Design Methodology for Axial Force Response of Pipe-in-Pipe: A Probabilistic Approach

2011 ◽  
Author(s):  
Olav Fyrileiv ◽  
Mark Marley ◽  
Sune Pettersen
Keyword(s):  
High Pressure ◽  
Axial Force ◽  
Probabilistic Approach ◽  
Design Approach ◽  
Electrical Heating ◽  
Buried Pipe ◽  
Worst Case ◽  
Operational Conditions ◽  
Offshore Development ◽  
Selection Of

As the easy oil is more or less gone, the typical offshore development faces several challenges in the future. These may be related to ultra deep water or difficult operational conditions like high pressure and temperatures. In addition there are often challenges related to flow, for example wax or hydrates during shut-downs or in tail production. Prevention of wax and hydrates is often solved by injection of chemicals or alternatively by some sort of heating, e.g. direct electrical heating. It may also to some degree be solved by superior thermal insulation or a combination of the methods mentioned. A thick insulation coating may give additional challenges with respect to submerged weight. Pipe-in-pipe (PIP) designs, where the flowline is insulated and covered by an outer pipe, solve this challenge and are becoming more and more popular. However, the pipe-in-pipe concepts also provide some specific challenges. DNV has recently been involved in a PIP project with quite challenging operational conditions. The combination of high temperature and high pressure (HTHP) and a corrosive well fluid with a buried pipe-in-pipe without any release of axial force leads to a very conservative design using conventional design approach. This challenge can be solved by applying a stochastic design approach avoiding conservative assumptions on top of each other. A probabilistic analysis targeting an acceptable probability of failure according to DNV-OS-F101 [1] resulted in an optimised design with a balanced selection of input parameters and avoiding ultra-conservative, worst case input combinations.

scholarly journals Study on the Phase Selection and Debye Temperature of Hyper-Peritectic Al-Ni Alloy under High Pressure

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 84
Author(s):  
Xiaohong Wang ◽  
Zhipeng Chen ◽  
Duo Dong ◽  
Dongdong Zhu ◽  
Hongwei Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Ambient Pressure ◽  
Competitive Growth ◽  
Phase Selection ◽  
Debye Temperatures ◽  
Ni Alloy ◽  
Temperature Heat ◽  
Low Temperature Heat Capacity ◽  
New Phase ◽  
Selection Of

The phase selection of hyper-peritectic Al-47wt.%Ni alloy solidified under different pressures was investigated. The results show that Al3Ni2 and Al3Ni phases coexist at ambient pressure, while another new phase α-Al exists simultaneously when solidified at high pressure. Based on the competitive growth theory of dendrite, a kinetic stabilization of metastable peritectic phases with respect to stable ones is predicted for different solidification pressures. It demonstrates that Al3Ni2 phase nucleates and grows directly from the undercooled liquid. Meanwhile, the Debye temperatures of Al-47wt.%Ni alloy that fabricated at different pressures were also calculated using the low temperature heat capacity curve.

scholarly journals Selection of Optimal Magnets for Traction Motors to Prevent Demagnetization

Machines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 124
Author(s):  
Dantam Rao ◽  
Madhan Bagianathan
Keyword(s):  
Flux Density ◽  
Electric Vehicles ◽  
Parallel Line ◽  
Low Grade ◽  
Lower Grade ◽  
Worst Case ◽  
Traction Motors ◽  
Knee Point ◽  
Point Of Intersection ◽  
Selection Of

Currently, permanent-magnet-type traction motors drive most electric vehicles. However, the potential demagnetization of magnets in these motors limits the performance of an electric vehicle. It is well known that during severe duty, the magnets are demagnetized if they operate beyond a ‘knee point’ in the B(H) curve. We show herein that the classic knee point definition can degrade a magnet by up to 4 grades. To prevent consequent excessive loss in performance, this paper defines the knee point k as the point of intersection of the B(H) curve and a parallel line that limits the reduction in its residual flux density to 1%. We show that operating above such a knee point will not be demagnetizing the magnets. It will also prevent a magnet from degenerating to a lower grade. The flux density at such a knee point, termed demag flux density, characterizes the onset of demagnetization. It rightly reflects the value of a magnet, so can be used as a basis to price the magnets. Including such knee points in the purchase specifications also helps avoid the penalty of getting the performance of a low-grade magnet out of a high-grade magnet. It also facilitates an accurate demagnetization analysis of traction motors in the worst-case conditions.

scholarly journals A Mixed-Method Design Approach for Empirically Based Selection of Unbiased Data Annotators

2021 ◽  
Author(s):  
Gautam Thakur ◽  
Janna Caspersen ◽  
Drahomira Herrmannova ◽  
Bryan Eaton ◽  
Jordan Burdette
Keyword(s):  
Mixed Method ◽  
Design Approach ◽  
Mixed Method Design ◽  
Selection Of

