scholarly journals Discrete Wavelet Transformation Approach for Surface Defects Detection in Friction Stir Welded Joints

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Akshansh Mishra
Keyword(s):  
Wavelet Transformation ◽  
Surface Defects ◽  
External Surface ◽  
Traverse Speed ◽  
Discrete Wavelet ◽  
Friction Stir ◽  
Input Parameters ◽  
Tool Tilt Angle ◽  
Joint Quality ◽  
Python Programming

AbstractFriction Stir Welding joint quality depends on input parameters such as tool rotational speed, tool traverse speed, tool tilt angle and an axial force. Surface defects formation occurs when these input parameters are not selected properly. The main objective of the recent paper is to develop Discrete Wavelet Transform algorithm by using Python programming and further subject it to the Friction Stir Welded samples for the identification of various external surface defects present.

Influence of Process Parameters on Microstructure of Friction Stir Processed Mg AZ31 Alloy

2017 ◽  
pp. 1293-1305
Author(s):  
G. Venkateswarlu ◽  
M.J. Davidson ◽  
G.R.N. Tagore ◽  
P. Sammaiah
Keyword(s):  
Plastic Deformation ◽  
Grain Refinement ◽  
Process Parameters ◽  
Tilt Angle ◽  
Friction Stir Processing ◽  
Rotational Speed ◽  
Traverse Speed ◽  
Homogeneous Microstructure ◽  
Friction Stir ◽  
Tool Tilt Angle

Friction stir processing (FSP) has been developed on the principles of friction stir welding (FSW) as an effective and efficien new method for grain refinement and microstructural modification, providing intense plastic deformation as well as higher strain rates than other conventional severe plastic deformation methods. FSP produces an equiaxed homogeneous microstructure consisting of fine grains, resulting in the enhancement of the properties of the material at room temperature. The objective of the present paper is to examine the influence of friction stir processing (FSP) parameters namely tool rotational speed (RS), tool traverse speed (TS) and tool tilt angle (TA) on the microstructures of friction stir processed AZ31B-O magnesium alloy. This investigation has focused on the microstructural changes occurred in the dynamically recrystallised nugget zone/ stir zone and the thermo mechanically affected zone during FSP. The results presented in this work indicate that all the three FSP process parameters have a significant effect on the resulting microstructure and also found that the rotational speed has greatly influenced the homogenization of the material. The grain refinement is higher at intermediate rotational speed (1150 rpm), traverse speed (32 mm / min and tilt angle (10). It is established that FSP can be a good grain refinement method for improving the properties of the material.

scholarly journals WSN-WCCS: A Wireless Sensor Network Wavelet Curve Ciphering System

2019 ◽  
Vol 25 (6) ◽  
pp. 67-82
Author(s):  
Nadia A. Shiltagh ◽  
Mahmood Z. Abdullah ◽  
Ahmed R. x Ahmed R. Zarzoor
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Network ◽  
Sensor Node ◽  
Wavelet Transformation ◽  
Wireless Sensor ◽  
Discrete Wavelet ◽  
Language Version ◽  
Cryptographic Algorithm ◽  
Leach Protocol ◽  
Python Programming

With wireless sensor network (WSN) wide applications in popularity, securing its data becomes a requirement. This can be accomplished by encrypting sensor node data. In this paper a new an efficient symmetric cryptographic algorithm is presented. This algorithm is called wireless sensor network wavelet curve ciphering system (WSN-WCCS).  The algorithm idea based on discrete wavelet transformation to generate keys for each node in WSN.  It implements on hierarchical clustering WSN using LEACH protocol. Python programming language version 2.7 was used to create the simulator of WSN framework and implement a WSN-WCCS algorithm. The simulation result of the proposed WSN-WCCS with other symmetric algorithms has shown that its execution time fastest among AES, 3DES and DES 15%, 55% and 17%.  

scholarly journals Influence of Friction Stir Processing Parameters on Mg ZE 41-SiC Surface Composite

2019 ◽  
Vol 8 (2) ◽  
pp. 6058-6061
Keyword(s):  
Process Parameters ◽  
Tilt Angle ◽  
Friction Stir Processing ◽  
Rotational Speed ◽  
Traverse Speed ◽  
Nano Particles ◽  
Micro Hardness ◽  
Friction Stir ◽  
Surface Composite ◽  
Tool Tilt Angle

In this study, the influence of friction stir processing process parameters (FSP), such as tool rotational speed, tool traverse speed, and the tool tilt angle on the mechanical properties of Sic reinforced surface magnesium rare earth ZE41 alloy composite was studied. The process was carried at tool rotational speeds of 710, 900, 1120, 1600, 1400 and 1800 rpm, tool traverse speeds of 16, 25, 40 and 63 mm/min and tool tilt angle of degree 1. Nano-particles of SiC (40 microns) were used as reinforcements to produce a composite surface. The grain refinement of the processed specimens was analyzed using scanning electron microscope. It is observed from the results that FSP process parameters influenced the surface composite area, SiC particles distribution and micro hardness of the composite. The outcomes indicated that the higher micro hardness was obtained at rotational speed of 1100 RPM, traverse speed 40mm/min and tilt angle 10 .

