Full-Scale Elevated Temperature Testing of Composite Repairs in Bending and Compression

2016 ◽  
Author(s):  
Colton Sheets ◽  
Robert Rettew ◽  
Chris Alexander ◽  
Tanya Axenova
Keyword(s):  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Water Immersion ◽  
Full Scale ◽  
Composite Repair ◽  
In Situ Conditions ◽  
Depth Analysis ◽  
Repair Systems ◽  
Full Scale Testing

The increasing use of composite repair systems in critical and complex applications has brought greater scrutiny to their design and performance. This has been especially true in high-temperature, immersed environment applications where ambient temperature test results with industry standard de-rating factors are all that is available for design. Since this approach does not always adequately capture environmental effects or the performance of composite systems at elevated temperatures, it is beneficial to perform full-scale testing which accurately replicates the in-situ application. In order to accomplish this, a full-scale testing program was developed that subjected multiple composite repair systems to internal and external loads at temperatures up to 120 °C with and without water immersion. This program involved the reinforcement of 12.75-inch × 0.375-inch pipe samples that had simulated corrosion defects. Full-scale load and pressure testing was conducted to simulate the long-term performance of the composite repair systems in the environmental conditions of the application. A strain based performance threshold of 0.4% strain at 120 °C and 100% SMYS was used to develop a competitive program that ranked the participating systems and reduced the number of acceptable repairs from six down to three. This approach increased the efficiency of the full-scale testing and allowed for more in-depth analysis of the top-performing systems. The results of the full-scale testing of six composite repair systems at elevated temperature allowed for a quantitative measure of their effectiveness under in-situ conditions. Several of the systems were shown to provide inadequate reinforcement under these conditions; however, it was also observed that appropriately designed and installed systems are capable of meeting the intense demands of elevated temperature, harsh-service conditions.

Experimental Study of Elevated Temperature Composite Repair Materials to Guide Integrity Decisions

2016 ◽  
Author(s):  
Colton Sheets ◽  
Robert Rettew ◽  
Chris Alexander ◽  
Denis Baranov ◽  
Patrick Harrell
Keyword(s):  
Experimental Study ◽  
Elevated Temperature ◽  
Composite Materials ◽  
Elevated Temperatures ◽  
Test Group ◽  
Small Scale ◽  
Composite Repair ◽  
Composite Systems ◽  
Repair Systems

Over the past two decades, a significant amount of research has been conducted on the use of composite materials for the repair and reinforcement of pipelines. This has led to vast improvements in the quality of composite systems used for pipeline repair and has increased the range of applications for which they are viable solutions (including corrosion and mechanical damage). By using composite repair systems, pipeline operators are often able to restore the structural integrity of damaged pipelines to levels equal to or even in excess of the original undamaged pipe. Although this research has led to substantial advancements in the quality of these repair systems, there are still specific applications where questions remain regarding the strength, durability, and effectiveness of composite repair systems, especially in elevated temperature, harsh environment conditions. This program initially involved composite repair systems from six manufacturers. The test group included both carbon and E-glass based systems. Performance based qualifications were used to reduce the size of the test group from the initial six systems down to three. The experimental study consisted of small-scale testing efforts that ranged from tensile tests performed over a range of temperatures to 10,000-hour material coupon tests at elevated temperatures. The elevated temperatures used for testing were intentionally selected by the operator to reflect the 248 °F design temperature of the target pipeline. Using small-scale qualification testing outlined in ASME PCC-2 – Repair of Pressure Equipment and Piping standard (Article 4.1, Nonmetallic Composite Repair Systems: High-Risk Applications) as a foundation, the test program described in this paper was able to demonstrate that, when properly designed, and installed, some composite materials are able to maintain their effectiveness at high temperatures. This study combined short-term and long-term testing of composite systems and demonstrated the advantages of a 10,000 hour test when aging properties are unknown. Finally, the study showed that, although high-temperature reinforcement using composite repair systems is feasible and commercially available, this capability is not standard practice across the composite repair industry. Proper analysis and verification using experimental methods, including full scale testing should be conducted prior to installation of a composite repair system in these types of harsh conditions.

