Description
A structure is consisted of an I-section beam and two tube trusses. The structure contains several imperfections and it is loaded by the force Fz. The problem is described by the following set of parameters. The self-weight is neglected in this example. Determine the deflections uy and uz and axial rotation φx at the endpoint (Point 4). The verification example is based on the example introduced by Gensichen and Lumpe (see the reference).
| Material | Steel S355 | Modulus of Elasticity | E | 210000.000 | MPa |
| Shear Modulus | G | 81000.000 | MPa | ||
| Geometry | Structure | Section 1 Length | L1 | 4.000 | m |
| Section 2 Length | L2 | 4.000 | m | ||
| Section 3 Length | L3 | 2.500 | m | ||
| Truss Support Position | a | 2.500 | m | ||
| Imperfections | Point 2 | ey2 | -40.000 | mm | |
| Point 4 | ey4 | 12.500 | mm | ||
| I-profile | Height | h | 400.000 | mm | |
| Width | b | 180.000 | mm | ||
| Web Thickness | s | 10.000 | mm | ||
| Flange Thickness | t1 | 14.000 | mm | ||
| Tube | Outer Diameter | D | 60.300 | mm | |
| Wall Thickness | t2 | 5.000 | mm | ||
| Load | Force | F | 14.000 | kN | |
| Eccentricity | eFy | 20.000 | mm | ||
| eFz | -193.00 | mm | |||
Analytical Solution
Analytical solution is not available. Results from software S3D are taken as reference.
RFEM and RSTAB Settings
- Modeled in RFEM 6.06
- The element size is lFE= 0.020 m
- Isotropic linear elastic material model is used
- The number of increments is 10
- Large Deformation Analysys is used
- The problem is modeled both by members and a combination of members and surface elements
Results
Two modeling techniques are used in RFEM 6. First, the I-section is modeled as a beam with imperfections and tubes as trusses (only N). Second, the tubes are trusses while the I-section beam is modeled by means of plates, considering the given imperfections. A fixed support at Point 1 is created by rigid line supports.
Results
| Quantity | S3D | RFEM 6 - Members | Ratio | RFEM 6 - Members and Plates | Ratio |
| uy [mm] | 14.800 | 16.300 | 1.101 | 15.900 | 1.074 |
| uz [mm] | 16.900 | 18.000 | 1.065 | 17.800 | 1.053 |
| φx [mrad] | 237.000 | 242.200 | 1.022 | 254.400 | 1.073 |
