Improved Friction Joint With Self-Locking Grips

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Andrei Costache ◽  
Kristian Glejbøl ◽  
Ion Marius Sivebæk ◽  
Christian Berggreen
Keyword(s):  
Load Transfer ◽  
Production Equipment ◽  
Experimental Results ◽  
Geometrical Parameters ◽  
Ongoing Research ◽  
Optimal Load ◽  
Test Parameters ◽  
Friction Joint ◽  
Flexible Risers ◽  
And Performance

Flexible risers are used in the oil industry to transport liquids and gas from the seafloor to extraction and production equipment at the sea surface. Ongoing research aims at using composite materials instead of steel, in order to reduce weight and increase stiffness. Ensuring an optimal load transfer between the composite and metal components is very important. This paper presents an improved method for anchoring a flat fiber-reinforced tendon using a double grip system with self-locking grips. The novelty is the combination of new experimental results and finite element (FE) analysis to develop a superior dry friction grip. Experimental results are carried using a dedicated test setup, through which the test parameters can be accurately controlled. The efficiency of the grip system during pullout is superior to results obtained with flat grips. Numerical results offer an in-depth understanding of the influence between friction, geometrical parameters, and performance, making it possible to optimize the design. Results show that this grip system offers immediate technical applications, in a variety of conditions.

Deformation at interfaces of Ti-6Al-4V/SiC fiber composites

1992 ◽  
Vol 50 (1) ◽  
pp. 158-159
Author(s):  
Warren J. Moberly ◽  
Daniel B. Miracle ◽  
S. Krishnamurthy
Keyword(s):  
Thermal Stresses ◽  
Load Transfer ◽  
Coefficient Of Thermal Expansion ◽  
Hot Isostatic Pressing ◽  
Matrix Composites ◽  
Ongoing Research ◽  
Aerospace Applications ◽  
Sic Fiber ◽  
The Matrix ◽  
Intermetallic Matrix Composites

Titanium-aluminum alloy metal matrix composites (MMC) and Ti-Al intermetallic matrix composites (IMC), reinforced with continuous SCS6 SiC fibers are leading candidates for high temperature aerospace applications such as the National Aerospace Plane (NASP). The nature of deformation at fiber / matrix interfaces is characterized in this ongoing research. One major concern is the mismatch in coefficient of thermal expansion (CTE) between the Ti-based matrix and the SiC fiber. This can lead to thermal stresses upon cooling down from the temperature incurred during hot isostatic pressing (HIP), which are sufficient to cause yielding in the matrix, and/or lead to fatigue from the thermal cycling that will be incurred during application, A second concern is the load transfer, from fiber to matrix, that is required if/when fiber fracture occurs. In both cases the stresses in the matrix are most severe at the interlace.

Platform Independent Analysis of Probabilities on Multithreaded Programs

2013 ◽  
Vol 1 (3) ◽  
pp. 48-65
Author(s):  
Yuting Chen
Keyword(s):  
Operating System ◽  
Static Analysis ◽  
Main Idea ◽  
Experimental Results ◽  
Machine To Machine ◽  
Concurrent Program ◽  
Acceptable Accuracy ◽  
Multithreaded Programs ◽  
Independent Analysis ◽  
And Performance

A concurrent program is intuitively associated with probability: the executions of the program can produce nondeterministic execution program paths due to the interleavings of threads, whereas some paths can always be executed more frequently than the others. An exploration of the probabilities on the execution paths is expected to provide engineers or compilers with support in helping, either at coding phase or at compile time, to optimize some hottest paths. However, it is not easy to take a static analysis of the probabilities on a concurrent program in that the scheduling of threads of a concurrent program usually depends on the operating system and hardware (e.g., processor) on which the program is executed, which may be vary from machine to machine. In this paper the authors propose a platform independent approach, called ProbPP, to analyzing probabilities on the execution paths of the multithreaded programs. The main idea of ProbPP is to calculate the probabilities on the basis of two kinds of probabilities: Primitive Dependent Probabilities (PDPs) representing the control dependent probabilities among the program statements and Thread Execution Probabilities (TEPs) representing the probabilities of threads being scheduled to execute. The authors have also conducted two preliminary experiments to evaluate the effectiveness and performance of ProbPP, and the experimental results show that ProbPP can provide engineers with acceptable accuracy.

