Learning Forum

[prataprathore1010]

Hello,

Everyone I know Ansys utilises hyperelastic material models such as Moony-Rivlin, neoprene, and ogden for analysis utilising strain rate to evaluate deformation, but how can we compare diverse material models such as natural rubber, epdm, CR, and SBR in real life? and how we related with the real one

Rubber is used to absorb vibration, however but it is nonlinear in nature, we are unable to undertake vibrational analyses such as modal and harmonic analysis due to incompressibility factors and the Poisson ratio of 0.499. So, how can we relate the results of the analysis to the theoretical vibrational isolation problem?

Thanks

[John Doyle]

With regards to your first question (i.e. how can we compare diverse material models such as natural rubber, EPDM, CR and SBR in real life?):It depends on what you are trying to compare.If you are interested in the structural response (Force-Deflection and Stress-strain) of each material in a particular application, you need to start with reliable test data.With test data, you can curve fit any of the material models (Neo-Hookean, Mooney-Rivlin, Ogden, Yeohetc) to represent the hyperelastic response.Sometimes there is more than one option that will work.Sometimes there is only one.It depends on how complicated the stress-strain relationships are and how challenging the loading is in the application.
Please refer to Section 4.6 of the Material Reference Guide for more details about these options.
With regards to your second question (i.e. how can we relate the results of the analysis to the theoretical vibrational isolation problem?) :I am not sure, but would harmonic viscoelasticity be helpful here?Please refer to Section 4.7.3 of Material Reference Guide.

[Deepakbath]

Propylene Ethylene Diene Monomer is an ethylene-propylene copolymer with a minor amount of a diene monomer that creates chemically unsaturated ethylene groups pendent from the main saturated chain. These aid cross-linking reactions without jeopardizing the polymer backbone's integrity. EPDM has exceptional heat, ozone, and chemical resistance thanks to this property. Physical qualities are excellent, and polar fluid resistance is generally good. EPDM can be compounded to provide great electrical resistance and has excellent low-temperature resistance.
Natural rubber is the only non-synthetic rubber on the market, and it has been in use since the turn of the century. It's made from the sap of the Hevea Brasiliensis tree, which can be found in sustainable plantations. It degrades completely.
One of the first oil-resistant synthetic rubbers was chloroprene rubber (CR), often known as Neoprene®. Its resistance to petroleum-based oils and fuels, on the other hand, is only moderate. It's a terrific all-around rubber with a decent combination of physical and chemical qualities. It outperforms natural rubber in terms of chemical, oil, ozone, and heat resistance, but it has a lower degree of physical qualities. Chloroprene has a weak water absorption rate and poor electrical characteristics. It has a low gas permeability and great flame resistance, as chloroprene is one of the few self-extinguishing rubbers. Neoprene provides excellent rubber-metal bonding as well as a high level of durability.
SBR (Styrene Butadiene Rubber) is a low-cost general-purpose rubber. Physical strength, resilience, and low-temperature qualities are typically lower to Natural Rubber, however heat-aging properties and abrasion resistance are usually superior.