An Investigation of the Impact of Forming Process Parameters in Single Point Incremental Forming Using Experimental and Numerical Verification

Incremental sheet forming (ISF) is an innovative cold forming operation and has enticed great interests owing to its flexibility and capability to manufacture various complex 3D shapes with low costs and minimum requirements. Single point incremental forming (SPIF) is the most popular type of ISF process and has high quality and less occurrence of defects for the formed products if the operating parameters are achieved and evaluated with high precision. In this study, the impact of tool diameter and forming angle on the forming force, thickness distribution, thinning ratio, effective plastic strain, forming depth and fracture behaviour was explored. AA1050 aluminium alloy and DC04 carbon steel were employed to produce a truncated cone in accordance with the SPIF process. A 3D finite element model was required to achieve a well-established investigation. The SPIF of a truncated cone numerical model was adopted to build a model with the same conditions as of the experimental work with aid of ANSYS software version 18 through using the workbench LS-DYNA model. The sheet metal modelling was carried out in accordance the Cowper Symonds power law hardening by taking the behaviour of the material as elastic–plastic, and the anisotropic properties were assumed to simulate the plasticity behaviour for two sheet metals. Results indicate that the DC04 carbon steel has a higher forming force, minimum thickness and lower thinning ratio compared with AA1050 aluminium alloy under the same operating conditions

Exploring resistance spot welding for grade 2 titanium alloy: experimental investigation and artificial neural network modeling

The resistance spot welding (RSW) process is still widely used to weld panels and bodies, particularly in the automotive, railroad, and aerospace industries. The purpose of this research is to examine how RSW factors such as welding current, welding pressure, welding time, holding time, squeezing time, and pulse welding affect the shear force, micro-hardness, and failure mode of spot welded titanium sheets (grade 2). Resistance spot welded joints of titanium sheets with similar and dissimilar thicknesses of 1–1 mm, 0.5–0.5 mm, and 1–0.5 mm were evaluated. The experimental conditions were arranged using the design of experiments (DOE). Moreover, artificial neural network (ANN) models were used. Different training and transfer functions were tested using the feed-forward backpropagation approach to find the optimal ANN model. According to the experimental results, the maximum shear force was 5.106, 4.234, and 4.421 kN for the 1–1, 0.5–0.5, and 1–0.5 mm cases, respectively. The hardness measurements showed noticeable improvement for the welded joints compared to the base metal. The findings revealed that the 0.5–0.5 mm case gives the highest nugget and heat-affected zone (HAZ) hardness compared to other cases. Moreover, different failure modes like pull-out nugget, interfacial, and partial failure between the pull-out nugget and interfacial failure were noticed. The ANN outcomes based on the mean squared error (MSE) and coefficient of determination (R2) as validation metrics demonstrated that using the Levenberg–Marquardt (Trainlm) training function with the log sigmoid transfer function (Logsig) gives the best prediction, where R2 and MSE values were 0.98433 and 0.01821, respectively

Modelling and Experimental Study of Dissimilar Arc Stud Welding of AISI 304L to AISI 316L Stainless Steel

This paper has aimed to try and establish a successful weld joint between AISI 304L stainless steel as a stud and AISI 316L stainless steel as a plate by using an arc stud welding process. The effect of different current and time welding on the torque results was experimentally studied, by using three-level of each process parameter. The post-weld heat treatment (PWHT) was carried out on the optimum sample of torque, to study the effect of PWHT on mechanical properties (torque and hardness) and microstructure of the welding zone. In the present work, A 3-D finite element model was developed by using ANSYS software version 18 to analyze the influence of time and current welding on the temperature distribution and residual stresses of the resultant welded joints. A transient thermal model was built to predict the temperature distribution whereas the residual stresses were determined by using a static structural model. The PWHT has been used to reduce the amount of residual stresses and enhance the mechanical properties of the welded joint. The micro-hardness based on the Vickers test and the microstructure of welded specimens with and without PWHT have been investigated. The simulation results reveal that the generated temperature and the residual stress is strongly affected by the time and current welding. The mechanical test results indicated that the PWHT prompted an improvement in the hardness values

Modelling and Experimental Study of Dissimilar Arc Stud Welding of AISI 304L to AISI 316L Stainless Steel

This paper has aimed to try and establish a successful weld joint between AISI 304L stainless steel as a stud and AISI 316L stainless steel as a plate by using an arc stud welding process. The effect of different current and time welding on the torque results was experimentally studied, by using three-level of each process parameter. The post-weld heat treatment (PWHT) was carried out on the optimum sample of torque, to study the effect of PWHT on mechanical properties (torque and hardness) and microstructure of the welding zone. In the present work, A 3-D finite element model was developed by using ANSYS software version 18 to analyze the influence of time and current welding on the temperature distribution and residual stresses of the resultant welded joints. A transient thermal model was built to predict the temperature distribution whereas the residual stresses were determined by using a static structural model. The PWHT has been used to reduce the amount of residual stresses and enhance the mechanical properties of the welded joint. The micro-hardness based on the Vickers test and the microstructure of welded specimens with and without PWHT have been investigated. The simulation results reveal that the generated temperature and the residual stress is strongly affected by the time and current welding. The mechanical test results indicated that the PWHT prompted an improvement in the hardness values

