No, I don't think so that I can model the material as multi-linear stress-strain law. Because material doesn't behave as perfectly elastic material. It is classified as a pseudo elastic material. The behavior is somewhat like in the figure 3(b) in http://what-when-how.com/mechanics-of-t … ry-alloys/.

No, for time being I would like to keep the constant temperature for the study. I just want to develop the mechanical behavior.

No, I haven't looked into it as of now. I will look into it and let you know if I need more information. Thank you for the information.

Thanks,
Amit Jain

Dear Amit,
please explain which effects/influences you wish to consider - how the history influences the response?

Ad 1. You can define new data attributes as you wish and store into them what you like when creating your own  UserMaterialDLL.

Ad 2. Please see ATENA Troubleshooting, 2.1.9.1 Reinforcement buckling and 2.2.12.3 Unbonded segments for basic ideas on bars not fully embedded in a volume material.

With some extra care, it is also possible to directly support a bar (or cable), at least using the ATENA-GiD interface (I am not sure about the Engineering 3D and 2D GUEs).

I am doubt that how can I store the stress value for each time step using the usermaterial dll file. As per my understanding this dll file is called for each time step and the variable which i will create using this file would be a local variable. How would I be able to access it next time step.

Please correct me if I am wrong. Also please let me know a way to do it.

Thank you

Hi,

I have updated the code and created the .dll file for the user material. But I could not be able to implement it into ATENA. I am getting the following error, which says that ATENA could not be able to load the .dll file

My implementation procedure is as follows:
1. I have created a model in ATENA 3D, similar to tensile testing of a cable. (The cable is connected with 3D-linear-elastic-isotropic steel cubes). At the first step, I am specifying cable to follow the linear elastic reinforcement material. The program runs well and gives the expected results.
2. Now I have exported the input file of the model and replace the following code

 
MATERIAL ID 335544322 NAME "Reinforcement"
TYPE "CCReinforcement"
   E       2.000000e+005
   ALPHA   1.200000e-005
   RHO     7.850000e-003
   COMPRESSION 1

with the code:

MATERIAL ID 335544322 NAME "SMA"
TYPE "CC3DUserMaterial"
UserMaterialDLL "OneDimSMA.dll"
   Ea       67000   // UserMaterialParams
   Em      26300  // UserMaterialParams
   Ca       8          // UserMaterialParams
   Cm      13.5     // UserMaterialParams
   Ms       18.4     // UserMaterialParams
   Mf       9          // UserMaterialParams
   As       34.5     // UserMaterialParams
   Af        49       // UserMaterialParams
   epsL    0.067  // UserMaterialParams
   T         53       // UserMaterialParams

I have tested the OneDimSMA.dll file by importing its function in another C++ program. In that program the required functions are getting imported from .dll file and runs as expected.

Please let me know, where am I doing mistake.

Thanks,
Amit Jain

Dear Dpryl,

I don't know why I got different file name in message. But I tried to do it again and now I am getting the same file name in message file as I specified in .inp file. Could you please let me know where am I doing wrong.

The message I received is as follows:
(Thread 1) CCException: Cannot find function UserDLLCalculateResponse in DLL: OneDimSMA.dll : The specified procedure could not be found.

Source line: 289, file: ..\..\Sources\CCMaterial\CCElastIsotropic\CCUserMaterial\CCUserMaterial_Misc.cpp, last modified at: Wed Jul 23 15:10:18 2014

As I said earlier that I could able to run this program with the in-build 1-D material definition.

Thanks,
Amit Jain

Could you please give me your email address or please give me a test mail to amitjn7042@gmail.com .

Yes I am exporting the .dll file with "__declspec(dllexport)" keyword before the declaration of the function. An example of the same is as follows:

__declspec(dllexport) UINT CDECL UserDLLCalculateResponse(
      double deps[], double teps[], double sigma[], double UserMaterialParams[], double UserMaterialState[]
){
/*...*/
}

I will send you the .dll file once I will receive an email address. I am using Visual Studio Express 2013 to compile the program and to generate the .dll file. I have also written a program to use the generated .dll file. I am able use the functions from .dll file. I don't know why I am getting this error while using .inp file.

Please let me know what other information should I provide you with .dll file.

I have sent you the required files and information. Please let me know if you need any more information.

Thanks,
Amit Jain

Hello, the most likely reason is that some runtime libraries used by your .DLL are missing on the other computer. For example, if you use the Microsoft Visual C++ or Intel FORTRAN compiler to create your .DLL, you need to install the Visual C++ runtime or the Intel FORTRAN runtime (of course, version corresponding to your compiler). You also need to include the runtime DLLs of any additional libraries used in your .DLL.
Regards.