biomechanics - lunds tekniska högskola · lecture1.ppt author: ingrid svensson created date:...

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Biomechanics

•! applies mechanics to biology

•! physiological and medical

applications are the main points in this course

Biomechanics

Biomechanics is the science

that examines forces acting upon and within a biological structure and effects produced by such forces.

B.M. Nigg

Historical background !!Leonardo da Vinci, 1452-1519 !!Andreas Vesalius, 1514-1564 !!Galileo Galilei, 1564-1642 !!William Harvey, 1578-1658 !!René Descartes, 1596-1650 !!Giovanni Alfonso Borelli, 1608-1679 !!Robert Boyle, 1627-1691 !!Robert Hooke, 1635-1703 !!Isac Newton, 1642-1727 !!Leonard Euler, 1707-1783 !!Thomas Young, 1773-1829 !!Jean Poiseuille, 1797-1869 !!Adolf Fick, 1829-1901 !!....

Leonardo da Vinci

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Andreas Vesalius

Anathomic theatre, Leyden 1610 Galileo Galilei, 1564-1642

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William Harvey, 1578-1658 Giovanni Alfonso Borelli, 1608-1679

The way of solving a Biomechanical problem

1.! How does the construction work mechanically ?

0. Description of the anatomy, the CAD-drawing.

Kinematics

Anatomy Limitations

2. What about the loading ?

Outer forces

Equations of equilibrium (forces) Equations of equilibrium (moments)

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2. What about the loading?

Internal forces

Loading

Loading

Bending

Tension Compression

Ligament

Cartilage Bending

Tension Compression

It is not obvious that the position follows unambiguous from the loading !

ONLY PASSIVE ELEMENTS The position is given from the loading

WITH ACTIVE ELEMENTS The position can be com- pletely different even if the loading is the same

3. Constitutive relations

Mechanical properties of the most important constituents of bone, muscles, tendons, ligaments, cartilage etc. STRAIN

STRESS

STRESS COMPACT BONE (APATITE AND COLLAGEN TENDON

(COLLAGEN)

STRAIN

Assistive technology, can it be an advantage?