Poisson's Ratio Definition Equation 
Poisson's ratio is defined as the negative of the ratio of the lateral strain to the axial strain for a uniaxial stress state. If a tensile load is applied to a material, the material will elongate on the axis of the load (perpendicular to the tensile stress plane).. 

Shear Stress in Shafts 
Shear Stress in Shafts  In solid mechanics, torsion is the twisting of an object due to an applied torque. It is expressed in newton metres (N·m) or footpound force (ft·lbf). In sections perpendicular to the torque axis, the resultant shear stress in this section is perpendicular to the radius. 

Free Body Diagram 
A free body diagram, is a drawing, sketch or diagram used illustrate and analyze the physics related forces and moments acting on an object. 

Heat Treatment  Stress Relieving 
Heat treating for stress relieving is a method to remove or reduce the internal stresses created in a metal due to the originating manufactuiring process. These manufactured stresses may be due to cold working to nonuniform cooling. Stress relieving is usually facilitated by heating a metal below the lower critical temperature and then cooling uniformly. 

Stress Concentration Fundamentals 
Stress concentration is defined as  Localized stress considerably higher than average (even in uniformly loaded cross sections of uniform thickness) due to abrupt changes in geometry or localized loading. 

Shrink Thermal Fit Review 
Shrinkfitting is a method in which two or more components are heated or cooled taking advantage of thermal expansion or comtraction to make a mate the components. 

Pressure Vessel External Pressure Calculations 
Vessels subject to external pressure may fail at well below the yield strength of the material. the critical factor rather than material strength. Failures can occur suddenly, by collapse of the component. 

