Paulin Research Group (PRG) is dedicated to understanding engineering principles
for our areas of interest. Our research efforts serve to provide essential
benchmarks for our software products. Research projects are identified and the scope
of the projects are defined to coincide with industrial applications. Examples
of our areas of interest are listed below.
- Flange leakage
Active Research Projects
Axially Constrained Pipe Buckling
Buckling due to internal pressure in an axially constrained tube is a phenomena
that can effect long pipelines on the seabed and some long GRE/FRP pipelines. Tests
using rubber, copper and GRE pipe from Future Pipe Inc are now underway, and are
being conducted in cooperation with Dynaflow Engineering.
Buried Piping in Soil
PRG is running a series of lateral and axial load soil tests comparing the American
Lifelines Alliance method against the Peng, CAESAR and B31.1 methods. Soils tested
are sand, clay, and mixtures. Virgin soil from the Freeport LNG facility is also
being tested for stiffness properties.
PRG is preparing a paper that demonstrates certain cryogenic properties of carbon
steel welds and plate. Fillet welds in flat plates, charpy specimens, core pipe
jacket specimens (similar to LNG pipe-in-pipe systems), and 505 tensile specimens
(notched and un-notched) are included in the test. The purpose of the test is to
evaluate the level of containment offered by carbon steel in a cryogenic environment.
This work is conducted collaboratively with Mr. Bob Robleto from KBR.
PRG is heavily involved in understanding fatigue phenomema in piping and pressure
vessel components subjected to pressure and thermal loads. The state of the industry
is to use stress indexes based on a relatively small number of fatigue tests.
Markl Fatigue Testing
PRG lab generation of a load-deflection curve for use in "Markl" type fatigue testing.
Loads and deflections are measured to generate a curve that describes the test
components reaction to loading. During the fatigue test, a specified deflection
was repeatedly applied. The actual load can then be estimated from the load-deflection
The "Markl" test rig with a horizontal vessel shown below is in place for an axial fatigue test
of the support saddle and shell. An axial load is applied to the vessel to simulate
sloshing or other events that would generate axial forces on the support saddles.
This test was used to verify the NozzlePRO approach to saddle design.
The Ammonia Storage Vessel Above was strain-gaged during hydro for verification of "Zick"
type stresses predicted using NozzlePRO. PRG also load-tested the manway located in the
elliptical head. Other testing included axial loading of the support saddles to verify
saddle stresses predicted in NozzlePRO.
RTJ Flange Joint Test
Flange joints are subjected to cyclic internal pressure service to measure groove
distortion. This research is essential in understanding flange connection effectiveness.
The tests support the AxiPRO software program.
Horizontal piping and vessels are supported with saddle supports commonly designed
using a method developed by L. P. Zick and documented in his paper published in 1951.
While the method is useful in designing for vertical load and includes the effects
of ovalization of vessel over the horns of the saddles, the method does not address
laterial and axial loading common in industrial applications.