Flashcards
Lectures 5+6
Flashcards do conjunto (30)
- 1InjuryMechanical disruption of tissue.
Can involve gradual degradation or suddenly - 2Elastic force (exposed to a force)Length of material changes.
Change is reversible when load is removed - 3Plastic region (exposed to a force)If forces are greater than the yield strength, then the length of the material will change at a faster rate than in elastic.
Change isn't reversible when load removed - 4FailureLoad exceeds strength of material
- 5Mechanical load eq.Stress=force over area
- 6Strain eq.Strain=change in length over initial length
- 75 ways loads can be appliedCompression.
Tension.
Shear.
Bending.
Torsion. - 8CompressionCaused by load bearing+muscle forces.
Stimulates growth in the bone.
Force is inwards (up/down) - 9TensionUsually caused by muscle forces.
Stimulates formation of apophyses.
Usually occur at site of muscle insertion.
Outwards (up/down) - 10Shear forcesBone fails more rapidly than compression or tension
cause epiphyseal fractures
Bone breaks from side forces - 11Bending forcesOne side of bone in compression, other in tension.
Fracture occurs tension side.
Twist movt. - 12TorsionTwisting force e.g. spinal fractures
- 13Bone strengthCompact bone.
Cylindrical sections.
Reduced by disease. - 14Direct injClose to site of load app.
- 15Indirect inj.Load is transferred through other tissues
- 16Angular displacementBreak away from middle
- 17Rotational displacementone side rotates
- 18DistractionPull apart
- 19OveridingPush together
- 20ImpactionPush together and break
- 21Lateral shiftMove either side
- 22Ligaments70% water
25% collagen
5% elastin etc - 23Lig strainsMicro-trauma: loads below normal strength of material, small failures in collagen.
Macro-trauma: Force is sufficient for partial/total rupture of fibres - 24WhiplashVertebral rotation at c6-7 and c7-t1 exceed physiological limits
- 252 stages of whiplash1.cervical spine forms s shape.
EXT of lower, FLEX of upper vert.
2.Cervical spine forms c shape.
lower level ext shows relaxation - 26ModelsHelps us understand how something works.
Perform unethical/impossible/expensive exp.
Enables predictions. - 27Mathematical modelsImperfect emulations of reality
Neglect factors e.g. aerodynamics - 28Numerical modellingTrident=static+fatigue+vibration+
interaction - 29Lumped parameter modelsSeperate properties of a biological structure.
Complex expr. built up
Allow validity of model to be determined. - 30Finite element analysisUsed when too many lumped parameters.
Builds models like lego.
Each structure made up of an array of elements (brick) with properties of each brick known.
Takes many supercomputers
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- FlashCards sobre Lectures 5+6, criado por johno barker em 29-05-2013.
- Criado por
- johno barker
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