scholarly journals Roll Bonding of Al-Based Composite Reinforced with C10 Steel Expanded Mesh Inlay

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1044
Author(s):  
Yaroslav Frolov ◽  
Maxim Nosko ◽  
Andrii Samsonenko ◽  
Oleksandr Bobukh ◽  
Oleg Remez
Keyword(s):  
Impact Energy ◽  
High Efficiency ◽  
Shape Change ◽  
Experimental Investigations ◽  
Aluminum Composite ◽  
Rolling Mills ◽  
Roll Bonding ◽  
Finite Element Software ◽  
Steel Mesh ◽  
Bonded Composite

The most complex issue related to the design of high efficiency composite materials is the behavior of the reinforcing component during the bonding process. This study presents numerical and experimental investigations of the shape change in the reinforcing inlay in an aluminum-steel mesh-aluminum composite during roll-bonding. A flat composite material consisting of two outer strips of an EN AW 1050 alloy and an inlay of expanded C10 steel mesh was obtained via hot roll bonding with nominal rolling reductions of 20%, 30%, 40% and 50% at a temperature of 500 °C. The experimental procedure was carried out using two separate rolling mills with diameters equal to 135 and 200 mm, respectively. A computer simulation of the roll bonding was performed using the finite element software QForm 9.0.10 by Micas Simulations Limited, Oxford, UK. The distortion of the mesh evaluated via the change in angle between its strands was described using computer tomography scanning. The dependence of the absorbed impact energy of the roll bonded composite on the parameters of the deformation zone was found. The results of the numerical simulation of the steel mesh shape change during roll bonding concur with the data from micro-CT scans of the composites. The diameter of rolls applied during the roll bonding, along with rolling reduction and temperature, have an influence on the resulting mechanical properties, i.e., the absorbed bending energy. Generally, the composites with reinforcement exhibit up to 20% higher impact energy in comparison with the non-reinforced composites.

scholarly journals Low Power Cusped Field Thruster Developed for the Space-Borne Gravitational Wave Detection Mission in China

2021 ◽  
Vol 11 (14) ◽  
pp. 6549
Author(s):  
Hui Liu ◽  
Ming Zeng ◽  
Xiang Niu ◽  
Hongyan Huang ◽  
Daren Yu
Keyword(s):  
Low Power ◽  
Gravitational Wave ◽  
Attitude Control ◽  
High Efficiency ◽  
Experimental Investigations ◽  
Attitude Control System ◽  
Gravitational Wave Detection ◽  
Wave Detection ◽  
Wide Range ◽  
Institute Of Technology

The microthruster is the crucial device of the drag-free attitude control system, essential for the space-borne gravitational wave detection mission. The cusped field thruster (also called the High Efficiency Multistage Plasma Thruster) becomes one of the candidate thrusters for the mission due to its low complexity and potential long life over a wide range of thrust. However, the prescribed minimum of thrust and thrust noise are considerable obstacles to downscaling works on cusped field thrusters. This article reviews the development of the low power cusped field thruster at the Harbin Institute of Technology since 2012, including the design of prototypes, experimental investigations and simulation studies. Progress has been made on the downscaling of cusped field thrusters, and a new concept of microwave discharge cusped field thruster has been introduced.

scholarly journals Experimental Evaluation of Airlift Performance for Vertical Pumping of Water in Underground Mines

2021 ◽  
Author(s):  
Parviz Enany ◽  
Oleksandr Shevchenko ◽  
Carsten Drebenstedt
Keyword(s):  
Water Flow ◽  
High Efficiency ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Injection System ◽  
Experimental Investigations ◽  
Flow Mode ◽  
New Device ◽  
Riser Pipe ◽  
Airlift Pump

