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.

• Cryogenic
• Fatigue
• Flange leakage
• Vibration

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.

 

Cryogenic Buckling

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.

Fatigue

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 curve.

 

Fatigue

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.

 

Hydrotest

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.

Saddles Supports

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.