In situ investigation of the impact of cyclic thermal variations impact on the mechanical properties of sandy soil.

2020 ◽  
Author(s):  
Sandrine Rosin-Paumier ◽  
Hossein Eslami ◽  
Farimah Masrouri
Keyword(s):  
Mechanical Properties ◽  
Sandy Soil ◽  
In Situ Investigation ◽  
Energy Piles ◽  
Before And After ◽  
Cyclic Variations ◽  
Loading Tests ◽  
Adjacent Soil ◽  
Comparison Of The Results ◽  
The Impact

<p>The incorporation of heat exchangers into geostructures leads to changes in the temperature of the adjacent soil, which may affect its hydro-mechanical properties. In this study, mini-pressiometer tests were carried out in the vicinity of three experimental energy piles of 12 meters length and 0.52-meter diameter installed in saturated sandy soil. Tests were carried out in three locations and in two different depths (namely 3 and 4 meters in depth) before and after cyclic variations of their temperature. The pressuremeter parameters are the pressuremeter modulus EM, the limit pressure PL and the creep-pressure Pf. These parameters characterize the properties of the soils; some measurements were done close to the energy piles (1.25 meters from the center of the pile) using a mini-pressuremeter cell (380 mm in height and 28 mm in diameter). The comparison of the results before and after the four warming-cooling cycles (8° to 19° C) showed a thin thickening of the material at 3 meters depth. These results are coherent with in-lab measurements and with the results of the pile loading tests carried out later on the same site.</p>

scholarly journals Effects of equal channel angular pressing and heat treatments on the microstructures and mechanical properties of selective laser melted and cast AlSi10Mg alloys

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Przemysław Snopiński ◽  
Mariusz Król ◽  
Marek Pagáč ◽  
Jana Petrů ◽  
Jiří Hajnyš ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Equal Channel Angular Pressing ◽  
Heat Treatments ◽  
Electron Backscattered Diffraction ◽  
Angular Pressing ◽  
Low Temperature Annealing ◽  
Transmission Electron ◽  
Before And After ◽  
The Impact

AbstractThis study investigated the impact of the equal channel angular pressing (ECAP) combined with heat treatments on the microstructure and mechanical properties of AlSi10Mg alloys fabricated via selective laser melting (SLM) and gravity casting. Special attention was directed towards determining the effect of post-fabrication heat treatments on the microstructural evolution of AlSi10Mg alloy fabricated using two different routes. Three initial alloy conditions were considered prior to ECAP deformation: (1) as-cast in solution treated (T4) condition, (2) SLM in T4 condition, (3) SLM subjected to low-temperature annealing. Light microscopy, transmission electron microscopy, X-ray diffraction line broadening analysis, and electron backscattered diffraction analysis were used to characterize the microstructures before and after ECAP. The results indicated that SLM followed by low-temperature annealing led to superior mechanical properties, relative to the two other conditions. Microscopic analyses revealed that the partial-cellular structure contributed to strong work hardening. This behavior enhanced the material’s strength because of the enhanced accumulation of geometrically necessary dislocations during ECAP deformation.

scholarly journals Influence of Mo Additions on the Mechanical Properties of Cast Duplex Stainless Steels before and after Thermal Aging

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 295
Author(s):  
Shilei Li ◽  
Yanli Wang ◽  
Xitao Wang
Keyword(s):  
Mechanical Properties ◽  
Stainless Steels ◽  
Thermal Aging ◽  
Decomposition Kinetics ◽  
Before And After ◽  
Mo Content ◽  
Impact Energies ◽  
The Impact ◽  
Hardness Values ◽  
Mo Additions

The influence of Mo additions on the mechanical properties of cast duplex stainless steel (CDSS) before and after thermal aging was investigated using a series of model alloys with different Mo contents ranging from 0 to 1.75 wt%. By increasing Mo content, the content, morphology, and distribution of ferrite in CDSS change significantly. After thermal aging at 400 °C for 3000 h, the impact properties of all CDSS specimens obviously decline, and their hardness values in ferrite significantly increase. The impact energies of the aged CDSS decline, and the proportion of cleavage features significantly increases with Mo content increasing. The spinodal decomposition kinetics in ferrite is not significantly affected by the Mo contents. High content and interconnected ferrite will lead to the severe embrittlement in CDSS after thermal aging.

