A simply-supported thick square plate is 10.0 m x 10.0 m and its thickness is 1 meter.

Case Description

A simply-supported thick square plate is 10.0 m x 10.0 m and its thickness is 1 meter. Determine the 4th through 10th natural frequencies.

Geometry

• L = 10 m
• t = 1 m

Study Type

• Modal Frequencies

Mesh Parameters

• Element Type = Solid, Tetrahedral
• Element Order = Parabolic
• Mesh Size = 1.67 m absolute (six across length of plate)
• Adaptive Mesh Refinement: None

Material Properties

• Modulus of elasticity = 2.0 X 105 MPa
• Density = 8000 kg/m3
• Poisson's ratio (v) = 0.3

Constraints

• Z direction constrained at all bottom edges

Comparison of Results

The first three modes are rigid-body modes. The 4th through 10th frequencies corresponds to out-of-plane modes.

Natural frequencies	F4	F5	F6	F7	F8	F9	F10
NAFEMS	45.897 Hz	109.44 Hz	109.44 Hz	167.89 Hz	193.59 Hz	206.19 Hz	206.19 Hz
Fusion Value	44.61 Hz	108.5 Hz	108.8 Hz	165.8 Hz	193.7 Hz	202.9 Hz	207.0 Hz
% Difference	-2.80 %	-1.59 %	-0.86 %	-1.24 %	0.057 %	-1.60 %	0.39 %

Reference

NAFEMS Publication Test No. FV52, The International Association for the Engineering Analysis Community, "NAFEMS Background To Benchmarks", G.A.O Davies, R.T. Fenner, R.W. Lewis, June, 1992.