Design of Pipeline Composite Repairs: From Lab Scale Tests to FEA and Full Scale Testing

2014 ◽  
Author(s):  
Remy Her ◽  
Jacques Renard ◽  
Vincent Gaffard ◽  
Yves Favry ◽  
Paul Wiet
Keyword(s):  
Finite Element ◽  
Full Scale ◽  
Combined Loading ◽  
Material Strength ◽  
Repair System ◽  
Loading Conditions ◽  
Original Design ◽  
Composite Repair ◽  
Repair Systems ◽  
Composite Properties

Composite repair systems are used for many years to restore locally the pipe strength where it has been affected by damage such as wall thickness reduction due to corrosion, dent, lamination or cracks. Composite repair systems are commonly qualified, designed and installed according to ASME PCC2 code or ISO 24817 standard requirements. In both of these codes, the Maximum Allowable Working Pressure (MAWP) of the damaged section must be determined to design the composite repair. To do so, codes such as ASME B31G for example for corrosion, are used. The composite repair systems is designed to “bridge the gap” between the MAWP of the damaged pipe and the original design pressure. The main weakness of available approaches is their applicability to combined loading conditions and various types of defects. The objective of this work is to set-up a “universal” methodology to design the composite repair by finite element calculations with directly taking into consideration the loading conditions and the influence of the defect on pipe strength (whatever its geometry and type). First a program of mechanical tests is defined to allow determining all the composite properties necessary to run the finite elements calculations. It consists in compression and tensile tests in various directions to account for the composite anisotropy and of Arcan tests to determine steel to composite interface behaviors in tension and shear. In parallel, a full scale burst test is performed on a repaired pipe section where a local wall thinning is previously machined. For this test, the composite repair was designed according to ISO 24817. Then, a finite element model integrating damaged pipe and composite repair system is built. It allowed simulating the test, comparing the results with experiments and validating damage models implemented to capture the various possible types of failures. In addition, sensitivity analysis considering composite properties variations evidenced by experiments are run. The composite behavior considered in this study is not time dependent. No degradation of the composite material strength due to ageing is taking into account. The roadmap for the next steps of this work is to clearly identify the ageing mechanisms, to perform tests in relevant conditions and to introduce ageing effects in the design process (and in particular in the composite constitutive laws).

scholarly journals A Review of Similitude Methods for Structural Engineering

2019 ◽  
Vol 71 (3) ◽  
Author(s):  
Alessandro Casaburo ◽  
Giuseppe Petrone ◽  
Francesco Franco ◽  
Sergio De Rosa
Keyword(s):  
Size Effects ◽  
Structural Engineering ◽  
Necessary Conditions ◽  
Rate Sensitivity ◽  
Full Scale ◽  
Test Article ◽  
Depth Analysis ◽  
Prototype Structure ◽  
Similitude Theory ◽  
Full Scale Testing

Similitude theory allows engineers, through a set of tools known as similitude methods, to establish the necessary conditions to design a scaled (up or down) model of a full-scale prototype structure. In recent years, to overcome the obstacles associated with full-scale testing, such as cost and setup, research on similitude methods has grown and their application has expanded into many branches of engineering. The aim of this paper is to provide as comprehensive a review as possible about similitude methods applied to structural engineering and their limitations due to size effects, rate sensitivity phenomena, etc. After a brief historical introduction and a more in-depth analysis of the main methods, the paper focuses on similitude applications classified, first, by test article, then by engineering fields.

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.

