0
Research Papers

Effect of Size-Dependent Cavitation on Micro- to Macroscopic Mechanical Behavior of Rubber-Blended Polymer

[+] Author and Article Information
Isamu Riku

Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8231, Japanriku@me.osakafu-u.ac.jp

Koji Mimura

Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8231, Japanmimura@me.osakafu-u.ac.jp

Yoshihiro Tomita

Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japantomita@mech.kobe-u.ac.jp

J. Eng. Mater. Technol 130(2), 021017 (Mar 19, 2008) (9 pages) doi:10.1115/1.2840964 History: Received July 27, 2007; Revised December 17, 2007; Published March 19, 2008

In rubber-blended polymer, the onset of cavitation in the particles relaxes the high triaxiality stress state and suppresses the onset of crazing in the polymer. As a result, large plastic deformation is substantially promoted compared with single-phase polymer. On the other hand, it is also well known that the onset of cavitation depends on the size of particle. To investigate the size dependence of cavitation behavior in the particle, a theoretical analysis is done employing a void model under plane strain condition, which takes into account the surface tension and the limiting stretch of the void. Continuously, to study the effect of the size-dependent cavitation on the micro- to macroscopic mechanical behavior of the blend, a computational model is proposed for the blend consisting of irregularly distributed heterogeneous particles containing the void with surface force. The results indicate that when the size of the particle decreases to a critical value that depends on both the initial shear modulus of particle and the surface tension on the surface of void, the increase of the critical stress for the onset of cavitation becomes remarkable and consequently, the onset of cavitation is eliminated. When the particle is embedded in polymer, the relation between average normal stress, which is acting on the interface of particle and matrix, and volumetric strain of particle shows dependence on the size of particle but no dependence on the triaxiality of macroscopic loading condition. For the blend consisting of particles smaller than the critical value, the onset of cavitation is eliminated in particles and as a result, the conformation of the shape of particle to the localized shear band in matrix becomes difficult and the shear deformation behavior tends to occur all over the matrix. Furthermore, in this case, the area of the maximum mean stress is confined to the area adjacent to the particle and the value of it increases almost linearly throughout the whole deformation process, which would lead to the onset of crazing in matrix. On the other hand, it is clarified that the onset of cavitation is predominant in the localized microscopic region containing heterogeneous particles and therefore, the plastic deformation is promoted in this region.

FIGURES IN THIS ARTICLE
<>
Copyright © 2008 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Relationship between the normal traction σnormalexternal and the initial radius b0 of the particle: (a) Different value of initial shear modulus of rubber material CR; (b) Different value of surface tension on the surface of void γ

Grahic Jump Location
Figure 2

Computational model for the blend consisting of irregularly distributed heterogeneous particles

Grahic Jump Location
Figure 3

Effect of the size-dependent cavitation on the average normal stress on the interface: (a) Computational model; (b) relationship between average normal stress σnormalaverage on the interface and volumetric strain ln(V∕V0) of particle under different macroscopic loading conditions

Grahic Jump Location
Figure 4

Relationship between volumetric strain ln(V∕V0) of particles and macroscopic equivalent strain Γe under different macroscopic loading conditions: (a) Γ̇1∕Γ̇2=−0.5; (b) Γ̇1∕Γ̇2=0; (c) Γ̇1∕Γ̇2=0.5

Grahic Jump Location
Figure 5

Relationship between macroscopic equivalent stress Σe and macroscopic equivalent strain Γe under different macroscopic loading conditions: (a) Γ̇1∕Γ̇2=−0.5; (b) Γ̇1∕Γ̇2=0; (c) Γ̇1∕Γ̇2=0.5

Grahic Jump Location
Figure 6

Relationship between macroscopic mean stress Σm and macroscopic volumetric strain Γv under different macroscopic loading conditions: (a) Γ̇1∕Γ̇2=−0.5; (b) Γ̇1∕Γ̇2=0; (c) Γ̇1∕Γ̇2=0.5

Grahic Jump Location
Figure 7

Equivalent plastic strain rate distributions under different macroscopic loading conditions

Grahic Jump Location
Figure 8

High mean stress regions’ distributions under different macroscopic loading conditions

Grahic Jump Location
Figure 9

Relationship between maximum mean stress σmeanmax in matrix and macroscopic equivalent strain Γe under different macroscopic loading conditions: (a) Γ̇1∕Γ̇2=−0.5; (b) Γ̇1∕Γ̇2=0.5; (c) Γ̇1∕Γ̇2=0.5

Grahic Jump Location
Figure 10

Equivalent plastic strain rate and maximum mean stress distributions (black or white lines) under macroscopic loading condition Γ̇1∕Γ̇2=0.5

Grahic Jump Location
Figure 11

The model of a cylinder of an incompressible material with a preexisting void

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In