Our site uses cookies necessary for its proper functioning. To improve your experience, other cookies may be used: you can choose to disable them. This can be changed at any time via the Cookies link at the bottom of the page.


A novel procedure for characterizing fatigue crack growth in CRB specimens via an optical technique

 

Papers

Plastic Pipes Conference Association # 2016 Berlin

Joerg Fischer, Paul J. Freudenthaler, Patrick R. Bradler, Reinhold W. Lang

Cyclic tests with cracked round bar (CRB) specimens have been used for some time to characterize the slow crack growth behavior of polyolefin pipe grade materials. In fact, most recently a standardized test procedure for cyclic CRB testing has been released in ISO 18489. To obtain kinetic data for cyclic crack growth curves, typically three extensometers attached at three angular positions around the specimen circumference (0°, 120° and 240°) are used to measure crack opening displacement (COD) values and to deal with the problem of asymmetric crack growth. From the COD values an average crack length is then calculated using appropriate specimen compliance equations. Utilizing the extensometer technique is, however, limited to a temperature range for which the extensometers are certified. At higher test temperatures and particularly testing materials in harsh liquid environments (e.g., oilfield liquids) an alternative technique for COD measurements at different specimen perimeter positions is needed. Hence, a technique has been developed and implemented in our laboratory in which the entire specimen is rotated in a tensiontorsion electrodynamic fatigue test machine, which allows for crack length measurements at various circumferential positions of the CRB specimen by an optical technique. Applying this technique, a much finer resolution of crack length measurements can be obtained in steps of 20° angular rotation, allowing for a total of 18 crack length measurements over the whole perimeter. The procedure for optical crack length measurement can be used in combination with conventional temperature chambers with a front window over a wide range of temperatures and it can also be used for superimposed tests in environmental liquids, again over a temperature range, as long as the liquids are sufficiently transparent. First results have been generated with polyethylene (PE) and polypropylene (PP) pipe grade materials.

Please note that the whole article content is available on PPCA website only :

Related papers

2021 Amsterdam : DEVELOPMENTS IN NORTH AMERICAN CONDUIT PRACTICES

Author(s) : Tom Stewart, Richard Hicks, Patrick Vibien, Lance MacNevin

Arguably, broadband technologies have become as vital to society as water delivery, waste removal and energy distribution. However, the role of plastic conduit in broadband is often overlooked within the piping industry and society in general. HDPE conduit is an essential component to the build -out of 5G cell...

2021 Amsterdam : EFFECT OF CHLORINATED WATER ON THE FATIGUE CRACK GROWTH RESISTANCE OF POLYETHYLENE COMPOUNDS WITH RECYCLATE CONTENT FOR PIPE APPLICATIONS

Author(s) : Paul J. Freudenthaler, Joerg Fischer, Mathias Eder, Reinhold W. Lang

For controlled water disinfection, typically chlorine is used and preliminary studies demonstrate its aging and crack growth acceleration effects on polyolefin pipe materials [1, 2]. Although the use of recycled plastics is not prohibited in some ISO standards for polyolefin piping systems [3–5], only small amounts...

2021 Amsterdam : MODIFIED PLAIN STRAIN GROOVED TENSILE TEST TO EVALUATE LARGE DIAMETER PE PIPES

Author(s) : Thomas R. Kratochvilla, Patrick Grünbeck, Christoph Bruckner, Raimund Eremiasch, Harald Wilhelm, Mario Vukelja

In the last decades pipe dimensions of extruded PE pipes have reached new orders of size. Today, PE pipes with outer diameters of up to DN/OD 3500 mm are produced and used for pressure pipe applications like seawater intake/discharge, outfall, sewage and industrial process piping systems. To test the long-term...

2021 Amsterdam : SMART TITANIUM DIOXIDE FOR ECONOMICAL AND ENVIRONMENTALLY SUSTAINABLE OPTIMIZATION OF PLASTIC PIPE FORMULATIONS

Author(s) : Andrew J. White, Paul Dietz

FP-Pigments is a global manufacturer of a unique series of titanium dioxide pigment products and have been supplying the coatings, plastics, paper and inks markets for over 10 years, helping our customers reduce their raw material costs while maintaining product quality and performance. We have plants in both...