Current Status, Design and Performance Trends for the Regenerative Flow Compressors and Pumps

2002 ◽  
Author(s):  
Mukarrum Raheel ◽  
Abraham Engeda
Keyword(s):  
Performance Improvement ◽  
Current Status ◽  
Ongoing Research ◽  
Performance Trends ◽  
The Family ◽  
Working Principle ◽  
Low Specific Speed ◽  
And Performance ◽  
Number Of Publications ◽  
Regenerative Flow

Regenerative flow compressors and pumps, hereafter called RFC/RFP have found many applications in industry; still they are the most neglected turbomachines in the family of dynamic compressors. The number of publications existing in literature is very small compared to the large number of papers about the centrifugal and axial turbocompressors. This paper gives a detail discussion of fundamentals and working principle of regenerative turbomachines. Regenerative compressors are compared with centrifugal compressors and the importance of regenerative turbomachines in low specific speed range is emphasized. The major findings of available literature on regenerative turbomachine are summarized. The current status, limitations and some of the challenges faced by RFC/RFP are assessed in context of performance improvement. The paper concludes with an overview of ongoing research and future directions to be followed for performance improvement of this neglected class of turbomachines.

scholarly journals Microcontroller Based Flexible Modulation Scheme of MLI Operation for Selective Lower Levels: A Knowledge Based Approach

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
R. K. Dhatrak ◽  
R. K. Nema ◽  
D. M. Deshpande
Keyword(s):  
Pulse Generation ◽  
Multilevel Inverter ◽  
Experimental Results ◽  
Modulation Scheme ◽  
Inductive Load ◽  
Medium Voltage ◽  
Knowledge Based ◽  
Common Mode Voltage ◽  
Power Modules ◽  
And Performance

In today’s industrial world multilevel inverter (MLI) got a significant importance in medium voltage application and also a very potential topic for researchers. It is experienced that studying and comparing results of multilevel inverter (MLI) at distinct levels are a costlier and time consuming issue for any researcher if he fabricate different inverters for each level, as designing power modules simultaneously for different level is a cumbersome task. In this paper a flexible quotient has been proposed to recognize possible conversion of available MLI to few lower level inverters by appropriately changing microcontroller programming. This is an attempt to obtain such change in levels through simulation using MATLAB Simulink on inductive load which may also be applied to induction motor. Experimental results of pulse generation using dsPIC33EP256MC202 demonstrate the feasibility of proposed scheme. Proposed flexible quotient successfully demonstrates that a five-level inverter may be operated as three and two levels also. The paper focuses on odd levels only as common mode voltage (CMV) can be reduced to zero and performance of drives is better than even level. Simulated and experimental results are given in paper.

scholarly journals Production Quality Improvements and Energy Cost Reductions Associated With Compressed Air

2006 ◽  
Author(s):  
Mark Krisa ◽  
David Voelker
Keyword(s):  
Production Quality ◽  
Production Equipment ◽  
Compressed Air ◽  
Quality Improvements ◽  
Citrus Industry ◽  
Point Of Use ◽  
Discharge Location ◽  
Supply Equipment ◽  
The Difference ◽  
And Performance

Compressed air is utilized throughout various production processes in the citrus industry and can influence production quality and operating costs. Within production equipment, compressed air is expanded from a higher pressure to perform various tasks. The pressure ahead of the final discharge location can have a direct impact on the operation of the specific process. Article pressure is the term used to describe the pressure located closest to the point where air is expanded to do work. Article pressure can be influenced by many variables that exist between supply equipment (compressors) and the point of use. Understanding the relationship between the supply pressure and the article pressure will facilitate the ability to maximize the repeatability and performance of production equipment and minimize the supply power required to operate the compressed air system. This paper will discuss variables that influence the difference between the pressure supplied by the compressor station and the pressure utilized within the production equipment. Illustrations and field examples will be utilized to describe issues. Troubleshooting methods will be discussed along with a description of how to trend variables that influence production so problems can be corrected before they influence productivity. Paper published with permission.

