Corrosion Rates and Changes in Mechanical Properties of Copper Alloys due to Seawater Exposure

2012 ◽  
Author(s):  
Andrew Drach ◽  
Igor Tsukrov ◽  
Todd Gross ◽  
Uwe Hofmann ◽  
Jochen Aufrecht ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Prolonged Exposure ◽  
North Atlantic Ocean ◽  
Copper Alloys ◽  
Image Correlation ◽  
Correlation Technique ◽  
Rectangular Plates ◽  
Material Loss ◽  
The North ◽  
The Difference

A field study on corrosion was conducted on several copper alloys subjected to prolonged exposure in seawater. Rectangular plates made of nine alloys were deployed for a year in the North Atlantic Ocean. Material loss rates were quantified by measuring the difference in weight between the initial virgin specimens and the cleaned specimens after recovery. Changes in mechanical properties due to the seawater exposure were quantified by performing standard uniaxial tension tests. Stress-strain dependence was obtained for each of the tested materials using the digital image correlation technique. Some degradation of tensile strength was observed in all alloys, but for most of them it was not substantial.

scholarly journals Mechanical Properties of a Typical Jurassic Shaximiao Sandstone Under Subzero and Deep in situ Temperature Conditions

2021 ◽  
Vol 9 ◽  
Author(s):  
R. He ◽  
L. He ◽  
B. Guan ◽  
C. M. Yuan ◽  
J. Xie ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Crack Front ◽  
Image Correlation ◽  
Correlation Technique ◽  
Direct Tension ◽  
Reservoir Stimulation ◽  
The Difference ◽  
Lower Temperature ◽  
Highly Strained

Insight into the difference between the mechanical properties of rocks at low and in situ deep reservoir temperatures is vital for achieving a better understanding of fracking technologies with supercritical CO2 and liquid nitrogen. To address this issue, the fracking-related mechanical properties of the Shaximiao Formation sandstone (SS) were investigated through direct tension, uniaxial compression, and three-point bending fracture tests at a typical low temperature (Tlow) of −10°C and a reservoir temperature (Tin situ) of 70°C. The results showed that the tensile strength σt, compressive strength σc, and fracture toughness KIC of the SS were all higher at Tlow than at Tin situ, although to different extents. The KIC of the SS increased slightly more than σt at the lower temperature, while both σt and KIC of the SS increased significantly more than σc at the lower temperature. In addition to the strength, the stiffness (particularly the tensile stiffness) and the brittleness indices of SS were similarly higher at Tlow than at Tin situ. In situ monitoring using the digital image correlation technique revealed that a highly strained band (HSB) always appeared at the crack front. However, because of the inhomogeneous microstructure of the SS, the HSB did not always develop along the line connecting the notch tip to the loading point. This was a possible cause of the highly dispersed KIC values of the SS. The HSB at the crack front was notably narrower at Tlow than at Tin situ, suggesting that low temperatures suppress the plastic deformation of rocks and are therefore beneficial to reservoir stimulation.

An investigation of storm waves in the North Atlantic Ocean

1955 ◽  
Vol 230 (1183) ◽  
pp. 560-569 ◽  
Keyword(s):  
Wind Speed ◽  
Shallow Water ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Deep Ocean ◽  
The North ◽  
Storm Waves ◽  
The Difference ◽  
Tidal Streams ◽  
Wave Recorder

Since February 1953 the Ocean Weather Ship Weather Explorer , using a shipborne wave recorder, has taken records of waves at the positions ‘India’ (61° 00' N, 15° 20' W) and ‘Juliet’ (52° 20' N, 20° 00'W). An investigation of the records shows that conditions of wave generation in the deep ocean are different from those on the continental shelf. In both deep and shallow water, the steepness of the highest waves decreases as the fetch increases until an equilibrium value is reached after about 100 miles. In deep water this equilibrium value increases with the wind speed, whereas in shallow water it tends to decrease with wind speed. Different empirical rules are required for wave prediction in the deep ocean and the shallow sea. The difference can probably be attributed to a greater effect of turbulence near the coast, where the depth is of the same order as the wavelength and there are active tidal streams.

