How can I use Frequency Sweep DMA data to define Prony Shear series at ANSYS WB?

More Gerges Youssef's questions See All

In ANSYS Workbench, I am facing problems in solving a transient structural model. Any suggestions?

The model has non-linear materials and frictional contact elements.I faced divergence many times, so I tried to: 1. Refine the mesh (approx. 100 K elements): took more time and failed to solve. 2....

11 December 2015 3,219 20 View

I have several FEA results sets, I want to estimate which one is the most accurate one compared to experimental results. Can I use R^2 (R-squared)?

The results are discrete values, where two parameters are varied for each reading (load and speed). Each reading is calculated only once (no replications). Please advise if I can use R^2 (R...

11 December 2015 10,051 8 View

How can I reduce bouncing of a component in Transient Structural ANSYS Workbench study?

I am preparing a study for a rubber sheet that is driven horizontally with a constant velocity against a cylindrical surface, where the rubber sheet is loaded with a constant vertical force. My...

10 November 2015 1,626 20 View

How to learn more about SPSS and its Application?

I would like to learn more about SPSS and Its application especially in regards to data analysis. Please suggest me how I can learn more about it. Thank you so much.

11 August 2024 9,101 4 View

Can I base on reverse DNA sequences to perform alignment, convert to amino acids and GenBank submission?

I have reverse sequences (AB1 format), can I base on reverse DNA sequences to perform nucleotide alignment, convert nucleotides to amino acids and deposit the sequence in GenBank database?

11 August 2024 5,138 1 View

Baseline drift in HPLC? What causes this?

Hello, Why do i see this baseline drift when i compare my blank (black) to the sample (blue)? Any suggestions as to why this happened? Thank you!

11 August 2024 3,770 4 View

Text-Communication from the M1 Hand Area using BCI—and then there is Elon Musk?

Willett, Shenoy et al. (2021) have developed a brain computer interface (BCI) that used neural signal collected from the hand area of the motor cortex (area M1) of a paralyzed patient. The...

10 August 2024 7,180 0 View

Has anyone applied Python in the field of textile engineering for data analysis, automation, or smart textiles?

I'm currently exploring the application of Python in textile engineering, specifically in areas like data analysis, process automation, and the development of smart textiles. I'm interested in...

10 August 2024 7,429 2 View

How can I use the cif data obtained from rietveld refinement extracted via gsas2, for microstructural analysis using ETEX software?

09 August 2024 7,718 0 View

How to define an anisotropic material with asymmetric elastic compliance/stiffness matrix in ANSYS APDL?

I need to model an anisotropic material in which the Poisson's ratio ν_12 ≠ ν_21 and so on. Therefore, the elastic compliance matrix wouldn't be a symmetric one. In ANSYS APDL, for TB,ANEL...

09 August 2024 5,048 2 View

How are iso-frequency contours plotted?

Let's say we have a standard, regular hexagonal honeycomb with a 3-arm primitive unit cell (something like the figure attached; the figure is only representative and not drawn to scale). The...

07 August 2024 1,937 1 View

How to prepare the nanoparticle treated fungal sample for Environmental SEM analysis?

A fungal strain was treated with nanoparticles. We want to do an environmental SEM analysis. So could anyone share your views on preparing the sample? Thank you.

07 August 2024 5,307 1 View

How to normalize and take the significance of the MTT OD values with 3 replicates for the same cell-line?

Hi, I have a question about normalizing the MTT OD values for doing the statistical analysis. So, if we have 3 different plates and we call them 3 different replicates, so, first we would...

07 August 2024 8,106 4 View

Scott Grindy

I believe your question is effectively about how to compute the discrete relaxation spectrum from oscillatory shear data. I suggest you start with Baumgaertel & Winter, Rheologica Acta, 1989, Vol 28, p 511.

Alternatively, there is a free MATLAB program which will effectively perform the same task: https://www.mathworks.com/matlabcentral/fileexchange/40458-respect

I'm not familiar with ANSYS, so I can't help you with that part.

Gerges Youssef

Hi Scott,

Thank you very much for your help.

Based on the test I did for a rubber sample (DMA frequency sweep at a constant temperature at shear mode), I want to extract the viscoelastic model parameters according to Prony Shear Relaxation (relative moduli and relaxation time (in seconds).

The experimental data I have is storage modulus, loss modulus, amplitude and strain % VS. Frequency.

I am not sure that the program you sent will do what is needed.

Please advise.

Best regards,

Sure it will - you might have to play with it a bit if your material has a non-zero modulus at infinite times. The program can compute the discrete relaxation spectrum from your storage & loss modulus, which is quite nearly the Prony Series representation of the relaxation modulus. If you need some review of the relation between relaxation modulus, storage & loss moduli, and the relaxation spectrum I'll refer you to the book "Viscoelastic Properties of Polymers" by J.D. Ferry.

Hello Scott,

I have almost no exposure at all in using Matlab. Can you help me in brief step how to get one of the data sets shown in the attached files using a frequency sweep DMA test results either using the matlab freeware respect, or using any other tool?

Your help will be highly appreciated!

I can't show you exactly what to do, unfortunately. If you have more questions, you should consult the "README.pdf" file located in ReSpect download, or contact the authors of that package. You may also find their article helpful: A Computer Program to Extract the Continuous and Discrete Relaxation Spectra from Dynamic Viscoelastic Measurements, Appl. Rheol. 23 (2013) 24628.

OK. Thanks for your help.

Ahmed Benalla

Hi Gerges

did you fix this problem?, i have the same question.