Decompression wave speed and crack velocity measurements during S4 test in water pressurized plastic pipes: Part 1. Experimental methods

2016 ◽  
Vol 53 ◽  
pp. 338-346 ◽  
Author(s):  
Vipin Vijayan ◽  
Hyunmin Bae ◽  
Tom Marti ◽  
Sunwoong Choi
Keyword(s):  
Crack Velocity ◽  
Wave Speed ◽  
Experimental Methods ◽  
Velocity Measurements ◽  
Plastic Pipes ◽  
Decompression Wave

scholarly journals Analysis of Proximity Consequences of Coil Windings in Electromagnetic Forming

2021 ◽  
Vol 5 (2) ◽  
pp. 45
Author(s):  
Siddhant Prakash Goyal ◽  
Mohammadjavad Lashkari ◽  
Awab Elsayed ◽  
Marlon Hahn ◽  
A. Erman Tekkaya
Keyword(s):  
Proximity Effect ◽  
Experimental Methods ◽  
Electromagnetic Forming ◽  
Velocity Measurements ◽  
Local Curvature ◽  
Metal Parts ◽  
Sheet Metal Parts ◽  
Geometrical Features ◽  
Physical Phenomena ◽  
Inverse Distance

Multiturn coils are required for manufacturing sheet metal parts with varying depths and special geometrical features using electromagnetic forming (EMF). Due to close coil turns, the physical phenomena of the proximity effect and Lorentz forces between the parallel coil windings are observed. This work attempts to investigate the mechanical consequences of these phenomena using numerical and experimental methods. A numerical model was developed in LS-DYNA. It was validated using experimental post-mortem strain and laser-based velocity measurements after and during the experiments, respectively. It was observed that the proximity effect in the parallel conductors led to current density localization at the closest or furthest ends of the conductor cross-section and high local curvature of the formed sheet. Further analysis of the forces between two coil windings explained the departure from the “inverse-distance” rule observed in the literature. Finally, some measures to prevent or reduce undesired coil deformation are provided.

Crack Velocity Measurements in Sea Ice

1994 ◽  
Vol 362 ◽  
Author(s):  
Oleg Gluschenkov ◽  
Victor Petrenko
Keyword(s):  
Sea Ice ◽  
Electrical Resistance ◽  
Crack Velocity ◽  
Electromagnetic Emission ◽  
High Sensitivity ◽  
Unfrozen Water ◽  
Dynamic Resistance ◽  
Velocity Measurements ◽  
Water Ice ◽  
Crack Dynamics

AbstractTo study crack dynamics in sea ice fast measurements of ice electrical resistance and an electromagnetic emission (EME) from cracks were used. The sample dimensions ranged from 0.05 to 30 meters. In a laboratory grown fresh water ice crack velocities varied from a few hundreds to a thousand meters per second while in the natural sea ice crack velocity was very low, about 10 m/s. This remarkable difference in the crack velocities is likely due to the dynamic resistance of unfrozen water in brine pockets and channels and to the high ductility of sea ice. It was found that the cracks propagate in ice discontinuously owing to the strong interaction with such microstructural elements as liquid inclusions and grain boundaries. The high sensitivity of the method allowed to detect nucleation of very first microcracks.

Measurements of Decompression Wave Speed in Natural Gas Containing 2-8% (Mole) Hydrogen by a Specialized Shock Tube

2016 ◽  
Author(s):  
K. K. Botros ◽  
S. Igi ◽  
J. Kondo
Keyword(s):  
Natural Gas ◽  
Shock Tube ◽  
Hydrogen Concentration ◽  
Wave Speed ◽  
Accurate Determination ◽  
Initial Pressure ◽  
Propagation Speed ◽  
Wave Speeds ◽  
Decompression Wave ◽  
Curve Method

The Battelle two-curve method is widely used throughout the industry to determine the required material toughness to arrest ductile (or tearing) pipe fracture. The method relies on accurate determination of the propagation speed of the decompression wave into the pipeline once the pipe ruptures. GASDECOM is typically used for calculating this speed, and idealizes the decompression process as isentropic and one-dimensional. While GASDECOM was initially validated against quite a range of gas compositions and initial pressure and temperature, it was not developed for mixtures containing hydrogen. Two shock tube tests were conducted to experimentally determine the decompression wave speed in lean natural gas mixtures containing hydrogen. The first test had hydrogen concentration of 2.88% (mole) while the second had hydrogen concentration of 8.28% (mole). The experimentally determined decompression wave speeds from the two tests were found to be very close to each other despite the relatively vast difference in the hydrogen concentrations for the two tests. It was also shown that the predictions of the decompression wave speed using the GERG-2008 equation of state agreed very well with that obtained from the shock tube measurements. It was concluded that there is no effects of the hydrogen concentration (between 0–10% mole) on the decompression wave speed, particularly at the lower part (towards the choked pressure) of the decompression wave speed curve.

