Combin39 in mechanical automatically using input force vs deflection data from an Excel file

Erik Kostson

How can we automatically (say via mechanical scripting) read some data from an excel file (where the first column in that file gives the displacements and the second one contains spring force values, like shown below), and then assign those values to a nonlinear spring (combin39) inside mechanical?

Mike.Thompson

@Erik Kostson , this question really has two distinct questions in it. I will address the idea of interacting with MS Excel first, as this is done in this post:
https://discuss.ansys.com/discussion/2195/how-to-interact-with-excel-from-mechanical-or-other-applications

Erik Kostson

There are many ways of doing this. An attempt of such script is seen below. It assumes that we have a force vs deflection file (combin.xlsx), and an existing spring object in mechanical (change as needed, but called here: Longitudinal - Solid To Solid ).

It will read in the force vs deflection data from the excel file , and based on this, create the apdl command snippet needed to define the nonlinear spring (combin39).

import clr
clr.AddReferenceByName('Microsoft.Office.Interop.Excel')
from Microsoft.Office.Interop import Excel
excel = Excel.ApplicationClass()
excel.Visible = False # makes the Excel application visible to the user
excel.ScreenUpdating = False     # Enables screen refreshing
# opening a workbook
filename = r"D:\combin.xlsx" #Specify existing Excel document
workbook = excel.Workbooks.Open(filename)
# adding a worksheet
ws=workbook.worksheets("Sheet1")


tempn='h'
ii=1
jj=1 # counter
disp=[]
forc=[]
while tempn!='':
    tempn=ws.Cells(ii,1).Text
    tempm=ws.Cells(ii,2).Text
    disp.append(str(tempn))
    forc.append(tempm)
    ii=ii+1
disp.pop()
forc.pop()

excel.Application.Quit()            ## Close Only the Excel file.
excel.Quit()                        ## Close entire Excel 

ment=0
mytext=["RMORE,"]
spring = DataModel.GetObjectsByName("Longitudinal - Solid To Solid")[0]
cs= spring.AddCommandSnippet()
cs.AppendText("et,_sid,39\n")
cs.AppendText("keyopt,_sid,4,1\n")
cs.AppendText("R," +"_sid," +str(disp[0]) + "," + str(forc[0]) +"," +str(disp[1]) + "," + str(forc[1]) +"," + str(disp[2]) + "," + str(forc[2]) + "\n")
ii=3
while ii <=len(disp)-1:
    if jj<4:
        mytext[ment]=mytext[ment] +str(disp[ii]) + "," + str(forc[ii]) +","
        jj=jj+1
    else :
        jj=1
        ment=ment+1
        mytext.append("RMORE,")
        ii=ii-1
    ii=ii+1
for line in mytext:
    cs.AppendText(line+"\n")