Manufacture of Ultra-Dense Knitted Superelastic Structures

2018 ◽  
Author(s):  
Henry Koon ◽  
Jack Laven ◽  
Julianna Abel
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Cell Structure ◽  
Axial Loading ◽  
Consumer Products ◽  
Niti Shape Memory Alloy ◽  
Structural Element ◽  
Loading Tests ◽  
Structural Architecture ◽  
The Impact

Knitted Textiles made from Nickel-Titanium (NiTi) shape memory alloy wires are a new structural element with enhanced properties for a variety of applications. Potential advantages of this structural form include enhanced bending flexibility, tailorable in-plane, and through-thickness mechanical performance, and energy absorption and damping. Inspection of the knit pattern reveals a repeating cell structure of interlocking loops. Because of this repeating structure, knits can be evaluated as cellular structures that leverage their loop-based architecture for mechanical robustness and flexibility. The flexibility and robustness of the structure can be further enhanced by manufacturing with superelastic NiTi. The stiffness of superelastic NiTi, however, makes traditional knit manufacturing techniques inadequate, so knit manufacturing in this research is aided by shape setting the superelastic wire to a predefined pattern mimicking the natural curve of a strand within a knit fabric. This predefined shape-set geometry determines the outcome of the knit’s mechanical performance and tunes the mechanical properties. In this research, the impact of the shape setting process on the material itself is explored through axial loading tests to quantify the effect that heat treatment has on a knit sample. A means of continuously shape setting and feeding the wire into traditional knitting machines is described. These processes lend themselves to mass production and build upon previous textile manufacturing technologies. This research also proposes an empirical exploration of superelastic NiTi knit mechanical performance and several new techniques for manufacturing such knits with adjustable knit parameters. Displacement-controlled axial loading tests in the vertical (wale) direction determined the recoverability of each knit sample in the research and were iteratively increased until failure resulted. Knit samples showed recoverable axial strains of 65–140%, which could be moderately altered based on knit pattern and loop parameters. Furthermore, this research demonstrates that improving the density of the knit increases the stiffness of the knit without any loss in recoverable strains. These results highlight the potential of this unique structural architecture that could be used to design fabrics with adjustable mechanical properties, expanding the design space for aerospace structures, medical devices, and consumer products.

scholarly journals The degradation of mechanical properties in halloysite nanoclay–polyester nanocomposites exposed to diluted methanol

2016 ◽  
Vol 51 (11) ◽  
pp. 1653-1664 ◽  
Author(s):  
Mohd Shahneel Saharudin ◽  
Rasheed Atif ◽  
Islam Shyha ◽  
Fawad Inam
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Degradation Of Mechanical Properties ◽  
Before And After ◽  
The Matrix ◽  
Methanol Exposure ◽  
The Impact ◽  
And Storage ◽  
Methanol System ◽  
Methanol Absorption

The degradation of mechanical properties in halloysite nanoclay–polyester nanocomposites was studied after an exposure of 24 h in diluted methanol system by clamping test specimens across steel templates. The glass transition temperature ( Tg) and storage modulus increased steadily with the increase of halloysite nanoclays before and after diluted methanol exposure. The addition of nano-fillers was found to reduce liquid uptake by 0.6% in case of 1 wt% reinforcement compared to monolithic polyester. The mechanical properties of polyester-based nanocomposites were found to decrease as a result of diluted methanol absorption. After diluted methanol exposure, the maximum microhardness, tensile, flexural and impact toughness values were observed at 1 wt% of halloysite nanoclay. The microhardness increased from 203 to 294 HV (45% increase). The Young’s modulus increased from 0.49 to 0.83 GPa (70% increase) and the tensile strength increased from 23 to 27 MPa (17.4% increase). The impact toughness increased from 0.19 to 0.54 kJ/m2 in diluted methanol system (184% increase). Surprisingly, the fracture toughness of all types of nanocomposites was found to increase after exposing to diluted methanol due to plasticization effect. Scanning electron microscope images of the fractured surfaces of tensile specimens revealed that the methanol increased the ductility of the matrix and reduced the mechanical properties of the nanocomposites.

scholarly journals Thermomechanical Behavior of Energy Pile Embedded in Sandy Soil

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Xu Huang ◽  
Yajun Wu ◽  
Huaifeng Peng ◽  
Yaohu Hao ◽  
Chenyang Lu
Keyword(s):  
Sandy Soil ◽  
Thermal Effects ◽  
Load Transfer ◽  
Energy Pile ◽  
Capacity Change ◽  
Energy Piles ◽  
Different Temperatures ◽  
Loading Tests ◽  
Plastic Displacement ◽  
Aluminum Pipe

The traditional energy pile (solid energy pile) has been implemented for decades. However, the design of different kinds of energy piles is still not well understood. In this study, a series of model tests were performed on an aluminum pipe energy pile (PEP) in dry sandy soil to investigate the thermal effects on the mechanical behaviors of pipe energy pile. The thermal responses of the PEP were also analyzed. Steady temperatures of the PEP under different working conditions were also compared with that of the solid energy pile. Different loading tests were carried out on four pipe energy piles under three different temperatures of 5, 35, and 50°C, respectively. The bearing capacity change can be interpreted through the load-displacement curves. Experiment results were also compared with the solid energy pile to evaluate bearing capacities of the PEP and the solid energy pile under different temperature conditions. The mobilized shaft resistance was also calculated and compared with the solid energy pile data and the results show that the PEP has a similar load transfer mechanism with the solid energy pile. It could also be found that, for PEPs under working load, plastic displacement would appear after a whole heating cycle.