2021 Amsterdam : UK WATER INDUSTRY RESEARCH REVEALING THE LONG- TERM AGEING PERFORMANCE OF POLYETHYLENE (PE) PIPES

Author(s) : Patrick Campbell, Joanne Claronino, Shana Meeus, Joseph Sanders, David Chrystie-Lowe

Polyethylene (PE) potable water mains, with design life of 50 years (BS EN 12201), have been in widespread use in the UK water industry for more than 30 years. PE pipe is light, flexible and reliable in comparison with other pipe materials and the UK water industry has made a considerable investment in replacing...

2018 Las-Vegas : Characterization of post-use polyethylene and polypropylene recyclate blends for pipe applications

Author(s) : Markus Gall, Reinhold W. Lang, Joerg Fischer, Ansgar Niehoff, Steven Schmidt

Despite recent efforts in promoting the utilization of recycled polymeric materials for more diverse and more advanced applications, there are still significant knowledge gaps with regards to the applicability of certain recyclate types for specific “re-use” purposes. When it comes to pipe applications, for instance,...

2018 Las-Vegas : Effect of beta-nucleation on aging and crack growth resistance of polypropylene exposed to chlorinated water

Author(s) : Joerg Fischer, Paul J. Freudenthaler, Patrick R. Bradler, Reinhold W. Lang, Susan C. Mantell

This research addresses the effect of nucleation on the global aging behavior and the fatigue crack growth (FCG) resistance of commercial alpha- and beta-nucleated polypropylene random copolymer pipe grades (PP-R) when exposed to chlorinated water (5 mg/l free chlorine) at an elevated temperature of 60°C. Comparing...

2018 Las-Vegas : Fatigue crack growth testing in chlorinated water at elevated temperatures - Test equipment and test procedure

Author(s) : Joerg Fischer, Patrick R. Bradler, Reinhold W. Lang

In the present paper, a novel test system for conducting fatigue crack growth (FCG) experiments under superimposed mechanical-environmental conditions is presented. FCG experiments were performed on a polypropylene (PP) grade and a short-glass fiber reinforced polyamide 66 (PA-GF) grade as model materials. The...

2016 Berlin : Fatigue crack growth resistance of polypropylene in chlorinated water at different temperatures

Author(s) : Joerg Fischer, Patrick R. Bradler, Reinhold W. Lang, Gernot M. Wallner

The present paper aims to study the crack growth resistance of a black-pigmented polypropylene pipe grade when exposed to elevated temperatures and various environmental media (air, deionized water, ionized water with a specific chloride content, and chlorinated water) under the simultaneous application of cyclic...

2016 Berlin : Quality and performance assessment of in-plant and post-use PE recyclates for pipe applications

Author(s) : Reinhold W. Lang, Patrick R. Bradler, Joerg Fischer, Dominik Poehlmann, Steven Schmidt, Ansgar Niehoff

In the present paper, a highly effective test and characterization concept for polymer recyclate materials is proposed and validated. Based on the proposed methods, a study was carried out to investigate the potential of in-plant and post-use PE recyclates from various applications to be utilized in PE recyclate...

2016 Berlin : Strain hardening modulus: a measure for ranking time to failure of random polypropylene pipe materials

Author(s) : Rieky Steenbakkers, Linda Havermans, Patrick Voets, Jonathan Rabiei, Rudy Deblieck

The resistance to Slow Crack Growth of HDPE is related to the strain hardening modulus as determined from a tensile test at 80 °C. Correlatio ns between traditional methods (e.g. Full Notched Creep Test, Notched Pipe Test) and other accelerated tests (e.g. fatigue testing) show that the same failure mechanism is...

2016 Berlin : Total overview of developments in PVC-O in size and couplers.

Author(s) : Paul van Doesburg, Berend Stel, Rob Spekreijse

PVC-O is the accepted pipe solution for the future. Worldwide, more and more countries go in the direction of PVC-O. The main applications for PVC-O at this moment are potable water, wastewater, irrigation and gas. PVC-O is produced for many years from the 80’s until 2007 the sizes were in majority small (mainly...

