Learning Forum

[xuhang578]

Hello friends.

     In my analysis, I need to generate deformation gradient in "Static Structural", but I am new to ANSYS and I have no idea about how to achieve that, could you please give me some help.

Regards,

Hang Xu

[peteroznewman]

Isn't Strain the same as deformation gradient?  

[xuhang578]

Dear friend, 

Thanks for you help and sorry for the late reply!

But I think strain describes the deformation condition of the same point before and after the displacement 

and gradient describes the differential deformation condition between the two adjacent points after the displacement.

Maybe my understanding is wrong, could you please help me to figure that.

 

Regards,

Hang xu

[peteroznewman]

Here is the definition of Engineering Strain. It is a change in length divided by the original length.

Strain at a point is just this definition as the original length approaches zero.

When you say deformation gradient, do you mean what is shown below taken from Wikipedia?

Please explain why you need the deformation gradient?  What is it for?  How will you use it?

[xuhang578]

Thanks for your explanation, it really helps me a lot!

I found that I have misunderstood the conception of "deformation gradient".

Base on the formulas, I believe you are right,  strain is the same as deformation gradient.

My major used to be image processing and I thought the gradient defined as below (from Wikipedia):

The gradient of image is calculated based on the adjacent pixels within one image, so I thought "deformation gradient" share the similar definition.

So I just simply extend the conception of "gradient of image" into 3D condition (Which is now proved to be wrong). Maybe I should call it "differential deformation" in 3D finite element method application. 

In my  application, I need to identity the deformation anomalous of a building, so I need the "differential deformation" data to support my analysis. For example, based on the differential deformation, I can identify the relative movement of the points in the building, which can be a indicator for the stability of the building.

I don‘t know weather the "differential deformation" can be generated by ANSYS directly, if not , maybe I should export the deformation data and do the post processing to achieve the "differential deformation".

[xuhang578]

Hi, my friend,

      I've finished to calculated this "differential deformation" in MATLAB in text format as below:

      

      But I don‘t know how to import this kind of data back to ANSYS WORKBENCH.

      Could please give me some advice about how to achieve it ?

      Or do you know how to calculate this "differential deformation" in ANSYS?

 

Regards,

Hang xu