Advanced Techniques for Establishing Long-Term Performance of Composite Repair Systems

2014 ◽  
Author(s):  
Chris Alexander
Keyword(s):  
The United States ◽  
Operating Conditions ◽  
Repair System ◽  
Composite Repair ◽  
Design Life ◽  
Repair Systems ◽  
Long Term Performance ◽  
Term Performance ◽  
Composite Repairs

Although composite materials are used to repair and reinforce a variety of anomalies in high pressure transmission gas and liquid pipelines, there continues to be widespread debate regarding what constitutes a long-term composite repair. The United States regulations require that composite repairs must be able to permanently restore the serviceability of the repaired pipeline, while in contrast the Canadian regulations take a more prescriptive approach by integrating the ASME PCC-2 and ISO 24817 composite repair standards along with a requirement for establishing a 50-year design life. In this paper the author provides a framework for what should be considered in qualifying a composite repair system for long-term performance by focusing on the critical technical aspects associated with a sound composite repair. The presentation includes a discussion on establishing an appropriate composite design stress using the existing standards, using full-scale testing to ensure that stresses in the repair do not exceed the designated composite design stresses, and guidance for operators in how to properly integrate their pipeline operating conditions to establish a design life. By implementing the recommendations presented in this paper, operators will be equipped with a resource for objectively evaluating the composite repair systems used to repair their pipeline systems.

Advanced Insights on Composite Repairs

2012 ◽  
Author(s):  
Chris Alexander ◽  
Jim Souza
Keyword(s):  
Composite Materials ◽  
Test Sample ◽  
Repair System ◽  
Strain Gages ◽  
Composite Repair ◽  
Pressure Cycling ◽  
Repair Systems ◽  
Long Term Performance ◽  
Term Performance

In response to inquiries from pipeline operators regarding the long-term performance of composite materials, manufacturers have performed additional tests to evaluate the performance of their composite repair systems. Insights were gained through these additional tests that demonstrated the long-term worthiness of the composite system. Of particular importance were two types of tests. The first involved the application of strain gages between layers of the composite repair system that was used to reinforce a corroded pipe test sample. As the sample was pressurized the strain gages permitted a comparison between the measured values and design stresses per the ASME PCC-2 design code. The second series of tests involved pressure cycling a 75% corroded sample to failure. In addition to the inter-layer strain measurements, the pressure cycling provides an important insight regarding the long-term performance of the composite repair. This paper addresses how the ASME PCC-2 Code, along with additional well-designed tests, can be used to design a composite repair system to ensure that it adequately reinforces a given defect. As composite materials are being used to repair pipeline anomalies beyond the corrosion-only defects, it is essential that pipeline operators utilize a systematic approach for ensuring the long-term performance of composite repair systems.

State of the Art Assessment of Composite Systems Used to Repair Transmission Pipelines

2006 ◽  
Author(s):  
Chris Alexander ◽  
Bob Francini
Keyword(s):  
Composite Materials ◽  
Third Party ◽  
Composite Repair ◽  
Critical Elements ◽  
Research Organizations ◽  
Repair Systems ◽  
Long Term Performance ◽  
Term Performance ◽  
Transmission Pipelines

For the past decade there has been relatively wide acceptance in using composite materials to repair damaged gas and liquid transmission pipelines. There have been numerous independent research programs performed by pipeline companies, research organizations, and manufacturers that have contributed to the acceptance of composites as a legitimate repair material. Additionally, insights have been gained by both pipeline operators and composite repair manufacturers during field installations. ASME has also responded by adding sections to both the ASME B31.4 and B31.8 pipeline codes, as well as currently developing a repair standard for non-metallic composite repair systems by the Post Construction Committee. Stress Engineering Services, Inc. and Kiefner & Associates, Inc. have been integrally involved in assessing the repair of pipeline systems, with the former having been involved in performing full-scale testing and analysis on most of the major U.S.-based composite repair systems. The purpose of this paper is to provide for the pipeline industry a third-party evaluation of composite repair systems and information that is needed to properly evaluate how composite materials should be used to repair high pressure pipelines. The contents of the paper will include discussions on what critical elements should be evaluated for each composite system, items of caution and concern, and the importance of evaluation to ensure safe long-term performance.

