scholarly journals Laboratory tests of soil-shell structures made of GRP - an evaluation of the soil medium

2018 ◽  
Vol 45 ◽  
pp. 00002
Author(s):  
Tomasz Abel
Keyword(s):  
Cross Sections ◽  
Circular Cross Section ◽  
High Strength ◽  
Shell Structures ◽  
Soil Medium ◽  
Section Shape ◽  
New Material ◽  
Materials Used ◽  
Laboratory Models ◽  
Made In

Soil-shell structures have been widely used for many years in road and network constructions where there are collisions of transport linear structures. A benefit of using such structures is the speed of construction and the durability of the materials used. Despite the wide use of different types of materials, in particular steel shells, new material solutions are still being sought. One material that has been used successfully for many years in the construction of underground network facilities is plastic from the group of duroplasts. Composite profiles with cross-sections reaching up to 3.0 m can be used in the construction of pipe culverts. These culverts are not only objects with a circular cross-section shape, but also other shapes with very good hydraulic parameters and high strength parameters. In order to determine the dependence between the strength of a composite shell and the surrounding soil, a series of tests of laboratory models made in a natural scale were carried out. The aim of the research was to determine the possibility of using duroplastic structures as culverts located under traffic routes, and to also determine the scope of cooperation of the structure with the soil medium and their mutual dependencies.

scholarly journals Study on Crush Tube Geometric Cross sections and Topology for Axial Crashworthiness

2020 ◽  
Vol 70 (3) ◽  
pp. 249-259
Author(s):  
T.J. Reddy ◽  
V. Narayanamurthy ◽  
Y.V.D. Rao
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Circular Cross Section ◽  
Road Vehicles ◽  
Element Analysis ◽  
Impact Forces ◽  
Axial Crush ◽  
Section Shape ◽  
Energy Absorbing ◽  
Initial Peak

Crush tubes are used as crash impact energy absorbing structure (EAS) and are located in the frontal compartment of road vehicles. Ideal crashworthiness of an EAS mandates that the equivalent decelerations due to impact forces should to be ≤ 20g; and crush force and stroke efficiencies should tend to unity. It is understood from the literature that no single geometric cross-section shape exhibits a near-ideal crashworthiness; and most EAS members exhibit a high initial peak crush force which is detrimental to the occupant safety, and moderate stroke and crush force efficiencies leading to a compromise in the total energy absorbed. In this paper, finite element analysis (FEA) methodology is formulated and experimentally validated for axial crush of a crush tube of SS304 material with circular cross section.  Subsequently, plastic deformation phenomenon and folding patterns in relation to crush force behaviour of crush tubes with various basic cross-sections of polygonal geometric shapes from triangle to octagon and circle are extensively studied through FEA. Further, two new geometric cross-section profiles with combination of basic shapes are proposed to combine the merits of different basic shapes. The crashworthiness of all basic cross-sections including the two proposed cross-section profiles is assessed based on standard parameters. The proposed new geometries may form a basis for the development of new EAS configurations for enhanced crashworthiness.

SCHMELZMETALL HOVADUR CCZ

Alloy Digest ◽  
2020 ◽  
Vol 69 (9) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Spot Welding ◽  
Zirconium Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Softening Temperature ◽  
Aged Condition ◽  
Heat Treated ◽  
High Softening Temperature ◽  
Made In

Abstract Schmelzmetall Hovadur CCZ is a heat-treatable, copper-chromium-zirconium alloy. In the solution heat-treated and artificially aged condition, this alloy exhibits high thermal and electrical conductivity along with high strength and a high softening temperature. Hovadur CCZ evolved from CuCr1 (CW105C), a precipitation-hardenable alloy first made in the 1930s for spot welding electrodes, for which strength and hardness at temperatures up to 500 °C (930 °F), as well as good electrical and thermal conductivity, are essential. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: Cu-912. Producer or source: Schmelzmetall AG.

On the generalized model of shell structures with functional cross-sections

2021 ◽  
pp. 114192
Author(s):  
Shahriar Dastjerdi ◽  
Mohammad Malikan ◽  
Victor A. Eremeyev ◽  
Bekir Akgöz ◽  
Ömer Civalek
Keyword(s):  
Cross Sections ◽  
Shell Structures ◽  
Generalized Model

scholarly journals Environmentally Friendly, High-Performance Fire Retardant Made from Cellulose and Graphite

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2400
Author(s):  
Leandra P. Santos ◽  
Douglas S. da Silva ◽  
Thais H. Morari ◽  
Fernando Galembeck
Keyword(s):  
High Performance ◽  
Raw Materials ◽  
Fire Retardant ◽  
Visual Observation ◽  
Flame Resistance ◽  
New Developments ◽  
New Class ◽  
New Material ◽  
Accredited Laboratory ◽  
Materials Used

