scholarly journals The Analytical Model of Stress Zone Formation of Ti4Al4V/AA1050/AA2519 Laminate Produced by Explosive Bonding

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 779
Author(s):  
Ireneusz Szachogluchowicz ◽  
Lucjan Sniezek ◽  
Krzysztof Grzelak ◽  
Heorhiy Sulym ◽  
Ihor Turchyn ◽  
...  
Keyword(s):  
Plane Surface ◽  
Welding Process ◽  
Analytical Description ◽  
Impact Angle ◽  
Composition Analysis ◽  
Zone Formation ◽  
Bond Zone ◽  
Stress Zone ◽  
Bonding Method ◽  
The Impact

This paper contains an analytical description of the deformation of the upper layer AA2519/AA1050/Ti6Al4V laminate produced by an explosive bonding method. The basic parameters of the explosive welding process that influence the quality of the bonding are the detonation velocity of the explosive, the explosion energy, and the impact angle of the combined materials. The developed description uses the theory of elastodynamic character of materials deformation at the connection point due to local traction load. The presence of high pressure during joining was limited to the region where the plane surface moving with a constant subsonic velocity. An analytical description of the residual stresses distribution was also a performer. Results of analytical investigations were verified by structure examination of the bond zone. The work was supplemented by the chemical composition analysis of the base materials and a monotonic stretching test characterizing the basic mechanical properties of the produced laminate.

Trajectory shaping guidance law design using constraint-combining multiplier

2021 ◽  
pp. 095441002098637
Author(s):  
Min-Guk Seo ◽  
Chang-Hun Lee ◽  
Tae-Hun Kim
Keyword(s):  
Design Method ◽  
Impact Angle ◽  
State Variables ◽  
Flight Trajectory ◽  
Potential Significance ◽  
Guidance Law ◽  
Terminal Constraints ◽  
The Impact ◽  
Guidance Laws ◽  
Impact Angle Constraint

A new design method for trajectory shaping guidance laws with the impact angle constraint is proposed in this study. The basic idea is that the multiplier introduced to combine the equations for the terminal constraints is used to shape a flight trajectory as desired. To this end, the general form of impact angle control guidance (IACG) is first derived as a function of an arbitrary constraint-combining multiplier using the optimal control. We reveal that the constraint-combining multiplier satisfying the kinematics can be expressed as a function of state variables. From this result, the constraint-combining multiplier to achieve a desired trajectory can be obtained. Accordingly, when the desired trajectory is designed to satisfy the terminal constraints, the proposed method directly can provide a closed form of IACG laws that can achieve the desired trajectory. The potential significance of the proposed result is that various trajectory shaping IACG laws that can cope with various guidance goals can be readily determined compared to existing approaches. In this study, several examples are shown to validate the proposed method. The results also indicate that previous IACG laws belong to the subset of the proposed result. Finally, the characteristics of the proposed guidance laws are analyzed through numerical simulations.

scholarly journals The effect of heat treatment and impact angle on the erosion behavior of nickel-tungsten carbide cold spray coating using response surface methodology

2021 ◽  
Author(s):  
Marios Kazasidis ◽  
Elisa Verna ◽  
Shuo Yin ◽  
Rocco Lupoi
Keyword(s):  
Heat Treatment ◽  
Response Surface Methodology ◽  
Mass Loss ◽  
Tungsten Carbide ◽  
Response Surface ◽  
Spray Coating ◽  
Impact Angle ◽  
Control Factors ◽  
Heat Treated ◽  
The Impact

AbstractThis study elucidates the performance of cold-sprayed tungsten carbide-nickel coating against solid particle impingement erosion using alumina (corundum) particles. After the coating fabrication, part of the specimens followed two different annealing heat treatment cycles with peak temperatures of 600 °C and 800 °C. The coatings were examined in terms of microstructure in the as-sprayed (AS) and the two heat-treated conditions (HT1, HT2). Subsequently, the erosion tests were carried out using design of experiments with two control factors and two replicate measurements in each case. The effect of the heat treatment on the mass loss of the coatings was investigated at the three levels (AS, HT1, HT2), as well as the impact angle of the erodents (30°, 60°, 90°). Finally, the response surface methodology (RSM) was applied to analyze and optimize the results, building the mathematical models that relate the significant variables and their interactions to the output response (mass loss) for each coating condition. The obtained results demonstrated that erosion minimization was achieved when the coating was heat treated at 600 °C and the angle was 90°.

