Local reinforcement effect of embedded strain gauges

A Ajovalasit,B Zuccarello,S Fragapane

doi:10.1051/epjconf/20100613003

Abstract

The reinforcement effect of strain gauges installed on low Young's modulus materials has received attention by many researchers with respect to both strain gauges installed on the surface [1,2] and embedded inside the material [3,4]. In the case of strain gauges installed on the surface, the evaluation of the local reinforcement effect gives [5] the following correction coefficient C, i.e. the ratio between the actual strain (without the strain gauge) and the strain ' measured by the strain gauge:

Highlights

The reinforcement effect of strain gauges installed on low Young's modulus materials has received attention by many researchers with respect to both strain gauges installed on the surface [1,2] and embedded inside the material [3,4].In the case of strain gauges installed on the surface, the evaluation of the local reinforcement effect gives [5] the following correction coefficient C, i.e. the ratio between the actual strain H and the strain H ' measured by the strain gauge: C H H ' (1) being Es*g M Esg tsg Lsg § ̈ ̈© Lg tsg Lsg tsg · ̧ ̧1
M Esg tsg Lsg where Esg is the Young’s modulus of the strain gauge, Es*g is a characteristic of the strain gauge which gives the strain gauge sensitivity to the reinforcement effect, Es is the Young’s modulus of the specimen, tsg, Lg, Lsg are respectively thickness, total gauge length and grid length of the strain gauge, and M is the mean value of a function M
In this paper the following assumptions used in the case of the strain gauge installed on the surface [5] are made, namely: (1) the specimen has the same width of the strain gauge, (2) the Young modulus and the thickness of the strain gauge is considered constant, that is independent from x (Figure 1), (3) the distribution of the shear stresses at the interface between the strain gauge and the surrounding material is approximated by an exponential function

Summary

Introduction

In the case of strain gauges installed on the surface, the evaluation of the local reinforcement effect gives [5] the following correction coefficient C, i.e. the ratio between the actual strain H M Esg tsg Lsg where Esg is the Young’s modulus of the strain gauge, Es*g is a characteristic of the strain gauge which gives the strain gauge sensitivity to the reinforcement effect (reduced Young’s modulus of the strain gauge), Es is the Young’s modulus of the specimen, tsg , Lg , Lsg are respectively thickness, total gauge length and grid length of the strain gauge, and M is the mean value of a function M

Results

Conclusion