Page 311 - Finite Element Modeling and Simulations with ANSYS Workbench

296 Finite Element Modeling and Simulation with ANSYS Workbench

8.6 The following figure shows a simple bracket made of structural steel with Young’s
modulus E = 200 GPa, Poisson’s ratio ν = 0.3, and density ρ = 7850 kg/m . The
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bracket has a front face profile shown below and an extrusion depth of 12 cm.
A through-hole of diameter 1.5 cm is centered on the bracket’s flat ends, one on
each side. Suppose that the bracket is fixed on the bottom, and is subjected to a
harmonic pressure load of magnitude 1000 N/cm on the top face. Use a solid
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model to compute:
a. The first five natural frequencies and the corresponding normal modes
b. The frequency response of the z directional deformation (along the front face
normal direction) of the front face of the bracket under the given harmonic
load

Load
All dimensions are in
centimeters.
10.000
1.500
1.500
R3.000
1.500

8.000 1.500

12.000
1.500
8.000

8.7 The following figure shows an L-shaped bracket made of structural steel with
Young’s modulus E = 200 GPa, Poisson’s ratio ν = 0.3, and density ρ = 7850 kg/m .
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The 4 cm thick L-shape with a cross-section profile shown in the figure is rig-
idly connected to a rectangular base of size 3 cm × 8 cm × 1 cm. Suppose that
the bracket is fixed on the right end at the base. A harmonic pressure of mag-
nitude 100 N/cm is applied on the protruding surface of the L-shape as shown
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below. Using the FEA, compute:
a. The first five natural frequencies and the corresponding normal modes
b. The frequency response of the y directional deformation (along the load
direction) of the bracket’s protruding top face under the given harmonic
load