The Experts below are selected from a list of 5718 Experts worldwide ranked by ideXlab platform
Kenneth G Budinski - One of the best experts on this subject based on the ideXlab platform.
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tribological properties of titanium alloys
Wear, 1991Co-Authors: Kenneth G BudinskiAbstract:Abstract Titanium is often the most cost-effective Corrosion-Resistant Material for applications in the chemical process industry that involve resistance to halides. Unfortunately, there are usually some components in these systems that involve relative sliding-titanium tribosystems — e.g. bolts and nuts, valves, piping connections, etc. Titanium and its alloys have had a reputation for poor tribocharacteristics, but detailed information on suitable counterfaces and wear specifics is scarce. This paper summarizes a study conducted on the two most widely used titanium alloys, Grade 2 commercially pure titanium and the age-hardenable Ti6Al4V. Dry sand-rubber wheel tests were conducted to assess abrasion resistance; fretting, galling and reciprocating pin-on-plane tests were conducted to determine if there is a “best” counterface for these two titanium alloys. The test results are distilled into recommendations for use of titanium alloys in tribosystems in the chemical process industry. Both alloys have poor abrasion resistance. Grade 2 pure titanium should be avoided in all titanium tribosystems and there are preferred counterfaces for the Ti6Al4V alloy, but the best metal-to-metal wear resistance is obtained when the alloy is anodized and coated with a dry film lubricant.
Stelios Kyriakides - One of the best experts on this subject based on the ideXlab platform.
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liner wrinkling and collapse of bi Material pipe under axial compression
International Journal of Solids and Structures, 2015Co-Authors: Lin Yuan, Stelios KyriakidesAbstract:Abstract Lined pipe describes a product where a carbon steel pipe is lined internally with a thin layer of a Corrosion Resistant Material in order to protect it from corrosive constituents in the hydrocarbons it carries. Most commonly the liner is brought into contact with the carrier pipe by mechanical expansion. Full-scale tests on this product have demonstrated that, under mechanical loads that plastically deform the composite structure, the thin liner can buckle and collapse inside an intact outer pipe making the structure unserviceable. This paper investigates the extent to which typical lined pipes can be axially compressed before liner collapse. Demonstration experiments on model lined systems illustrate that the liner, although supported by contact with the outer pipe, first buckles unilaterally into an axisymmetric wrinkling mode at a relatively low strain. The wrinkles grow stably with compression but yield to a non-axisymmetric diamond-type mode that results in the collapse of the liner at a higher strain. This process has been modeled numerically starting with simulation of the mechanical expansion through which the composite structure is manufactured. The sensitivity of the collapse strain to the various parameters of the problem is studied and amongst other findings it is shown to be very sensitive to small geometric imperfections in the liner. It is also demonstrated that even modest amounts of internal pressure can delay liner collapse up to strains at which the outer pipe collapses.
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liner wrinkling and collapse of girth welded bi Material pipe under bending
Applied Ocean Research, 2015Co-Authors: Lin Yuan, Stelios KyriakidesAbstract:Abstract Pipelines and flowlines that carry corrosive hydrocarbons are often protected by lining them internally with a thin layer of a Corrosion Resistant Material. In the most economic method, the liner is brought in contact with a carbon steel carrier pipe by mechanical expansion. In applications involving severe plastic bending, such as winding onto a large diameter drum as is done in the reeling installation method, such a liner can wrinkle and collapse while the carrier pipe remains intact. Collapse has been shown to be sensitive to small initial geometric imperfections in the liner. A numerical framework for establishing the extent to which lined pipe can be bent before liner collapse was presented in [14] , [15] , [16] . This framework, suitably extended is used here to examine the effect of girth welds on liner collapse. The modeling starts by simulating the expansion process that plastically deforms the two tubes bringing them into contact. Bending plastically the composite structure leads to differential ovalization of the two tubes and detachment of the liner. The girth weld locally prevents this detachment creating a periodic boundary disturbance in the liner. With increasing bending the periodic disturbance grows and eventually yields to buckling into a shell-type diamond-shaped mode that causes the liner to collapse inside the intact outer pipe. The problem is investigated using a 12-inch carrier pipe base case. Comparing the collapse curvature of a girth-welded liner with imperfect liners free of welds that have the same collapse curvature, it is concluded that girth welds constitute a “weak” spot on the line. Results from a parametric study of factors that influence the collapse of a girth-welded are presented followed by recommendations.
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liner wrinkling and collapse of bi Material pipe under bending
International Journal of Solids and Structures, 2014Co-Authors: Lin Yuan, Stelios KyriakidesAbstract:Abstract Lining internally a carbon steel pipe with a thin layer of Corrosion Resistant Material is an economical method for protecting offshore tubulars from the corrosive ingredients of hydrocarbons. In applications involving severe plastic bending, such as in the reeling installation process, the liner can detach from the outer pipe and develop large amplitude buckles that compromise the flow. This paper outlines a numerical framework for establishing the extent to which lined pipe can be bent before liner collapse. The modeling starts with the simulation of the inflation process through which the two tubes develop interference contact pressure. Bending the composite structure leads to differential ovalization and eventually separation of part of the liner from the outer pipe. The unsupported strip of the liner on the compressed side first wrinkles and at higher curvature buckles and collapses in a diamond shaped mode. The sensitivity of the collapse curvature to the various parameters of the problem is studied, and amongst other findings the onset of collapse is shown to be very sensitive to small geometric imperfections in the liner. It is also demonstrated that bending the pipe under modest amounts of internal pressure can delay liner collapse to curvatures that make it reelable.