Measurements of Decompression Wave Speed in Pure Carbon Dioxide and Comparison With Predictions by Equation of State

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
K. K. Botros ◽  
J. Geerligs ◽  
B. Rothwell ◽  
T. Robinson
Keyword(s):  
Carbon Dioxide ◽  
Large Scale ◽  
Wave Speed ◽  
Equations Of State ◽  
Initial Conditions ◽  
Thermodynamic Characteristics ◽  
Point Of View ◽  
Decompression Wave ◽  
Rapid Transients

Carbon dioxide capture and storage (CCS) is one of the technologies that have been proposed to reduce emissions of carbon dioxide (CO2) to the atmosphere. CCS will require the transportation of the CO2 from the “capture” locations to the “storage” locations via large-scale pipeline projects. One of the key requirements for the design and operation of pipelines in all jurisdictions is fracture control. Supercritical CO2 is a particularly challenging fluid from this point of view, because its thermodynamic characteristics are such that a very high driving force for fracture can be sustained for a long time. Even though CO2 is not flammable, it is an asphyxiating gas that is denser than air, and can collect in low-lying areas. Additionally, it is well known that any pipeline rupture, regardless of the nature of the fluid it is transporting, has a damaging reputational, commercial, logistic, and end user impact. Therefore, it is as important to control fracture in a CO2 pipeline as in one transporting a flammable fluid. With materials specified appropriately for the prevention of brittle failure, the key element is the control of propagating ductile (or tearing) fracture. The determination of the required toughness for the arrest of ductile fracture requires knowledge of the decompression behavior of the contained fluid, which in turn requires accurate knowledge of its thermodynamic characteristics along the decompression isentrope. While thermodynamic models based on appropriate EOS (equations of state) are available that will, in principle, allow determination of the decompression wave speed, they, in general, have not been fully validated for very rapid transients following a rupture. This paper presents experimental results of the decompression wave speed obtained from shock tube tests conducted on pure CO2 from different initial conditions, and comparison with predictions by models based on GERG-2008, Peng-Robinson, and BWRS equations of state (EOS). These tests were conducted as a baseline before introducing various impurities.

Determination of Decompression Wave Speed in Rich Gas Mixtures

2008 ◽  
Vol 82 (5) ◽  
pp. 880-891 ◽  
Author(s):  
Kamal K. Botros ◽  
Wojciech Studzinski ◽  
John Geerligs ◽  
Alan Glover
Keyword(s):  
Wave Speed ◽  
Gas Mixtures ◽  
Decompression Wave

Measurement of Decompression Wave Speed in Rich Gas Mixtures at High Pressures (370 bars) Using a Specialized Rupture Tube

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
K. K. Botros ◽  
J. Geerligs ◽  
R. J. Eiber
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Wave Speed ◽  
High Pressures ◽  
Equations Of State ◽  
Gas Mixtures ◽  
Internal Diameter ◽  
Decompression Wave ◽  
Predicted Values ◽  
Fracture Arrest

Measurements of decompression wave speed in conventional and rich natural gas mixtures following rupture of a high-pressure pipe have been conducted. A high-pressure stainless steel rupture tube (internal diameter=38.1 mm and 42 m long) has been constructed and instrumented with 16 high frequency-response pressure transducers mounted very close to the rupture end and along the length of the tube to capture the pressure-time traces of the decompression wave. Tests were conducted for initial pressures of 33–37 MPa-a and a temperature range of 21–68°C. The experimentally determined decompression wave speeds were compared with both GASDECOM and PIPEDECOM predictions with and without nonequilibrium condensation delays at phase crossing. The interception points of the isentropes representing the decompression process with the corresponding phase envelope of each mixture were correlated with the respective plateaus observed in the decompression wave speed profiles. Additionally, speeds of sound in the undisturbed gas mixtures at the initial pressures and temperatures were compared with predictions by five equations of state, namely, BWRS, AGA-8, Peng–Robinson, Soave–Redlich–Kwong, and Groupe Européen de Recherches Gaziéres. The measured gas decompression curves were used to predict the fracture arrest toughness needed to assure fracture control in natural gas pipelines. The rupture tube test results have shown that the Charpy fracture arrest values predicted using GASEDCOM are within +7% (conservative) and −11% (nonconservative) of the rupture tube predicted values. Similarly, PIPEDECOM with no temperature delay provides fracture arrest values that are within +13% and −20% of the rupture tube predicted values, while PIPEDECOM with a 1°C temperature delay provides fracture arrest values that are within 0% and −20% of the rupture tube predicted values. Ideally, it would be better if the predicted values by the equations of state were above the rupture tube predicted values to make the predictions conservative but that was not always the case.

Sign in / Sign up

Export Citation Format

Share Document