspecting constraint equations written in vector form. For the kinds of constraints commonly encountered, the constraint equations are expressed in terms of dot products involving velocities of the affected points or particles and angular velocities of the bodies concerned. The technique of expressing constraint equations in vector form and identifying constraint forces by inspection is useful when one is deriving explicit, analytical equations of motion by hand or with the aid of symbolic algebra software, as demonstrated with several examples.

scholarly journals CASES OF INTEGRABILITY CORRESPONDING TO THE PENDULUM MOTION IN FOUR-DIMENSIONAL SPACE

2017 ◽  
Vol 23 (1) ◽  
pp. 41-58
Author(s):  
M. V. Shamolin
Keyword(s):  
Rigid Body ◽  
Force Fields ◽  
Characteristic Point ◽  
Dimensional Space ◽  
Equations Of Motion ◽  
Rigid Bodies ◽  
The Body ◽  
Pendulum Motion ◽  
Nonconservative Force ◽  
Similar Force

In this article, we systemize some results on the study of the equations of motion of dynamically symmetric fixed four-dimensional rigid bodies–pendulums located in a nonconservative force fields. The form of these equations is taken from the dynamics of real fixed rigid bodies placed in a homogeneous flow of a medium. In parallel, we study the problem of the motion of a free four-dimensional rigid body also located in a similar force fields. Herewith, this free rigid body is influenced by a nonconservative tracing force; under action of this force, either the magnitude of the velocity of some characteristic point of the body remains constant, which means that the system possesses a nonintegrable servo constraint. We also show the nontrivial topological and mechanical analogies.

Modeling and Simulation of Shoulder-Humerus Complex via Multibody Dynamics for a Walking Elder Using a Cane

2016 ◽  
Author(s):  
Shanzhong (Shawn) Duan
Keyword(s):  
Multibody Dynamics ◽  
Sports Medicine ◽  
Soft Tissues ◽  
Equations Of Motion ◽  
Computer Software ◽  
Rigid Bodies ◽  
Upper Body ◽  
Upper Arm ◽  
Shoulder Blade ◽  
Multibody Dynamics Model

The shoulder is a very mobile joint. Because of the mobility, the shoulder is considered to have an inherent weakness. The joint consists of three major bones, the clavicle, scapula and humerus. These bones are more commonly called the collarbone, shoulder blade, and upper arm bone, respectively. Collectively, the shoulder is referred to as the scapula-humeral-clavicle complex. The joint between the humerus and scapula is a ball-socket joint. The joint between the scapula and acromial process allows for some movement but is primarily fixed. The ligaments, tendons, and muscles surround the shoulder to provide stability, movement, and limit the amount of rotation. In this paper, a multibody dynamics model of the shoulder-upper arm complex is presented. Three major bones clavicle, scapula, and Humerus in the shoulder-upper arm complex are represented by rigid bodies. The soft tissues such as tendons, ligaments, and muscles are modeled as springs and actuators respectively attached to the rigid bodies. The joints between the bones are expressed as ideal kinematic joints. Kane’s equations are then used to derive equations of motion of this multibody system. Based on the model, an elder who uses a cane with his or her shoulder-upper arm complex force to support his or her upper body weight during walking is analyzed. Commercial computer software is used to create the multibody shoulder-upper arm complex computational model and then carry out simulation. The model may be utilized in motion analysis of elderly people and sports medicine to study fatigue mechanism and prevent injuries of the shoulder-upper arm complex.

scholarly journals NEW CASE OF INTEGRABILITY IN DYNAMICS OF MULTI-DIMENSIONAL BODY

2017 ◽  
Vol 18 (9) ◽  
pp. 136-150
Author(s):  
N.V. Pokhodnya ◽  
M.V. Shamolin
Keyword(s):  
Rigid Body ◽  
Equations Of Motion ◽  
Dynamical Symmetry ◽  
Jet Flow ◽  
Rigid Bodies ◽  
The Body ◽  
Phase Variable ◽  
Resisting Medium ◽  
Servo Constraints ◽  
Typical Point

In this chapter the new results are systematized on study of the equations of motion of dynamically symmetrical four-dimensional (4D—) rigid body which residing in a certain nonconservative field of forces in case of special dynamical symmetry. Its type is unoriginal from dynamics of the real smaller-dimensional rigid bodies of interacting with a resisting medium on the laws of a jet flow, under which the nonconservative tracing force acts onto the body and forces both the value of velocity of a certain typical point of the rigid body and the certain phase variable to remain as constant in all time, that means the presence in system nonintegrable servo-constraints.

Modeling and Simulation of Shoulder-Humerus Complex via Multibody Dynamics

2013 ◽  
Author(s):  
Nicholas D. Harrington ◽  
Shanzhong (Shawn) Duan
Keyword(s):  
Multibody Dynamics ◽  
Sports Medicine ◽  
Soft Tissues ◽  
Equations Of Motion ◽  
Computer Software ◽  
Rigid Bodies ◽  
Upper Body ◽  
Dynamics Model ◽  
Upper Arm ◽  
Multibody Dynamics Model

In this paper, a multibody dynamics model of the shoulder-upper arm complex is presented. Three major bones clavicle, scapula, and humerus in the shoulder-upper arm complex are represented by rigid bodies. The soft tissues such as tendons, ligaments, and muscles are modeled as springs and dampers respectively attached to the rigid bodies. The joints between the bones are expressed as ideal kinematic joints. Kane’s equations are then used to derive equations of motion of this multibody system. Based on the model, a person’s stand-up motion, aided by shoulder-upper arm complex force for lifting his/her upper body weight is analyzed. Commercial computer software is used to create the multibody shoulder-upper arm complex computational model and then carry out simulation. The model may be utilized in motion analysis of elderly people and sports medicine to study fatigue mechanism and prevent injuries of the shoulder-upper arm complex.

Sign in / Sign up

Export Citation Format

Share Document