# creep

## Two open PhD positions in multi-physics process and performance modeling of alloys at the University of Tennessee

We have two open PhD position starting in the Fall semester 2020 at the Computational Laboratory for the Mechanics of Interfaces at the University of Tennessee - Knoxville (http://clmi.utk.edu). First research topic centers upon the modeling of texture evolution during processing (e.g. cogging and rolling) of titanium alloys using crystal plasticity and Fast Fourier Transform methods to couple the mesoscale and specimen scale.

## Question about implicit creep subroutine in Abaqus

The implicit implementation of creep in abaqus requires dh/d(\delta \epsilon_c ) as Jacobian in Newton-Raphson's iteration. The derivative can be expanded as shown in the figure attached. The term dh/dq, the one underlined by a green stroke, is expected to be provided by users through specifying DECRA, whereas the term dq/d(\delta \epsilon), underlined by a red one, is confusing me. It seems that that term is computed by Abaqus but I have no idea how it is done. The same question applies to the last derivative on the right hand side.

## Abaqus is not reporting any CEEQ in coupled temp-displacement step

Hi all,

I am modeling a simple coupled temp-displecment analysis with the following step information:

** MATERIALS

**

*Material, name=Material-1

*Conductivity

1e-06,

*Creep, law=HYPERB

44000., 0.005,   4.2, 45000., 8.314

*Elastic

60000., 0.34

*Expansion, zero=25.

1.4e-05,

*Plastic

20.,  0.

60., 0.1

**

** PHYSICAL CONSTANTS

**

*Physical Constants, absolute zero=-273., universal gas=8.314

** STEP: Step-1

**

## Creep strain vs time graph as input in abaqus

I have a creep strain vs
time graph. How can that be used as input for creep? In defining creep,
abaqus asks for power law multiplier, eq stress order and time order?
how can those be found from creep strain vs time graph?

## UMAT and UEXPAN subroutines

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I am having problems in writing the umat and uexpan subroutines applicable to the creep model defined in

Has anybody written the algorithm?

## PhD student position at Arizona State University

One PhD student position is available at Arizona State University for fall 2014. Research background in at least one of the following areas is preferred.

1. Fatigue, creep, and corrosion analysis of materials

2. Computational mechanics and micromechanics

3. Damage detection for composite materials

Interested candidates please send application documents to yongming.liu@asu.edu

Thanks!

## Modelling time dependent concrete properties in ABAQUS

I am
carrying out a non-linear analysis of a concrete section subjected to construction
loading. I am looking to model the time-dependent effects of the material
properties as well as creep and shrinkage properties of concrete. In the ABAQUS
manual it states the General Static procedure
cannot be used to model time dependent effects. Naturally the Riks Method would be ideal to account of
the non-linear effects however it doesn’t allow for the use of multiple steps in
the analysis which is necessary to model the various stages of construction

## Developmental Thermal Barrier Coating Bond Coats

Authors: Amit Pandey 1, 2, Vladimir K. Tolpygo 3,  Kevin J. Hemker 1

1. The Johns Hopkins University, Department of Mechanical Engineering

2. Oak Ridge National Laboratory, Materials Science and Technology Division

## Nonlinear Dynamics - 2013. Registration deadline extended till January 28th

Dear Colleagues,

The new deadline for abstract (plain text, 400 word limit) submission is now January 28, 2013.

The 4th conference "Nonlinear Dynamics -2013" will be held from 19 until 22 June, 2013 in Sevastopol (Ukraine).

The conference is organised by:

## Difference between Creep rate and creep strain rate

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Hi all,

Do you know what is the difference between Creep rate and creep strain rate?

Thanks beforehand...

## creep subroutine ABAQUS

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Dear all

I'm trying to write ABAQUS subroutine for creep.

## Need help in Creep modeling in ANSYS

Can Anyone help me how to do creep modeling in ansys?

I need to follow the creep law __>      effective creep strain (e at time t) = S. T. e^(-H)

S=(a0)^t.(sigma)^(a1) ;     T = t^(a2)+(a3).t^(a4)+(a5)t^(a6)   ; H = (a7)/[(theta)+273.16]

a0 to a7 are material constants.

I have the experimental data and tried to fit the curve in Ansys to obtain the material constants.

I tried to follow the ansys help file steps. But facing erros messages.

If any one could give me a sample apdl code it would be helpful.