Experimental and numerical assessment on failure pressure of textured pipelines

2021 ◽  
pp. 1-20
Author(s):  
Hassan Karampour ◽  
Mahmoud Alrsai ◽  
Hossein Khalilpasha ◽  
Faris Albermani
Keyword(s):  
Ductile Failure ◽  
Tensile Tests ◽  
External Pressure ◽  
Burst Pressure ◽  
Failure Pressure ◽  
Numerical Assessment ◽  
Pressure Tests ◽  
Physical Tests ◽  
Smooth Pipe ◽  
Do So

Abstract A series of physical tests and finite element (FE) analyses are conducted to evaluate the failure of smooth (conventional) and textured (proposed concept) pipes. To do so, hydrostatic pressure tests are performed on aluminium beverage cans (ductile failure) and additively manufactured Ti6Al4V-0406 titanium pipes (brittle failure). Mechanical material properties are obtained from tensile tests of coupon samples. In absence of physical burst pressure tests, FE models are validated against experimental results of external pressure tests and are used to predict the buckle initiation (Pi) and burst pressure (Pb) capacity of the textured pipes with different number of circumferential triangles, N, and base angles, a. Results show that buckle initiation pressures of the textured concept is 2.34 and 1.80 times greater than those of the smooth aluminium cans and titanium pipes, respectively. However, the burst pressure of the textured pipe can only get 3% greater than the smooth pipe. Based on the current results a textured pipe with N=6 and a=30° is the optimum textured design.

Coalescence of Complex Cracks in Ex-Service Carbon Steel Pipe Bends During Burst Pressure Tests

2010 ◽  
Author(s):  
Xinjian Duan ◽  
Michael J. Kozluk ◽  
Tracy Gendron ◽  
John Slade
Keyword(s):  
Carbon Steel ◽  
Mixed Mode ◽  
Burst Pressure ◽  
Plastic Collapse ◽  
Failure Pressure ◽  
Pressure Tests ◽  
Main Fracture ◽  
Post Test ◽  
Full Power ◽  
Design Pressure

This paper presents burst pressure tests of two ex-service, 2 1/2-inch, SA-106 Grade B pipe bends with multiple part-through-wall axial cracks. The two pipes tested were sections of outlet feeders that were removed from the Point Lepreau Generating Station after 18.6 and 19.5 effective full-power years of service. The field of cracks was tightly distributed in the longitudinal and transverse directions of pipe bends on both inside surface and outside surfaces. The total length of the crack fields were 40 mm and 100 mm, respectively. The deepest crack was 73% through-wall. The burst pressure tests were performed at 90°C. The failure pressure was more than 4 times the design pressure. Post-test metallurgical examinations revealed mixed mode failures on the main fracture surface. The failure of the specimens was controlled by local plastic collapse of the ligaments of a small number of the deepest cracks in the field of cracks.

scholarly journals Study of the Ultraviolet Effect and Thermal Analysis on Polypropylene Nonwoven Geotextile

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1080
Author(s):  
Clever Aparecido Valentin ◽  
Marcelo Kobelnik ◽  
Yara Barbosa Franco ◽  
Fernando Luiz Lavoie ◽  
Jefferson Lins da Silva ◽  
...  
Keyword(s):  
Uv Light ◽  
Polymeric Materials ◽  
Tensile Tests ◽  
Thermomechanical Analysis ◽  
Material Stiffness ◽  
Before And After ◽  
Electron Microscopy Analysis ◽  
Physical Tests ◽  
Nonwoven Geotextile

The use of polymeric materials such as geosynthetics in infrastructure works has been increasing over the last decades, as they bring down costs and provide long-term benefits. However, the aging of polymers raises the question of its long-term durability and for this reason researchers have been studying a sort of techniques to search for the required renewal time. This paper examined a commercial polypropylene (PP) nonwoven geotextile before and after 500 h and 1000 h exposure to ultraviolet (UV) light by performing laboratory accelerated ultraviolet-aging tests. The state of the polymeric material after UV exposure was studied through a wide set of tests, including mechanical and physical tests and thermoanalytical tests and scanning electron microscopy analysis. The calorimetric evaluations (DSC) showed distinct behaviors in sample melting points, attributed to the UV radiation effect on the aged samples. Furthermore, after exposure, the samples presented low thermal stability in the thermomechanical analysis (TMA), with a continuing decrease in their thicknesses. The tensile tests showed an increase in material stiffness after exposition. This study demonstrates that UV aging has effects on the properties of the polypropylene polymer.