Composite Repair Performance at Elevated Temperatures

2014 ◽  
Author(s):  
Chris Alexander ◽  
Jim Souza ◽  
Casey Whalen
Keyword(s):  
Composite Materials ◽  
Elevated Temperatures ◽  
Critical Role ◽  
Ambient Conditions ◽  
Composite Repair ◽  
Repair Materials ◽  
Performance Curves ◽  
Repair Systems ◽  
Composite Repairs

For the better part of the past 20 years composite materials have been used to repair damaged piping and pressurized components in plants, refineries, and pipelines. The use of composite materials has been accompanied by comprehensive research programs focused on the development and assessment of using composite technology for restoring integrity to damaged piping and pressurized components. Of particular interest are composite repair standards such as ISO 24817 and ASME PCC-2 that provide technical guidance in how to properly design composite repair systems. The vast body of research completed to date has involved assessments at ambient conditions; however, at the present time there is significant interest in evaluating the performance of composite repair materials at elevated temperatures. This paper is focused on the topic of high temperature composite repairs and addresses the critical role of utilizing temperature-based mechanical properties to establish a composite repair design. The backbone of this effort is the development of composite performance curves that correlate change in strength as a function of temperature. A discussion on supporting full-scale pressure test results are included, along with guidance for users in how to properly design composite repair systems for applications at elevated temperatures.

Long-Term Duration of Composite Repair Systems for Pipeline Defects

2021 ◽  
Vol 1035 ◽  
pp. 870-877
Author(s):  
Lian Xun Ming ◽  
Deng Zun Yao ◽  
Bin Chen ◽  
Zhen Heng Teng ◽  
Lin Wang
Keyword(s):  
Composite Materials ◽  
Water Immersion ◽  
Prediction Equation ◽  
Field Application ◽  
Composite Repair ◽  
Micro Cracks ◽  
Aging Properties ◽  
Repair Systems ◽  
Hydrolysis Of

Composite repair systems of buried pipeline will be affected by moisture and other factors due to anti-corrosion and construction problems. These environmental factors will reduce the service life of the composite system. In this paper, the performance of composite and interface between composite and steel under the action of water were studied. It was found that the formation of micro-cracks on the surface of composite materials and the hydrolysis of epoxy resin were the important reasons for the Performance degradation. Moreover, the aging properties of composite materials and their interfaces under water immersion were analyzed by residual strength theory, and the life prediction equation of composite materials and interfaces were obtained, which can be useful to the field application of composite repair systems.

In Situ Testing and Heterogeneity of UFG Cu at Elevated Temperatures

2015 ◽  
Vol 1127 ◽  
pp. 67-72
Author(s):  
Martin Petrenec ◽  
Petr Král ◽  
Jiří Dvořák ◽  
Milan Svoboda ◽  
Vàclav Sklenička
Keyword(s):  
Elevated Temperature ◽  
Tensile Test ◽  
Grain Growth ◽  
Elevated Temperatures ◽  
Tensile Deformation ◽  
Constant Strain Rate ◽  
Electron Back Scatter Diffraction ◽  
Coarse Grained ◽  
Ultrafine Grained

Experiments were conducted to investigate deformation-induced processes during in-situ tensile test at elevated temperature. Consequently the microstructure after creep loading was examined by 3D Electron Back Scatter Diffraction (EBSD) technique. The billets of coarse-grained copper were processed by equal-channel angular pressing (ECAP) at room temperature using a die that had an internal angle of 90° between the two parts of the channel and an outer arc of curvature of ~ 20°, where these two parts intersect. The pressing speed was 10 mm/min. To obtain an ultrafine-grained (UFG) material, the billets were subsequently pressed by route Bc by 8 ECAP passes to give the mean grain size ~ 0.7 μm. The constant strain-rate test in tension was performed at 473 K using testing GATAN stage Microtest 2000EW with EH 2000 heated grips which is configured for in-situ electron back scatter diffraction (EBSD) observations. Microstructure was examined by FEG-SEM TESCAN MIRA 3 XM equipped by EBSD detector HKL NordlysMax from OXFORD INSTRUMENT. The tensile test was interrupted by fast stress reductions after different deformation step and observation of microstructure changes was performed. Despite of a considerable interest in ECAP processing method, there are not many works documenting microstructure evolution and changes during creep testing and determining creep mechanisms of ultrafine-grained materials processed by ECAP. It was found that creep resistance of UFG pure Al and Cu is considerably improved after one ECAP pass in comparison with coarse grained material, however, further repetitive pressing leads to a noticeable deterioration in creep properties of ECAP material. Recently it was observed the coarsening of the grains in microstructure of ECAP copper during creep at elevated temperature. It was suggested that creep behaviour is controlled by storage and dynamic recovery of dislocations at high-angle boundaries. In the present work was found that ultrafine-grained microstructure is instable and significant grain growth has already occurred during heating to the testing temperature. Static recrystallization during heating led to the formation of high fraction of special boundaries Σ3 and Σ9. The tensile deformation at 473 K led to the additional grain growth and formation of new grains. Microstructure was investigated also by 3D EBSD.