Effect of Heat Treatment on Microstructure Evolution and Mechanical Behavior of SKLB3 Alloy

2017 ◽  
Vol 898 ◽  
pp. 380-386
Author(s):  
Wei Yuan ◽  
Dong Mei Liu ◽  
Qiang Song Wang ◽  
Guo Liang Xie
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Energy ◽  
Hot Forging ◽  
Charpy Impact ◽  
Aging Treatment ◽  
Ni Alloy ◽  
Before And After ◽  
Different Temperatures ◽  
The Impact

In this paper, the effect of heat treatment on the microstructure and mechanical properties of hot forging Cu-Ni alloy was studied. Specimens of hot forged Cu-Ni alloy were subjected to first solution treated at 900oC for 2hrs and then aged at different temperatures for 2hrs. The mechanical properties including tensile performance and impact energy, and the microstructure were measured for specimens before and after heat treatment. The results show that both solution and aging treatment have an influence on the grain growth. After heat treatment, the tensile strength decreases very slightly but the yield strength decreases seriously from 235.96MPa to 136.12MPa, while the elongation increases sharply from 36% to 48%. It was also observed that hardness values of the heat-treated alloys are all lower than that of the hot forged alloy. The measurement of Charpy impact energy with V-type notch was performed at 298K and 77K for different specimens. At both temperatures, the impact energies of the specimens are higher than 200J. The microstructure results show that at both temperatures, the alloys are fractured in a ductile mode.

scholarly journals The Morphology, Structure, Mechanical Properties and Biocompatibility of Nanotubular Titania Coatings before and after Autoclaving Process

2019 ◽  
Vol 8 (2) ◽  
pp. 272 ◽  
Author(s):  
Aleksandra Radtke ◽  
Michalina Ehlert ◽  
Tomasz Jędrzejewski ◽  
Michał Bartmański
Keyword(s):  
Mechanical Properties ◽  
Adsorbed Water ◽  
Potential Range ◽  
Amorphous Titania ◽  
Before And After ◽  
Argon Stream ◽  
Titanium Alloy Ti6al4v ◽  
Diffuse Reflectance Infrared ◽  
Titania Coatings ◽  
The Impact

The autoclaving process is one of the sterilization procedures of implantable devices. Therefore, it is important to assess the impact of hot steam at high pressure on the morphology, structure, and properties of implants modified by nanocomposite coatings. In our works, we focused on studies on amorphous titania nanotubes produced by titanium alloy (Ti6Al4V) electrochemical oxidation in the potential range 5–60 V. Half of the samples were drying in argon stream at room temperature, and the second ones were drying additionally with the use of immersion in acetone and drying at 396 K. Samples were subjected to autoclaving and after sterilization they were structurally and morphologically characterized using Raman spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) and scanning electron microscopy (SEM). They were characterized in terms of wettability, mechanical properties, and biocompatibility. Obtained results proved that the autoclaving of amorphous titania nanotube coatings produced at lower potentials (5–15 V) does not affect their morphology and structure regardless of the drying method before autoclaving. Nanotubular coatings produced using higher potentials (20–60 V) require removal of adsorbed water particles from their surface. Otherwise, autoclaving leads to the destruction of the architecture of nanotubular coatings, which is associated with the changing of their mechanical and biointegration properties.

The Impact of Corrosion on the Mechanical Behavior of Bolt

2010 ◽  
Vol 168-170 ◽  
pp. 408-411
Author(s):  
Xiao Yong Li
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Corrosion Test ◽  
Laboratory Tests ◽  
Structural Integrity ◽  
Mechanical Performance ◽  
Rock Bolt ◽  
Before And After ◽  
The Impact ◽  
Strength And Ductility