scholarly journals Local Mechanical Properties and Microstructure of EN AW 6082 Aluminium Alloy Processed via ECAP–Conform Technique

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2572 ◽  
Author(s):  
Radek Procházka ◽  
Peter Sláma ◽  
Jaromír Dlouhý ◽  
Pavel Konopík ◽  
Zuzanka Trojanová
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Tensile Testing ◽  
Electron Backscatter Diffraction ◽  
Extrusion Direction ◽  
Strain Differences ◽  
Image Correlation ◽  
Correlation Technique ◽  
Plastic Properties ◽  
2D Digital Image Correlation

An ultrafine-grained EN AW 6082 aluminum alloy was prepared by continuous serve plastic deformation (i.e., thermo-mechanical equal channel angular pressing (ECAP)–Conform process). A miniaturized tensile testing technique was used for estimating local mechanical properties with the aim to reveal the inhomogeneity of elastic and plastic properties in a workpiece volume. These inhomogeneities may appear due to the irregular shear strain distribution in a Conformed wire. Miniaturized samples for tensile testing were cut from the Conformed workpiece. Elongation of miniaturized samples was measured with a 2D digital image correlation technique as the optical extensometer. Tensile test characteristics, such as the yield strength and ultimate tensile strength, were consequently compared with results of conventional and hardness tests. The microstructure of Conformed bars was studied in the cross-section perpendicular and parallel to the extrusion direction using scanning electron microscope (SEM) and electron backscatter diffraction (EBSD) analysis. The microstructure of samples exhibits pronounced inhomogeneity, which is reflected by the hardness and tensile test results. Estimated distinctions between peripheral and central parts of the Conformed wires are probably a consequence of the significant strain differences realized in the upper and bottom wire parts.

Mechanical characterization of tetraxial textiles

2017 ◽  
Vol 48 (1) ◽  
pp. 3-24 ◽  
Author(s):  
Mehdi Ghazimoradi ◽  
Valter Carvelli ◽  
Maria Chiara Marchesi ◽  
Roberto Frassine
Keyword(s):  
Mechanical Properties ◽  
Strain Field ◽  
Mechanical Characterization ◽  
Tensile Tests ◽  
Image Correlation ◽  
Correlation Technique ◽  
Digital Image Correlation Technique ◽  
Experimental Campaign ◽  
Out Of Plane

In this paper, the mechanical properties of different tetraxial fabrics are investigated. Fabrics were produced using an innovative loom capable of weaving four threads at the same time with complete discretion of yarn type and count. The experimental investigation deals with in-plane and out-of-plane mechanical testing of tetraxial fabrics, as well as yarns made of four different materials (polyethylene terephthalate, glass, aramid, and basalt). The digital image correlation technique was used to measure the in-plane strain field for both uniaxial and biaxial tensile tests. The extensive experimental campaign allowed for a complete mechanical characterization of this novel fabric architecture including interlacement of different yarns.

Measurement of NOx and Ozone over the North Atlantic Ocean.

2020 ◽  
Author(s):  
James Lee ◽  
Freya Squires ◽  
Simone Andersen ◽  
Jim Hopkins ◽  
Dominika Pasternak ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Atmospheric Measurements ◽  
The North ◽  
Research Aircraft ◽  
Natural Emissions ◽  
The North Atlantic ◽  
The Difference ◽  
The Uk

