Analysis Type:

Dynamic Frequency

Model Type:

3D

Comparison:

ANSYS No. 90

Reference:

Thomson, W. T. Vibration Theory and Applications. PrenticeHall, Inc., Englewood Cliffs, N. J., 2nd Printing, 1965.

Description:

Determine the response of the twomassspring system when excited by a harmonic force acting on mass at point B.

Element Type:  mass (2), spring (3)  
Units:  IPS  
Dimensions:  spring length: 1 (arbitrary)  
Mass Properties:  
M: 0.5  Mxx: 0  Mxy: 0  Mxz: 0 
Myy: 0  Myz: 0  Mzz: 0  
Spring Properties: (extensional stiffness)  
Kxx: 200  Kxy: 0  Kxz: 0  
Kyy: 0  Kyz: 0  Kzz: 0 
Constraints:  Location:  Degrees of Freedom: 
constraint1  placed on points A and D placed on points B and C  fixed in all DOF fixed in all DOF except TransX 
Loads:  Location/Magnitude:  Distribution:  Spatial Variation: 
load1  placed on point B: FX = 200  N/A  N/A 
Loc  Theory  ANSYS  Structure1  % Diff  
Frequency = 1.5 Hz Disp/phase at B, C (m=dispx_2, 3/ phase_2, 3)  point B  0.8227/0  0.8227/0  0.8227/0  0% 
point C  0.4627/0  0.4627/0  0.4627/0  0%  
Frequency = 4.0 Hz Disp/phase at A, B (m=dispx_2, 3/ phase_2, 3)  point B  0.5115/ 180  0.5115/ 180  0.5115/180  0% 
point C  1.2153/ 180  1.2153/ 180  1.215/180  0%  
Frequency = 6.5Hz Disp/phase at A, B (m=dispx_2, 3/ phase_2, 3)  point B  0.5851/ 180  0.5851/ 180  0.5851/180  0% 
point C  0.2697/0  0.2697/0  0.2697/0  0%  
Convergence %: 0% on Frequency & Local Disp  Max P: 1  No. Equations: 2 
Analysis Type:  Dynamic Frequency 
Model Type:  Beam 
Comparison:  NAFEMS Benchmark 
Reference:  Selected Benchmarks for Forced Vibration, Report No. E1261/R002 Issue 03.2/9 February 1989 , pp. 17. Test 5H 
Description:  Determine response of simple supported square section beam when excited by Harmonic force uniformly distributed over beam. 
Element Type:  Square Beam  
Units:  MKS  
Dimensions:  L: 10.0, a =2  
Material Properties:  Mass Density: 8000 Young's Modulus: 2e11  Poisson's Ratio: 0.3 
Constraints:  Location:  Degrees of Freedom: 
Placed on point A Placed on point B :  Fixed in TransX, TransY, TransZ and Rotation Rx Fixed in TransY and TransZ 
Loads  Details 
Force Fy = 1e6 N/m, damping = 2 % in all 16 modes used, frequency range 0 to 60 Hz 
NAFEMS  Structure  % Diff  
Peak Displacement at midspan (mm))  13.45  13.5129  0.467 
Frequency (Hz)  42.65  42.6002  0.116 
Analysis Type:  Dynamic Frequency 
Model Type:  3D 
Comparison:  NAFEMS Benchmark 
Reference:  Selected Benchmarks for Forced Vibration, Report No. E1261/R002 Issue 03./ 9 th February 1989, pp 23. Test 13H 
Description:  Determine response of simple supported thin square plate when excited by Harmonic force uniformly distributed over plate. 
Element Type:  Shell  
Units:  MKS  
Dimensions:  L: 10.0, thickness: 0.05  
Material Properties:  Mass Density: 8000 Young's Modulus: 2e11  Poisson's Ratio: 0.3 
Constraints:  Location:  Degrees of Freedom: 
Placed on edges AD and BC : Placed on edges AB and DC :  fixed in TransY, TransZ , RotX, and RotZ fixed in TransX, TransZ , RotY, and RotZ 
Loads  Details 
Force Fy = 100 Pa , damping = 2 % in all 16 modes used, frequency range 0 to 4.16 Hz 
NAFEMS  Structure  % Diff  
Peak Displacement at centre of plate (mm)  45.42  45.4466  0.0585 
Frequency (Hz)  2.377  2.37603  0.0408 