Development of a New Approach for Incorporating Tool Tilting in Friction Stir Welding

2013 ◽  
Vol 701 ◽  
pp. 378-381 ◽  
Author(s):  
Bilal Ghazanfar ◽  
Mokhtar Awang ◽  
Sajjad Raza Khan ◽  
Hasan Fawad
Keyword(s):  
Friction Stir Welding ◽  
Tilt Angle ◽  
Traverse Speed ◽  
Tool Geometry ◽  
New Approach ◽  
Friction Stir ◽  
Milling Machines ◽  
Vertical Milling Machine ◽  
Zero Degree ◽  
Tool Tilt Angle

Friction Stir Welding (FSW) is a simple process involving a rotating tool (with an extended pin) traversing on the joining line of the two work pieces leaving behind the required weld. Tool geometry (pin and shoulder), rotational speed, traverse speed, and tilt angle are important parameters which determine the resultant properties of weld. Milling machines due to rotating tool and traversing can be used as a method of doing laboratory scale FSW experiment. In cases where milling machines have a fixed head, limitation of zero degree tool tilt angle results in substantial defects (e.g. tunnel defect) in weldments. In this study a new approach is developed and adopted for overcoming this limitation of a fixed head vertical milling machine to incorporate the flexibility of tool tilt. The results for welding with and without this approach are presented along with discussion and conclusion.

scholarly journals Experimental Behaviour of Tensile Properties of Aa2014-T6 Aluminium Alloy using FSW and Gtaw Process

2019 ◽  
Vol 9 (2) ◽  
pp. 1566-1569
Keyword(s):  
Aluminium Alloy ◽  
Research Work ◽  
Traverse Speed ◽  
Constant Current ◽  
Friction Stir ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Tool Tilt Angle ◽  
The Comparative Study ◽  
Tool Pin

In the bringout research work carried out the comparative study of weld characteristics of Aluminium Alloy AA2014-T6 weldments, joined by employing two processes namely Friction Stir Welding (FSW) and Gas Tungsten Arc Welding (GTAW). FSW was performed with three different geometrical tool pin profiles like triangular, square, pentagon with process variables like tool rotational speed of 1400rpm, traverse speed of 86mm/min and tool tilt angle 3⁰. GTAW process was carried out by using constant current welding (CCW) and pulse current welding (PCW) at a frequencies of 2Hz and 4Hz respectively. This work lead to study the Ultimate Tensile Strength (UTS), 0.2%Yield Strength (YS) and % Elongation (%El) of AA2014-T6 weldments produced by FSW and GTAW

scholarly journals Modeling and Optimization of Friction Stir Welding Parameters for Joining Dissimilar Aluminum Alloys

2018 ◽  
Vol 4 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Mohamed Mohamed Abd Elnabi ◽  
Tarek Abd Elsadek Osman ◽  
Alaa Eldeen El Mokadem ◽  
Abou Bakr Elshalakany 
Keyword(s):  
Friction Stir Welding ◽  
Base Metal ◽  
Tilt Angle ◽  
Rotational Speed ◽  
Traverse Speed ◽  
Welding Parameters ◽  
Plunge Depth ◽  
Friction Stir ◽  
Confidence Levels ◽  
Tool Tilt Angle

The objectives of this work are to optimize the process parameters on the mechanical properties (ultimate tensile strength (UTS) and ductility) of dissimilar joints between AA5454 and AA7075 produced by friction stir welding and to determine which of them is significant by using Taguchi L16 optimization method. Seven parameters at two levels were selected in this study. The selected parameters are tool rotational speed, traverse speed, pin profile (based on taper angle), D/d ratio, tool tilt angle, plunge depth, and base metal location. Then, mathematical models are built as function of significant parameters/ interactions using Response Surface Methodology. The results of this work showed that the rotational speed, traverse speed, D/d ratio and plunge depth are significant parameters in determining UTS (Mean, Signal to noise ratio (S/N)) at different confidence levels, but pin profile, location of base metal and tool tilt angle are insignificant parameters at any confidence levels. The traverse speed has the highest contribution to the process for UTS about 18.577 % and 16.943 % for S/N ratio and mean, respectively. The accuracy of the models according to the UTS is 97.678 % and 99.56 %for mean and S/N ratio, respectively. The maximum joint efficiency, compared to the strength of the AA5454, is 85.3%.

