What Is Common Between Strain, Marshmallow and a Strain Gage?
Is the bridge I cross during my commute in danger of falling down?
Will an earthquake crumble my office?
Will that airplane actually fly?
Are you stressed?
These are just a few of the questions you can study with a handy little device called a strain gage (sometimes spelled "gauge").
You can design and program sophisticated computer models based on AI (Artificial Intelligence), but the certain way for getting answers to how a material is coping under pressure is to use foil strain gages and measure the behavior when actual forces are applied to it.
To civil or mechanical engineer, stress and strain are incredibly vital. If you're designing anything, from a jet or a boat engine , to a bridge or wind turbine or just an airplane wing, you know it's going to be subject to different forces. Will the structure break apart after repeated stresses and strains when it’s exposed to cyclic loading (fatigue), where repeated deformation causes the metal to weaken and suddenly snap?
So, let’s start with a simple question, what is Strain? The simple answer is , a stress-induced change in length of a body in some direction relative to the undistorted length of that body in the same direction. (Tensile strain, Compressive strain, Shear strain)
When an external stress (force) is applied on an object or material, the length changes. The ratio of this change in length of the object relative to its original length is called strain.
Did you know that different materials behave in very different ways under similar amounts of stress?
Strain = Change in the length of the body / Original length
stress = force / area