R.d. Mccright - One of the best experts on this subject based on the ideXlab platform.
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General Corrosion and Localized Corrosion of Waste Package Outer Barrier
2000Co-Authors: J C Farmer, R.d. MccrightAbstract:Alloy 22 is an extremely Corrosion Resistant Material, with a very stable passive film. Based upon exposures in the LTCTF, the GC rates of Alloy 22 are typically below the level of detection, with four outliers having reported rates up to 0.75 #mu#m per year. In any event, over the 10,000 year life of the repository, GC of the Alloy 22 (assumed to be 2 cm thick) should not be life limiting. Because measured Corrosion potentials are far below threshold potentials, localized breakdown of the passive film is unlikely under plausible conditions, even in SSW at 120 deg C. The pH in ambient-temperature crevices formed from Alloy 22 have been determined experimentally, with only modest lowering of the crevice pH observed under plausible conditions. Extreme lowering of the crevice pH was only observed under situations where the applied potential at the crevice mouth was sufficient to result in catastrophic breakdown of the passive film above the threshold potential in non-buffered conditions not characteristic of the Yucca Mountain environment. In cases where naturally ocurring buffers are present in the crevice solution, little or no lowering of the pH was observed, even with significant applied potential. With exposures of twelve months, no evidence of crevice Corrosion has been observed in SDW, SCW and SAW at temperatures up to 90 deg C. An abstracted model has been presented, with parameters determined experimentally, that should enable performance assessment to account for the general and localized Corrosion of this Material. A feature of this model is the use of the Materials specification to limit the range of Corrosion and threshold potentials, thereby making sure that substandard Materials prone to localized attack are avoided. Model validation will be covered in part by a companion SMR on abstraction of this model.
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Modeling the Corrosion of high-level waste containers: CAM-CRM interface
1998Co-Authors: P.j. Bedrossian, Joseph C. Farmer, R.d. MccrightAbstract:A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-layer canister. In this particular design, the inner barrier is made of a Corrosion Resistant Material (CRM) such as Alloy 825, 625 or C-22, while the outer barrier is made of a Corrosion-allowance Material (CAM) such as A516 or Monel 400. At the present time, Alloy C-22 and A516 are favored. This publication addresses the development of models to account for Corrosion of Alloy C-22 surfaces exposed directly to the Near Field Environment (NFE), as well as to the exacerbated conditions in the CAM-CRM crevice.
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Crevice Corrosion {ampersand} pitting of high-level waste containers: integration of deterministic {ampersand} probabilistic models
1997Co-Authors: Joseph C. Farmer, R.d. MccrightAbstract:A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-layer canister. In this particular design, the inner barrier is made of a Corrosion Resistant Material (CRM) such as Alloy 625 or C-22, while the outer barrier is made of a Corrosion-allowance Material (CAM) such as carbon steel or Alloy 400. An integrated predictive model is being developed to account for the effects of localized environmental conditions in the CRM-CAM crevice on the initiation and propagation of pits through the CRM.
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LONG-TERM Corrosion TESTING OF CANDIDATE MaterialS FOR HIGH-LEVEL RADIOACTIVE WASTE CONTAINMENT
1997Co-Authors: John C. Estill, R.d. Mccright, S. Doughty, G. E. Gdowski, S R Gordon, Kenneth J. King, F. WangAbstract:Preliminary results are presented from the long-term Corrosion test program of candidate Materials for the high-level radioactive waste packages that would be emplaced in the potential repository at Yucca Mountain, Nevada. The present waste package design is based on a multi-barrier concept having an inner container of a Corrosion Resistant Material and an outer container of a Corrosion allowance Material. Test specimens have been exposed to simulated bounding environments that may credibly develop in the vicinity of the waste packages. Corrosion rates have been calculated for weight loss and crevice specimens, and U-bend specimens have been examined for evidence of stress Corrosion cracking (SCC). Galvanic testing has been started recently and initial results are forthcoming. Pitting characterization of test specimens will be conducted in the coming year. This test program is expected to continue for a minimum of five years so that long-term Corrosion data can be determined to support Corrosion model development, performance assessment, and waste package design.
Lin Yuan - One of the best experts on this subject based on the ideXlab platform.
