Effects of tranverse sensitivity of electrical resistance starin gauges on stain measurement

Abstract

Measurement of strain, as accurately as possible at critical points on any machine part or other such engineering structural part is a very important aspect of determining the quality of the design concerned. For this purpose, the most widely used appliance in these days is undoubtedly the electrical resistance strain gauge. This is because of the small size, ease of fixing to the structure, and the wide variety of electronic appliances available for interpreting the small outputs sensed. Unfortunately, there are a few errors in the readings of these gauges like that due to the test temperature variation, transverse sensitivity of the gauge itself, fatigue effects etc. In this thesis, the transverse sensitivity correction factors and their determination; quicker and easier methods for calculating data for sketching the concerned Mohr's circles and calculation of stresses and strains there of; variation of the correction factor when used on different materials; different gauge configurations that are amenable to easier calculations of corrected readings are some of the main topics examined in detail both theoretically and experimentally. Experimental confirmation of the main theoretical suggestions is the main contribution of this thesis. It is essentially aimed at providing 1) the novice with up to date information on the topic and 2) the design engineer with results which he can use with more confidence.