Description
A thin plate is fixed on one side (φz=0) and loaded by means of the distributed torque on the other side. First, the plate is modeled as a planar surface. Furthermore, the plate is modeled as one-quarter of the cylinder surface. The planar model's width is equal to the length of one-quarter of the circle of the curved model. The curved model has thus almost equal torsional constant J as the planar model. Determine the maximum rotation of the plate φz,max for both geometrical models and compare the results using both the Kichhoff and the Mindlin plate theory.
Material | Steel | Modulus of Elasticity | E | 210000.000 | MPa |
Poisson's Ratio | ν | 0.300 | - | ||
Geometry | Curved Model Radius | r | 100.000 | mm | |
Planar Model Width | s | 157.080 | mm | ||
Plate Thickness | h | 200.000 | mm | ||
Plate Height | t | 3.000 | mm | ||
Load | Distributed Torque | m | 1268.720 | Nm/m |
Analytical Solution
The torsional constant for the planar plate (rectangular cross-section) can be calculated according to the the following formula:
Considering the same width of the planar and curved plate the identical torsional constant can be used. The width of the planar plate is the same as length of one quarter of the circle of the curved model: s=πr/2. The torsional constants of the planar plate and curved plate are compared also using program SHAPE-THIN: Jp=1396,710 mm4, Jc=1392.670 mm4. Using torsional constant, which is calculated in above mentioned formula, the maximum rotation on the top of the plate (z=h) can be determined as follows:
RFEM Settings
- Modeled in RFEM 5.26 and RRFEM 6.06
- The element size is lFE= 0.002 m
- Geometrically linear analysis is considered
- The number of increments is 5
- Plate entity is used
- Quadrangular elements are used
Results
Model | Analytical Solution | RFEM 6 | RFEM 5 | ||
φz,max [°] | φz,max [°] | Ratio [-] | φz,max [°] | Ratio [-] | |
Planar, Kirchhoff | 20.000 | 20.163 | 1.008 | 20.163 | 1.008 |
Curved, Kirchhoff | 20.163 | 1.008 | 20.163 | 1.008 | |
Planar, Mindlin | 20.666 | 1.033 | 20.733 | 1.037 | |
Curved, Mindlin | 20.797 | 1.040 | 20.863 | 1.044 |