Comparing Circular vs Rectangular Diaphragm Strain Gage Pressure Transducers

[engineer23]

I am currently trying to learn about pressure transducers. There are two configurations which have been suggested for a particular pressure transducer -- 1) a circular diaphragm strain gage and 2) a rectangular diaphragm strain gage. Each configuration has four strain gages. For 1) there are two strain gages to measure compressive and another two to measure tensile. They are oriented at right angles to one another (from the top view, looks like a cross within a circle). In configuration 2) each of the four strain gages is placed at a corner of the square at a 45 degree angle.

Is suggested configuration 1) preferable? It is my understanding that pressure transducers are calibrated by correlating a certain change in circumference with a unit pressure. Does it have to do with the way a circle deforms vs. the way a square deforms? Or does it have to do with orienting the strain gages at 90 degrees vs 45 degrees?

 

[anorlunda]

ping @jim hardy