Experimental and numerical analysis on pressure effect of polymethyl methacrylate (PMMA) structure in electric-resistance strain measurement

In deep sea engineering, strain gauges set outside of structure would be subjected to external hydrostatic pressure. The pressure effect in electric-resistance strain measurement would be derived in theory. A simplified model of strain gauges in finite element analysis (FEA) had been proposed and also verified by theoretical and real beam model results. After pressure effect analysis of metal based on presented FEA and theoretical methods, two block specimens of PMMA material had been designed and accomplished high pressure test. The presented FEA had agreed well with the experimental results. Compared with theoretical data and series of multi- parameter model calculation, the presented FEA exposed that the pressure effect should not be neglected in electric-resistance strain measurement to PMMA material, and the measured strain would have difference with that real strain appearing on flat surface of structure, especially for high pressure loading.