A Study on the Coupled Thermal and Damage Effects in Deforming Solids

2011 ◽  
Vol 312-315 ◽  
pp. 229-234
Author(s):  
M. Vaz ◽  
Pablo A. Muñoz-Rojas ◽  
M.R. Lange
Keyword(s):  
Metal Forming ◽  
Ductile Failure ◽  
Tensile Tests ◽  
Thermal Softening ◽  
Mechanical Degradation ◽  
Material Behaviour ◽  
Temperature Variations ◽  
Damage Models ◽  
Notched Specimens ◽  
Fully Coupled

Mechanical degradation and ductile failure in metal forming operations can be successfully modelled using fully coupled damage models. In addition, it has been largely reported in the literature that temperature variations affect material behaviour, especially thermal softening. This paper presents a numerical discussion of the coupled effects between ductile damage and temperature evolution based on the simulation of tensile tests of notched specimens.

scholarly journals Mind the Gap: A Systematic Approach to the International Criminal Court’s Arrest Warrants Enforcement Problem

2018 ◽  
Author(s):  
Nadia Banteka
Keyword(s):  
Civil Society ◽  
Law Enforcement ◽  
Systematic Approach ◽  
External Pressure ◽  
Development Aid ◽  
Political Role ◽  
The Us ◽  
Improve Compliance ◽  
Positive Inducements ◽  
Do So

ICCTs have been established on a belying enforcement paradox between their significant mandate and their inherent lack of enforcement powers due to absence of systemic law enforcement. This article is premised on the idea that ICCTs fail to procure substantial results due to their delusive persistence in rejecting the factoring of politics in their operation. Thus, I suggest a perspective for arrest warrant enforcement that not only recognizes the relevance of politics but also capitalizes on it. Accordingly, I argue that by fully comprehending its enforcement tools and making use of its political role, the ICC may increase its rates in the apprehension of suspects, and therefore secure higher levels of judicial enforcement. Based on different compliance theories, I argue that the Office of The Prosecutor of the ICC (OTP) can improve compliance with ICC arrest warrants by making use of third states and non-state actors. In Part I, I address the way states and international actors may assist the OTP towards unwilling to arrest states through inducements, reputational sanctions, and support for enforcement agencies. I propose that external pressure in the form of positive inducements (membership, development aid) or negative inducements (travel bans, asset freezes) as well as condemnation and reputational damage towards non-compliant states, are likely to increase compliance with arrest warrants. In Part II, I examine a strategy for the OTP towards states that are willing to arrest but are unable to do so. In these cases, the OTP would benefit from improving its institutional capacity to identify and use overlapping interests with activist states in the field of human rights and international justice through the establishment of a diplomatic arm within its Jurisdiction, Complementarity and Cooperation Division (JCCD). I unpack the question of what this engagement may look like by examining such a potential relationship between the US and the ICC. Finally, in Part III, I focus on the instances, where civil society has the ability to influence third states or situation states to assist in the execution of arrest warrants. I argue that the OTP ought to include more actively different actors within the global civil society, such as NGOs, transnational networks, and individuals, during its bargaining efforts.

Development of Defect Interaction Criteria for Pipeline Girth Welds Subjected to Plastic Collapse Conditions

2006 ◽  
Author(s):  
Wim De Waele ◽  
Rudi Denys ◽  
Antoon Lefevre
Keyword(s):  
Large Scale ◽  
Specific Interaction ◽  
Ductile Failure ◽  
Elastic Interaction ◽  
Tensile Tests ◽  
Ductile Material ◽  
Plastic Collapse ◽  
Material Behaviour ◽  
Defect Interaction ◽  
Girth Welds

