Hi All,

 I would like to use Abaqus to model the viscoelastic material  behaviour of a polymer.

I have material data from a simple uniaxial creep experiment (nominal strain vs time).  I tried to use the viscoelastic material model in Abaqus.  I am a bit confused as to how I need to enter my data (what format). 

The manual says I have to specify the normalized bulk and normalized shear compliance . 

I wish to inform the imechanica community about my recent book,  Polymer Engineering Science and Viscoelasticity, Springer, 2008. THe book starts at the beginning and contains both the physics of polymers and the mathematics of viscoelasticity. It is also unique in the history of mechanics in being the (first ever?) father-daughter book. Those interested in polymer mechanics may find this a useful resource! It may be found in your library or further information can be found here
http://www.springer.com/chemistry/polymer/book/978-0-387-73860-4?details...

An internship position is available in the area of Finite Element Analysis of Elastomers in the Simulation and Modeling Group at Schlumberger, Sugar Land, TX.

I am trying to implement quasi static fracture in a discrete lattice model, with material being viscoelastic. Do i need to use an incremental-iterative method? Please give your suggestions.

Greetings all,

I am trying to use gerenalized maxwell viscoelastic model for polyimide polymer films (Kapton) in MSC Marc (or ABAQUS). I have never used the prony series representation of the maxwell model (hereditary integral approach). Has anyone ever used MSC Marc to incorporate the prony series relaxation to the material? or ABAQUS? Here is my game plan for doing this:

 1. I have the uniaxial relaxation curve for the polymer film, I obtain elastic modulus as a function of time for this model by curvefitting the relaxation curve and then obtain the prony series coefficients.

Nanoindentation testing of time-dependent materials is becoming increasingly relevant with advances in areas such as polymer science and the study of materials in biological systems. However, mechanical characterization at micrometer or nanometer length scales is not trivial in such materials that may be highly compliant, heterogeneous, or possess unique morphological characteristics. Although many researchers have made progress in overcoming key challenges that are involved in testing non-traditional materials, significant advancements must still be made to optimize testing methodologies and analytical techniques.

Before we start this issue of J-club, I would like to recommend Prof. Langer's lecture for his MRS Von Hippel Award in the 2005 MRS Fall Meeting (Langer, 2006). His lecture not only delineated the history of the new exciting field of drug delivery and controlled release, but also told us many interesting stories happened in his career development. With Prof. Langer's pioneer work, many new materials are developed for designing new drug delivery and controlled drug release systems.

Does any one know how to implement other viscoelastic material models, like Burgers' model, in ABAQUS? To my knowledge only Prony series can be used to model visoelastic materials in ABAQUS/standard. 

thanks,

Milliyon

About a year ago, Zak Stone introduced me to YouTube with this video titled amazing liquid. I wonder how much of this behavior is understood. There must be a lot of fantastic videos of mechanical phenomena on YouTube. Perhaps we can embed them in iMechanica, and comment on them. Teng Li has provided an instruction of how to embed videos. You can check out a few other interesting videos in iMechanica video channel.