Dynamic Test Method for the Evaluation of Butt Welds

Additional Information - Posters # 1998 Gothenburg

When butt welds fail in servicc it is normal to find that the initiation site of the fracture occurs at the point where the roll bead attaches to the main body of the pipe. The ratio of hoop stress to longitudinal stress for 'thin walled' pipe is approximately 2 : 1 and so it is more likely that these transverse service failures result from the combined effect of the service load and extraneous third party loading. Attempts to measure the behaviour of welds by using il~temal pressurisation are frustrated by this inherent load ratio, but still further by the fact that the weld bead provides additional circumferential reinforcement. If an attempt is made to accelerate the failure process by applying high internal pressurisation the saniple fails in the body of the pipe and not at the weld. This paper describes how dynamic loading has heen applied to both a pressurised and non-pressurised system to cause failure to occur at the weld beadlpipe wall interface in a way and with a fracture morphology analogous to that seen in service.

Please note that the whole article content is available on PPCA website onlySource : 1998 Gothenburg


Related papers

INCREASING HDPE BUTT FUSION PRODUCTIVITY BY OPTIMIZING THE COOL TIME BASED ON THERMAL MASS CHARACTERISTICS WITHOUT COMPROMISING JOINT STRENGTH

Author(s) : Amanda Hawkins, Jason Lawrence, Xiangli Meng 2018 Las-Vegas

High Density Polyethylene pipes are used in various applications due to the material’s superior chemical resistance, pressure capability, and ductility. For the material to perform at the optimal design criteria, the connections and fabrications must be fused using repeatable procedures that specify proper fusion...

POLYOLEFIN PIPES IN THE MIDDLE EAST- TODAY AND TOMORROW

Author(s) : Robert Lawrence, Mohana Murali 2018 Las-Vegas

The paper covers the growth of the polyethylene pipe sector in the Middle East from the 90s to the present. The initial slow uptake was related to ignorance of the material properties from the end users through to designers and installers. Recently the Middle East has become a world leader in the use of ever larger...

PIPE BURSTING ASBESTOS CEMENT PIPE IN COMPLIANCE WITH ENVIRONMENTAL PROTECTION AGENCY’S REGULATIONS AND SCIENTIFIC DATA COLLECTION ON THE PROJECT

Author(s) : Edward Alan Ambler, John Matthews, Lawrence Pultz, Ryan Stowe 2016 Berlin

This paper summarizes the design and implementation of the largest asbestos cement pipe bursting project performed to date within the United States. The paper also presents regulatory information required to properly track and document an asbestos cement pipe bursting project while meeting the National Emissions...

Butt Fusion in Logistically Challenging Jobsites

Author(s) : Jason A. Lawrence 2014 Chicago

Traditional butt fusion technology relies upon high power electrical sources such as power grids or site generators to provide the power for facing operations, heating operations, and the required machine movements. Some jobsites, however, pose special challenges, such as remote location and the lack or unreliability...

Introducing PO Pipes into the Middle East – Rising to the Technical Challenges

Author(s) : Robert J Lawrence 2014 Chicago

In the Middle East the environment is exceptionally aggressive for all pipe systems due to the high temperatures, the high groundwater table and the very saline soils. This obviously makes metallic pipes and cement based pipes high risk options but it also poses challenges for polyolefin (PO). In this paper the author...

STRESS ANALYSIS OF ELBOWS AND TEES OF PLASTIC PIPES USING FINITE ELEMENT ANALYSIS

Author(s) : A.C. Seibi, R. J. Lawrence, R. Jepson and Z. Tarik 2012 Barcelona

Design and fabrication of plastic pipe fittings have been governed by ISO 4427 where pressure derating factors of 0.8 and 0.5 have been used respectively for fabricated elbows and tees. However, laboratory data generally indicate that these derating factors are very conservative. Moreover, the design of distribution...

Resistance of PVC-U and PVC-M to Cyclic Fatigue

Author(s) : Whittle, Teo 2004 Milan

PVC-U and PVC-M pipes may be used in applications where they are subjected to cyclic pressures generated by the operation of pumps and valves. It is therefore important that the pipe material’s response to cyclic loading is quantified and that pipelines are designed and operated within the material’s established...

Measurement of Scores and Scratches on PE Pipes used in No-Dig Operations

Author(s) : Stokes, Potter, Muhl, Acland 2001 Munich

Research indicates that the scoring of polyethylene pipes that can occur during directional drilling operations in clay soils will not exceed the specification of 10% pipe wall scoring depth. However, a higher level of damage may occur in different types of soils from these operations. Further investigations from...

Optimising the Performance of Ferrule Straps with PVC Pipes

Author(s) : Stokes, Potter, Metcalfe, Bowman, Graham 2001 Munich

The response of three different forms of polyvinyl chloride (PVC) pipe has been explored when the pipes had attached to them ferrule straps. Pipes were subjected to fluctuating internal pressure (fatigue) loading at 20°C, and the lifetimes, location of any failures and the types of failures recorded. Tests were made...

A New Approach to the Instrumented Falling Weight Method

Author(s) : Lawrence, Rasbash, Potter, Teo 1998 Gothenburg

Structured wall plastic pipe has been in existence for many years, but there remains a need for an appropriate method for assessing the durability of their comparatively thin walls in actual service. In normal operation this has not manifest itself as a problem, but the fact that damage can be sustained during...

Members of the Association

BOREALISBOROUGEINEOS O&PIRPCKorea Petrochemical IND. Co., LTDLyondellBasellPetroChina Dushanzi Petrochemical CompanyPRIME POLYMERSABICSCG Chemicals & Thai PolyethyleneSinopecTASNEE
TOP