Experimental and Theoretical Investigation of Performance of a Solar Chimney Model Part II: Model Development and Validation

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Ibrahim A Abuashe ◽  
Bashir H Arebi ◽  
Essaied M Shuia
Keyword(s):  
Mathematical Model ◽  
Power Output ◽  
Model Development ◽  
Geometrical Parameters ◽  
Balance Equations ◽  
Solar Chimney ◽  
And Performance ◽  
Development And Validation ◽  
The Mathematical Model ◽  
Good Agreement

A mathematical model based on the momentum, continuity and energy balance equations was developed to simulate the behavior of the air flow inside the solar chimney system. The model can estimate the power output and performance of solar chimney systems. The developed mathematical model is validated by the experimental data that were collected from small pilot solar chimney; (experiment was presented in part I). Good agreement was obtained between the experimental results and that from the mathematical model. The model can be used to analyze the solar chimney systems and to determine the effect of geometrical parameters such as chimney height and collector diameter on the power output and the efficiency of the system

Effects of Multi-Robot Team Formations on Distributed Area Coverage

2019 ◽  
pp. 1192-1219
Author(s):  
Prithviraj Dasgupta ◽  
Taylor Whipple ◽  
Ke Cheng
Keyword(s):  
Mobile Robots ◽  
Area Coverage ◽  
Experimental Results ◽  
Wheel Slip ◽  
Robot System ◽  
Multiple Mobile Robots ◽  
Unknown Environment ◽  
Robot Teams ◽  
And Performance ◽  
Multi Robot

This paper examines the problem of distributed coverage of an initially unknown environment using a multi-robot system. Specifically, focus is on a coverage technique for coordinating teams of multiple mobile robots that are deployed and maintained in a certain formation while covering the environment. The technique is analyzed theoretically and experimentally to verify its operation and performance within the Webots robot simulator, as well as on physical robots. Experimental results show that the described coverage technique with robot teams moving in formation can perform comparably with a technique where the robots move individually while covering the environment. The authors also quantify the effect of various parameters of the system, such as the size of the robot teams, the presence of localization, and wheel slip noise, as well as environment related features like the size of the environment and the presence of obstacles and walls on the performance of the area coverage operation.

Indiana Subdrainage Experience and Application

1996 ◽  
Vol 1519 (1) ◽  
pp. 41-50
Author(s):  
Hossam F. Hassan ◽  
Thomas D. White ◽  
Rebecca McDaniel ◽  
David Andrewski
Keyword(s):  
Data Acquisition ◽  
Test Site ◽  
Ongoing Research ◽  
Pressure Transducers ◽  
Camera Systems ◽  
Maintenance Program ◽  
Inspection And Maintenance ◽  
And Performance ◽  
Moisture Conditions ◽  
Pavement Instrumentation

The applications of pavement subdrainage in the state of Indiana are presented. A recent study evaluated pavement subdrainage systems and measured and predicted moisture conditions underneath various types of pavements. Camera systems were used for internal inspection of the edge and geocomposite drains. Pavement instrumentation included moisture blocks, pressure transducers, temperature probes, rain and outflow tipping buckets, and a data acquisition system. Ongoing research using a test site on I-469 at Fort Wayne, Indiana, is aimed at finding the optimum location and layer configuration in flexible pavement; it uses those instruments as well as a TDR system, neutron probes, resistivity probe trees, and an enhanced data acquisition process. The research is a long-term project that will build on the data base of material hydraulic characteristics and performance. Indiana Department of Transportation has formed a committee to address issues related to use of subdrainage. Some of the recommendations from the committee were to abandon geocomposite drains, use bigger concrete protector walls at outlet pipes, and implement a routine inspection and maintenance program for drainage systems.

Precision Diagnosis of Electric Multiple Units for Performance Evaluation

2007 ◽  
Vol 353-358 ◽  
pp. 2585-2588 ◽  
Author(s):  
Jeong Guk Kim ◽  
Kyung Taek Park ◽  
Sung Cheol Yoon ◽  
Sung Tae Kwon
Keyword(s):  
Load Transfer ◽  
Three Dimensional ◽  
Engineering Analysis ◽  
Actual Performance ◽  
Analysis Techniques ◽  
Electrical Systems ◽  
Dimensional Measurements ◽  
Wear Evaluation ◽  
And Performance ◽  
Multiple Units

The precision diagnosis of subway electric multiple units (EMUs) was conducted with various types of engineering analysis techniques for the current performance and wear evaluation. The evaluation was conducted on detailed parts of EMUs, such as car bodies, bogies, braking systems, and electrical systems of EMUs. Several characterization means including nondestructive evaluation techniques, corrosion testing, and three-dimensional measurements, were employed for the evaluation of car bodies and bogies. For braking system, degradation and performance tests were conducted, while the functional and degradation tests were performed on electrical system in order to identify the actual performance of the system. Moreover, stress and structural analyses using commercial finite element method (FEM) software provided important information on stress distribution and load transfer mechanisms. In this investigation, various advanced engineering analysis techniques for the safety analysis of subway EMUs have been introduced and the analysis results have been used to provide the critical information for the criteria of safety assessment.

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