scholarly journals Experimental studies on the possibility of using a pulsed laser for spot welding of thin metallic foils

2020 ◽  
Vol 10 (1) ◽  
pp. 674-680
Author(s):  
Piotr Sęk
Keyword(s):  
Experimental Studies ◽  
Pulsed Laser ◽  
Welding Process ◽  
Pulse Mode ◽  
Weld Strength ◽  
Spot Welds ◽  
Butt Welding ◽  
Strength Tests ◽  
Metallic Foils ◽  
The Impact

AbstractThe purpose of the experiment was to study the influence of the laser beam in pulse mode on metallic foils in order to obtain a spot weld. The welding process was carried out using the overlap weld method, using spot welds in various quantities. The Nd - YAG BLS 720 pulsed laser was used to conduct the experiment. The impact of the number of spot welds on the value of force needed to break the sample was examined. A number of measurements were carried out to determine the best process parameters. Butt welding and overlap welding were also performed using a continuous weld consisting of spot welds. Weld strength tests were performed to select the most appropriate parameters for the process under consideration.

Explosive Welding of SS304 and Al6061 Using Copper as Interlayer – Development of Trial Methodology and its Optimisation

2015 ◽  
Vol 830-831 ◽  
pp. 306-309
Author(s):  
Niraj Srivastava ◽  
Abhishek Upadhyay ◽  
Sandeep Kumar ◽  
Diva ◽  
Jaspreet Singh ◽  
...  
Keyword(s):  
Explosive Welding ◽  
Welding Process ◽  
Al Alloy ◽  
Flyer Plate ◽  
Trial Methodology ◽  
Al 6061 ◽  
Velocity Of Detonation ◽  
Copper Interlayer ◽  
Weldability Window ◽  
The Impact

This paper explains the technique of explosive welding for joining SS304 and Al 6061 using Copper interlayer. The joining was done in two stages. In the first stage SS304 (thickness: 20 mm) was joined to Copper (thickness: 3mm). Second stage involved joining of SS-Cu plate to Al 6061 (thickness: 8 mm).The paper presents detailed discussion on important parameters required for explosive welded process. The most important parameter is minimum and maximum flyer plate velocity required for creating the impact. Collision angle and angle of impact are also discussed. Another important parameter is the Velocity of detonation (VOD) of explosive to be used. The explosives used have VOD of the order of 2500 m/s and 1600 m/sec. Since the explosive welding process involves formation of jet between two surface, therefore surface conditions of the base and flyer plate like its flatness, roughness and cleanliness which are very critical for proper joining have been discussed in this paper. Chisel test (which is considered to be most rugged test) was conducted on the joint. The test confirmed successful joining.The paper explains how use of trimonite expands the weldability window in comparison to NGU when used for direct SS to Al alloy welding.It also compares the results obtained by use of two different powder explosives to obtain the same tri-layered plate via two different routes. The results are particularly interesting because both the explosives have substantial difference in their properties such as Velocity of Detonation, Gurney Characteristic Velocity, density and homogeneity which can be used as advantages from different angles of views.

scholarly journals The impact of image and performance enhancing drugs on bi-ventricular structure and function in strength-trained athletes and the association to fat-free mass

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
B Morrison ◽  
N Chester ◽  
R Mcgregor-Cheers ◽  
G Kleinnibbelink ◽  
C Johnson ◽  
...  
Keyword(s):  
Allometric Scaling ◽  
Strain Imaging ◽  
Fat Free Mass ◽  
Composition Analysis ◽  
Lv Mass ◽  
Significant Difference ◽  
And Performance ◽  
Performance Enhancing Drugs ◽  
The Impact ◽  
Performance Enhancing