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liner wrinkling and collapse of bi Material pipe under axial compression
International Journal of Solids and Structures, 2015Co-Authors: Lin Yuan, Stelios KyriakidesAbstract:Abstract Lined pipe describes a product where a carbon steel pipe is lined internally with a thin layer of a Corrosion Resistant Material in order to protect it from corrosive constituents in the hydrocarbons it carries. Most commonly the liner is brought into contact with the carrier pipe by mechanical expansion. Full-scale tests on this product have demonstrated that, under mechanical loads that plastically deform the composite structure, the thin liner can buckle and collapse inside an intact outer pipe making the structure unserviceable. This paper investigates the extent to which typical lined pipes can be axially compressed before liner collapse. Demonstration experiments on model lined systems illustrate that the liner, although supported by contact with the outer pipe, first buckles unilaterally into an axisymmetric wrinkling mode at a relatively low strain. The wrinkles grow stably with compression but yield to a non-axisymmetric diamond-type mode that results in the collapse of the liner at a higher strain. This process has been modeled numerically starting with simulation of the mechanical expansion through which the composite structure is manufactured. The sensitivity of the collapse strain to the various parameters of the problem is studied and amongst other findings it is shown to be very sensitive to small geometric imperfections in the liner. It is also demonstrated that even modest amounts of internal pressure can delay liner collapse up to strains at which the outer pipe collapses.
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liner wrinkling and collapse of girth welded bi Material pipe under bending
Applied Ocean Research, 2015Co-Authors: Lin Yuan, Stelios KyriakidesAbstract:Abstract Pipelines and flowlines that carry corrosive hydrocarbons are often protected by lining them internally with a thin layer of a Corrosion Resistant Material. In the most economic method, the liner is brought in contact with a carbon steel carrier pipe by mechanical expansion. In applications involving severe plastic bending, such as winding onto a large diameter drum as is done in the reeling installation method, such a liner can wrinkle and collapse while the carrier pipe remains intact. Collapse has been shown to be sensitive to small initial geometric imperfections in the liner. A numerical framework for establishing the extent to which lined pipe can be bent before liner collapse was presented in [14] , [15] , [16] . This framework, suitably extended is used here to examine the effect of girth welds on liner collapse. The modeling starts by simulating the expansion process that plastically deforms the two tubes bringing them into contact. Bending plastically the composite structure leads to differential ovalization of the two tubes and detachment of the liner. The girth weld locally prevents this detachment creating a periodic boundary disturbance in the liner. With increasing bending the periodic disturbance grows and eventually yields to buckling into a shell-type diamond-shaped mode that causes the liner to collapse inside the intact outer pipe. The problem is investigated using a 12-inch carrier pipe base case. Comparing the collapse curvature of a girth-welded liner with imperfect liners free of welds that have the same collapse curvature, it is concluded that girth welds constitute a “weak” spot on the line. Results from a parametric study of factors that influence the collapse of a girth-welded are presented followed by recommendations.
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liner wrinkling and collapse of bi Material pipe under bending
International Journal of Solids and Structures, 2014Co-Authors: Lin Yuan, Stelios KyriakidesAbstract:Abstract Lining internally a carbon steel pipe with a thin layer of Corrosion Resistant Material is an economical method for protecting offshore tubulars from the corrosive ingredients of hydrocarbons. In applications involving severe plastic bending, such as in the reeling installation process, the liner can detach from the outer pipe and develop large amplitude buckles that compromise the flow. This paper outlines a numerical framework for establishing the extent to which lined pipe can be bent before liner collapse. The modeling starts with the simulation of the inflation process through which the two tubes develop interference contact pressure. Bending the composite structure leads to differential ovalization and eventually separation of part of the liner from the outer pipe. The unsupported strip of the liner on the compressed side first wrinkles and at higher curvature buckles and collapses in a diamond shaped mode. The sensitivity of the collapse curvature to the various parameters of the problem is studied, and amongst other findings the onset of collapse is shown to be very sensitive to small geometric imperfections in the liner. It is also demonstrated that bending the pipe under modest amounts of internal pressure can delay liner collapse to curvatures that make it reelable.
J. S. Huang - One of the best experts on this subject based on the ideXlab platform.
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Development of integrated mechanistically-based degradation-mode models for performance assessment of high-level waste containers
1999Co-Authors: P.j. Bedrossian, John C. Estill, Robert W. Hopper, J. S. Huang, D. Mccright, J. Horn, A. Roy, F. Wang, Joseph C. Farmer, Keith R. WilfingerAbstract:A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-layer canister. In this particular design, the inner barrier is made of a Corrosion Resistant Material (CRM) such as Alloy 825, 625 or C-22, while the outer barrier is made of a Corrosion-allowance Material (CAM) such as A516 Gr 55, a carbon steel, or Monel 400. At the present time, Alloy C-22 and A516 G4 55 are favored.
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Stress Corrosion cracking in canistered waste package containers: Welds and base metals
1998Co-Authors: J. S. HuangAbstract:The current design of waste package containers include outer barrier using Corrosion allowable Material (CAM) such as A516 carbon steel and inner barrier of Corrosion Resistant Material (CRM) such as alloy 625 and C22. There is concern whether stress Corrosion cracking would occur at welds or base metals. The current memo documents the results of our analysis on this topic.
