Hi All,

I would like to know if anyone has had the opportunity to investigate cellular rubbers rheology. I am thinking of characterizing the viscoelastic properties of cellular rubber during cure and after cure in the rheometer, using ASTM D6601. What I am expecting is a distorted cellular structure due to very constrained foam expansion during the blowing agent's decomposition, so the results would obviously be different than the ones obtained from a DMTA machine.

Would like to hear from anyone with some rheology / viscoelastic characterization experience.

Thanks,

Muhammad Farhan

Dear All,

Why rubber and like soft materials are incompressible? I do not want any explanation in formula like, volumetric strain is zero or poissons ratio is 0.5 etc. Physically whats happening when we apply compressive load? For example take a gas, when you compress, the density will change. Is there any of the properties are changing?

Thank you,

Muthu Kumar M

Elastomers are outstanding in their ability to repeatedly endure large deformations, and they are often applied where fatigue performance is a critical consideration. Because the macromolecular structure of elastomers gives rise to a number of unique behaviors, appropriately specialized methods are needed to characterize, analyze, and design for durability. This 2-day course provides the know-how for engineering durable elastomeric components and systems. The course is taught at Axel Products, and includes live demos of typical behavior.
Instructor: Dr. Will Mars, President of Endurica LLC

For more info, see: http://www.endurica.com/PDF/EngineeringDurableElastomerStructuresv8.pdf

Cost: $2000

The 7th European Conference on Constitutive Models for Rubber will take place in the Dublin Institute of Technology (DIT), Dublin, Ireland, 20-23 September 2011.

Deadline for abstract submission: the 5th of December 2010

Website: http://www.eventelephant.com/eccmr2011dublin

Regards,

   Erwan 

Hi everyone,
 
 I'm searching some solution to absorb vibration. I'm trying to find materials and their properties to compare between them and chose one to design a vibration damper. Their application will be on the base of an avionics enclosure wich is onboard of a UAV (Unmanned Aerial Vehicle).

I'm the university, I learned mx''+cx'+kx=0, the free vibration equilibrium equation and all that stuff. But how should I search for a material wich have a good 'c'? Should I search for viscoelastic materials? I eared that ruber or cork are very good vibration absorbers, but how to quantify and compare it?

I would aprecciate some help... thanks in advance
Best regards
Sonia PireX

ECCMR 2009 - Sixth European Conference on Constitutive Models for Rubber

Held at TU Dresden, Germany, September 7-10, 2009. 

www.eccmr.org

2009-04-24 17:16:02

Hi all,

I am currently in my second year in Engineering school in France. I am doing research on 3D crack propagation in Rubber composites like tires.

And I wonder what is the best method to compute GI, GII and GIII. I have difficulties to choose between methods like EDI and VCCT for example.

I work in the finite strains case with static and dynamic. I also have difficulties to find papers on this subject with comparisons.

Can anyone please help me out with that

Thank You

Best Regards

Joachim Guilié

Dear colleagues, this is a paper on the experimental determination of temperature field at the crack tip in a natural rubber using a motion compensation technique. The contribution of the non-uniformity of the IR detectors and the Narcissus effect is taking into account to determine the temperature field.

JB LE CAM

Rubber-like material is the generic term to define quasi-linear solid polymers. It encompasses elastomers (natural such as Natural Rubber (NR), and synthetic such as Styrene Butadiene Rubber (SBR), but also other large strain elastic materials such as heat-softened thermoplastics (especially for blow-molding simulation) , but also for biological materials such as muscles, tendons, blood vessel (see for example this book).

The key point to understand their behaviour is the nature of elasticity involved in these materials: the elasticity is mainly entropic. Then it is classically referred to as “Entropic elasticity” and “Rubber elasticity ” and the constitutive equations are derived from the general framework of large strain hyperelasticity (usually these materials are considered homogeneous, isotropic, incompressible and elastic). Nevertheless, the mechanical response of these materials and especially Natural Rubber is highly more complicated: they exhibit stress-softening, long-term viscoelasticity, initial or induced anisotropy, hysteresis, volume change, ...

The Shore A and D hardness tests are widely used by the rubber industry.  However, I'm not sure what practical use these numbers can be put to during design.  My current feeling is that Shore hardness numbers can at best give you a feel for the texture of the rubber - a Shore A value of 5 = gummy bear texture, Shore A = 40 implies erasure texture etc.

Can someone explain how Shore hardness values can be used in the design of mechanical components made of rubber?

Thanks in advance,

Biswajit 

Dear all,

Infinity asked me for posting more information about one of our papers. It was published in 2006 in Rubber Chemistry and Technology and proposes a comparison and a ranking of 20 different hyperelastic constitutive models for rubber (from the Mooney model (1940) to the micro-sphere model (2004)) in the incompressible case.

Marckmann G. et Verron E., Comparison of hyperelastic models for rubberlike materials, Rubber Chemistry and Technology, 79(5), 835-858, 2006.

Here are some of my recent papers about mechanics of rubber material. They concern constitutive modelling, fatigue and fracture.