Laser-ultrasonic measurements of the elastic properties of a static and a moving paper web and of the web tension
暂无分享,去创建一个
Non-contact, non-invasive laser-ultrasonic measurements of the tensile stiffness index (TSI) and orientation (TSO) of a paper web and of the applied tension to the web are reported. The generation of ultrasound in paper is performed in the damage free thermoelastic regime by using a short pulse TEA-CO2 laser. The 10.6 μm infrared wavelength of the TEA-CO2 laser generates a stable and reproducible source of ultrasound, which was verified for several types of paper. For generation and detection spots separated by a known distance, plate or membrane waves are generated and detected, and the in-plane modulus and the tension applied to the sheet are measured. By detecting waves propagating in various directions the anisotropy of the in-plane modulus is determined. For overlapping generation and detection spots, the compression modulus is measured.
[1] B. Drinkwater,et al. Review of progress, QNDE , 1999 .
[2] I. A. Viktorov. Rayleigh and Lamb Waves: Physical Theory and Applications , 1967 .