VM-NR1677-01-2-a

VM-NR1677-01-2-a
NUREG/CR-1677: Volume 1, Benchmark Problem No. 2

Overview

Reference:P.Bezler, M. Hartzman & M. Reich, Dynamic Analysis of Uniform Support Motion Response Spectrum Method, (NUREG/CR-1677), Brookhaven National Laboratory, August 1980, Problem 2, Pages 48-80.
Analysis Type(s):
Modal analysis (ANTYPE = 2)
Spectral analysis (ANTYPE = 8)
Element Type(s):
Elastic straight pipe elements (PIPE16)
Structural Mass element (MASS21)
Input Listing:

Test Case

This benchmark problem contains three-dimensional multi-branched piping systems (refer to Figure 620: FE model of the Benchmark Problem). The total mass of the system is represented by structural mass element (MASS21) specified at individual nodes. Modal and response spectrum analysis is 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.

Figure 620: FE model of the Benchmark Problem

FE model of the Benchmark Problem

Material PropertiesGeometric PropertiesLoading

Pipe Elements:

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

Mass Elements (lb-sec2/in):

(Mass is isotropic)

Mass @ node 1: M = 0.447000518e-01
Mass @ node 2: M = 0.447000518e-01
Mass @ node 3: M = 0.447000518e-01
Mass @ node 4: M = 0.447000518e-01
Mass @ node 5: M = 0.432699275e-01
Mass @ node 6: M = 0.893995859e-02
Mass @ node 7: M = 0.432699275e-01
Mass @ node 8: M = 0.893995859e-02
Mass @ node 9: M = 0.893995859e-02
Mass @ node 10: M = 0.432699275e-01
Mass @ node 11: M = 0.893995859e-02
Mass @ node 12: M = 0.432699275e-01
Mass @ node 13: M = 0.893995859e-02
Mass @ node 14: M = 0.893995859e-02

Straight Pipe:

Outer Diameter = 2.375 in
Wall Thickness = 0.154 in

Acceleration response spectrum curve defined by SV and FREQ commands

Results Comparison

Table 37: Frequencies Obtained from Modal Solution

ModeTargetMechanical APDLRatio
18.7128.7111.00
28.8068.8061.00
317.51017.5071.00
440.37040.3661.00
541.63041.6251.00

Table 38: Maximum Displacements and Rotations Obtained from Spectrum Solve

Result NodeTargetMechanical APDLRatio
UX at node6 0.4610.4611.000
UY at node8 0.0020.0021.006
UZ at node8 0.446 0.4501.009
ROTX at node1 0.0060.006 1.009
ROTY at node90.000 0.000 1.009
ROTZ at node10.0060.0061.00

Table 39: Element Forces and Moments Obtained from Spectrum Solve

ResultTargetMechanical APDLRatio
Element 1
PX(I)555.400558.9871.006
VY(I)108.200109.2741.010
VZ(I)109.300109.2390.999
TX(I)1.6101.62331.008
MY(I)5135.0005182.5571.009
MZ(I)5229.0005228.6021.000
 
PX(J) 555.400558.9871.006
VY(J) 108.800109.2741.004
VZ(J) 109.300109.2390.999
TX(J) 1.610 1.62331.008
MY(J) 276.900279.4131.009
MZ(J)235.100235.1111.000
Element 18
PX(I) 14.00014.0311.002
VY(I) 297.200297.1571.000
VZ(I) 12.28012.3901.009
TX(I) 0.01410.0141.000
MY(I) 47.71048.1411.009
MZ(I) 1480.0001486.0251.004
 
PX(J) 14.00014.0311.002
VY(J) 297.200297.1571.000
VZ(J) 12.28012.3901.009
TX(J) 0.01410.0141.000
MY(J) 60.43060.9361.008
MZ(J)4049.004049.0041.000


Note:  PX (I) and PX (J) = Section axial force at node I and J.

VY (I) and VY (J) = Section shear forces along Y direction at node I and J.

VZ (I) and VZ (J) = Section shear forces along Z direction at node I and J.

TX (I) and TX (J) = Section torsional moment at node I and J.

MY (I) and MY (J) = Section bending moments along Y direction at node I and J.

MZ (I) and MZ (J) = Section bending moments along Z direction at node I and J.

The element forces and moments along Y and Z directions are flipped between Mechanical APDL and NRC results.