scholarly journals Intelligent long-term performance analysis in power electronics systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Saeed Peyghami ◽  
Tomislav Dragicevic ◽  
Frede Blaabjerg
Keyword(s):  
Performance Indicator ◽  
Thermal Characteristics ◽  
Operating Conditions ◽  
System Level ◽  
Power Electronic ◽  
Reliability Modeling ◽  
Artificial Neural Network Ann ◽  
Long Term Performance ◽  
Term Performance

AbstractThis paper proposes a long-term performance indicator for power electronic converters based on their reliability. The converter reliability is represented by the proposed constant lifetime curves, which have been developed using Artificial Neural Network (ANN) under different operating conditions. Unlike the state-of-the-art theoretical reliability modeling approaches, which employ detailed electro-thermal characteristics and lifetime models of converter components, the proposed method provides a nonparametric surrogate model of the converter based on limited non-linear data from theoretical reliability analysis. The proposed approach can quickly predict the converter lifetime under given operating conditions without a further need for extended, time-consuming electro-thermal analysis. Moreover, the proposed lifetime curves can present the long-term performance of converters facilitating optimal system-level design for reliability, reliable operation and maintenance planning in power electronic systems. Numerical case studies evaluate the effectiveness of the proposed reliability modeling approach.

Investigation of long-term operation and biomass activity in a membrane bioreactor system

2011 ◽  
Vol 63 (9) ◽  
pp. 1906-1912 ◽  
Author(s):  
Simos Malamis ◽  
Andreas Andreadakis ◽  
Daniel Mamais ◽  
Constantinos Noutsopoulos
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Operating Conditions ◽  
Term Operation ◽  
Solids Retention ◽  
Biomass Activity ◽  
Long Term Performance ◽  
Term Performance

The aim of this work was to evaluate the long-term performance of a Membrane Bioreactor (MBR) that operated continuously for 2.5 years and to assess membrane fouling and biomass activity under various operating conditions. Furthermore, a method for the characterisation of influent wastewater was developed based on its separation into various fractions. The MBR system operated at the solids retention times (SRT) of 10, 15, 20 and 33 days. The increase of SRT resulted in a decrease of the fouling rate associated with the reduction of extracellular polymeric substances. Moreover, the SRT increase resulted in a significant reduction of the Oxygen Uptake Rate (OUR) due to the lower availability of substrate and in a notable decrease of the maximum OUR since high SRT allowed the development of slower growing microorganisms. Biomass consisted of small flocs due to extensive deflocculation caused by intense aeration. Finally, the method developed for wastewater characterisation is straightforward and less time consuming than the usual method that is employed.

Long-Term Evaluation of the Bonding Strength of Composite Repairs

2012 ◽  
Author(s):  
Khalid Farrag ◽  
Kevin Stutenberg
Keyword(s):  
Shear Strength ◽  
Elevated Temperatures ◽  
Water Solution ◽  
Effect Of Temperature ◽  
Shear Tests ◽  
Composite Repair ◽  
Testing Program ◽  
Repair Systems ◽  
Composite Repairs

The long-term performance of composite repair systems depends on their structural integrity and interaction with the carrier pipe. The adhesives used in the composites are critical components that not only bond the repair to the pipe, but also bond the individual layers of the repair to one another. The durability of the inter-laminate adhesive bond is required to ensure adequate load transfer between the pipe and the composite layers over the predicted lifetime of the repair. A testing program was performed to evaluate the shear strength of the adhesives used in composite repairs. The testing program evaluated the performance of seven commercially-available composite repair systems and it consisted of short-term and long-term shear tests on the adhesives and cathodic disbondment tests on the repair systems. The long-term shear tests were performed for 10,000 hours on samples submerged in a water solution with pH value of 9 and at various loading levels at temperatures of 70°F, 105°F and 140°F. The results of the long-term tests at elevated temperatures were extrapolated to predict the shear strengths at longer durations. The 20-year shear strengths of the composites were estimated using: (a) direct extrapolation of the best-fit curves and (b) the application of the rate process procedure. The results demonstrated the significant effect of temperature on the bond strength of the composites and provided a comparative analysis to evaluate the long-term shear strength and cathodic disbondment of the composite repair systems.

