OS09W0063 Piezoresistivity Measurement of CFRP for Reliable Gage Factor

2003 ◽  
Vol 2003.2 (0) ◽  
pp. _OS09W0063-_OS09W0063
Author(s):  
Akira Todoroki ◽  
Jyunji Yoshida ◽  
Yoshinobu Shimamura
Keyword(s):  
Gage Factor

A Criterion for the Constancy of the Gage Factor of SR-4 Type Strain Gages

1956 ◽  
Vol 23 (3) ◽  
pp. 474-476
Author(s):  
G. C. Kuczynski
Keyword(s):  
Type Strain ◽  
Experimental Results ◽  
Strain Gages ◽  
Theoretical Conclusion ◽  
Gage Factor

Abstract It has been shown that the criterion of the gage-factor constancy of SR-4 type strain gages is that it is equal to 2 or nearly so. The experimental results agree with this theoretical conclusion.

Smart self-sensory carbon-based textile reinforced concrete structures for structural health monitoring

2020 ◽  
pp. 147592172095112
Author(s):  
Lidor Yosef ◽  
Yiska Goldfeld
Keyword(s):  
Reinforced Concrete ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Electrical Resistance ◽  
Textile Reinforced Concrete ◽  
Resistance Change ◽  
Gage Factor ◽  
Structural Health ◽  
Monitoring Procedure ◽  
Loading Procedure

The goal of this study is to develop a structural health monitoring methodology for smart self-sensory carbon-based textile reinforced concrete elements. The self-sensory concept is based on measuring the electrical resistance change in the carbon roving reinforcement and by means of an engineering gage factor, correlating the relative electrical resistance change to an integral value of strain along the location of the roving. The concept of the nonlinear engineering gage factor that captures the unique micro-structural mechanism of the roving within the concrete matrix is demonstrated and validated. The estimated value of strain is compared to a theoretical value calculated by assuming a healthy state. The amount of discrepancy between the two strain values makes it possible to indicate and distinguish between the structural states. The study experimentally demonstrates the engineering gage factor concept and the structural health monitoring procedure by mechanically loading two textile reinforced concrete beams, one by a monotonic loading procedure and the other by a cyclic loading procedure. It is presented that the proposed structural health monitoring procedure succeeded in estimating the strain and in clearly distinguishing between the structural states.

Sensor Characteristics of Carbon Fiber Mat

2006 ◽  
Vol 326-328 ◽  
pp. 1451-1454 ◽  
Author(s):  
Xiao Yu Zhang ◽  
Zhuo Qiu Li ◽  
Xian Hui Song ◽  
Yong Lv
Keyword(s):  
Carbon Fiber ◽  
Concrete Structure ◽  
Fiber Reinforced Concrete ◽  
Static Characteristics ◽  
Gage Factor ◽  
Thin Carbon ◽  
On Line ◽  
New Type ◽  
New Skin ◽  
Good Agreement

Structural health monitoring (SHM) is becoming a popular topic. Carbon fiber reinforced concrete (CFRC) is an intrinsically smart material that can sense strain. The resistivity increases reversibly under tension and decreases under compression. A new skin-like sensor —cement-based smart layer had been put forward, which can serve as whole field strain sensor. The smart layer is satisfactorily consistent with concrete structure. The smart layer is a thin carbon fiber mat cementbased composite material layer with finite electrodes. It can cover the surface of concrete structure, and provide on-line reliable information about the deformation of whole concrete structure. The static characteristics of the new-type sensor had been researched. Its gage factor is 20-25 under tension and 25-30 under compression within the elastic deformation range. Furthermore the smart layer has satisfactory linearity and repeatability. In this paper, the sensor characteristics of the bare carbon fiber mat have been reached. The resistivity of carbon fiber mat has good agreement with strain under uniaxial tension. The gage factor can be up to 375, and the sensor limit can be up to 10000 microstrain. The strain and the fractional change in electrical resistance .R/R0 are totally reversible and reproducible under cyclic loading and amplitude-variable cyclic tensile loading.

Calibration of MEMS Strain Sensors Fabricated on Silicon

2001 ◽  
Author(s):  
Li Cao ◽  
Chuck Hautamaki ◽  
Jia Zhou ◽  
Tae Song Kim ◽  
Sue Mantell
Keyword(s):  
Silicon Wafer ◽  
Near Field ◽  
Strain Sensor ◽  
Field Strain ◽  
Sensor Calibration ◽  
Far Field ◽  
Calibration Technique ◽  
Gage Factor ◽  
Mems Sensor ◽  
Aluminum Specimen

Abstract A calibration technique for measuring MEMS strain sensor performance is described. The sensor calibration technique entails developing a repeatable relationship (gage factor) between the change in sensor nominal resistance and the strain measured at the sensor. The calibration technique involves creating a “pseudo” strain sensor consisting of a strain gage mounted on a silicon wafer. Two identical test specimens are evaluated: the pseudo sensor mounted (with adhesive) on an aluminum specimen (or embedded in a specimen), and a MEMS strain sensor mounted on an aluminum specimen (or embedded in a specimen). The dimensions of the silicon wafer for both the pseudo sensor and MEMS sensor are identical. The specimens are loaded by tensile test. For the pseudo sensor specimen, a relationship is established between the strain applied to the specimen (far field strain) and the strain at the sensor (near field strain). Once the relationship between near field and far field strain is known, a relationship between near field strain and change in resistance of the uncalibrated MEMs sensor is established. This relationship between strain at the sensor and change in resistance is the gage factor. Two different MEMS strain sensor designs were fabricated by patterning polysilicon on a 500 micron thick silicon wafer: monofilament and membrane sensors. Gage factors for the MEMS sensors were determined following the calibration procedure. The results also lead to a conclusion that wafer geometry influences the strain transfer to the sensor.

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