Multiple defects in welds, when detected, have to be assessed for interaction. Current defect interaction rules are largely based on linear elastic fracture mechanics principles (brittle material behaviour). Pipeline welding codes, however, specify toughness requirements to ensure ductile failure by plastic collapse. Therefore, the use of current (elastic) interaction rules for ductile girth welds can lead to unnecessary and possibly harmful weld repairs or cutouts. This paper reports on an assessment of the engineering significance of existing pipeline specific interaction criteria and on the development of new criteria. Rules for the interaction of coplanar surface breaking defects and ductile material behaviour have been developed on the basis of the performance requirement of remote yielding. The results of large-scale tensile tests illustrate that current interaction rules have a high degree of conservatism for plastic collapse conditions. The test data have been used to demonstrate that the developed procedure can be safely used for ductile girth welds.

High Pressure On-Chip Valves for Thermoplastic Microfluidics

2009 ◽  
Author(s):  
Chien-Fu Chen ◽  
Jikun Liu ◽  
Chien-Cheng Chang ◽  
Don L. DeVoe
Keyword(s):  
High Pressure ◽  
Dead Volume ◽  
Burst Pressure ◽  
Poly Ethylene Glycol ◽  
Stainless Steel Needle ◽  
Pressure Tests ◽  
Smooth Contact ◽  
Poly Ethylene ◽  
Pressure Resistance ◽  
On Chip

A high-pressure microvalve technology based on the integration of discrete elastomeric elements into rigid thermoplastic chips is described. The low-dead-volume valves employ deformable polydimethylsiloxane (PDMS) plugs actuated using a threaded stainless steel needle, allowing exceptionally high pressure resistance to be achieved. The simple fabrication process is made possible through the use of poly(ethylene glycol) (PEG) as a removable blocking material to avoid contamination of PDMS within the flow channel while yielding a smooth contact surface with the PDMS valve surface. Burst pressure tests reveal that the valves can withstand over 24MPa without leakage.

Tensile Tests for Cast Stainless Steel: Evolution of the RCC-M Code

2018 ◽  
Author(s):  
Arnaud Blouin ◽  
Mathieu Couvrat ◽  
Félix Latourte ◽  
Julian Soulacroix
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Ultimate Tensile Strength ◽  
Tensile Tests ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Different Diameters ◽  
Cast Stainless Steel ◽  
Acceptance Tests ◽  
Do So

In the framework of a pressurized water reactor primary loop replacement, elbows of different types were produced in cast austenitic stainless steel grade Z3CN 20-09 M. For that type of component, acceptance tests to check the sufficient mechanical properties include room and hot temperature tensile tests, following the RCC-M CMS – 1040 and EN 10002 specifications. A large test campaign on standard 10mm diameter specimens was performed and exhibited a high scattering in yield stress and ultimate tensile strength values. As a consequence, some acceptance tensile tests failed to meet the required minimal values, especially the ultimate tensile strength. Optical and electronic microscopy revealed that the low values were due to the presence of very large grain compared to the specimen gage diameter. However, tensile tests strongly rely on the hypothesis that the specimen gage part can be considered as a representative volume element containing a number of grains large enough so that their variation in size and orientation gives a homogeneous response. To confirm the origin of the scattering, a huge experimental tensile test campaign with specimens of different diameters was conducted. In parallel, FE calculations were also performed. From all those results, it was concluded that it was necessary to improve the RCC-M code for that type of test for cast stainless steel: to do so, a modification sheet was sent and is being investigated by AFCEN.

“Social Movement Theory” as a Baseline Legitimizing Narrative: Corporate Exploitation, Anti-Hegemonic Opposition and the Contested Academy

2017 ◽  
Vol 10 (1) ◽  
pp. 36-49 ◽  
Author(s):  
Nicholas A. Jackson
Keyword(s):  
Social Movement ◽  
External Pressure ◽  
Social Movement Theory ◽  
Movement Theory ◽  
Contested Space ◽  
Negative Impacts ◽  
Object Of Study ◽  
Do So ◽  
Intellectual Activism

