The Art of Practical and Precise Strain Based ... - Webprofile.info

CHAPTER 1Strain-BasedMeasurementIntroduction:Applications Note 1-1: IntroductionThe Wheatstone Bridge strain-gaged sensor type is, by a large margin,the most popular transducer element in use. Unfortunately, thestrain-based sensor is also the most misapplied sensor type. By someestimates, as much as 80% of all new sensor purchases are made inthe act of replacing a prior sensor technology or type. This representsa massive waste of human effort as well as financial resources. Historically,the costs of these errors in judgement have been buriedwithin research and development budgets. The objective of this workis to show how we can work smarter, rather than harder, by gaininginsight into the simple physics of the strain-based sensor so thaterrors in physical measurement are minimized. When a measurementis made we are attempting to understand our product or process underspecific operating conditions. Based upon our measurements we perceivespecific values when the true value of a parameter may be quitedifferent. The difference between the truth and the perception is error.A ten percent error in the magnitude of peak strain experienced by acomponent in use implies two consequences; the fatigue life expect-The Art of Practical and Precise Strain Based Measurement 2nd Edition © 1999 CHAPTER 1-1