Research On Detection Method Of Rubber Steel Cord Based On Terahertz Time Domain Spectroscopy

Rubber coated steel cords is an important part of the tire.The quality of tire is directly affected by the quality of rubber coated steel cord.Tire rubber layer and rubber coated steel cord layer are prone to various quality defects in the molding.There are many shortcomings for widely used inspection technique like random sample inspection or X-ray detection etc.Terahertz non-destructive detection technique has the advantages of safety,high efficiency,non-contact and anti-distrub,so it is of great value to use of terahertz non-destructive detection technique in rubber coated steel cord online inspection.Our researches focus on non-destructive inspection of rubber-coated steel cord with terahertz time-domain spectroscopy technique.The main results of this research are as follows:(1)Based on terahertz time-domain spectral technique,transmission/reflection scheme of thickness measure for rubber sheet and rubber-coated steel cord are established.(2)The transmission characteristics of linearly polarized terahertz wave incident on rubber-coated steel cord,and the resonance enhancement phenomenon were systematically studied.The CST simulation software was used to simulate the electric field distribution of a linearly polarized terahertz wave incident on a one-dimensional steel wire grid.The mechanism of resonance enhancement and the effect to the transmission of terahertz waves were elaborated.(3)The terahertz time-domain spectroscopy system was used for transmission measurement and reflection measurement of two rubber sheets(thicknesses is 2.10mm and 2.18mm,respectively)and two rubber-coated steel cords(thickness is 1.48mm and 1.22mm,and steel wire diameter is 1.00mm and 0.60mm,steel wire spacing is 1.45mm and 1.05mm),respectively.We verify the feasibility using terahertz time-domain spectroscopy to measure rubber sheet thickness and rubber-coated steel cord thickness.(4)Outside the cavity scheme of terahertz time-domain spectrometer was used to scan and image the rubber-coated steel cord(thickness 1.22mm,wire diameter 0.60mm,wire spacing 1.05mm).The results verify the feasibility of terahertz scanning image for online inspection of the rubber steel cord.This study shows that the terahertz time-domain spectroscopy technique could be used as an online inspection method for rubber sheet and rubber-coated steel cord thickness measurement.The terahertz scanning imaging technique can monitor the cord uniformity of rubber-coated steel cord,and the terahertz non-destructive detection technology has important application potential in the online quality monitoring of rubber-coated steel cord production.