Investigation of Clamp Design for Temporary Attachment to Metal Pipe

1990 ◽  
Vol 112 (1) ◽  
pp. 92-96
Author(s):  
J. A. Johnson ◽  
J. M. Henderson
Keyword(s):  
Comparative Study ◽  
Relative Motion ◽  
Axial Force ◽  
Steel Pipe ◽  
Worst Case ◽  
Operating Condition ◽  
Metal Pipe

A comparative study of different configurations of locator pads used to attach a portable piping lathe to a section of steel pipe was performed. The axial force exerted by adjustment screws attached to the locator pads was determined experimentally. The minimum axial force required to restrain relative motion between the lathe and the pipe during a worst case operating condition was used as a criterion to determine the effectiveness of a particular contact pad. Six different geometric variations and two different materials were investigated and it was found that aluminum, in a simple configuration, provided the best clamping capability.

Enhanced Early Warning Diagnostic Rules for Gas Turbines Leveraging on Bayesian Networks

2020 ◽  
Author(s):  
Ernesto Escobedo ◽  
Liliana Arguello ◽  
Marzia Sepe ◽  
Ilaria Parrella ◽  
Stefano Cioncolini ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Probabilistic Approach ◽  
Training Dataset ◽  
Auxiliary Equipment ◽  
Data Set ◽  
Deep Dive ◽  
Industrial Systems ◽  
Business Application ◽  
Model Training ◽  
Selection Of

Abstract The monitoring and diagnostics of Industrial systems is increasing in complexity with larger volume of data collected and with many methods and analytics able to correlate data and events. The setup and training of these methods and analytics are one of the impacting factors in the selection of the most appropriate solution to provide an efficient and effective service, that requires the selection of the most suitable data set for training of models with consequent need of time and knowledge. The study and the related experiences proposed in this paper describe a methodology for tracking features, detecting outliers and derive, in a probabilistic way, diagnostic thresholds to be applied by means of hierarchical models that simplify or remove the selection of the proper training dataset by a subject matter expert at any deployment. This method applies to Industrial systems employing a large number of similar machines connected to a remote data center, with the purpose to alert one or more operators when a feature exceeds the healthy distribution. Some relevant use cases are presented for an aeroderivative gas turbine covering also its auxiliary equipment, with deep dive on the hydraulic starting system. The results, in terms of early anomaly detection and reduced model training effort, are compared with traditional monitoring approaches like fixed threshold. Moreover, this study explains the advantages of this probabilistic approach in a business application like the fleet monitoring and diagnostic advanced services.

Application of Variational Geometry to the Analysis of Mechanical Tolerances

1989 ◽  
Author(s):  
P. M. Martino ◽  
G. A. Gabriele
Keyword(s):  
Mechanical Design ◽  
Worst Case Analysis ◽  
Prototype System ◽  
Tolerance Design ◽  
Worst Case ◽  
Geometric Tolerances ◽  
Solid Models ◽  
The Cost ◽  
Selection Of

Abstract The proper selection of tolerances is an important part of mechanical design that can have a significant impact on the cost and quality of the final product. Yet, despite their importance, current techniques for tolerance design are rather primitive and often based on experience and trial and error. Better tolerance design methods have been proposed but are seldom used because of the difficulty in formulating the necessary design equations for practical problems. In this paper we propose a technique for the automatic formulation of the design equations, or design functions, which is based on the use of solid models and variational geometry. A prototype system has been developed which can model conventional and statistical tolernaces, and a limited set of geometric tolerances. The prototype system is limited to the modeling of single parts, but can perform both a worst case analysis and a statistical analysis. Results on several simple parts with known characteristics are presented which demonstrate the accuracy of the system and the types of analysis it can perform. The paper concludes with a discussion of extensions to the prototype system to a broader range of geometry and the handling of assemblies.

High Pressure Liquid Chromatography of Ester and Salt Formulations of 2-Methyl-4-Chlorophenoxyacetic Acid

1979 ◽  
Vol 62 (4) ◽  
pp. 738-741
Author(s):  
Timothy Stevens ◽  
Robert B Grorud
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Collaborative Study ◽  
Internal Standard ◽  
Hplc Method ◽  
Hplc Assay ◽  
High Pressure Liquid Chromatographic ◽  
Chlorophenoxyacetic Acid ◽  
Liquid Chromatographic ◽  
Selection Of

Abstract A high pressure liquid chromatographic (HPLC) assay of amine salt and ester formulations of MCPA has been collaboratively studied. The AOAC 2,4-D HPLC method has been modified for application to MCPA products. The MCPA methodology is identical to that of 2,4-D except in strength of mobile solvent, pH of mobile solvent, heating of ester formulations to 50°C to ensure complete saponification, and the use of glass microfiber filters. The method is specific and separates all known impurities. Examination of chromatograms and percentage results from 8 collaborators indicate that selection of a practical internal standard would improve precision in the procedure and a second collaborative study is recommended.

Sign in / Sign up

Export Citation Format

Share Document