Fixed Beam Under Gravitational Load

Overview

The aim of this test case is to validate the following functions:

• gravitational load

The simulation results of SimScale were compared to the analytical results derived from [Roark]. The meshes used in (A) and (B) were created with the parametrized-tetrahedralization-tool on the SimScale platform and then downloaded. Both meshes were then rotated and uploaded again. These were used in case (C) and (D). With this method we achieve the exact same mash for the rotated and non-rotated case.

Import validation project into workspace

Geometry

The beam has a cross section A of 0.05 x 0.05 m² and a length = 1.0 m.

Analysis type and Domain

Tool Type : CalculiX/Code_Aster

Analysis Type : Static

Mesh and Element types :

Case	Mesh type	Number of nodes	Element type
(A)	linear tetrahedral	6598	3D isoparametric
(B)	quadratic tetrahedral	44494	3D isoparametric
(C)	linear tetrahedral	6598	3D isoparametric
(D)	quadratic tetrahedral	44494	3D isoparametric

Simulation Setup

Material:

• isotropic: E = 205 GPa, ν = 0.3, ρ = 7870 kg/m³

Constraints:

• • Face ABCD is fixed: dx=dy=dz=0.0

Loads:

• • • Case (A) and (B): gravitational load g = 9.81 m/s² pointing in the negative z-direction: (0,0,-1)
    • Case (C) and (D): gravitational load g = 9.81 m/s² now rotated +45° around the x-axis: (0,0,-1)

Reference Solution

$$w_a l= V \rho g$$

$$w_a = 193.01175 \frac {N} {m}$$

$$I=\frac{bh^3}{12}=5.20833 \cdot 10^{-7} m^4$$

$$y(l) = -\frac{w_a l^4}{8 E I} = -2.2597 \cdot 10^{-4} m$$

The equation[1] used to solve the problem is derived in [Roark]. In equation[1] the gravitational load is converted in a line load w_a.

Results

Comparison of the displacement at the free end in the direction of the gravitation vector.

Comparison of the displacements at the free end in [m]¶

Case	Tool Type	[Roark]	SimScale	Error
(A)	CalculiX	-2.2597E-4	-2.1340E-4	5.56%
(B)	CalculiX	-2.2597E-4	-2.2559E-4	0.17%
(C)	CalculiX	-2.2597E-4	-2.1340E-4	5.56%
(D)	CalculiX	-2.2597E-4	-2.2560E-4	0.16%
(A)	Code_Aster	-2.2597E-4	-2.1340E-4	5.56%
(B)	Code_Aster	-2.2597E-4	-2.2559E-4	0.17%
(C)	Code_Aster	-2.2597E-4	-2.1340E-4	5.56%
(D)	Code_Aster	-2.2597E-4	-2.2560E-4	0.16%

References

[Roark]

(1, 2, 3) (2011)”Roark’s Formulas For Stress And Strain, Eighth Edition”, W. C. Young, R. G. Budynas, A. M. Sadegh

Last updated: June 22nd, 2020

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part of: Large Eddy Simulation: Flow over a cylinder