2014 Chicago : A Risk Based Approach to Prioritizing Aldyl Piping Replacements in Gas Distribution Systems

Author(s) : Dr. Ken Oliphant, William Luff, Dr. Peter Angelo, Patrick Vibien

Managing aging pipeline infrastructure is an important part of overall pipeline risk management. The critical risk management questions for an aging infrastructure are: how quickly should replacement occur and what parts of the system should be prioritized for replacement. To answer these questions it is necessary to...

2014 Chicago : An Assessment of the Approach to Validate Polyethylene Pipe in Potable Water Systems

Author(s) : Dr. Ken Oliphant, Patrick Vibien, Dr. Michael Conrad, Sarah Chung

A new methodology has been developed to validate the performance of polyethylene piping materials in potable water applications. The methodology is based on several research programs which examined a standardized accelerated test methodology (ASTM F2263 Standard Test Method for Evaluating the Oxidative Resistance of...

2014 Chicago : Evolution of Piping Systems-A Brief History of Innovation

Author(s) : Riccardo Barbone, Georg Fischer

This short paper reviews the major milestones in the history of piping systems. A special emphasis is given to the sources and reasons for innovation. Starting with nature as a basis and discovering the basic laws of hydraulics, man has been driven to innovate by emulating nature. The political and social forces that...

2014 Chicago : Lifetime Assessment of Polyethylene Pipes in Oil and Gas Infrastructure

Author(s) : P. F. Schoeffl, R.W. Lang

To accommodate the recent industrial interests to utilize PE-HD pipes for oil field applications (e.g. injection water pipes, flow lines), this paper introduces a “fully integrated test concept” to allow a comprehensive pipe lifetime prediction under severe environmental conditions. Moreover, experimental set-ups and...

2014 Chicago : PAS-55 / ISO 55000 As a New Asset Management Approach to Achieving Long-Term Reliability and Risk Reduction in Gas Distribution Pipelines

Author(s) : Dr. Ken Oliphant, Patrick Vibien

New and formal approaches to Asset Management (AM), such as the PAS-55 and ISO 55000 Asset Management standards have been developed over the past decade. These AM standards can be applied to pipelines and cover all stages of a pipeline's lifecycle - acquisition, operation, maintenance and renewal/disposal and provide...

2014 Chicago : The Effects of Dual Cooling on the Rapid Crack Propagation Performance of Polyethylene Pipes

Author(s) : Mark J. Lamborn, Pam L. Maeger, Rick E. Kunc, Vivek Rohatgi, Paul J. DesLauriers, Ashish M. Sukhadia

Dual cooling is a post-extrusion cool down process employed for polyethylene (PE) pipe, whereby either water or ambient air is forced through the pipe bore following extrusion, in order to accelerate cooling. The primary benefits offered by the dual cooling process are increased production rates and reduced resin...

2014 Chicago : Ultrasonic Phased Array Inspection of Polyethylene Pipelines & Fittings Used for Gas Distribution

Author(s) : GUEUGNAUT Dominique, ANGELINI Florent, BOUJLAL Adil, BOUAFFRE Romuald, SEVRE Bertrand, LOUET Patrick

Polyethylene (PE) is a widespread material for the manufacturing of gas and water distribution pipelines and a large number of PE electrofusion pipe joints can be found over the thousands of kilometres of PE pipeplines all over the world, thus generating an increasing interest in checking the quality of these joints....

2012 Barcelona : Molecular and morphological parameters governing yield failure of PE pipe materials

Author(s) : Anna M. Hartl, A. Buryak and R.W. Lang

The ductile behaviour of PE in Region I of the pipe failure regime is mainly governed by the time/ and temperature-dependent yield stress of the polymer [1]. Two different deformation mechanisms are relevant in PE. One governing shorter times and/or lower temperatures and the other longer times and/or higher...

Members of the Association

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