Many materials and additives perform well as fire retardants and suppressants, but there is an ever-growing list of unfulfilled demands requiring new developments. This work explores the outstanding dispersant and adhesive performances of cellulose to create a new effective fire-retardant: exfoliated and reassembled graphite (ERG). This is a new 2D polyfunctional material formed by drying aqueous dispersions of graphite and cellulose on wood, canvas, and other lignocellulosic materials, thus producing adherent layers that reduce the damage caused by a flame to the substrates. Visual observation, thermal images and surface temperature measurements reveal fast heat transfer away from the flamed spots, suppressing flare formation. Pinewood coated with ERG underwent standard flame resistance tests in an accredited laboratory, reaching the highest possible class for combustible substrates. The fire-retardant performance of ERG derives from its thermal stability in air and from its ability to transfer heat to the environment, by conduction and radiation. This new material may thus lead a new class of flame-retardant coatings based on a hitherto unexplored mechanism for fire retardation and showing several technical advantages: the precursor dispersions are water-based, the raw materials used are commodities, and the production process can be performed on commonly used equipment with minimal waste.

scholarly journals Asymptotic Behavior of Stable Structures Made of Beams

2021 ◽  
Author(s):  
Georges Griso ◽  
Larysa Khilkova ◽  
Julia Orlik ◽  
Olena Sivak
Keyword(s):  
Asymptotic Behavior ◽  
Cross Section ◽  
Cross Sections ◽  
Linear Elasticity ◽  
Circular Cross Section ◽  
Linear Elasticity Theory ◽  
Linear Elastic ◽  
The Cross ◽  
Small Rotation ◽  
Stable Structures

AbstractIn this paper, we study the asymptotic behavior of an $\varepsilon $ ε -periodic 3D stable structure made of beams of circular cross-section of radius $r$ r when the periodicity parameter $\varepsilon $ ε and the ratio ${r/\varepsilon }$ r / ε simultaneously tend to 0. The analysis is performed within the frame of linear elasticity theory and it is based on the known decomposition of the beam displacements into a beam centerline displacement, a small rotation of the cross-sections and a warping (the deformation of the cross-sections). This decomposition allows to obtain Korn type inequalities. We introduce two unfolding operators, one for the homogenization of the set of beam centerlines and another for the dimension reduction of the beams. The limit homogenized problem is still a linear elastic, second order PDE.

scholarly journals Effect of liquid cooling on PCR performance with the parametric study of cross-section shapes of microchannels

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yousef Alihosseini ◽  
Mohammad Reza Azaddel ◽  
Sahel Moslemi ◽  
Mehdi Mohammadi ◽  
Ali Pormohammad ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Heat Sink ◽  
Evaluation Criteria ◽  
Circular Cross Section ◽  
Microchannel Heat Sink ◽  
Liquid Cooling ◽  
Maximum Heat ◽  
Maximum Heat Transfer

AbstractIn recent years, PCR-based methods as a rapid and high accurate technique in the industry and medical fields have been expanded rapidly. Where we are faced with the COVID-19 pandemic, the necessity of a rapid diagnosis has felt more than ever. In the current interdisciplinary study, we have proposed, developed, and characterized a state-of-the-art liquid cooling design to accelerate the PCR procedure. A numerical simulation approach is utilized to evaluate 15 different cross-sections of the microchannel heat sink and select the best shape to achieve this goal. Also, crucial heat sink parameters are characterized, e.g., heat transfer coefficient, pressure drop, performance evaluation criteria, and fluid flow. The achieved result showed that the circular cross-section is the most efficient shape for the microchannel heat sink, which has a maximum heat transfer enhancement of 25% compared to the square shape at the Reynolds number of 1150. In the next phase of the study, the circular cross-section microchannel is located below the PCR device to evaluate the cooling rate of the PCR. Also, the results demonstrate that it takes 16.5 s to cool saliva samples in the PCR well, which saves up to 157.5 s for the whole amplification procedure compared to the conventional air fans. Another advantage of using the microchannel heat sink is that it takes up a little space compared to other common cooling methods.

Numerical Investigation of Cross-Section on Aluminum A6063 Thin-Walled Structures under Low-Velocity Impact Loading

2014 ◽  
Vol 1019 ◽  
pp. 96-102
Author(s):  
Ali Taherkhani ◽  
Ali Alavi Nia
Keyword(s):  
Energy Absorption ◽  
Cross Section ◽  
Cross Sections ◽  
Peak Load ◽  
Circular Cross Section ◽  
Absorption Capacity ◽  
Energy Absorption Capacity ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
Crush Strength

In this study, the energy absorption capacity and crush strength of cylindrical thin-walled structures is investigated using nonlinear Finite Elements code LS-DYNA. For the thin-walled structure, Aluminum A6063 is used and its behaviour is modeled using power-law equation. In order to better investigate the performance of tubes, the simulation was also carried out on structures with other types of cross-sections such as triangle, square, rectangle, and hexagonal, and their results, namely, energy absorption, crush strength, peak load, and the displacement at the end of tubes was compared to each other. It was seen that the circular cross-section has the highest energy absorption capacity and crush strength, while they are the lowest for the triangular cross-section. It was concluded that increasing the number of sides increases the energy absorption capacity and the crush strength. On the other hand, by comparing the results between the square and rectangular cross-sections, it can be found out that eliminating the symmetry of the cross-section decreases the energy absorption capacity and the crush strength. The crush behaviour of the structure was also studied by changing the mass and the velocity of the striker, simultaneously while its total kinetic energy is kept constant. It was seen that the energy absorption of the structure is more sensitive to the striker velocity than its mass.

