VM-WB-MECH-081

VM-WB-MECH-081
Statically Indeterminate Reaction Force Analysis

Overview

Reference:

Bezler, P., Hartzman, M., & Reich, M. (1980). Dynamic Analysis of Uniform Support Motion Response Spectrum Method (NUREG/CR-1677) (pp. 48-80). Brookhaven National Laboratory.

Solver(s):

Ansys Mechanical

Analysis Type(s):
Modal analysis
Spectral analysis
Element Type(s):
Elastic straight pipe elements
Structural Mass element

Test Case

This benchmark problem contains three-dimensional multi-branched piping systems. The total mass of the system is represented by structural mass elements specified at individual nodes. Modal and response spectrum analyses are performed on the piping model. Frequencies obtained from modal solve and the nodal/element solution obtained from spectrum solve are compared against reference results. The NUREG intermodal/interspatial results are used for comparison.

This benchmark problem is also presented in

VM-NR1677-01-2-a

in the Mechanical APDL Verification Manual.

Figure 106: Schematic

Schematic

Material PropertiesGeometric PropertiesLoading

Pipe Elements:

E = 27.8999 x 106 psi.
Nu = 0.3
Density = 2.587991718 x 10-10 lb-sec2/in4

Mass Elements (lb-sec2/in):

(Mass is isotropic)

Mass @ node 1: M = 0.447000518 x 10-1
Mass @ node 2: M = 0.447000518 x 10-1
Mass @ node 3: M = 0.447000518 x 10-1
Mass @ node 4: M = 0.447000518 x 10-1
Mass @ node 5: M = 0.432699275 x 10-1
Mass @ node 6: M = 0.893995859 x 10-2
Mass @ node 7: M = 0.432699275 x 10-1
Mass @ node 8: M = 0.893995859 x 10-2
Mass @ node 9: M = 0.893995859 x 10-2
Mass @ node 10: M = 0.432699275 x 10-1
Mass @ node 11: M = 0.893995859 x 10-2
Mass @ node 12: M = 0.432699275 x 10-1
Mass @ node 13: M = 0.893995859 x 10-2
Mass @ node 14: M = 0.893995859 x 10-2

Straight Pipe:

Outer Diameter = 2.375 in
Wall Thickness = 0.154 in

Acceleration response spectrum curve defined by SV and FREQ commands.

Results Comparison

ResultsTargetMechanicalError (%)
18.712 8.71210.001
28.806 8.80910.035
317.51017.509-0.006
440.37040.368-0.005
541.63041.6420.029
Results NodeTargetMechanicalError (%)
UX at node60.46186000.46186000.00
UY at node80.00257470.00257470.00
UZ at node80.44659100.44949000.65