title: A numerical model for ultrasonic measurements of swelling and mechanical properties of a swollen PVA hydrogel.
abstract: This paper presents a numerical model for the evaluation of mechanical properties of a relatively thin hydrogel. The model utilizes a system identification method to evaluate the acoustical parameters from ultrasonic measurement data. The model involves the calculation of the forward model based on an ultrasonic wave propagation incorporating diffraction effect. Ultrasonic measurements of a hydrogel are also performed in a reflection mode. A Nonlinear Least Square (NLS) algorithm is employed to minimize difference between the results from the model and the experimental data. The acoustical parameters associated with the model are effectively modified to achieve the minimum error. As a result, the parameters of PVA hydrogels namely thickness, density, an ultrasonic attenuation coefficient and dispersion velocity are effectively determined. In order to validate the model, the conventional density measurements of hydrogels were also performed.
authors.affiliation: PhotoAcoustic Sensors and Systems (PASS LAB) and Department of Electronics, Faculty of Engineering, King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand.
authors.forename: M
authors.initials: M
authors.lastname: Lohakan
authors.forename: T
authors.initials: T
authors.lastname: Jamnongkan
authors.forename: C
authors.initials: C
authors.lastname: Pintavirooj
authors.forename: S
authors.initials: S
authors.lastname: Kaewpirom
authors.forename: S
authors.initials: S
authors.lastname: Boonsang
mesh_terms: D000465:Algorithms; D002138:Calibration; D004867:Equipment Design; D020100:Hydrogels / Q000737:chemistry*; D016018:Least-Squares Analysis; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D014465:Ultrasonics
chemical_list: D020100:Hydrogels; D011142:Polyvinyl Alcohol