# Viscoelastic

## Does anyone know how ABAQUS calculate ALLCD (viscoelastic energy dissipation)

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Hi,

I am doing some study with viscoelastic energy dissipation. I have a basic question for ABAQUS.

In ABAQUS, I notice there is a function to calculate Energy dissipated by creep, swelling, and viscoelasticity (ALLCD). You are able to plot energy change with time.

But want to know how ABAQUS calculates energy dissipation with time? What equation does it use?

## Online finite element analysis of nanoindentation (indentation)

Dear All,

We (the NanoBIO Node at Illinois ) have a preliminary release of an online finite element analysis of nanoindentation (indentation) tool using FEAP

This preliminary release is limited to linear elastic material, axisymmetric geometry, spherical rigid indenter, and various boundary conditions.

## Hyperelastic and Viscoelastic material modelling

I have a doubt regarding the Hyperelastic and Viscoelastic material modelling in ANSYS using Mooney-Rivlin material constants.

ANSYS theory manual says that for large deformation and large strains, the material modelling (i.e. constitutive behaviour) is same for hyperelastic and viscoelastic. Is it so?

Generally,  Mooney-Rivlin material constants are used to model Hyperelastic behaviour (rubber-like materials).

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## Tunable electrical and mechanical responses of PDMS and polypyrrole nanowire composites

Journal of Physics D: Applied Physics

Ping Du, Xi Lin, Xin Zhang

Volume 46, Number 19, Page 195303

doi:10.1088/0022-3727/46/19/195303

A generic experimental procedure is presented in this work to enhance
the electrical responses of polydimethylsiloxane (PDMS) through
incorporation of conducting polymer nanowires, while maintaining the
desirable mechanical flexibility of PDMS. The conducting polypyrrole

## Investigation of Cellular Contraction Forces in the Frequency Domain Using a PDMS Micropillar-Based Force Transducer

Journal of Microelectromechanical Systems
Ping Du; Chen Cheng; Hongbing Lu; Xin Zhang
Volume: 22, Issue: 1, Page(s): 44 - 53

DOI: 10.1109/JMEMS.2012.2213070

## viscoelastic material characterization and modeling

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Hi,

I used TA DMA tested the viscoelastic material properties (stress relaxation test). When I did Time-Temperature Superposion to create the mater curve, i found some of the shift-X values were negative (those points after Tg), which cannot be fit to WLF function. ANybody knows the reason behind this?  I excluded those point when fit the WLF coefficients, is this acceptable?

And I found the C1 and C2 of one material are negative, can i still use it at high temperature? thank you

## Viscoelasticity Kelvin-voigt model in Abaqus

Hi all,

I'm trying to model kelvin-Voigt type material (response of it during time)

The equation is very basic : sigma*epsilon+d/dt epsilon*viscosity coefficient(eta)

i'm wondering how to impliment the viscous term eta in Pa.s (experimental results gave me the value) in my model.

The theory is very simple but i can't figure out how to do such thing in Abaqus.

I tried Pony type but i don't now how to calculate the coefficients..

Can you help me?

## Viscoelastic model parameters in LS-Dyna

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I'm using elastic solid elements to model wave propagation in an
structure in LS-DYNA. I need to add the effect of dissipation in the
system by using viscoelastic material model (MAT_006). All I know from
my material is storage & loss modulus (E=E'+E"*i). I was wondering
how can I transform these parameters into G0, GI and BETA needed by
MAT_006 (G=Gi+(G0-Gi)*exp(-beta*t))?

## ansys viscoelastic model

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Hi

## Viscoelastic material model in abaqus-am i taking the correvt approach

Hi all,

I have been trying to gain an understanding of representing a viscoelastic material in abaqus. To do this i have been trying to represent polypropylene using data obtained from creep curves found in literature (attached). To now what i have been doing is the following: Note i am using Abaqus 6.7

In material manager: selecting Elastic-inputting Instantaneous Youngs Modulus, E, Poissons, v, (E=1.8GPa, v=0.4) and setting the moduli time scale to instantaneous. And Viscoelastic-Domain:Time, Time=Creep Test data and inputting Shear Test Data

hello i am writing u from ethiopia now i am doing  design and modeling of motorcycle helmet using viscoelastic materials but i couldn't be able to understand how to use the material models so please help me by showing the prosudure how to use viscoelastic materials proporty

yours araya

## Indentation test modelling on Ansys

I am currently doing simulation on Ansys regarding the indentation test for viscoelastic material. I have some problem with the contact element.. Can someone help me on?