Updated Review of Stone Matrix Asphalt and Superpave® Projects

2003 ◽  
Vol 1832 (1) ◽  
pp. 217-223 ◽  
Author(s):  
Donald E. Watson
Keyword(s):  
Material Properties ◽  
The United States ◽  
Mix Design ◽  
Stone Matrix Asphalt ◽  
High Traffic Volume ◽  
Long Term Performance ◽  
Term Performance ◽  
Stone Matrix

Stone matrix asphalt (SMA) and Superpave® represent relatively new mix design technologies in the United States. Therefore, a condition survey was conducted of mixes that had been in service for several years to evaluate the long-term performance of SMA and Superpave projects. This study is a follow-up to a 1995 review of SMA projects and a 1998 review of Superpave projects. Both SMA and Superpave are acknowledged to be rut-resistant mixes, and this resistance was shown to be the case during this project review. However, a significant amount of cracking occurred early in the life of some of these mixtures. Overall, the SMA mixtures appeared to be more durable than the Superpave mixtures evaluated. The SMA mixtures have been in place about 2½ years longer than the Superpave mixtures, but the overall condition is about the same. Some of the primary conclusions from the survey are as follows: both SMA and Superpave mixtures were shown to be rut-resistant even when placed on facilities with high traffic volume; much of the observed cracking, especially load cracking, appeared to be more related to problems other than mix design or material properties; and SMA mixtures can be expected to last longer than Superpave mixtures before reaching the same condition level.

Long-term Performance Analysis of CdTe PV module in real operating conditions

2018 ◽  
Vol 5 (11) ◽  
pp. 23210-23217 ◽  
Author(s):  
Rahul Rawat ◽  
S.C. Kaushik ◽  
O.S. Sastry ◽  
Birinchi Bora ◽  
Y.K. Singh
Keyword(s):  
Performance Analysis ◽  
Operating Conditions ◽  
Pv Module ◽  
Long Term Performance ◽  
Term Performance

Doe Progress in Assessing the Long Term Performance of Waste Package Materials

1986 ◽  
Vol 84 ◽  
Author(s):  
A. Berusch ◽  
E. Gause
Keyword(s):  
Site Characterization ◽  
The United States ◽  
High Level Waste ◽  
Design Studies ◽  
Waste Package ◽  
License Application ◽  
High Level ◽  
Long Term Performance ◽  
Term Performance

Summary:Each of the projects has made significant progress toward the eventual operation of a repository for the disposal of high-level radioactive wastes in the United States. Although much has been accomplished, much remains to be done. For example, the Site Characterization Plans for BWIP and NNWSI are nearing completion to be followed by initiation of site characterization activities. The Site Characterization Plan for the selected salt site is scheduled for completion later in 1987. Waste package advanced conceptual design studies are currently scheduled to begin at each project before the end of FY 1987. These efforts will lead to selections of concepts to be detailed in the license application design phase. Compliance with the NRC criteria that require long-term waste package performance will be demonstrated by DOE by performing all of the aforementioned activities. In doing so, the DOE will also be assured that its plan for the safe disposal of high-level waste will be satisfactorily implemented.

Asphalt Trackbed Technology Development: The First 20 Years

2000 ◽  
Vol 1713 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jerry G. Rose ◽  
E. Ray Brown ◽  
Monica L. Osborne
Keyword(s):  
Technology Development ◽  
The United States ◽  
Optimum Moisture Content ◽  
Performance Evaluations ◽  
Track Structure ◽  
Maintenance Costs ◽  
Rail Network ◽  
Long Term Performance ◽  
Term Performance

The evolution of hot-mix asphalt (HMA) trackbed technology is documented as presently practiced in the United States. Criteria used in selecting sites for and the attendant benefits of HMA trackbeds, based on long-term performance evaluations, are discussed. Prevailing practices for selecting ideal HMA mix parameters, trackbed section designs, and application procedures are described in detail. Primary attention is directed at the “underlayment” procedure in which the HMA serves as a premium subballast layer within the track structure to enhance the support, waterproofing, and confinement properties of the subballast. The roadbed or subgrade materials underlying the HMA mats maintain near-optimum moisture content. The HMA appears to undergo little if any weathering or deterioration in the trackbed environment. The resultant benefits are decreased maintenance costs, fewer slow orders, fewer operational interferences, and improved operational efficiency of the rail network overall.

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