Design and Application of Internal-stress Sensor of Concrete

To measure the internal-stress of concrete directly,a kind of PVDF stress sensor of soft underlayer was designed.The PVDF film was conglutinated between two pieces of insulating film. The thickness of the PVDF film was 50 microns,and the effective work area of the sensor was 1 centimeter by 1 centimeter. The sensor was encapsulated and then fixed inside the concrete specimen. The experiments were carried out,and the internal-stress history of concrete was obtained. Compare with data obtained by strain gauge,the peak value of internal-stress of aluminium alloy and concrete obtained by PVDF stress sensor are 10. 7% and19. 3% lower separately.