Week - 10 Hyperelastic Material Models

*AIM:-

Material modeling of MAT-077_H, 077_o, Hyperelastic rubber and odgen rubber card fro raw data and fit the experimental values to the raw data by curve.

*Objectives:-

1) Extract the engineering stress/strain data from the given image.

2) Convert the data in to the SI unit by calculation.(Here unit system is gm,mm,ms)

3) Plot the data as the curve to define the material card.

4) Set up the simulation for the tensile test and degbone specimen to get the results.

5) Validate the output data by checking that it matches with the original data.

*Procedure:-

-First of all image is available in the challange page. It is the test data.

-Lab test data image is provided where the data points should be exported to excel sheet.

* Engineering stress-strain curve:-

-The data given is in engineering stress/ strain.

-Eng stress vs strain value is plotted up to strain rate of 100% which is 1.

- After that this data is copy and paste in to the Notepad++ and arrange the column which we required.

*Material creation:-

To varify and validate the given material data with material models of MOONEY-RIVLIN amd ogden adogbone specimen is taken for the analysis.

-Here N=1

-The value of rho and poission ratio is taken as a rubber material.

-SGL= Specimen gauge length

-SW= Specimen width

-ST= Specimen thickness

-The load curve is engineering stress nd strain data.

*Session_shell:-

-ELFORM=2

-Thickness=1.5

*Part creation:-

-Assign material and session in to the part.

*Boundary condition:-
1) SPC:-

i) All one end nodes are fixed

ii) Only fixed in y-direction

2)Prescribe motion:-

-here we provide the displacement.

-For that first of all create load curve.

-After that go to model and part> keyword manager> all> boundary> Prescribe_motion

*Control cards:-

1) Control implicit auto:-

-Here provide IAUTO value is 1.

2) Control implicit general:-

-Here Provide, IMFLAG=0

DT0= 0.01

3) Control implicit solver:-

-here provide LSOLVR=6

*Termination card:-

-Here we required ENDTIm=1 ms

* Model check:-

-After assigning all the keyword check the model using the model checker and find any error or not.If any type of error then remove it.

-After that save the file as a".k" format.

-Run the file in the solver. if it's end as a normal termination then model is correct.

*Material model validation:-

The d3hsp file for each materila model is opened in notepad++ and the material constant of mooney rivlin and odgen as well as final fit data of stretch and engg stress is obtain in each case.

-From the output file of material verification, d3hsp file opened in the notepad++ and mooney rivlin constant obtain are

c1= 0.1768

c2= 0.1474

-The data obtain from d3hsp file is extension(stretch) and true stress which is converted in to engg stress and engg strain.

-Here, Engg strain=stretch-1

Engg stress= true stress/(1+Engg strain)

-For material model validation , the value of N change to 0 in the material card. This value is inputed in to MAT_77_H .

-The data obtain from d3hsp file is extension(stretch) and true stress which is converted in to engg stress and engg strain to verify with experimental data.

*Now genrate the odgen material card:-

*plotting the result:-

-After that open D3 file in LSPP.

1)Animation is as shown below:-

i) Mooney-rivlin material model:-

ii)Odgen material model:-

2)Animation of von-mises stress is as shown below:-

i) Mooney-rivlin material model:-

ii)Odgen material model:-

3)Animation of effective plastic strain is as shown below:-

i) Mooney-rivlin material model:-

*Graph of effective stress vs time-

*Graph of effective strain vs time:-

*graph of effective stress vs effective strain:-