scholarly journals Influence of curing temperature and stress conditions on mechanical properties of cementing paste backfill

2016 ◽  
Vol 53 (1) ◽  
pp. 148-161 ◽  
Author(s):  
Megan L. Walske ◽  
Heather McWilliam ◽  
James Doherty ◽  
Andy Fourie
Keyword(s):  
Mechanical Properties ◽  
Effective Stress ◽  
Elevated Temperatures ◽  
Small Strain ◽  
Curing Temperature ◽  
Temperature Conditions ◽  
In Situ Conditions ◽  
Paste Backfill ◽  
Temperature Controlled

Cemented paste backfill (CPB) has been observed to achieve greater cemented strength when cured in situ compared with equivalent mixes cured and tested in a laboratory environment. This is in part due to the development of effective stress and generation of elevated temperatures by exothermic cement hydration reactions occurring during curing in a typical underground stope environment. This differs from curing in typical laboratory environments, where little or no effective stresses are generated and curing occurs under constant-temperature conditions. This paper outlines the development, calibration, and testing of a temperature-controlled hydration cell that provides closer representation of in situ conditions by controlling the rate and final amount of specimen temperature increase, in addition to curing under effective stress. The temperature-controlled hydration cell was used to examine the effect of curing under combined effective stress and temperature conditions on the development of small-strain stiffness over a 7 day curing period and the unconfined compressive strength at the end of this period. Curing with both elevated temperature and effective stress was found to significantly increase the mechanical properties of CPB compared with curing at elevated effective stress or ambient temperatures alone.

Numerical modelling of full-scale subsea lander Amalia with in situ conditions

2020 ◽  
Vol 173 (4) ◽  
pp. 110-119
Author(s):  
Filipe Assis Gonçalves ◽  
Miguel Onofre Gomes ◽  
Nuno Mathias ◽  
Tiago Morais ◽  
Tiago Ferradosa
Keyword(s):  
Numerical Modelling ◽  
Full Scale ◽  
In Situ Conditions

scholarly journals Fabrication, Microstructure, and Microhardness at High Temperature of In Situ Synthesized Ti3Al/Al2O3 Composites

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 617
Author(s):  
Do Thanh Binh ◽  
Tran Duc Huy ◽  
Tran Viet Thuong ◽  
Duong Ngoc Binh ◽  
Hiroyuki Miyamoto
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Planetary Mill ◽  
Argon Atmosphere ◽  
Powder Metallurgy Method ◽  
Microstructure Formation ◽  
Al2o3 Composite ◽  
Al2o3 Particles

In this study, in situ Al2O3-reinforced Ti3Al composite was fabricated after 8 h of milling and sintering at 850 °C. A mixture of TiO2 and Al powders were mechanically milled in a planetary mill, cold-compacted and sintered under a protected argon atmosphere. The microstructure and microhardness of the Al2O3 embedded in Ti3Al matrix at both room and elevated temperature has been reported. The obtained results showed that the Ti3Al/Al2O3 composite was successfully synthesized via the powder metallurgy method. Ti3Al phase and Al2O3 particles were formed after 8 h of milling and sintering at 850 °C. The microstructure formation of round and uniformly distributed Al2O3 particles in the Ti3Al matrix improved the microhardness of the composite. At normal temperature, the microhardness of the material measured about 11.5 GPa. Meanwhile, at elevated temperatures, from 600 to 800 °C, it decreased from 4.18 GPa to 3.15 GPa.

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