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

Author(s):  
Shanzhong (Shawn) Duan

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.

Author(s):  
Nicholas D. Harrington ◽  
Shanzhong (Shawn) Duan

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.


Author(s):  
Shanzhong Shawn Duan ◽  
Keith M. Baumgarten

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.


Author(s):  
Shahriar G. Ahmadi ◽  
Tamer M. Wasfy ◽  
Hatem M. Wasfy ◽  
Jeanne M. Peters

A high-fidelity multibody dynamics model for simulating a backhoe digging operation is presented. The backhoe components including: frame, manipulator, track, wheels and sprockets are modeled as rigid bodies. The soil is modeled using cubic shaped particles for simulating sand with appropriate inter-particle normal and frictional forces. A penalty technique is used to impose both joint and normal contact constraints (including track-wheels, track-terrain, bucket-particles and particles-particles contact). An asperity-based friction model is used to model joint and contact friction. A Cartesian Eulerian grid contact search algorithm is used to allow fast contact detection between particles. A recursive bounding box contact search algorithm is used to allow fast contact detection between polygonal contact surfaces. The governing equations of motion are solved along with joint/constraint equations using a time-accurate explicit solution procedure. The model can help improve the performance of construction equipment by predicting the actuator and joint forces and the vehicle stability during digging for various vehicle design alternatives.


Author(s):  
Shanzhong (Shawn) Duan

Whole-body vibrations (WBV) have been used for enhancing muscle strength and bone density of human bodies, training athletes and dancers, and helping people with disabling conditions and rehabilitations. On the other hand, WBV-induced occupational diseases have been reported. Researchers in automotive, farm equipment, and heavy machinery have put forward a few models for studying harmful vibrations on human bodies. This paper will review the effects of frequencies and magnitudes of WBV on a human body. Discussion of effects of frequencies and magnitudes on a human body will provide a preliminary boundary line between good and bad whole-body vibrations. Two multibody dynamics models and associated application cases will be proposed to show how the models may be used to represent whole-body vibrations under both good and bad vibrations. Three basic vibration elements associated with whole-body vibrations of the human body are handled as follows: (1) ligaments are modeled as spring elements; (2) muscles and tendons are modeled as damping elements; (3) bones are modeled as rigid bodies with masses/inertias and connected by idealized massless joints. In such a biomechanical vibration system, the spring elements (ligaments) help hold the human body skeleton structure in a stable condition, pass spring forces and potential energy to rigid bodies (bones) for bone vibrational motions. The damping elements (muscles and tendons) play roles of a damper and absorb energy input from the whole-body vibration resource. Based on the proposed multibody dynamics models, Kane’s method is then used to develop equations of motion. The equations will be further used for development of simulation algorithms to understand frequencies and magnitudes of both good and bad whole-body vibrations. The models may be utilized to understand why frequencies and magnitudes of whole-body vibrations will provide benefits to human health under one situation but cause occupational diseases under another scenario.


Author(s):  
Cagkan Yildiz ◽  
Tamer M. Wasfy

A time-accurate multibody dynamics model for predicting the transient response of toroidal traction drives is presented. The model can be used to predict the system’s transient response due to variations in the input speed, variations in the output load, and changing the speed ratio. The model supports half and full-toroidal configurations, multiple transmitters and multiple cavities. The multibody system representing the toroidal drive is modeled using rigid bodies, revolute joints and rotational actuators. A penalty model is used to impose the joint/contact constraints. The contact model detects contact between discrete points on the surface of the transmitter and an analytical surface representation of the input and output shafts’ toroidal surfaces. A recursive bounding sphere contact search algorithm is used to allow fast contact detection. An elasto-hydrodynamic lubrication model is used for the tangential contact traction forces between the transmitter and the toroid. The governing equations of motion are solved along with joint/constraint equations using a time-accurate explicit solution procedure. The model is partially validated by comparing to previously published steady-state models. The model can help improve the design of toroidal continuous-variable transmission systems including increasing the torque capacity and durability.


IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 32171-32187
Author(s):  
Shaoyang Qiu ◽  
Hongxiang Ren ◽  
Haijiang Li ◽  
Yi Zhou ◽  
Delong Wang

Author(s):  
Guang Dong ◽  
Zheng-Dong Ma ◽  
Gregory Hulbert ◽  
Noboru Kikuchi

The topology optimization method is extended for the optimization of geometrically nonlinear, time-dependent multibody dynamics systems undergoing nonlinear responses. In particular, this paper focuses on sensitivity analysis methods for topology optimization of general multibody dynamics systems, which include large displacements and rotations and dynamic loading. The generalized-α method is employed to solve the multibody dynamics system equations of motion. The developed time integration incorporated sensitivity analysis method is based on a linear approximation of two consecutive time steps, such that the generalized-α method is only applied once in the time integration of the equations of motion. This approach significantly reduces the computational costs associated with sensitivity analysis. To show the effectiveness of the developed procedures, topology optimization of a ground structure embedded in a planar multibody dynamics system under dynamic loading is presented.


Author(s):  
Francisco González ◽  
Pierangelo Masarati ◽  
Javier Cuadrado ◽  
Miguel A. Naya

Formulating the dynamics equations of a mechanical system following a multibody dynamics approach often leads to a set of highly nonlinear differential-algebraic equations (DAEs). While this form of the equations of motion is suitable for a wide range of practical applications, in some cases it is necessary to have access to the linearized system dynamics. This is the case when stability and modal analyses are to be carried out; the definition of plant and system models for certain control algorithms and state estimators also requires a linear expression of the dynamics. A number of methods for the linearization of multibody dynamics can be found in the literature. They differ in both the approach that they follow to handle the equations of motion and the way in which they deliver their results, which in turn are determined by the selection of the generalized coordinates used to describe the mechanical system. This selection is closely related to the way in which the kinematic constraints of the system are treated. Three major approaches can be distinguished and used to categorize most of the linearization methods published so far. In this work, we demonstrate the properties of each approach in the linearization of systems in static equilibrium, illustrating them with the study of two representative examples.


Volume 2 ◽  
2004 ◽  
Author(s):  
Serdar Aritan ◽  
S. Olutunde Oyadiji ◽  
Roger M. Bartlett

The aim of this study was to characterise the bulk modulus properties of the upper arm under relaxed and controlled contraction which is defined as 25% of the maximum voluntary contraction. A new testing machine was designed to generate constant load on the upper arm and measure the deformation over time. The machine consists of a device which is effectively a cuff that applies controllable pressure on a 47 mm wide band of the upper arm. Six different loads (10, 20, 30, 40, 50 and 60 kgf) were applied over a period of time of up to a maximum of 120 seconds. The deflection-time curves obtained show strongly non-linear response of the bulk tissue. The non-linearity manifested by these deflection-time curves is in terms of both time- and load-dependency. For each load, the creep behaviour follows an exponential law typical of viscoelastic materials. At low loads (below 30kgf), the creep response increases fairly linearly as the load is increased from 10 kgf to 30 kgf. But at high loads (above 30 kgf), the creep response increases only slightly as the load is increased from 30 kgf to 60 kgf. Beyond a load of 60 kgf, the deflection or creep becomes negligible. This implies that the upper arm has reached the state of incompressibility. The creep behaviour of the upper arm was simulated using four Voigt viscoelastic models in series. The three obvious soft tissues of the upper arm, namely skin, fat and muscle, were modelled in series. The effects of blood vessels and connective tissue were also modelled in series with the other tissues.


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