ABSTRACT
This chapter introduces the reader to the concepts of force, stress, and strain. It reviews how to solve for the magnitude of forces and use the forces to calculate normal stresses. The chapter reviews how these stresses affect objects through changes in the objects’ lengths. It aims to allow the engineer to alter the design to better survive the dynamic environment of the human body. Normal stresses are caused by forces that act perpendicular to a surface. Normal stresses can be tensile or compressive. Tensile stresses occur when one have two forces acting on an object from different directions along the same axis. Shearing stresses occur when a force acts parallel to a surface or two transverse forces are applied to a member. A normal force can cause shearing stresses on adjacent planes, or two forces of equal magnitude but opposite direction can cause a shearing stress when they are separated by a plane.