<p>Tropospheric ozone (O<sub>3</sub>) can adversely affect human health and environmental ecosystems and it is therefore vitally important to understand its formation pathways from both natural and anthropogenic precursors. Background O<sub>3</sub> levels in the Northern Hemisphere have increased by more than a factor of two over the last century and it is believed that this increase is strongly tied to the increase in and distribution of anthropogenic nitrogen oxide (N0<sub>x</sub>) emissions. This is important as the changing level of O<sub>3</sub> in the background troposphere impacts the ability of countries downwind to achieve their air quality standards.</p><p>As part of the NERC funded North Atlantic Climate System Integrated Study (ACSiS) and Methane Observations and Yearly Assessments (MOYA) projects, multiple research flights have taken place over the North Atlantic Ocean, spanning an area from 55<sup>o</sup>N to 12<sup>o</sup>N and 8<sup>o</sup>W to 25<sup>o</sup>W using the UK’s large research aircraft (The Facility for Airborne Atmospheric Measurements – FAAM). Flights took place in all seasons from 2017 – 2020. A variety of gas and aerosol measurements were made, including NO<sub>x</sub>, O<sub>3, </sub>CO and a range of VOCs and an overview of the data is presented here. Measurements were taken in a range of air masses, including biomass burning outflow from West Africa, urban outflow from Europe and emissions from the busy shipping lanes to the West of Portugal.</p><p>Data was analysed to assess O<sub>3</sub> formation from the different emission sources, in particular examining the difference between anthropogenic and natural emissions. In addition, the output of regional chemistry models is compared to the data in order to assess the performance of the models in predicting O<sub>3</sub> and its precursors.</p>

Microstructure and mechanical properties of specimens produced using the wire-arc additive manufacturing process

2019 ◽  
pp. 095440621988332
Author(s):  
A Astarita ◽  
G Campatelli ◽  
P Corigliano ◽  
G Epasto ◽  
F Montevecchi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Tensile Tests ◽  
Mechanical Tests ◽  
Image Correlation ◽  
Correlation Technique ◽  
Layer Stacking ◽  
Static Tensile ◽  
X Ray Computed ◽  
Wire Arc Additive Manufacturing

The additive manufacturing technique is becoming popular and promising in recent years. Some steel ER70S-6 specimens were produced by wire arc additive manufacturing. Before the tensile tests, 3D X-ray computed tomography was applied to detect the presence of internal defects due to the production process. Static tensile tests were performed in order to analyze the influence of the different directions (deposition and layer stacking directions) on the mechanical properties. The digital image correlation technique was applied during the tests for detecting the displacement and strain fields, while infrared thermography was applied for detecting the temperature field of the specimen surface. After the mechanical tests, scanning electron microscopy was employed to analyze the fracture surfaces of the specimens. The results showed the presence of small defects that did not affect the mechanical properties of the specimens and no significant anisotropy was detected in the two directions (deposition and layer stacking directions).

Initial research of changes in mechanical properties of polymer-graphene composite with use of Digital Image Correlation

2020 ◽  
Vol 24 (4) ◽  
pp. 19-30
Author(s):  
Anna Makuch ◽  
Grzegorz Mońka ◽  
Joanna Klimek ◽  
Konstanty Skalski
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Correlation Technique ◽  
Camera System ◽  
Graphene Composite ◽  
Uniaxial Tensile Testing ◽  
The Impact

The problem of the possibility of using digital image correlation to assess changes in the mechanical properties of a polymer composite with the addition of graphene (1% by weight) in the form of flakes was taken up in the paper. Samples for uniaxial tensile testing were produced by selective laser sintering from polyamide powder particles and multi-flake graphene. In the tests carried out using the three-camera system, a variable strain distribution was recorded in the heterogenic PA-G composite material. Maps developed in the evaluation process – in particular, tangential deformations – allowed to conclude the impact of axial load on PA-G behaviour in time in the area of the polymer matrix, graphene agglomerates, and their interfaces. The research showed that the digital image correlation technique is a perfect complement to traditional mechanical tests when determining the properties of new heterogeneous composites, in particular, polyamide-graphene composite. Real-time observation of changes in the material map allows for a detailed analyzes of complex micromechanical aspects.

Sign in / Sign up

Export Citation Format

Share Document