F-07 (3D Frame Vibration) |
  
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F-07 (3D Frame Vibration) |
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Objective
To verify the behavior of the beam element in large 3D frame vibration
Problem Description
A 3D single story frame structure with a length = 27.25 in, width = 17.25 in and height = 18.625 in, is fixed at the bottom. Nodes are inserted at 8.625 in from the top corner nodes along the length, width and height.
Material: E = 2.79e+007 lb/in2, v = 0.3
Sections: A = 1.07453 in2, Ay = Az = 0.537266 in2, Iz = Iy = 0.665747 in4, J = 1.33149 in4
Masses: Corner nodes = 0.0253816 lb-sec2/in (X, Y and Z directions)
All other nodes except supports: 0.00894223 lb-sec2/in (X, Y and Z directions)
Finite Element Model
18 beam elements
Model type: 2D Frame (shear deformation included)
Results
The first 10 natural frequencies are compared with another independent program Larsa [Ref. 1].
Units: Hz
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ENERCALC 3D |
Larsa |
Mode 1 |
111.2088 |
111.21 |
Mode 2 |
115.7695 |
115.77 |
Mode 3 |
137.1354 |
137.13 |
Mode 4 |
215.7477 |
215.74 |
Mode 5 |
404.1712 |
404.16 |
Mode 6 |
422.5145 |
422.50 |
Mode 7 |
451.4604 |
451.45 |
Mode 8 |
548.8147 |
548.80 |
Mode 9 |
733.3148 |
733.29 |
Mode 10 |
758.2787 |
758.26 |
Comments
The results given by ENERCALC 3D are very close to the referenced values.
