Analysis of pipelines
Stress analysis of pipelines is solved using the program PPS_GaP. The
program is based on original algorithms developed for in the National institute
for machine design in Prague from year 1965 to 1989. The software was intended
for calculations of domestic (Czechoslovak) thermal plant lifetime.
During the years from 1989 to 1995, the code was translated from the language FORTRAN
to language Borland C++. This version provides GUI for interactive work on a PC.
The program PPS_GaP calculates working stress of a pipeline with
respect to the stress categorisation according to the U. S. code ASME BPV, Sec.
III, Div. 1.
It makes load separation into:
- internal pressure
- dead load and other permanent external load
- thermal expansion
Stress components are divided into:
Calculated working stresses are check in categories:
- primary membrane stress (internal pressure, dead load)
- primary membrane + bending stress (internal pressure, dead load)
- secondary membrane + bending stress (thermal expansion)
- total load
The allowable stress is derived from the basic value of the axial stress
valid for primary membrane stress. The effective stress
(stress intensity) can be calculated according to the von Mises energy
hypothesis or according to the maximum shear hypothesis (Tresca criterion).
Besides a calculation according to the code ASME BPV, Sec. III, Div. 1,
part "Detailed Analysis", the program allows to switch to the calculation
modes according to the codes ASME
B31.1 and ASME B31.3.
The program determines the stress state in straight parts and elbows of
pipelines. The stress state in T-pieces and similarly shaped bodies is
calculated using another program based of FEM with 3D elements.
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