AbstractThis paper presents experimental studies on the optimization of air–water flow in an airlift pump. Airlift pumps use compressed gas to verticall transport liquids and slurries. Due to the lack of theoretical equations for designing and predicting flow regimes, experimental investigations must be carried out to find the best condition to operate an airlift pump at high efficiency. We used a new air injection system and different submergence ratios to evaluate the output of a simple pump for vertical displacement of water in an underground mine. The tests were carried out in a new device with 5.64 m height and 10.2 cm circular riser pipe. Three air-jacket pipes, at different gas flows in the range of 0.002–0.09 m3/s were investigated with eight submergence ratios. It was found that with the same air flow rate, the most efficient flow of water was achieved when an air jacket with 3 mm diameter holes was used with a submergence ratio between 0.6 and 0.75. In addition, a comparison of practical results with two theoretical models proposed by other investigators showed that neither was able to accurately predict airlift performance in air–water flow mode.

Impact Dynamics Analysis of Shed Tunnel Structure Hit by Collapse Rock-Fall

2011 ◽  
Vol 99-100 ◽  
pp. 1023-1026 ◽  
Author(s):  
Lu Yang ◽  
Shi Min Li ◽  
Dai Heng Chen ◽  
Zhi Min Wu
Keyword(s):  
Contact Force ◽  
Impact Energy ◽  
Incident Angle ◽  
Great Influence ◽  
Rock Fall ◽  
Tunnel Structure ◽  
Protective Structure ◽  
Additional Energy ◽  
Finite Element Software ◽  
The Impact

This paper bases on the prototype of the actual shed tunnel structure, study on contact force, displacement, damage, energy of shed tunnel under impact of rock-fall. By ABAQUS finite element software to simulate the process of roll-fall impact knowable: Rock-fall at different speeds and incident angle shocks on shed tunnel has great influence to concrete protective structure of contact force and displacement; Concrete protective structure damage the worst hit area of occurred with roll-fall contact area, the second is inclined leg column top and in connection with the pillars of the beam damage is also very serious, In practical projects first should pay attention to strengthen the intensity of the pillars with beam joints and prevent damage; From the angle of energy we can see that shed tunnel is mainly through the concrete protective structure to absorb and consumption impact energy, soil cushion absorption and consumption impact energy is very limited, to alleviate the impact of concrete protective layer rolling damage, and suggestions in shed tunnel bearing place additional energy shock absorber to increases protection structure system soft degrees under the condition of minimize the shed tunnel weight, achieve the purpose of decrease shock energy.

Ultrasonic Vibration-Assisted Laser Engineered Net Shaping of Inconel 718 Parts: Microstructural and Mechanical Characterization

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Fuda Ning ◽  
Yingbin Hu ◽  
Zhichao Liu ◽  
Xinlin Wang ◽  
Yuzhou Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ultrasonic Vibration ◽  
Inconel 718 ◽  
High Efficiency ◽  
Experimental Investigations ◽  
Laser Engineered Net Shaping ◽  
Average Grain Size ◽  
Fabrication Defects ◽  
Heterogeneous Microstructures ◽  
Net Shaping

Laser engineered net shaping (LENS) has become a promising technology in direct manufacturing or repairing of high-performance metal parts. Investigations on LENS manufacturing of Inconel 718 (IN718) parts have been conducted for potential applications in the aircraft turbine component manufacturing or repairing. Fabrication defects, such as pores and heterogeneous microstructures, are inevitably induced in the parts, affecting part qualities and mechanical properties. Therefore, it is necessary to investigate a high-efficiency LENS process for the high-quality IN718 part fabrication. Ultrasonic vibration has been implemented into various melting material solidification processes for part performance improvements. However, there is a lack of studies on the utilization of ultrasonic vibration in LENS process for IN718 part manufacturing. In this paper, ultrasonic vibration-assisted (UV-A) LENS process is, thus, proposed to fabricate IN718 parts for the potential reduction of fabrication defects. Experimental investigations are conducted to study the effects of ultrasonic vibration on microstructures and mechanical properties of LENS-fabricated parts under two levels of laser power. The results showed that ultrasonic vibration could reduce the mean porosity to 0.1%, refine the microstructure with an average grain size of 5 μm, and fragment the detrimental Laves precipitated phase into small particles in a uniform distribution, thus enhancing yield strength, ultimate tensile strength (UTS), microhardness, and wear resistance of the fabricated IN718 parts.