scholarly journals Corrosion Study on Wellbore Materials for the CO2 Injection Process

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 115
Author(s):  
Le Quynh Hoa ◽  
Ralph Bäßler ◽  
Dirk Bettge ◽  
Enrico Buggisch ◽  
Bernadette Nicole Schiller ◽  
...  
Keyword(s):  
Cross Sections ◽  
Low Cost ◽  
Co2 Injection ◽  
Uniform Corrosion ◽  
Injection Wells ◽  
Safety Issues ◽  
Carbonation Process ◽  
Injection Process ◽  
Materials Used ◽  
Low Alloyed Steel

For reliability and safety issues of injection wells, corrosion resistance of materials used needs to be determined. Herein, representative low-cost materials, including carbon steel X70/1.8977 and low alloyed steel 1.7225, were embedded in mortar to mimic the realistic casing-mortar interface. Two types of cement were investigated: (1) Dyckerhoff Variodur commercial Portland cement, representing a highly acidic resistant cement and (2) Wollastonite, which can react with CO2 and become stable under a CO2 stream due to the carbonation process. Exposure tests were performed under 10 MPa and at 333 K in artificial aquifer fluid for up to 20 weeks, revealing crevice corrosion and uniform corrosion instead of expected pitting corrosion. To clarify the role of cement, simulated pore water was made by dispersing cement powder in aquifer fluid and used as a solution to expose steels. Surface analysis, accompanied by element mapping on exposed specimens and their cross-sections, was carried out to trace the chloride intrusion and corrosion process that followed.

Implementation of HSLA-100 Steel in Aircraft Carrier Construction—CVN 74

1995 ◽  
Vol 11 (02) ◽  
pp. 97-101
Author(s):  
J. P. Christein ◽  
J. L. Warren
Keyword(s):  
Hydrogen Embrittlement ◽  
High Strength ◽  
High Yield ◽  
Aircraft Carrier ◽  
Implementation Plan ◽  
New Material ◽  
Welding Procedure

High strength low alloy (HSLA)-100 steel was developed to be less sensitive to hydrogen embrittlement than high yield (HY)-100 steel. The primary benefits sought through the use of this new steel were savings in energy, labor, and scheduling that would result from reduced preheat for welding. This paper reviews the overall efforts required to implement the use of HSLA-100 steel during CVN 74 aircraft carrier construction. It discusses the engineering and design effort required to incorporate a new material on a vessel midway through construction. Also included is a discussion of the development of an implementation plan which ensures successful welding procedure qualification, production welding, and inspection of HSLA-100 welds. Results confirm that HSLA-100 steel can be successfully substituted for HV-100 steel in a shipyard environment, and that significant benefits can be realized from reduced welding preheat. Also, key elements of future applications of HSLA-100 are presented.

Torsion of Noncylindrical Shafts of Circular Cross Section

1950 ◽  
Vol 17 (3) ◽  
pp. 275-282
Author(s):  
H. J. Reissner ◽  
G. J. Wennagel
Keyword(s):  
Cross Sections ◽  
Inverse Method ◽  
Direct Method ◽  
Circular Cross Section ◽  
Theory Of Elasticity ◽  
Elementary Functions ◽  
Single Term ◽  
Circumferential Displacement ◽  
Basic Differential Equation ◽  
Technical Interest

Abstract The theory of torsion of noncylindrical bodies of revolution, initiated by J. H. Michell and A. Föppl, is stated by a basic differential equation of the circumferential displacement and by a boundary condition of the shear stress along the generator surface. The solution of these two equations by the “direct” method of first assuming the boundary shape has not lent itself to closed solutions in terms of elementary functions, so that only approximation, infinite series, and experimental methods have been applied. A semi-inverse method analogous to Saint Venant’s semi-inverse method for cylindrical bodies has the disadvantage of the restriction to special boundary shapes but the advantage of exact solutions by means of elementary functions. By this method, bodies of conical, ellipsoidal, and hyperbolic boundary shapes have been obtained in a simple analysis. One class of integrals leading to other boundary shapes seems not to have been analyzed up to now, namely, the integrals in the form of a product of two functions of, respectively, axial (z) and radial (r) co-ordinates. A first suggestion of this possibility was given in Love’s treatise on the mathematical theory of elasticity. In the present paper, the classes of boundary shapes, displacements, and stress distributions are investigated analytically and numerically. The extent of the numerical investigation contains only the results of single-term integrals for full and hollow cross sections of technical interest. The detailed analysis of the boundary shapes, following from series integrals, presents essential mathematical obstacles. Overcoming these difficulties might lead to a multitude of solutions of interesting boundary shapes, and stress and strain distribution.

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