08:58 Nov-05-2008 P V SASTRYp R & D, NDT tecniques metallurgy TAKEN VRS FROM THE POSITION OF SR. DEPUTY GENERAL MANAGER BHEL CORPORATE R&D, India, Joined Jan 2003 195
Re: Bold load cell - Load cells normally use electrical strain gauges as sensing elements. When the bolt is loaded the strain gauge shows change in the resistance 'delta r' corresponding to change in the length 'delt l'. ('delta l'/L is strain where L is length )
The load cell needs to be connected to an instrument that has a bridge circuit and basically measures the small change in the resistance. When an appropriate gauge factor given by the manufacturer is incorporated, the out put of the instrument is directly in strain.
The strain out put can be manually processed to get stress or the intrument can also be programmed with a specific computation sequence to directly read in terms of stress or any other parameter like troque etc.
The load cell normally has a minimum of two strain gauges, one active gauge for measuring the change in length and the other dummy gauge for temperature compnesation.
It can also haved futher complications like more gauges for eliminating the bending stresses and measuring only pure tesnile strain.
In any case the basic out put of the cell is only strain.
I tried to be brief and simple and you are welcome to contact for any further information. ---------- Start Original Message ----------- : Hi, : i have a bolt load cell,what will be the output of the load cell, : is it strain or stress or displacement. ------------ End Original Message ------------