Design and HIL Validation of an Effective Super-Twisting Controller for Stick-Slip Suppression in Drill-String Systems

2021 ◽  
Author(s):  
Abdelbasset Krama ◽  
Mohamed Gharib ◽  
Shady S. Refaat ◽  
Alan Palazzolo
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Sliding Mode ◽  
Drill String ◽  
Experimental Investigations ◽  
Small Scale ◽  
Oil Well ◽  
Stick Slip ◽  
Rock Interaction ◽  
The Real

Abstract This paper presents a novel controller for drill string systems based on a super-twisting sliding mode theory. The aim is to eliminate the stick-slip vibration and maintain a constant drill string velocity at the desired reference value. The proposed controller inherently attenuates the torsional vibration while ensuring the stability and high efficiency of the drill string. A discontinuous lumped-parameter torsional model of vertical drill strings based on four components (rotary table, drill pipes, drill collars and drill bit) is considered. The Karnopp friction model is adopted to simulate the nonlinear bit-rock interaction phenomena. In order to provide a more accurate evaluation, the proposed drill string controller is implemented with the induction motor, a variable frequency drive and a gearbox to closely mirror the real environment of oil well drill strings. The increasing demand for prototyping and testing high-power plants in realistic and safe environments has led to the advancement of new types of experimental investigations without hurting the real system or building a small-scale prototype for testing. The dynamic performance of the proposed controller has been investigated with MATLAB software as well as in a novel hardware in-the-loop (HIL) testing platform. A power plant is modeled and implemented in the real-time simulator OPAL-RT 5600, whereas the controllers are implemented in the dSPACE 1103 control board. The results obtained through simulation and HIL testing demonstrate the feasibility and high performance of the proposed controller.

scholarly journals Skew Rolling of Rods from Scrap Rail Heads

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2970 ◽  
Author(s):  
Tomczak ◽  
Pater ◽  
Bulzak
Keyword(s):  
Experimental Tests ◽  
Rolling Process ◽  
Industrial Applications ◽  
Experimental Investigations ◽  
Longitudinal Rolling ◽  
Rolling Mills ◽  
Second Stage ◽  
New Process ◽  
Skew Rolling ◽  
Theoretical Considerations

This paper presents the results of theoretical and experimental investigations of a new process of rolling rods from scrap rail heads. First, the industrial applications of scrap railway rails and methods of their recycling are discussed, and then the concept of two-stage rolling of rods from heads cut off from scrap rails is proposed. In the first stage of the process, a rail head preform was rolled in a hexagonal pass of a longitudinal rolling mill. Then in the second stage, the hexagonal bar was skew rolled into a rod in a helical roll pass. Theoretical considerations were based on finite element numerical modelling. The rolling process was simulated under 3D deformation using Forge NxT v.1.1 software developed by Transvalor Company. Calculations were carried out to determine the material flow kinematics, strength, and thermal parameters of the process and to identify the phenomena that might constrain its implementation. The numerical results were verified in experimental tests, during which preforms and rods were formed from scrap rail heads. The tests were conducted in longitudinal and skew rolling mills. The results indicate that rods can be effectively formed from scrap rail heads in just two steps. Rods obtained using the proposed method can be used as full-featured, semifinished products for the manufacture of various types of machine parts.

scholarly journals Acoustic monitoring of a prestressed concrete beam reinforced by adhesively bonded composite

2018 ◽  
Vol 199 ◽  
pp. 09013
Author(s):  
Sylvain Chataigner ◽  
Laurent Gaillet ◽  
Yannick Falaise ◽  
Jean-François David ◽  
Richard Michel ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Concrete Structures ◽  
Experimental Investigations ◽  
Adhesively Bonded ◽  
Shear Tests ◽  
Prestressed Concrete Beam ◽  
Bonded Composite ◽  
Composite Reinforcement

