A clamping force is the force applied with a fastener or clamp to an object. These calculations can become quite complicated, as a very large number of external variables are taken into account. In addition, it is not always possible to know or measure the value of these variables, making an accurate answer difficult to obtain. However, you can approximate clamping force calculations, which can give you a rough estimate of the answer. This is outlined below.
Determine the area of the cross-section of the clamp. For example, a clamp with a circular cross-section and a radius of 3 centimetres will have an area of the radius multiplied by the square of the constant pi (i.e., the number multiplied by itself), which gives an area of 29.6 centimetres squared (cm^2).
Multiply the cross-sectional area of the clamp by the numbers 2 and pi. In the above example, this gives the number 186.04cm^2. Call this result "A."
Multiply result A by the ring recovery stress of the clamp, which is roughly approximated as 200,000,000 Pascals (Pascals being the unit of measurement for stress). In this example, this gives a final result of 37,200,000,000 Newtons (or 37.2 gigaNewtons). This is the approximate clamping force.
The approximate clamping force will depend on the geometry of the clamp you use.