Abstract Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Canadian Institute of Health Research Michael Smith Foreign Study Supplement Background Image and performance enhancing drugs (IPED) cause cardiac enlargement and dysfunction. Previous work has not assessed impact of user status (current [CU] vs. past [PU]) or allometric scaling cardiac dimensions for individual differences in fat-free mass (FFM). Purpose To investigate CU and PU of IPED and allometric scaling on LV and RV remodeling in strength-trained athletes. Methods Thirty-four (29 ± 6 years; 82% male) strength-trained athletes were recruited. Fourteen were CU, 9 PU and 11 non-users (NU) of IPEDs.  Participants underwent bioelectric impedance body composition analysis, IPED and training questionnaire and 2D echocardiography with strain imaging. All structural data was allometrically scaled to FFM according to the laws of geometric similarity. Results CU and PU had significantly higher FFM compared to NU (82.4 ± 10.1 kg vs. 72.0 ± 6.3 kg vs. 58.2 ± 14.0 kg). Absolute values of all RV and LV size were larger between CU and NU. LV mean wall thickness (MWT) was larger in CU compared to PU but there were no differences between PU and NU. Allometric scaling eliminated all differences with exception of LV mass and LVMWT. LVEF was significantly lower in CU and PU compared to NU (55 ± 3 vs. 57 ± 4 vs. 61 ± 4) whilst LV GLS was lower in CU compared to PU and NU and LV GCS was lower in CU compared to NU but not PU. There was no significant difference between groups for RV functional indices. Conclusion  Strength-trained athletes currently using IPEDs have bi-ventricular enlargement as well as reduced LV function. Allometric scaling highlights that increased size is partially associated with a larger FFM, with exception of LVMWT which is independently increased through IPED use. PUs demonstrate reverse structural remodeling whilst functional differences partially remain. CU PU NU RVD1 (mm) 45 ± 5* 43 ± 6 37 ± 6 Scaled RVD1 (mm/kg^0.33) 10.5 ± 0.9 10.4 ± 1.5 9.7 ± 1.0 LVd (mm) 58 ± 7* 55 ± 4 50 ± 4 Scaled LVd (mm/kg^0.33) 13.4 ± 1.2 13.3 ± 0.7 13.1 ± 0.6 MWT (mm) 10 ± 1*” 8 ± 1 8 ± 1 Scaled MWT (mm/kg^0.33) 2.3 ± 0.2*” 2.0 ± 0.1 2.0 ± 0.2 LVEDV (ml) 169 ± 42* 135 ± 28 116 ± 28 Scaled LVEDV (ml/kg) 2.0 ± 0.4 1.9 ± 0.3 2.0 ± 0.2 LV Mass (g) 255 ± 85*” 179 ± 30 137 ± 40 LV mass index (g/kg) 3.1 ± 0.8* 2.5 ± 0.3 2.4 ± 0.4 * CU and NU “ CU and PU ^ PU and NU Abstract Figure. Myocardial strain imaging

High-Temperature Erosion Resistance of Coatings for Gas Turbine

1992 ◽  
Vol 114 (2) ◽  
pp. 242-249 ◽  
Author(s):  
W. Tabakoff ◽  
A. Hamed ◽  
M. Metwally ◽  
M. Pasin
Keyword(s):  
High Temperature ◽  
Protective Coatings ◽  
Coal Ash ◽  
Mass Effect ◽  
Impact Angle ◽  
Unit Weight ◽  
Weight Losses ◽  
Aluminide Coatings ◽  
Particle Flows ◽  
The Impact

An experimental investigation was conducted to study the ash particle rebound characteristics and the associated erosion behavior of superalloys and aluminide coatings subjected to gas-particle flows at elevated temperature. A three-component LDV system was used to measure the restitution parameters of 15 micron mean diameter coal-ash particles impacting some widely used superalloys and coatings at different angles. The presented results show the variation of the particle restitution ratios with the impingement angle for the coated and uncoated superalloys. The erosion behaviors of INCO-738, MAR 246 and X40 superalloys and protective coatings C, N, RT22 and RT22B also have been investigated experimentally at high temperature using a specially designed erosion tunnel. The erosion results show the effect of velocity, temperature and the impact angle on the erosion rate (weight loss per unit weight of particles). Based on the experimental results of the particle mass effect on both weight losses and erosion rates, the coating lives have been estimated for different particle concentrations.

