This class will introduce fundamental concepts of statics and solid mechanics and apply them to study the mechanical behavior bones, blood vessels, and connective tissues such as tendon and skin. Topics to be covered include the structure and mechanical properties of tissues, such as bone, tendon, cartilage and cell cytoskeleton; concepts of small and large deformation; stress; constitutive relationships that relate the two, including elasticity, anisotropy, and viscoelasticity; and experimental methods for measuring mechanical properties.
This course contains content produced by faculty members other than the listed instructors including: Dr. Thao Nguyen.
The course materials are divided into modules which can be accessed by clicking Course Modules on the course menu. The modules run for a period of seven (7) days and are made available the Thursday prior. A module will have several sections including the overview, content, readings, discussions, and assignments. You are encouraged to preview all sections of the module before starting. You should regularly check the Calendar and Announcements for assignment due dates.
It is expected that each module will take approximately 8–9 hours per week to complete. Here is an approximate breakdown: reading the assigned sections of the texts (approximately 1–2 hours per week) as well as some outside reading, listening to the audio annotated slide presentations (approximately 1-2 hours per week), and homework and projects (approximately 4–5 hours per week).
Timely feedback on students' performance is an established learning tool, so we will endeavor to grade and return to you, as quickly as possible, all material that you submit. Homework will normally be graded and returned via the website within a week. If you do not receive a grade on homework that you have turned in, please ask of its whereabouts; it may need to be resubmitted.
Module # | Module Title | Module Overview | Learning Activities and Assessments | Module Resources |
1 | Review of Statics | Review concepts of free body diagrams and equilibrium in the form of balance of forces and moments | HW 1 | Required: Humphrey – Chapter 1
Lecture notes |
2 | Concepts of Stress | Introduce and define concepts of traction and stress.
Derive the formulas for stress transformation based on static equilibrium and define the state of stress and principal stresses.
| HW 2 | Required: Humphrey – Chapter 2.1-2.4
Lecture notes |
3 | Concepts of Strain | Introduce and define concepts of deformation gradient, Green-Lagrange, and small strain. We will also derive formulas for Strain transformation and states of strain.
| HW3 | Required: Humphrey – Chapter 2.5 Lecture notes
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4 | Bone and constitutive equations for hard tissues | Introduce structure and mechanical properties of bone; Generalized Hooke’s Law for isotropy, transverse isotropy and orthotropy. Introduce structure of bone. | HW4 Midterm Project is Assigned | Required: Textbook Humphrey – Chapter 2.6-2.7 Lecture notes
Recommended Rho et al. 1998, “Mechanical properties and the hierarchical structure of bone”
Oftadeh et al. 2015, “ Biomechanics and Mechanobiologyof Trabecular Bone: A Review”
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5 | Axial Loaded Rods and torsion | Understand concepts of boundary value problems. Derive force-displacement response for an axially loaded rod and the torque-angle of twist for torsion. | HW5 | Required:
Humphrey – Chapter 3.1-3.3 and 4.1-4.6, Appendix 4
Lecture notes
|
6 | Blood Vessels and Pressure Vessels | Introduction to blood vessels
Derive Laplace’s law for thin-walled cylindrical pressure vessel with different end conditions and spherical pressure vessels.
Derive stress response for thick-walled pressure vessel. Discover the relationships between the two. | HW6 | Required: Humphrey – Chapter 3.3-3.6
Lecture notes
|
7a | Cell cytoskeleton and Beam bending part 1 | Introduce concepts of cell cytoskeleton and methods developed to measure the stiffness of cytoskeletal fibers and cellular contractility.
Derive the equilibrium equations relating lateral forces, shear forces and moments.
Introduce model for the strain-curvature relationship.
Derive the stress-moment relationship from equilibrium | HW7a | Required: Humphrey – Chapter 5.1-5.2, 5.4
Lecture notes
Recommended S. Park and Y. Chen “Mechanics of Biological Systems
3.9.2 Atomic Force Microscopy
4.6.4 Microbead-based traction force microscopy
4.6.5 Micropillar-based traction force microscopy
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7b | Beam bending part 2 | Derive the beam bending equations for the lateral deflection.
