Biomechanics Lecture II
Terms in this set (...)
Info about magnitude: like mass, length, & temp.
Info about magnitude & direction: like velocity & force.
Length of an arrow
Angle of an arrow
Body positions & movements relative to the world
Body-based system like cardinal planes & axes of the whole body.
Relative position between two segments
Study of motion
Spin about an axis
Where an object is located eiither 2D or 3D
How far an object moves in space over time and in which direction it moves. VECTOR quantity
How fast an object moves over a time and in which direction it moves. VECTOR quantity
Rate at which velocity changes in space over time and in which direction in velocity changes.
Study of the action of forces.
push or pull on an object
quantity of matter in an object
resistance to a change in motion
proportional to mass & the distribution of mass about the axis of rotation
Newtons 2nd law
force = mass x acceleration
Relationship between force & deformation for linear springs.
x-->amount of deformation caused by the applied force
Unit of force
Newton's First law
with no net force, a body remains at rest or at constant velocity until a force acts upon it.
Newton's Third Law
For every contact force there is an equal and opposite reaction force
Force that tends to cause rotation about an axis
Creates torque about a joint and applies force to a tissue
No acceleration - can be movement but, stays at a constant velocity.
accounts for the presence of accelerations
Deformation caused by a pressing or squeezing force
Deformation caused by a pulling or stretching force
Deformation caused by a sliding force
Deformation caused by a twisting force
Deformation caused by a combination of compression & tension forces.
Affect the concave side
Affect the convex side.
Forces being applied to the outside of the two end of the bone.
Action of applied forces.
The internal resistance of a material to an external load.
(the intensity of the force)
unit of stress
Normal or axial Stress
The intensity of internal forces acting perpendicular to a plane of cut.
Shear or tangential stress
Intensity of internal forces acting parallel to a plane of cut.
Amount of deformation of a material under load expressed as a ratio of its initial dimension.
Normal or axial strain
In the direction of the long axis-can either be lengthening or shortening deformation
When an object lengthens
The object's width usually decreases.
When an object shortens
The object's width usually increases
the distortion caused by shear stress.
Common tool used to examine the mechanical behavior of a material under load
Where deformation is not permanent
Where deformation is permanent
beginning of the plastic region
point of ultimate failure of the tissue
the area under the curve
Material exhibits properties of viscous fluids & elastic solids
Four characteristics of viscoelastic materials
2. Strain-rate dependency
Deform instantaneously under applied load, and regain their shape instantaneously when the applied load is removed.
Response of viscoelastic materials
Depends on how quickly the load is applied or removed
Strain Rate Dependency
Viscoelastic materials have different stress-strain relationships when deformed at different rates.
Behavior is increasing strain under a constant load
Behavior is a reduction in stress while at a constant length
Stiff vs. compliant
The slope of the linear region
Brittle vs ductile
Deformation in plastic region
homogeneous vs. heterogeneous
Comparision of mechanical behavior in different locations
Isotropic vs. anisotropic
Comparison of mechanical behavior when loaded in different directions.
greater resistance to deformation at a given stress
materials deform more easily at lower stresses
Refers to the property of sudden failure without plastic deformation
Materials exhibit a large plastic deformation before failure.
Materials have the same mechanical properties/behaviors regardless of location.
Properties change depending on the location in the tissue examined
Mechanical properties are independent of the direction of loading
mechanical properties change with direction of loading.
Can occur from a single max load or repeated sub-max loads.
When failure occurs due to repeated sub-max loads
Chapter 3- Kinetic Concepts
KNH 381 Exam3
EXS 322 Chapters 4-6
Elbow (Slides 39-87)
Elbow (Slides 1-38)
CP (Slides 40-116)
Biomechanics Lecture Three-Test One
Biomechanics-Bone adaptation- Test one