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Unformatted text preview: erties
= 5000 ft
OD = 4.5 in = (4.5/12) ft
ID = 3.83 in = (3.83/12) ft
Jo = 29.3 lb-ft-sec2
Ip = 0.0009226 ft4
ANSYS Verification Manual . ANSYS Release 9.0 . 002114 . © SAS IP, Inc. 1–135 VM57 Analysis Assumptions and Modeling Notes
The drill pipe is modeled first using pipe elements (PIPE16) with the subspace solver and then using beam elements
(BEAM4) with the Householder Solver. Young's modulus (E) is calculated as E = 2G (1 + υ)*144 = 4.4928 x 109lb/ft2
and pipe thickness is calculated as (OD - ID)/2.
In the case of beam elements (BEAM4), the polar moment of inertia could have been omitted since it defaults
to IYY + IZZ, both of which must be input.
Twelve torsional master degrees of freedom (MDOF) are selected; one at the collar and eleven along the length
of the pipe. Results Comparison
Target ANSYS Ratio f1, Hz 0.3833 0.3834 1.000 f2, Hz 1.260 1.264 1.003 Beam Elements f1, Hz 0.3833 0.3834 1.000 f2, Hz 1.260 1.264 1.003 Pipe Elements 1. 1–136 Solution recalculated ANSYS Verification Manual . ANSYS Release 9.0 . 002114 . © SAS IP, Inc. VM58: Cent...
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