How to extract the pressure loads from .cdb file

[Saivellampati]

I have a cdb file which is having pressure loads. In mapdl we have a method Mapdl.flist() which is giving only force loads. Can someone explain how to get pressure loads information from this Mapdl.
I am loading the cdb file by following process.

from ansys.mapdl.core import Mapdl
filedata = mapdl.input("test_1.cdb")

[mikerife]

Hi @Saivellampati
Where did the cdb file come from and are the pressure value(s) directly applied or applied by a table array? Or would you not necessarily know this before obtaining/loading the cdb file?
Mike

[mikerife]

@Saivellampati one other consideration is that a pressure can be applied to nodes or to a face on an element. Or an edge if a line element. Anyway the point is that there are different MAPDL commands to define a nodal pressure load versus a element face load. And so different commands, SFLIST and SFELIST, to list them. Then there is the value; if the value is done by a table then the preprocessor will not list the value, just the table name. Only after solving, and hence transferring the applied pressure value from the table to the FEM, would there be a value.

Mike

[germa89]

Hi @Saivellampati, can you share the CDB file?

[Saivellampati]

Hi @germa89, file is attached

test_1.zip

[germa89]

HI @Saivellampati

the SF and SFE loads post processing commands are not supported yet.

However you can do some string processing by doing (from #772):

# turning off printing after each page break
mapdl.post1()
mapdl.header('OFF', 'OFF', 'OFF', 'OFF', 'OFF', 'OFF')
nsigfig = 10
mapdl.format('', 'E', nsigfig + 9, nsigfig)
mapdl.page(1E9, '', -1, 240)

#
sfe = mapdl.sfelist()

sfe object will be:

 LIST ELEMENT SURFACE LOAD PRES FOR ALL SELECTED ELEMENTS

 *** MAPDL - ENGINEERING ANALYSIS SYSTEM  RELEASE 2025 R1          25.1BETA ***
 Ansys Mechanical Enterprise                       
 00000031  VERSION=LINUX x64     03:54:14  AUG 07, 2024 CP=      4.626

 test--____ (A5)                                                               




 ELEMENT  LKEY     FACE NODES     REAL       IMAGINARY
     912     1         113       0.0000      0.0000                   
                       112       0.0000      0.0000    
                       102       0.0000      0.0000    
                       102       0.0000      0.0000    
     913     1         152       0.0000      0.0000                   
                       151       0.0000      0.0000    
                       128       0.0000      0.0000    
                       128       0.0000      0.0000    
     914     1         101       0.0000      0.0000                   
                       152       0.0000      0.0000    
                       128       0.0000      0.0000    
                        95       0.0000      0.0000    
     915     1         101       0.0000      0.0000                   
                        95       0.0000      0.0000    
                       143       0.0000      0.0000    
                       144       0.0000      0.0000    
     916     1          95       0.0000      0.0000                   
                       128       0.0000      0.0000    
                       142       0.0000      0.0000    
                       143       0.0000      0.0000    
     917     1         101       0.0000      0.0000                  

then you can workout some scheme to parse the text like:

for i, line in enumerate(sfe.splitlines()):
    if "LEMENT" in line and "LKEY" in line and "FACE NODES" in line:
        results = sfe.splitlines()[i+1:]

import re

lines = []

for line in results:
    line = re.findall(r"(\d+\.*\d*)", line)


    if len(line) == 5: # begining group
        group = line[:2]
        data = line[2:]

    elif len(line) == 3:
        data = line
    else:
        raise Exception("weird line")
    
    lines.append([*group, *data])

array = np.array(lines).astype(float)

which gives you array as:

array([[9.120e+02, 1.000e+00, 1.130e+02, 0.000e+00, 0.000e+00],
       [9.120e+02, 1.000e+00, 1.120e+02, 0.000e+00, 0.000e+00],
       [9.120e+02, 1.000e+00, 1.020e+02, 0.000e+00, 0.000e+00],
       ...,
       [1.009e+03, 3.000e+00, 2.333e+03, 0.000e+00, 0.000e+00],
       [1.009e+03, 3.000e+00, 2.332e+03, 0.000e+00, 0.000e+00],
       [1.009e+03, 3.000e+00, 2.316e+03, 0.000e+00, 0.000e+00]])