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Multiple Load Cases with CADRE Lite 3

Multiple Load Cases with CADRE Lite 3

(OP)
Has anyone found a way to automate the solving of multiple load cases with CADRE Lite 3.  I know this is probably asking too much but I do like the software.  I will be doing a job where I will have about 40 to 50 load cases.  With some older DOS software I was able to redirect keystrokes from an input file to run a program, and with Windows programs I have been able to use VB and the sendkeys command to control things.  But CADRE doesn't always have keyboard equivalents to buttons on dialog boxes, and sometimes opens in unpredictable states so tabbing around in a dialog doesn't work either.

Logically I know I should be using something else.  I think RISA handles multiple load cases well, but I just need an analysis program because I do code checking in a calculation program.

-Mike

RE: Multiple Load Cases with CADRE Lite 3

There is no automation in running load cases in either CADRE Lite or CADRE Pro.  It would be a very easy thing to incorporate but the decision was made early on not to go that route because it was considered to be a throw back to the batch processing days and it can lead to some confusion when later trying to reload a model (some perhaps with different restraints) and retrace your steps.  

This could be debated of course, but with the capacity of machines today, there is a lot less need for keeping separate load sets and using a single model.  In fact, I usually make a separate "model" for each final load case and save it in a separate directory along with the results of that case.  In the end, its all archived on CD after the report is written.  That way there is little room for error in trying to duplicate a calculation years later.

My main use for saving and reloading load conditions is to build up the final load case from component loads, but once the case is construted, it is loaded onto a model and saved that way.

Jim
CADRE Analytic     

Jim Haynes
www.cadreanalytic.com

RE: Multiple Load Cases with CADRE Lite 3

(OP)
James,

I will be using CADRE to design a steel structure for 26 load combinations built up from 10 basic load cases.  I think CADRE has a good way of creating load files (it's been a few months since I have used the program) and then saving results to a file.  I was hoping to do this with a script file or some other automated way.

Once a solution is run I would calculate stresses in a calculation program or spreadsheet and modify the structure as needed, then run a solution again.  In my view, if I understand your suggestion correctly, modifying 26 models and solving for its own load case as you suggest would be more work that changing the model just once and then reloading and solving 26 load combinations.

But in all fairness I should try this a few more times before I give up.  I think that a little organization will go a long way towards making this all work better.

Thanks for your comments.

-Mike

RE: Multiple Load Cases with CADRE Lite 3

(OP)
An update.

I have found that the problem with sending keystokes to CADRE with the VB SendKey command was that I needed to pause briefly after the AppActivate command.  This has worked every time now for about 30 tests.

If anyone has comments, questions, or suggestions, just post to this thread.

-Mike

RE: Multiple Load Cases with CADRE Lite 3

(OP)
Another update.

As indicated in my original post I was interested in automating CADRE to run multiple load cases.  While the "Global load management" dialog is very useful to build a load case by merging load files from basic loads, CADRE is not set up with automation to do this, as confirmed by James.  I have written a VB (Visual Basic) program that partially automates this process, and I just wanted to let anyone interested in this know that it can be done.

The way this works is to use VB to feed keystrokes to CADRE with the "SendKeys" command.  Start with the "Global load management" dialog open and press "Remove" to remove existing loads on the model and to give the VB program a place to start.  From that point a VB program can take over and get or merge files in just about any way wanted.  When done a F9 key can be sent to run a solution.  You then manually recover whatever results are needed and save, then go back to the VB program to run another load.

Your VB program needs to shift focus to CADRE in order to run it.  This is done with the command AppActivate "Global load management" because you are mainly automating this dialog box.  I have found that to get this all to work you need to pause about 1/2 second before sending keystrokes.  Keystrokes are sent with the "Sendkeys" command.

This is important for several reasons.  One is that the building codes have made it more explicit to consider quartering wind loads and orthogonal seismic loads, which is resulting in many more load combinations than in the past.  Typically in the range of 10 to 30 combinations.  Another reason is that I like CADRE, which is of course a personal opinion.  But in my view it is a powerful program that is well thought out.

If there are any questions, comments, or other experiences related to this topic and CADRE, please post a response here.  I'd be interested in the feedback.

Regards,
-Mike

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