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wvmars's picture

Engineering Analyst position with focus on FEA, elastomers, and fatigue life prediction

Endurica, LLC is a growing software and consulting services company headquartered in Findlay, Ohio, USA. The
company develops and sells solutions that enable customers to manage durability of elastomeric products. Our
physics-based solutions include computer-aided engineering software that numerically simulates the fatigue life
of elastomeric products, a materials characterization service, and project-oriented consulting services. Our
software is distributed globally in partnership with Dassault Systemes.

Difference between different material models for Hyperelastic material


I am doing a project on rubber couplings and it is a bit difficult for me to decide between the material models availavle in Ansys 14. I am new to this field and want some assistance in choosing the material model. So, can anyone help me to theoroticall explain the difference between the different material models available in Ansys? 

Zhigang Suo's picture

Elasticity of rubber-like materials

In the notes on the general theory of finite deformation, we have left the free energy function unspecified. The notes here describe free energy function commonly used to describe the elasticity of rubber-like materials.  These notes are part of a course on advanced elasticity

Constitutive models for rubber


I found a very useful explanation about hyperelasticity here:

 In the proof3, there is a good explanation (I can't found anything better than this one) of how we can express the Cauchy stresses in terms of the principal streches.

I am interested to incompressible material, so this is the equation:

Planar tension test = Pure shear test for rubber? Explanations


 I know what is this test and I know under certain conditions (low deformations and specimen's wide 10 times its lenght), a planar tension test is equal to pure shear test.

But I don't know why if we are doing a tension test we have pure shear.

Let me explain:

    ^ 1-Axis
 |           |    ---> 2-Axis

Thermodynamic model for strain-induced crystallization in rubber - Eccomas

Natural rubber (NR) is known to crystallize under strain (SIC) so that NR samples subjected to loading-unloading cycles exhibit hysteresis. A brief review of the numerous experiments conducted on this material is given. Detailed information on the microstructure is therefore available, particularly simultaneous measurements of stress versus elongation and

wvmars's picture

Seeking Engineering Analyst with ABAQUS Experience

Endurica LLC ( is a growing, high-technology, small business startup with customers in the defense, heavy equipment, offshore, and automotive sectors. We deliver world-leading solutions and services for managing elastomer durability issues at the conceptual / CAE stage. We are located in Findlay, Ohio.

farhan3d's picture

Viscoelastic properties of pre- and post-cure cellular rubbers using rheometer

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.

Muthukumar M's picture

Why Rubber is incompressible?

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

wvmars's picture

Short Course: Engineering of Durable Elastomeric Structures, 26-27 July 2011, Ann Arbor, Michigan

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.

verron's picture

European Conference on Constitutive Models for Rubber - ECCMR 7

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





Material selection for vibration damping

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).

wvmars's picture

European Conference on Constitutive Models for Rubber - ECCMR VI

ECCMR 2009 - Sixth European Conference on Constitutive Models for Rubber

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

GI GII GIII computation in Rubber composites like tires (Comparaison between methods)

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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

LECAM's picture

Experimental temperature field at the crack tip in a natural rubber

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.


What is the Shore A hardness used for?

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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,

verron's picture

Comparison of hyperelastic models for rubberlike materials

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.

verron's picture

Recent papers on rubber mechanics

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

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

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