Optimization of Input Parameters on Friction Stir Welding of Dissimilar Aluminium Alloys AA2014 and AA6061 using Taguchi Technique

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
M. Ramamurthy ◽  
P. Balasubramanian ◽  
R. Kumar
Keyword(s):  
Friction Stir Welding ◽  
Tilt Angle ◽  
Signal To Noise Ratio ◽  
Input Parameter ◽  
Fusion Welding ◽  
Standard Size ◽  
Friction Stir ◽  
Input Parameters ◽  
Tool Tilt Angle ◽  
Important Position

Friction stir welding holds an important position among many solid state metal joining processes which finds several applications where fusion welding methods are not suitable to form defect less welds. FSW is an innovative metal joining technique used in joining of aluminium and magnesium alloys whereas the problems encountered with conventional fusion welding were prevented. The present research is to optimize the input parameters and analyse the mechanical properties in the joining of alloys AA2014 and AA6061. The input parameters which are taken into account for this study are tool rotational speed, tool transverse speed and tool tilt angle. The experiments were being conducted according to the factorial design of experiments. After that standard size specimens were cut by EDM process from the welded joints. Tensile and hardness tests were done on the specimens and the values of ultimate tensile strength, Yield strength, % of Elongation and Vickers Hardness number were measured. By finding the signal to noise ratio the optimum input parameters were identified. The values are 560rpm, 100mm/min and 2 degrees respectively. The importance of each input parameter was evaluated by ANOVA method which indicates that the parameter tool tilt angle is having higher contribution of 38.73%.

Evaluvation of Multiresolution Watermarking Algorithm

2017 ◽  
Vol 7 (8) ◽  
pp. 85
Author(s):  
S. Thabasu Kannan ◽  
S. Azhagu Senthil
Keyword(s):  
Digital Watermarking ◽  
Wavelet Transformation ◽  
Signal To Noise Ratio ◽  
Rapid Development ◽  
Threshold Value ◽  
Discrete Wavelet ◽  
Digital Production ◽  
Common Framework ◽  
Sampling Operation ◽  
Watermarking Scheme

Now-a-days watermarking plays a pivotal role in most of the industries for providing security to their own as well as hired or leased data. This paper its main aim is to study the multiresolution watermarking algorithms and also choosing the effective and efficient one for improving the resistance in data compression. Computational savings from such a multiresolution watermarking framework is obvious. The multiresolutional property makes our watermarking scheme robust to image/video down sampling operation by a power of two in either space or time. There is no common framework for multiresolutional digital watermarking of both images and video. A multiresolution watermarking based on the wavelet transformation is selected in each frequency band of the Discrete Wavelet Transform (DWT) domain and therefore it can resist the destruction of image processing.   The rapid development of Internet introduces a new set of challenging problems regarding security. One of the most significant problems is to prevent unauthorized copying of digital production from distribution. Digital watermarking has provided a powerful way to claim intellectual protection. We proposed an idea for enhancing the robustness of extracted watermarks. Watermark can be treated as a transmitted signal, while the destruction from attackers is regarded as a noisy distortion in channel.  For the implementation, we have used minimum nine coordinate positions. The watermarking algorithms to be taken for this study are Corvi algorithm and Wang algorithm. In all graph, we have plotted X axis as peak signal to noise ratio (PSNR) and y axis as Correlation with original watermark. The threshold value ά is set to 5. The result is smaller than the threshold value then it is feasible, otherwise it is not.

Prediction and optimization of mechanical properties of PA6/NBR/graphene nanocomposites fabricated by friction stir processing

2021 ◽  
pp. 009524432110200
Author(s):  
Ali Ghorbankhan ◽  
Mohammad Reza Nakhaei ◽  
Ghasem Naderi
Keyword(s):  
Tensile Strength ◽  
Impact Strength ◽  
Rotational Speed ◽  
Traverse Speed ◽  
Differential Scanning Calorimetric ◽  
Butadiene Rubber ◽  
Friction Stir ◽  
Graphene Nanocomposite ◽  
Graphene Nanoparticles ◽  
Input Variables

The friction stir process (FSP) method used to prepare polyamide 6 (PA6)/nitrile-butadiene rubber (NBR) nanocomposites with 1 wt% Graphene nanoparticles. Response surface methodology (RSM) and Box-Behnken design were used to study the effects of four input variables including tool rotational speed (ω), shoulder temperature (T), traverse speed (S), and the number of passes (N) on tensile strength and impact strength of PA6/NBR/Graphene nanocomposite. In order to investigate the dispersion state of Graphene and the morphology of the PA6/NBR blend in the presence of Graphene, wide x-ray patterns (WAX), scanning electron microscopy (SEM) were performed. Furthermore and differential scanning calorimetric (DSC) was used to investigate the thermal properties of PA6/NBR containing 1 wt% Graphene nanoparticles. The results confirmed that at the optimum range of input variables, PA6/NBR/Graphene nanocomposite provided good thermal stability as well as the highest tensile strength, and impact strength. This is caused by the large surface area to volume ratio of the dispersed layered Graphene in PA6/NBR blends. Under optimal conditions of the rotational speed of 1200 rpm, traverse speed of 20 mm/min, shoulder temperature of 125°C, and number pass of 3, the maximum tensile strength and impact strength are 70.4 MPa and 70.3 J/m, respectively.

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