A-01 (Simple 3d-Truss - Model Type 3D Frame) |
  
|
A-01 (Simple 3d-Truss - Model Type 3D Frame) |
|
Objective
To verify the behavior of the 3d frame element with moment releases
Problem Description
A simple 3d truss is supported and loaded as shown below. Nodal X, Y, and Z coordinates are given in parenthesis.
Material properties: E = 200 KN/mm2, ν = 0.3
Section properties: A12 = 2e4 mm2, A13 = 3e4 mm2, A14 = 4e4 mm2, A15 = 3e4 mm2
All members Iz = 1e10 mm4, Iy = 1e10 mm4 , J = 1e10 mm4
Nodal forces applied at node 1: Px = 200 KN, Py = 600 KN, Pz = -800 KN
Finite Element Model
4 beam elements
Model type: 3D Frame & Shell
Moment Releases
The following table shows one way to apply moment releases. Please note that we only apply torsional moment release either (not both) end of a member.
Member Id |
Start oz |
End oz |
Start oy |
End oy |
Start ox |
End ox |
1 |
Released |
Released |
Released |
Released |
Released |
Not Released |
2 |
Released |
Released |
Released |
Released |
Released |
Not Released |
3 |
Released |
Released |
Released |
Released |
Released |
Not Released |
4 |
Released |
Released |
Released |
Released |
Not Released |
Not Released |
Results
The displacements and support reactions are given in [Ref 1].
Units: displacement-mm; reaction-KN
|
ENERCALC 3D |
[Ref 1] |
||||
|
X |
Y |
Z |
X |
Y |
Z |
Displacement @ N1 |
0.1779 |
2.722 |
-0.4865 |
0.1783 |
2.722 |
-0.4863 |
Reactions @ N2 |
-76.39 |
-152.78 |
-305.56 |
-76.4 |
-152.8 |
-305.6 |
Reactions @ N3 |
170.83 |
-113.88 |
-227.77 |
170.8 |
-113.8 |
-227.7 |
Reactions @ N4 |
-470.83 |
-156.94 |
627.77 |
-470.7 |
-156.9 |
627.8 |
Reactions @ N5 |
176.39 |
-176.39 |
705.56 |
176.3 |
-176.3 |
705.5 |
Comments
The results given by ENERCALC 3D are very close to the referenced values. The results in this example using 3D Frame & Shell model with moment releases are identical to those in the previous example using 3D Truss model. It is generally easier and more efficient to use 3D Truss model type if your model contains only truss members as the program will automatically suppress global OX, OY and OZ DOFs. On the other hand, 3D Frame and Shell model type (with proper moment releases) should be used if your model contains both truss and frame members.
Reference
[1]. McGuire, Gallagher and Ziemian, “Matrix Structural Analysis” 2nd Edition, pp104, John Wiley & Sons, Inc., 2000
