The vCalc Shear Stress equation computes the stress causing a displacement of a surface of a volume as shown in the image.  In the image surface A is displaced by a distance x.

The shear strain, `gamma`, results from the shear stress, `tau`, caused by the force F_||.

original author: Billy

Inputs

The strain is computed as the ratio of the following:

• `F_"||"` - the force acting parallel to the surface A.
• A - the area of the surface of the object under stress.

Reference

Young, Hugh and Freeman, Roger.  University Physics With Modern Physics.  Addison-Wesley, 2008. 12th Edition, (ISBN-13: 978-0321500625 ISBN-10: 0321500628 ) Pg 367, eq 11.15