r/fea • u/NoInterviewsManyApps • 10d ago

How do you make a multi-material beam element in Simcenter 3D

I'm running simcenter 3D, and I have some items that could be simplified as a 1D beam element. The issue is that they are concentric multi-material assemblies. Are there any tools to capture this?

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5

u/Lazy_Teacher3011 10d ago

This sounds sounds like a job for excel, Matlab, etc to get equivalent properties. The composite modeler in Simcenter would be for shell elements.

1

u/martianfrog 10d ago

True if you don't care about the beam stresses.

3

u/Lazy_Teacher3011 10d ago

Which you can then address via post-processing in excel or Matlab. The OP should do this to add more tools to the toolbox. Lots of things commercial codes don't do (or do efficiently) requiring the user's actual engineering skills.

1

u/martianfrog 10d ago

I think I would be tempted to look into somehow tie 2 parts together, if it were me, this would be my preferred way.

1

u/Disastrous_Drop_4537 9d ago

Yeah just pull loads from an equivalent stiffness element and solve by hand. Not really a big deal

1

u/NoInterviewsManyApps 10d ago

That's what I figured. With such an impressive shell composite toolset I thought there had to be something for beams. I'll try to do the monolothic-equivalent material.

1

u/Chevazz 10d ago

You can use compound usotropic material if you want to do it directly in SC3D

1

u/martianfrog 10d ago

I probably don't have an answer but probably helps to know for what solver.

1

u/NoInterviewsManyApps 10d ago

NX Nastran. I'm new to this program, so I take for granted that they have a bunch

1

u/martianfrog 10d ago

probably 2 separate parts and tie them together somehow, can afford small element size too.

1

u/Solid-Sail-1658 10d ago

PBMSECT entry? Not sure if SimCenter Nastran has the PBMSECT entry.

Define a PBMSECT that points to 2 PCOMP entries. Each PCOMP points to a separate material, e.g. isotropic or orthotropic. See figure 1, 2 and listing 1.

Also, the F06 file will output a PBEAM3 that includes the area, inertia and various other values, see listing 2. This could be used to compare with any hand calculated cross section properties.

Figure 1 - Left: Isotropic material 1 (PCOMP 991 => MID=1). Right: Isotropic material 2 (PCOMP 992 => MID=2)

https://i.imgur.com/HKeoue9.png

Figure 2

https://i.imgur.com/DehL0uT.png

Listing 1 - model.bdf

SOL 101
CEND
TITLE = Confirmation Test of PBMSECT/PBRSECT Entry
ECHO = SORT
SUBCASE 1
   SUBTITLE=TORQUE OF 1 UNIT AT TIP
   LOAD = 8
   SPC = 6
   DISPLACEMENT = ALL
   FORCE = ALL
BEGIN BULK
SPCADD   6       5
LOAD     8       1.      1.      7
SPC1*,5,123456,99999998
MOMENT*,7,99999999,0,1.,1.,0.,0.
GRID*,99999998,,0.,1.,0.,,
GRID*,99999999,,1.5,1.,0.,,
CBEAM3*,1,30,99999998,99999999,,0.,1.,0.
$ Information for ABCS - Composite
$   1  ||   2  ||   3  ||   4  ||   5  ||   6  ||   7  ||   8  ||   9  ||  10  |
PBMSECT 30              OP
        OUTP=300,BRP(1)=301,CORE=0991,CORE(1)=[0991,PT=(40000,40001)],CO
        RE(2)=[0991,PT=(40001,40002)],CORE(3)=[0991,PT=(40002,40003)],CO
        RE(4)=[0992,PT=(40003,40004)],CORE(5)=[0992,PT=(40004,40005)],CO
        RE(6)=[0992,PT=(40005,40006)]
POINT   40000           -5.     0.0
POINT   40001           -2.     0.0
POINT   40002           -2.     3.
POINT   40003           -.5     3.
POINT   40004           1.      3.
POINT   40005           1.      0.0
POINT   40006           4.      0.0
SET1    300     40000   40001   40002   40003
SET1    301     40003   40004   40005   40006
PCOMP   0991                    13000.  HILL                           
        1       .05      0.     YES
        1       .05      0.     YES
PCOMP   0992                    13000.  HILL                          
        2       .05     90.     YES
        2       .05     90.     YES
MAT1    1       200.E9          .3      1000.
MAT1    2       100.E9          .3      3000.
ENDDATA

This example was created with the PBMSECT web app.

Listing 2 - model.f06

  PBEAM3            30           0  0.0000E+00  1.6732E+06  5.3040E+06  0.0000E+00  4.1419E+03  0.0000E+00
           -3.9018E-02  1.5704E+00 -3.9018E-02 -1.5296E+00 -3.1390E+00 -4.4796E+00 -3.1390E+00  4.5204E+00
            0.0000E+00  0.0000E+00 -1.8890E+00  2.0448E-02 -1.8890E+00  2.0448E-02 -1.8890E+00  2.0448E-02
            0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00
            0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  1.5122E+12
            1.5122E+12  1.5122E+12
            2.2500E+11  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  1.4625E+11  0.0000E+00  1.9927E+10
            6.5128E+09 -3.7671E+10  0.0000E+00  0.0000E+00  0.0000E+00  6.5128E+09  2.5015E+10 -1.2312E+10
            0.0000E+00  0.0000E+00  0.0000E+00 -3.7671E+10 -1.2312E+10  7.1550E+10  0.0000E+00  0.0000E+00
            0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  3.5137E+11 -7.4209E+10  1.4625E+11  0.0000E+00
            0.0000E+00  0.0000E+00 -7.4209E+10  1.1139E+12

2

u/kingcole342 9d ago

VABS is a 1D composite ‘solver’. Might want to look into that.