Piezoresistive strain gauge sensor and signal conditioner for sensor applications

Thangamani Uthirapathi, (2007) Piezoresistive strain gauge sensor and signal conditioner for sensor applications. Masters thesis, Universiti Malaysia Sabah.

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Abstract

Piezoresistive strain gauge is one of the most popular and widely accepted sensors for strain measurement An analytical modeling is carried out for the gauge on the rectangular membrane called as substrate which includes resistivity of the plezoresistive material. Pro ENGINEER and ANSYS Multi physics software are used for the design and analysis respectively. Finite element analysis is used to find maximum strain sensitive area on the substrate. This helps to design the gauge with desired orientation to achieve maximum sensitivity. Polyimide is chosen as a substrate for strain gauge design among Polystrene and Silicon. Constantan is used as a gauge material for strain gauge design since its high peel strength makes the gauge less sensitive to mechanical damage during installation. A force sensor is designed on thin rectangular plate using the strain gauge which Is designed by ANSYS simulation. Temperature is one of the Important factor that affects the sensor performance. Hence the effect of temperature on the strain gauge and force sensor is considered In this research. A solution is given at sensor level in this research to do temperature compensation. Four-channel active element signal conditioner is developed that overcomes the drawbacks of passive element Wheatstone bridge. The hardware is developed on the printed circuit board (PCB) with its own dual power supply. EASYPC software and UV exposure, wet etching technique is used to design and fabricate the PCB. A temperature compensated force sensor is developed to verify the active element Signal conditioner linearity. The data acquisition board with 16-bit simultaneous sampling rate analog to digital converter (AOC) Is used to support real-time sensor data processing. MATIAS platform and its data acquisition toolboxes are used to process the real-time sensor data. The developed signal conditioner would suit for all kinds of sensor applications. A high gain of 93.9dB, a CMRR of 89.73dB, a delay of 25µsec, and a rise time of 150µsec are achieved by this signal conditioner. The self temperature compensating force sensor sensitivity Is 0.01MΩ/N and a resolution is 0.15 mN. The sensitivity of the strain gauge designed by ANSYS is 0.425 µɛ/mPa.

Item Type:Thesis (Masters)
Uncontrolled Keywords:strain measurement, gauge, rectangular membrane, polyimide, constantan, temperature, ANSYS Multi physic
Subjects:T Technology > TJ Mechanical engineering and machinery
Divisions:SCHOOL > School of Engineering and Information Technology
ID Code:10224
Deposited By:IR Admin
Deposited On:23 Dec 2014 10:33
Last Modified:23 Dec 2014 10:33

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