Peculiar stress-strain behavior of elastomer foams revealed by X-ray CT and mechanical measurements with various deformations

2018 Fiscal Year Final Research Report

• Project/Area Number: 15H03868
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Polymer/Textile materials
• Research Institution: Kyoto Institute of Technology
• Principal Investigator: Urayama Kenji 京都工芸繊維大学, 材料化学系, 教授 (20263147)
• Co-Investigator(Kenkyū-buntansha): 西川 幸宏 京都工芸繊維大学, 材料化学系, 准教授 (60332285)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: エラストマー / 発泡 / 大変形

Outline of Final Research Achievements

Large deformation behavior of elastomer foams with different cell-types (closed- or open cells) is investigated by various types of deformation. Independently of cell type, the stress-strain behavior in tension and compression can not be commonly expressed by a strain energy function, unlike incompressible elastomers. Poisson's ratio in tension is estimated to be ca. 0.25 regardless of cell type, while Poisson's ratio in compression is almost zero for open cells. X-ray CT observation reveals the occurrence of the buckling deformation of constitutive cells under compression. The stress-strain data in uniaxial and biaxial tension are well described by the strain energy function without cross-effect of strains, independently of cell type.

Free Research Field

高分子物性

Academic Significance and Societal Importance of the Research Achievements

発泡エラストマーは軽量かつ高圧縮性のために様々な工業用途に用いられている。用途に応じて，独立気泡や連続気泡など気泡の分散形態が異なるエラストマーが用いられている。気泡の分散形態と圧縮挙動についてはよく調べられているが，伸長挙動についてはほとんど調べられていない。本研究成果は，発泡エラストマーは伸長と圧縮では，気泡セルの座屈挙動の有無があるために，その挙動が著しく異なることを明確に示した。対照的に気泡を含まないエラストマーの場合，伸長側のひずみエネルギー密度関数が信頼性に足るものであれば，圧縮挙動は高精度で予測できる。