First Advisor

Alexander Hunt

Term of Graduation

Summer 2021

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Mechanical Engineering


Mechanical and Materials Engineering




Forelimb, Rats, Viscoelasticity, Biomechanics, Muscles



Physical Description

1 online resource (viii, 81 pages)


This paper presents a biomechanical model of the rat forelimb to test theories of determining viscoelastic muscle parameters. Several biomechanical models of rat hindlimbs have been developed and have explored the effects of multi-muscle control during locomotion. The forelimb model uses two ball-and-socket joints to model clavicle and scapula movement. A third ball-and-socket joint is used at the shoulder and two hinge joints are used at the elbow and wrist. Scapula motion is further constrained by muscle and spring elements. Each forelimb has 11 degrees of freedom, and 23 Hill-type muscles. The model has been created in Animatlab, which includes both a neural design component and a physics environment. Muscle paths are hand guided to approximate the origin and insertion points necessary to replicate multi-body articulation. Most muscles are represented with a single linear muscle path, except in cases where muscle wrapping was necessary around joints or bones. Explored in this work are multiple methods for setting passive muscle parameters, including the use of scaling heuristics and optimization with experimental data. Stiffness and damping muscle parameters are being validated against kinematic and kinetic data from the rat.


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