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This test lets you check analysis free vibrations results
for a compressor blade in the context of a modal (or frequency) case. You
will use 2D meshes. |
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Reference:
- OLSON,M.D.,LINDBERG,G.M., Vibration analysis of cantilevered
curved plates using a new cylindrical shell finite element, 2nd Conf.
Matrix Methods in Structural Mechanics, WPAFB, Ohio 1968.
- OLSON,M.D.,LINDBERG,G.M., Dynamic analysis of shallow shells
with a doubly curved triangular finite element, JSV, Vol. 19, No 3, pp
299-318, 1971.
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Specifications
Geometry Specifications
Length:
L = 304.8 mm |
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Radius:
R = 609.6 mm |
Thickness:
th = 3.048 mm |
Angle:
A = 28.6479 deg
(or 0.5 rad) |
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Analysis Specifications
Young Modulus (material):
E = 2.0685e+011 N_m2 |
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Poisson's Ratio (material):
ν
= 0.3 |
Density:
ρ
= 7857.2 Kg/m3 |
Mesh Specifications:
11 x 11 nodes |
Restraints:
BC straight edge is free
AD straight edge is clamped |
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Results
The table below presents the frequencies of the first six
modes (mesh specifications: 11 x 11 nodes).
Mode
|
Reference value
[Hz] |
Computed value [Hz] |
Linear triangle
(TR3) |
Parabolic triangle
(TR6) |
Linear quadrangle
(QD4) |
Parabolic quadrangle
(QD8) |
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|
|
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1 |
85.6 |
84.2461 |
82.8426 |
83.6888 |
85.7079 |
2 |
134.5 |
141.824 |
136.908 |
136.16 |
138.555 |
3 |
259.0 |
248.017 |
242.163 |
252.195 |
245.927 |
4 |
351.0 |
341.879 |
333.202 |
337.331 |
340.94 |
5 |
395.0 |
380.636 |
373.174 |
381.633 |
382.989 |
6 |
531.0 |
538.508 |
517.818 |
546.994 |
527.982 |
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To Perform the Test:
The
Free_vibrations_compressor_blade_QD8.CATAnalysis document presents a
complete analysis of this case, computed with a mesh formed of parabolic
and quadrangular elements (QD8).
To compute the case with linear quadrangle (QD4), linear
triangle (TR3) and parabolic triangle (TR6) elements, proceed as follow:
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Open the CATAnalysis document.
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In the Advanced Meshing Tools workbench,
replace the mesh specifications as indicated above.
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In the Generative Structural Analysis
workbench, compute the case.
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