A New Approach to the Instrumented Falling Weight Method

Fracture # 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 maintenance operations has highlighted the deficiency. The possibilit) of damage has prompted much debate about how it might occur. It is not the purpose of this paper to pursue this ongoing debate but clearly these procedures are capable of imposing an impact condition on the internal wall of the pipe. To address the problem of determining a pipe's resistance to these practices, it has been suggested by some in the UK Water Industry, that the use of an impact test. already existing as an IS0 standard, might provide an insight. However. this established standard was designed to assess the impact characteristics of flat injection moulded plaques or samples cut from sheet but structured wall pipe products are by their very nature contoured and for this approach to be viable, considerable techrucal difficulties have to be overcome. This paper discusses briefly the need and then outlines an approach that minimises the structural and dynamic problems that can occur when accessing samples that have a complex geometry.

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 Review of the Latest Stage of a Method That Allows the Testing of Large

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

The short term testing of any plastic pipe for its prospective longevity in service is extremely difficult because it requires some accelerated technique which needs to work within or verv close to the normal operatin? strains if extensive creep processes are to be avoided. The problem has now been exacerbated by the...

Dynamic Pressure Testing

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

There is increasing evidence that dynamic testing is a most powerful. if not the only practical, method of evaluating whole plastic pipe for its long term service potential. Indeed in some instances this method is used as the primary indicator of performance in the researcNdevelopmentaI process of these...

Dynamic Test Method for the Evaluation of Butt Welds

Author(s) : Lawrence, Potter, Teo 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...

Product Development Using the Dynamic (Cycle Pressure) Test

Author(s) : Ansell, Lawrence 1998 Gothenburg

Recent years have seen the steadily increasing use of thermoplastics for pipes and fittings for domestic hot and cold water supply and heating installations. Plastic pipe systems, in particular those that incorporate a push-in design offer considerable advantages over conventional pipe systems. However, manufacturers...

A Fracture Consideration of the Sinusoidial Behaviour of Fast Fracture in Plastics Pipes

Author(s) : Lawrence 1995 Edinburgh

Department of Manufacturing Enginineering and Design. University of East London, Dagenham Essex. RM8 2AS. UK. Abstract The phenomenon of rapid crack propagation in a pre-notched plastic pipes that are filled or partially filled with pressurised pas has now k e n incorporated into an indostrial requirement typically I...

Behaviour of notched fatigue data

Author(s) : Lawrence, Potter, Teo 1995 Edinburgh

This paper first outlines the case supporting the use of a fatigue based test method for plastlc pipes. listing the factors that have to be addressed in its use and by reference to a large body of other work justifies its adoption into the pipe industry. It then presents further evidence that support the case that...

Factors affecting the implementation of Vee notched plastic pipe tests

Author(s) : Lawrence, Potter, Teo 1995 Edinburgh

The ultimate reliability of the data generated on tests, both static and dynamic, on "notched" plastic pipes samples is cmcially dependent upon the perfection of the actual notch root and the material immediately surrounding it. This paper d d e r s a number of the important factors relating to the production of the...

Fundamental Justification of a Fatigue Based Quality Control Test on All Sizes of Plastic Pipe

Author(s) : Lawrence 1992 Eindhoven

The limited demand for very large bore plastic pipes systems has resulted in a dearth of associated test data or strategy, but the need to now transport large quantities of water demand closer attention to this problem. The 'type testing' and routine (Q.C. ) testing of plastic pipe systems is already a difficult area,...

The Possibility of Assessing the Long Term Performance of PE Pipes Using a Quality Control Fatigue Test

Author(s) : Greig, Lawrence 1988 Bath

Hydrostatic s~ress rupture testing at 80°C of polyethylene gas pipe currently takes sver 1000 ho7.1rs to determine its good stress cracking performance. This is excessively long for quailty control purposes so a rapid rest is being developed using fatigue pressurlsac. :on, 2gajn on notched...

The Investigation into the Use of Fatigue in Accelerated Quality Control Procedure for 50 Years Life Prediction

Author(s) : Lawrence 1985 York

Polyethylene gas supply systems are designed for a minimum of 50 years life, but as long term data, both laboratory and field is difficult to obtain, long term assessments are based on an extrapolation of Quality Control and other short term tests. An essential requirement is that Polyethylene should be highly...

The Developing Market for Plastics Pipes in the Middle East and the Need for the GPPA

Author(s) : Lawrence 2008 Budapest

Members of the Association

BOREALISBOROUGEFormosa Plastics CorporationINEOS O&PIRPCKorea Petrochemical IND. Co., LTD (KPIC)LyondellBasellPetroChina Dushanzi Petrochemical CompanyPRIME POLYMERSABICSCG Chemicals & Thai PolyethyleneSinopecTASNEE
TOP