Derive the theory of beam buckling
| HW7b Midterm Project is due | Required: Textbooks 5.3., 5.5, 5.6 Appendix 5 Lecture notes
Recommended Kis et al. 2002 “Nanomechanics of Microtubules”
Kinisho and Yanagida (1998) “Force measurements by micromanipulation a single actin filament by glass needles
Kurachi et al. (1995) “Buckling of a single microtubule by optical trapping forces.. “ |
8 | Introduction to collagenous soft tissues
Stress and strains for large deformation | Introduce structure of collagenous soft tissues
Introduce concepts of true stress and true strain.
Introduce finite deformation kinematics and models of traction and stress. | HW8 Final Project is assigned
| Required: Humphrey – Chapter 6.1
Fung Chapter 7.1-7.4
Lecture notes
|
9a | Hyperelasticity: part 1 | Introduce concepts of hyperelasticity, Fung’s model, and incompressible hyperelastic model | HW 8
| Required: Humphrey – Chapter 6.2-6.6
Lecture notes
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9b | Hyperelasticity: part 2 | Introduce structure tensor models of soft tissues, distributed fiber models, Gasser, Ogfen and Holzapfel model. | HW9b
| Required: J. Merodio and R. W. Ogden (2005) “Mechanical response of fiber-reinforced incompressible non-linearly elastic solids”.
Gasser et al. (2006) “Hyperelastic modelling of arterial layers with distributed collagen fibre orientations”
Tonge et al. (2013), “Full-field bulge test for planar anisotropic tissues: Part II – A thin shell method for determining material parameters and comparison of two distributed fiber modeling approaches”
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10 | Viscoelasticity: Applications to soft tissues | Introduce small-strain theory of viscoelasticity and the resulting time-dependent and frequency dependent behaviors. | Work on your research paper | Required: Fung Chapter 2.11-2.13, 7.6 Lecture notes
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11 | Cartilage and Poroelastcity: | Introduction to structure of cartilage
Introduction to small strain theory of poroelasticity and application to unconfined compression, |
| Required: Lecture notes
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12 | Final |
| Final Project is due |
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To learn about the structure and mechanical properties of tissue, understand how mechanics can be applied to measure the mechanical properties of tissues, and analyze for the stresses and deformation of tissues in response to mechanical loading.
Biosolid mechanics is a diverse topic that spans the fracture of bones to the mechanotransduction of cells. I will rely mostly on class notes and assign reading from the required textbook: J.D. Humphrey. The textbook presents a rigorous non-tensor treatment of mechanics with relevant biological applications and is a great introductory textbook. I will also assign required reading from research papers and a few sections from the optional textbook by Y.C. Fung. These should be available in the course contents and from the library.
Humphrey, J. D., & O’Rourke, S. L. (2015). An Introduction to Biomechanics: Solids and Fluids, Analysis and Design. Springer. ISBN: 978-1-4939-2622-0 [e-version]
Optional
Fung, Y. C. (1993). Biomechanics: Mechanical Properties of Living Tissues. Springer. ISBN 978-1-4757-2257-4 [e-version]
Homework Assignments: 50%
Midterm Project: 25%
Final Project 25%
Note that HW grades will be assigned based on the cumulative score and will be curved depending the grade distribution of the class unless everyone gets 80% and above. Then we will follow the grading policy below.
Extensions for HW and project deadlines must be requested at least 24 hours in advance. This is so I can time the release of HW solutions. Otherwise, late HW and projects are not accepted.
EP uses a +/- grading system (see “Grading System”, Graduate Programs catalog, p. 10).
Score Range | Letter Grade |
---|---|
100-98 | = A+ |
97-94 | = A |
93-90 | = A− |
89-87 | = B+ |
86-83 | = B |
82-80 | = B− |
79-77 | = C+ |
76-73 | = C |
72-70 | = C− |
69-67 | = D+ |
66-63 | = D |
<63 | = F |
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