Analysis on the Impact Force of a Ship Colliding with a Bridge Pier

2012 ◽  
Vol 193-194 ◽  
pp. 693-701
Author(s):  
Jian Guo Ding ◽  
Zhi Qiao
Keyword(s):  
Mechanical Model ◽  
Mass Velocity ◽  
Impact Force ◽  
Impact Angle ◽  
Bridge Pier ◽  
Velocity Coefficient ◽  
The Impact

Because many accidents in China involve a ship in a barge fleet colliding with a bridge pier, determining the impact force of the ship is important. To obtain an equation that describes the impact force of a ship colliding with a bridge pier, a mechanical model of the collision is simplified, and the results from other researchers are applied. Based on the equation, it is found that the impact force of a ship colliding with a bridge pier is not only relevant to the mass，velocity, board thicknesses of the ship, and the impact angle, but also to the remaining velocity coefficient. It has been demonstrated that the result from the proposed equation in this paper is in accordance with that of Gkss’s test in Wosin G theory.

Microstructure and mechanical properties of ADC12/6063-T6 aluminum alloy butt joint achieved by metal inert gas groove welding

2018 ◽  
Vol 233 (10) ◽  
pp. 2120-2124
Author(s):  
Ye Wang ◽  
Mi Zhao ◽  
Hongyu Xu ◽  
Maoliang Hu ◽  
Zesheng Ji
Keyword(s):  
Mechanical Properties ◽  
Arc Welding ◽  
Welding Process ◽  
Weld Interface ◽  
Butt Joint ◽  
Inert Gas ◽  
Butt Joints ◽  
Arc Welding Process ◽  
The Impact ◽  
Silicon Particles

Metal inert gas arc welding process was implemented to join 6063T6 wrought alloy and ADC12 die-casting alloy using ER4047 filler metal. The microstructure of the weld seam and weld interface was investigated. The bonding strength of the butt joints was tested by Charpy U-notch impact test and tensile test. The results showed that a sound welding butt joint with finely silicon particles and excellent mechanical properties was formed, and the size of the silicon particles was nearly 2 μm. Compared with 6063T6 wrought alloy, the impact absorbing energies and the tensile strengths of the butt joint were higher and reached 1.173 kJ/cm2 and 205 MPa, respectively, and the fractures of all tensile specimens occur at the 6063T6 aluminum.

scholarly journals The Role of Silicon Heterojunction and TCO Barriers on the Operation of Silicon Heterojunction Solar Cells: Comparison between Theory and Experiment

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yaser Abdulraheem ◽  
Moustafa Ghannam ◽  
Hariharsudan Sivaramakrishnan Radhakrishnan ◽  
Ivan Gordon
Keyword(s):  
Solar Cells ◽  
Large Scale ◽  
Surface Passivation ◽  
Series Resistance ◽  
Crystalline Silicon ◽  
Thermionic Emission ◽  
Analytical Description ◽  
Theoretical Explanation ◽  
The Impact

Photovoltaic devices based on amorphous silicon/crystalline silicon (a-Si:H/c-Si) heterojunction interfaces hold the highest efficiency as of date in the class of silicon-based devices with efficiencies exceeding 26% and are regarded as a promising technology for large-scale terrestrial PV applications. The detailed understanding behind the operation of this type of device is crucial to improving and optimizing its performance. SHJ solar cells have primarily two main interfaces that play a major role in their operation: the transparent conductive oxide (TCO)/a-Si:H interface and the a-Si:H/c-Si heterojunction interface. In the work presented here, a detailed analytical description is provided for the impact of both interfaces on the performance of such devices and especially on the device fill factor ( FF ). It has been found that the TCO work function can dramatically impact the FF by introducing a series resistance element in addition to limiting the forward biased current under illumination causing the well-known S-shape characteristic in the I-V curve of such devices. On the other hand, it is shown that the thermionic emission barrier at the heterojunction interface can play a major role in introducing an added series resistance factor due to the intrinsic a-Si:H buffer layer that is usually introduced to improve surface passivation. Theoretical explanation on the role of both interfaces on device operation based on 1D device simulation is experimentally verified. The I-V characteristics of fabricated devices were compared to the curves produced by simulation, and the observed degradation in the FF of fabricated devices was explained in light of analytical findings from simulation.

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