Corrosion is a negative contributor on the structural integrity of rock bolt and leads to degradation of the mechanical properties of steel rock bolt. Exposure to chloride, seawater, salt and saltwater and deicing chemical environments influences rock bolt and weakens it. In order to evaluate the influence of corrosion and the size of the steel on the mechanical properties of rock bolt, an experimental investigation was conducted on rock bolt whose rebar is 8, 12, 16, and 18 mm diameter, and which were artificially corroded for 10, 20, 30, 45, 60, 90, and 120 days. By the simulation corrosion test of loaded and unloaded bolts in Na2SO4 solution, the relation curves of the mechanical performance with the corrosive conditions and the corrosion time are given. The mechanical performance is compared between these two types of bolts. At the same time, the influential trend of the load on the mechanical performance of the corroded bolt is analyzed. The laboratory tests suggest that corrosion duration and rebar size had a significant impact on the strength and ductility degradation of the specimens. after being corroded in Na2SO4 solution, both the ultimate bearing capacity and the maximal tensility of loaded bolt decrease far more than those of unloaded bolt, and the endurance and service life of loaded bolt will also be shortened much more severely. The tensile mechanical properties before and after corrosion indicated progressive variation and drastic drop in their values.

scholarly journals PENGARUH TEMPERATUR KALSINASI TERHADAP SIFAT MEKANIK MATERIAL SCAFFOLD HIDROKSIAPATIT DARI TULANG KAMBING

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Setiawan Eka Prawira ◽  
Joko Triyono ◽  
Teguh Triyono
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Calcination Temperature ◽  
Sem Analysis ◽  
Temperature Variations ◽  
Calcination Process ◽  
Before And After ◽  
Calcination Method ◽  
The Impact ◽  
High Calcination Temperature

<p><em>In this study, a preliminary study on the preparation of hydroxyapatite (HAp) as bone filler was made from sheep femur bone by calcination method</em><em>. The femur of the sheep is cut into a form of scaffold with dimensions of 5 mm x 5 mm x 5 mm. The calcination process is performed at four variations of temperature (700<sup>o</sup>C, 900<sup>o</sup>C, 1100<sup>o</sup>C, 1300<sup>o</sup>C). Characterization of scaffold material done before and after calcination process, it intended to find out the influence and relationship between calcination of temperature on the mechanical properties of SHA material. The results of hardness testing show that the higher calcination temperature then the SHA material hardness value also increased. The optimum hardness value occurs at 1100<sup>o</sup>C calcination temperature of 38.23±0.985VHN. Meanwhile, high calcination temperature will also decrease the compressive strength of SHA material. The value of the optimum compressive strength is achieved at 1100<sup>o</sup>C calcination temperature of 2.23±0.249 MPa. The morphology of SHA scaffold was analyzed by Scanning Electronic Microscopy (SEM). The observation of SEM shows the occurrence of porous interconnections in all temperature variations. SEM analysis results show that porous interconnect is formed at all temperature variations with diameter size ± 100-500μm. Very high calcination temperature will give the impact of HAp wall is getting thinner and the porous diameter is getting bigger. Porous interconnection damage is also seen at 1300°C which causes the mechanical properties of SHA to decrease.</em></p>

scholarly journals Impact of Drilling Fluid Contamination on Performance of Rock-Based Geopolymers

SPE Journal ◽  
2021 ◽  
pp. 1-8
Author(s):  
E. Eid ◽  
H. Tranggono ◽  
M. Khalifeh ◽  
S. Salehi ◽  
A. Saasen
Keyword(s):  
Mechanical Properties ◽  
Drilling Fluid ◽  
Petroleum Industry ◽  
Early Time ◽  
American Petroleum Institute ◽  
Drilling Fluids ◽  
Before And After ◽  
Pressure Water ◽  
Time Strength ◽  
The Impact

Summary Our objective is to present selected rheological and mechanical properties of rock-based geopolymers contaminated with different concentrations of drilling fluids. The possible flash setting and the maximum intake of drilling fluids before seeing a dramatic deterioration of the geopolymers are presented. Rock-based geopolymers designed for cementing conductor and surface casing were prepared and cured for up to 28 days at 22°C and atmospheric pressure. Water-based drilling fluids (WBDFs) and oil-based drilling fluids (OBDFs) were designed in accordance with the recommendations from the petroleum industry. The fluid samples were prepared, and their viscous behavior was characterized before and after hot-rolling. The geopolymeric slurries were mixed and then blended with the prepared drilling fluid volumes. The contaminated geopolymeric slurries were cured and tested at different time intervals. American Petroleum Institute (API) Class G neat cement was used as a reference. These samples were cured and contaminated with the same drilling fluids. The properties of contaminated geopolymer slurries were benchmarked with those of the contaminated Class G cement. The obtained mechanical properties showed that the rock-based geopolymers are more sensitive to WBDFs than to OBDFs. However, for contaminated Portland cement samples, the obtained results were opposite, and the contamination effect of OBDF on cement was more noticeable than WBDF. The impact of geopolymer contamination is a function of curing time. Although geopolymeric samples showed dramatic strength retrogression at the early time, strength buildup of the samples compensated for the impact of contamination.

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