Characterization of micro- to macroscopic deformation behavior of amorphous polymer with heterogeneous distribution of microstructures

To evaluate the effect of the size of the microstructure on the mechanical property of the cavitated rubber blended (voided) amorphous polymer, the FEM simulation based on the rate form second-order homogenization method, in which rates of the macroscopic strain and strain gradient are given to the microstructure, was performed. Computational simulations of micro-to macroscopic deformation behaviors of amorphous polymers including different sizes and volume fractions of the voids were performed. Non-affine molecular chain network theory was employed to represent the inelastic deformation behavior of the amorphous polymer matrix. With the increase in the volume fraction of the void, decrease and periodical fluctuation of stress and localized deformation in the macroscopic field were observed, and were more emphasized with the increase in the size of the void. These results were closely related to the non-uniform deformation and volume increase of the void in the microscopic field.

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About Puncture Testing Applied for Mechanical Characterization of Fetal Membranes

Journal of Biomechanical Engineering ◽

10.1115/1.4028446 ◽

2014 ◽

Vol 136 (11) ◽

Cited By ~ 6

Author(s):

Wilfried Bürzle ◽

Edoardo Mazza ◽

John J. Moore

Keyword(s):

Deformation Behavior ◽

Mechanical Characterization ◽

Ex Vivo ◽

Fetal Membrane ◽

Membrane Rupture ◽

Resistance To Deformation ◽

Ex Vivo Testing ◽

Insight Into

Puncture testing has been applied in several studies for the mechanical characterization of human fetal membrane (FM) tissue, and significant knowledge has been gained from these investigations. When comparing results of mechanical testing (puncture, inflation, and uniaxial tension), we have observed discrepancies in the rupture sequence of FM tissue and significant differences in the deformation behavior. This study was undertaken to clarify these discrepancies. Puncture experiments on FM samples were performed to reproduce previous findings, and numerical simulations were carried out to rationalize particular aspects of membrane failure. The results demonstrate that both rupture sequence and resistance to deformation depend on the samples' fixation. Soft fixation leads to slippage in the clamping, which reduces mechanical loading of the amnion layer and results in chorion rupturing first. Conversely, the stiffer, stronger, and less extensible amnion layer fails first if tight fixation is used. The results provide a novel insight into the interpretation of ex vivo testing as well as in vivo membrane rupture.

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The High Temperature Deformation Behavior of A Cr2Nb Ordered Intermetallic System

MRS Proceedings ◽

10.1557/proc-213-739 ◽

1990 ◽

Vol 213 ◽

Cited By ~ 3

Author(s):

G. E. Vignoul ◽

J.M. Sanchez ◽

J. K. Tien

Keyword(s):

Deformation Behavior ◽

Elevated Temperatures ◽

High Temperature Deformation ◽

Temperature Deformation ◽

Deformation Law ◽

Ordered Intermetallic ◽

Intermetallic System ◽

Increasing Temperature ◽

Stress Term

ABSTRACTA basic characterization of the deformation behavior of Cr2Nb by microindention at ambient and elevated temperatures (up to 1400 °C) was undertaken. The microhardness of this system was seen to decrease with increasing temperature, from 1040 MPa at 25°C to 322 MPa at 1400 °C. Further, the microindention creep behavior of this system was studied by varying time on load at T = 1000 and 1200°C. Analysis of the data showed that m = 24 and Qapp = 477.61 kJ/mole. These unusually high values are indicative of the existence of an effective resisting stress against creep. When the data was fit against a microindention creep deformation law which was modified to incorporate an effective resisting stress term, it was determined that m = 4.5, Qcreep = 357 kJ/mole and the resisting stress term σr = 300 MPa.

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