archery

Main Forum
1

Hello Sir,
I want to apply force at the full draw length of archery. my model consists of 436 steps. say at 300th step the archer pulls the bow string at its full draw and the force applied by archer at full draw is 214 newtons. how do i apply this force at that particular position of the archer. also can i reduce the number of steps and still have the model perform all the operations? when i changed the frame offset number in trial specific data my model was not performing all the operations from start to end. it was skipping some of the operations.

2

Hi Aviktha,

Archery is an interesting application. I did not have time to look into your model, but I presume that you have measured the force necessary to load the bow and have this saved as a function of the loading movement. When you load the bow, you effectively pull the two hands apart against this force.

I would then create an AnyKinPLine between the two hands and apply an AnyForce to this measure and make the AnyForce dependent on the length of the measure according to the recorded function. Don’t forget to make the force negative because it works against the elongation of the AnyKinPLine.

Best regards,
John

3

can i input load curve starting from 300th frame till the end in anyscript.?

4

You can define the force curve any way you like. However, it is not a good idea to base it on frames. The frame numbers may change if you change the number of time steps in the analysis. It would be better to make the force a function of time or bow deflection.

5

I am unable to get .xml file of load acting on scapula. i have created files_out folder and followed the tutorial steps. please help me where i have gone wrong.

6

Hi Aviktha

Most likely something to do with the paths in your implementation. Could you see the error message?

Regards,
Pavel

7

Iam not getting any error. i am able to run the model but after i run it following the script i am not getting .xml file

8

Do you run this particular operation to generate the XML? It will not be picked automatically unless you add it to the PostOperation of the InverseDynamics.

If you do - it is most likely the problem of paths. Try to make them exactly the same as in the tutorials and premake the Output folders (they need to be created before you call the converter, or through a batch file in the same operation sequence). You could also try to run the converter from the command line to make sure that it runs, you have license, that files are not missing, etc. + you will see the error message.

Regards,
Pavel

9

can you please help me in applying force as a function of time.? an idea of how to go about with the anyscript.

10 
AnyForce3D MyForce = {

    //F = {0, 0, 0};
    Flocal = {0, 0, 10}*Main.MyStudy.t.; // linear increase from 0 to 10*tEnd of your study
    AnyRefFrame &ref = Main.Model.Segments.SomeNode; // this is the force appl. ref. frame
  };

Regards,
Pavel