The use of adhesively bonded composite reinforcement is relatively widely used for concrete structures. Yet, some questions remain regarding its use in the case of prestressed concrete structures especially in relation with the influence of existing cracking and the verification of the encountered damage phenomena at real scale. French National Organism CEREMA with the help of French motorway bridge owners association ASFA and French National Research Organism IFSTTAR realized several real size experimental investigations of an old prestressed concrete beam coming from a deconstructed bridge to answer these questions (Project CLERVAL). Both flexure and shear tests up to failure were carried out and several measurement methods were used to understand the role of the composite reinforcement on the behavior of the structure and the damage scenario. Acoustic emission was one of these methods and two different systems were investigated. The proposed communication will first describe the two used acoustic systems and their dedication (localized acoustic emission and overall acoustic survey). A specific development will then be presented aiming at optimizing the obtained acoustic phenomena localization taking into account the anisotropy of the prestressed concrete beam. Finally, main results will then be presented for both flexure and shear tests.

Toward 20% Efficiency With a-Si // poly-Si Tandem Solar Cell

1992 ◽  
Vol 258 ◽  
Author(s):  
M. Yoshimi ◽  
W. Ma ◽  
T. Horiuchi ◽  
C. C. Lim ◽  
S. C. De ◽  
...  
Keyword(s):  
Solar Cell ◽  
High Efficiency ◽  
Low Cost ◽  
Cell Structure ◽  
Experimental Investigations ◽  
Total Efficiency ◽  
Tandem Solar Cell ◽  
Structure Variation ◽  
Technical Data ◽  
Bottom Cell

ABSTRACTA series of experimental investigations has been made on the a-Si // poly-Si tandem solar cell which is one of the most promised candidate of high cost-performance photovoltaic cell, e.g., high efficiency, low cost with almost no light induced degradation. Employing high conductivity with wide optical band gap p type microcrystalline SiC (μ-SiC) as a window material together with a-SiC as an interface buffer layer and also n type μc-Si as a back ohmic contact layer in the poly-Si based bottom cell, the conversion efficiency of 17.2 % has been obtained. Combining an optically transparent a-Si p-i-n cell as a top cell with an optical coupler between the top and the poly-Si bottom cell, a total efficiency of 20.3 % has been obtained so far on the four-terminal stacked mode structure. A systematic technical data for the optimization of cell structure variation on the developed tandem solar cells are presented and further possibility to improving the performance are discussed.

Adaptable pneumatic shock absorber

2018 ◽  
Vol 25 (3) ◽  
pp. 711-721 ◽  
Author(s):  
Rami Faraj ◽  
Cezary Graczykowski ◽  
Jan Holnicki-Szulc
Keyword(s):  
Active Control ◽  
Smart Materials ◽  
Shock Absorber ◽  
High Efficiency ◽  
Low Cost ◽  
Electronic System ◽  
Experimental Investigations ◽  
Adaptation Mechanism ◽  
Impact Absorption ◽  
Pneumatic Shock

Recent progress in the field of sensors, actuators, and smart materials allows the construction of more and more efficient controllable pneumatic dampers for shock absorption. Typically, such devices apply online semi-active control techniques, which utilize electromagnetic, piezoelectric, or magnetostrictive valves. As a result, they are characterized by a high efficiency of impact absorption, but simultaneously by a complicated construction and a specialized electronic system. The alternative solutions are semi-passive absorbers that ensure a similar performance by using a much simpler, low-cost construction and a less complicated adaptation mechanism. This paper introduces an adaptable semi-passive single-chamber pneumatic shock absorber, SOFT-DROP, which provides the optimal impact absorption and energy dissipation after a single reconfiguration performed at the beginning of the process. The high effectiveness of the proposed concept is proved in numerical and experimental investigations of the device. Moreover, the proposed semi-passive damper is also compared against already known pneumatic absorbers that utilize semi-active control methods. Ultimately, the device might be used in an airdrop system for delivery of light packages.

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