HSC 216 Final Exam

Internal force divided by the cross-sectional area of the surface the force acts on Units: Pa or N/m^2

Tension, Compression, Shear

Axial or normal stress occuring as a result of pulling force or load Causes deformation in stretching and elongating in the direction of the load

Axial stress that results from loads pushing or pulling compressing material molecules more closely together Objects tend to deform by shortening in the direction of the external forces

Transverse stress that acts parallel to anaylsis plane Tends to slide object molecules past each other Resulting deformation changes orientation of sides of object

Combination of 2+ internal loads Bending and Torsion

Multiple or varying stresses in analysis plane Objects with greater depth (larger cross-sectional area) withstand greater bending load Causes curving deformation- tension side elongates, compression side shortens ex: long bones

Occurs when torques act about long axis at each end of the object ("twist" or "pivot") Moment arm limited by diameter of object (increase diameter = increase torque) Objects designed to resist torsion have circular cross-sections

Quantification of material deformation Linear and shear strain

Results from a change in object's length Produced by tension and compression Stress in uniform throughout Change is length/original length

Results from a change in object's orientation of object's molecules ("molecules slip past each other") Units: radians

Specific ratio of changes in these measures exists for all material types Range from 0.1-0.5 (usually around 0.25-0.35) ex: vertebral column

Rigid framework of the body, supports structures, protects tissues, creates a system of rigid levers

Skull, vertebra and lungs

Arms, hands, scapula, pelvis, legs, and feet