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Unformatted text preview: ME 260 Homework #1 MEASUREMENT TECHNIQUES Due on February 8, 2007 Dr. B. Zhang (Instructor) Office Hours 8:00-10:00 (Mon &Wed) UTE Building, Room 384 and by appointment Phone: 486-2072 email@example.com 1. A strain gage having a nominal resistance of 350 , and a gauge factor of 1.8 is mounted in an equal-arm bridge, which is balanced at a zero applied strain condition. The gauge is mounted on a 1-cm 2 aluminum rod, having E m =70 GPa. The gauge senses axial strain. The bridge output is 1 mV for a bridge input of 5 V. What is the applied load, assuming the rod is in uni-axial tension? KNOWN : A strain gage has a nominal resistance of 350 , and GF =1.8, and senses axial strain. The gage is mounted on a 1 cm 2 aluminum rod ( E m =70 GPa), E o =1 mV, E i =5 V. FIND : Applied load, assuming uniaxial tension. SOLUTION : For an equal arm bridge, as the following parameters are known: 4 / R R E E i o = = 28 . 5 001 . 350 4 4 i o E E R R Since we have ( 29 GF R R = and m E = and C N A F = where 2 4 2 m 10 1 cm 1- = = C A Then ( 29 N GF R R E A F m C N 3111 8 . 1 350 28 . 10 70 10 1 9 4 = = =- 2. Consider a structural member subject to loads that produce both axial and bending stresses, as shown in Fig. 1a. Two strain gauges are to be mounted on the member and connected in a Wheatstone bridge (Fig. 1b) in such a way that the bridge output indicates the axial component of strain only (the installation is bending compensated). strain only (the installation is bending compensated)....
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This homework help was uploaded on 04/22/2008 for the course ME 260 taught by Professor Zhang during the Spring '08 term at UConn.
- Spring '08