Scholars and administrators created “Social Movement Theory” (SMT) and associated institutions in order to establish a field of “contested politics” buttressed by “scholarly synthesis.” In this article, I place SMT as an object of study itself within the contested space of the corporate academy. SMT is a baseline legitimizing narrative that the domesticated academy produces and that corporate entities then use as preemptive inoculation against anti-hegemonic opposition by geographically separating governmentalities of often brutal and arbitrary material exploitation from depoliticized, dehistoricized and scientistic spectacles of consumerist legitimization. I summarize key ways that administrators govern the corporate academy and remove historical and social specificity, followed by analysis of exemplary cases demonstrating how SMT is placed within “peer-reviewed” scholarship. In contrast to SMT's over-riding goal of “synthesis,” I argue that effective social movement scholarship is contingent, situated and explicitly engaged with power (willing to “reveal a stand”), including difficult questions about who exercises power, how, and especially under what guises of corporate authority. Done well, such intellectual-activism must be conducted independent of current corporate academic strictures, and indeed will likely involve direct anti-hegemonic challenges to the corporate academy. Intellectual-activists that choose to do so can face significant negative impacts ranging from “double-shift” marginalization through loss of academic privileges, total career destruction, banishment from the academic canon and even physical endangerment. Therefore, effective transformation of social movement scholarship requires transformation of the contested academy, both projects very difficult for embedded academics absent external pressure from intellectual-activists.

Exploratory Study on Engineering Ceramics Pressure Hulls for Deep-Sea Submergence Services

2005 ◽  
Vol 39 (3) ◽  
pp. 49-55 ◽  
Author(s):  
Yusuke Yano ◽  
Shinichi Takagawa
Keyword(s):  
Deep Sea ◽  
Syntactic Foam ◽  
Structural Materials ◽  
External Pressure ◽  
Engineering Ceramics ◽  
Practical Applications ◽  
Collapse Strength ◽  
Reinforced Plastic ◽  
Pressure Tests ◽  
The Relationship

An underwater vehicle for deep-sea operation should be as light as possible; therefore, development of premium structural materials such as titanium alloy, glass, and carbon-fiber-reinforced plastic (CFRP) for external pressure hulls has been ongoing. Engineering ceramics is one of the candidate materials, and the study of engineering ceramics has been underway for many years; however practical applications have been limited.The main purpose of this study is to establish the methodology of fabrication of ceramics pressure hulls for deep-sea submergence services. As the first step, prototypes of the spherical shells were fabricated from engineering ceramics, and their local radii of curvatures and wall thickness were precisely measured. In addition to these measurements, the strain on hemispheres and their collapse strength were measured by pressure tests in order to evaluate the relationship between spherical irregularities and collapse strength. The strength-to-weight ratios of fabricated pressure hulls were significantly higher than that of syntactic foam for deep-sea operations, therefore it is expected that engineering ceramics can be among the promising structural materials for lightening of an underwater vehicle's body.

Surface Stress Analysis of Internally Corroded Pipes Under External Pressure

2017 ◽  
Author(s):  
Zhanfeng Chen ◽  
Xiaoli Shen ◽  
Hao Ye ◽  
Sunting Yan ◽  
Zhijiang Jin
Keyword(s):  
Surface Stress ◽  
Internal Surface ◽  
Approximate Solutions ◽  
External Pressure ◽  
Diameter Ratio ◽  
Stress Distributions ◽  
Failure Pressure ◽  
Hoop Stresses ◽  
Stress Function Method ◽  
Maximum Stresses

Corrosion often leads to the failure of transporting pipelines. The surface stresses on the corroded pipes are related to the failure pressure. In this paper, a double circular arc (DCA) model is developed to calculate the surface stress of the internal corroded pipes under external pressure. In addition, a critical corrosion ratio and a critical thickness-to-diameter ratio are presented to determine the location of the maximum stress. Based on the stress function method and bipolar coordinates, an analytical solution of the DCA model was obtained. And then the stress distributions on the internal and external surfaces of the corroded pipes were determined. Next, the equivalent and hoop stresses at several locations in the cross section of the corroded pipes were discussed. The calculated results were validated using finite element method (FEM). Results show that the maximum stresses vary from the internal surface to the external surface with the increase of the corrosion ratio or the thickness-to-diameter ratio. Our research provides a benchmark for approximate solutions to predict the failure pressure and assess the integrity of the corroded pipelines.

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