title: A novel method for the accurate evaluation of Poisson's ratio of soft polymer materials.
abstract: A new method with a simple algorithm was developed to accurately measure Poisson's ratio of soft materials such as polyvinyl alcohol hydrogel (PVA-H) with a custom experimental apparatus consisting of a tension device, a micro X-Y stage, an optical microscope, and a charge-coupled device camera. In the proposed method, the initial positions of the four vertices of an arbitrarily selected quadrilateral from the sample surface were first measured to generate a 2D 1st-order 4-node quadrilateral element for finite element numerical analysis. Next, minimum and maximum principal strains were calculated from differences between the initial and deformed shapes of the quadrilateral under tension. Finally, Poisson's ratio of PVA-H was determined by the ratio of minimum principal strain to maximum principal strain. This novel method has an advantage in the accurate evaluation of Poisson's ratio despite misalignment between specimens and experimental devices. In this study, Poisson's ratio of PVA-H was 0.44 ± 0.025 (n = 6) for 2.6-47.0% elongations with a tendency to decrease with increasing elongation. The current evaluation method of Poisson's ratio with a simple measurement system can be employed to a real-time automated vision-tracking system which is used to accurately evaluate the material properties of various soft materials.
authors.affiliation: System Research and Development, Samsung Heavy Industries, Geoje 656-710, Republic of Korea.
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Lee
authors.forename: Sang-Soo
authors.initials: SS
authors.lastname: Lee
authors.forename: Jun-Dong
authors.initials: JD
authors.lastname: Chang
authors.forename: Mark S
authors.initials: MS
authors.lastname: Thompson
authors.forename: Dong-Joong
authors.initials: DJ
authors.lastname: Kang
authors.forename: Sungchan
authors.initials: S
authors.lastname: Park
authors.forename: Seonghun
authors.initials: S
authors.lastname: Park
mesh_terms: D000465:Algorithms; D019245:Compressive Strength; D055119:Elastic Modulus; D004548:Elasticity; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006244:Hardness; D006245:Hardness Tests / Q000295:instrumentation*; D020100:Hydrogels / Q000737:chemistry*; D008422:Materials Testing / Q000295:instrumentation*; D008853:Microscopy / Q000295:instrumentation*; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D013314:Stress, Mechanical; D013718:Tensile Strength
chemical_list: D020100:Hydrogels; D011142:Polyvinyl Alcohol