Question

2) One arm of a Wheatstone bridge is a 50 k2 strain gauge (S = 2.0). This strain gauge is bonded to a metal fixture for tensile loading, and the metal has a Young's Modulus E-2.5 MPa. The other 3 arms are fixed 50 kO resistors. The bridge is powered by 5Vv DC as shown, and Eo is the output voltage. a) Derive a relationship for Eo as a function of tensile stress o in the metal substrate, ΔL . Remember that: AR = Rx GF x e, and' that is, find the function Eo(o) I. E =where E is the strain and AR the change in the resistance due to strain b) Is this a linear function of stress? Gauge axis Tensile loading ww 5V DC

Answer 1

EG B 5VDC 7.Cy the atrain aug Reais tau ce B5 XR2 VA 5F 5 x/50 50f50 - 2.5V

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VA 2 5 V. 1+GX166) EVAB -VA-V6 1 2.5 J.t4XI66 (144x16'8 C1+GX16'6 2.5 2-5 X4X106) L+4X166) -106 E0 E (6)= 9,01 b From eah peen obsewed Cam be Ee Aineen funchian f from e (2) that n not eMacth However Ge Can tnte, VA 2.5 2 R 2.Rg E- VnG2.5(- 2-5 25 DRS 2fg0

2-5 ARg fo(6)-25 -2 t5 2 ZXGFX 25 2XO Z5X106 E1696) Tn thi Cere Dnnan functiar strer Linear functia of strers 2E