Artificial neural networks and experimental analysis of the resistance spot welding parameters effect on the welded joint quality of AISI 304

The automobile industry relies primarily on spot welding operations, particularly resistance spot welding (RSW). The performance and durability of the resistance spot-welded joints are significantly impacted by the welding quality outputs, such as the shear force, nugget diameter, failure mode, and the hardness of the welded joints. In light of this, the present study sought to determine how the aforementioned welding quality outputs of 0.5 and 1 mm thick austenitic stainless steel AISI 304 were affected by RSW parameters, such as welding current, welding time, pressure, holding time, squeezing time, and pulse welding. In order to guarantee precise evaluation and experimental analysis, it is essential that they are supported by a numerical model using an intelligent model. The primary objective of this research is to develop and enhance an intelligent model employing artificial neural network (ANN) models. This model aims to provide deeper knowledge of how the RSW parameters affect the quality of optimum joint behavior. The proposed neural network (NN) models were executed using different ANN structures with various training and transfer functions based on the feedforward backpropagation approach to find the optimal model. The performance of the ANN models was evaluated in accordance with validation metrics, like the mean squared error (MSE) and correlation coefficient (R2). Assessing the experimental findings revealed the maximum shear force and nugget diameter emerged to be 8.6 kN and 5.4 mm for the case of 1–1 mm, 3.298 kN and 4.1 mm for the case of 0.5–0.5 mm, and 4.031 kN and 4.9 mm for the case of 0.5–1 mm. Based on the results of the Pareto charts generated by the Minitab program, the most important parameter for the 1–1 mm case was the welding current; for the 0.5–0.5 mm case, it was pulse welding; and for the 0.5–1 mm case, it was holding time. When looking at the hardness results, it is clear that the nugget zone is much higher than the heat-affected zone (HZ) and base metal (BM) in all three cases. The ANN models showed that the one-output shear force model gave the best prediction, relating to the highest R and the lowest MSE compared to the one-output nugget diameter model and two-output structure. However, the Levenberg–Marquardt backpropagation (Trainlm) training function with the log sigmoid transfer function recorded the best prediction results of both ANN structures

Intermixing at the InxSy/Cu2ZnSn(S,Se)4 Heterojunction and Its Impact on the Chemical and Electronic Interface Structure

We report on the chemical and electronic structure of the interface between a thermally co-evaporated InxSy buffer and a Cu2ZnSn(S,Se)4 (CZTSSe) absorber for thin-film solar cells. To date, such cells have achieved energy conversion efficiencies up to 8.6%. Using surface-sensitive X-ray and UV photoelectron spectroscopy, combined with inverse photoemission and bulk-sensitive soft X-ray emission spectroscopy, we find a complex character of the buffer layer. It includes oxygen, as well as selenium and copper that diffused from the absorber into the InxSy buffer, exhibits an electronic band gap of 2.50 ± 0.18 eV at the surface, and leads to a small cliff in the conduction band alignment at the InxSy/CZTSSe interface. After an efficiency-increasing annealing step at 180 °C in nitrogen atmosphere, additional selenium diffusion leads to a reduced band gap at the buffer layer surface (2.28 ± 0.18 eV)

A sub-regional outlook of renewable energy potential: the case of Jordan, Syria and Lebanon

This paper addresses the current status and the potentials of renewable energy applications in the selected Middle East countries; Jordan, Syria, and Lebanon. The energy and environmental situations within these primary target areas reflect many similarities and share serious common problems. These include an almost total dependence on imported oil products as the primary energy source, rapidly growing populations that are escalating the demand for energy, and only rudimentary efforts currently underway to mitigate the greenhouse and other adverse environmental effects of energy utilization. Lebanon is highly urbanized compared to Syria and Jordan with much smaller area and has not been fully engaged in pilot projects for use of renewable energy. Applications of solar energy in that region have been growing since 1970. Solar water heating with support of policies in Jordan has achieved measurable market penetration. Lebanon and Syria have not made reasonable progress in solar applications due to subsidized electricity supply to the end user. The technical and economic feasibility of wind energy utilization in Lebanon has not been yet fully explored, while it has advanced with two operating wind farms in Jordan, and one pilot wind farm in Syria. Similarly, the transfer of biomass technology has been successful in Jordan while it remains at the assessment level in Lebanon and Syria coupled with small pilot projects

Investigation of enhanced double weight code in point to point access networks

© 2020 Published under licence by IOP Publishing Ltd. In this paper, an investigation and evaluation to enhanced double weight (EDW) code is performed, a new technique for code structuring and building using modified arithmetical model has been given for the code in place of employing previous technique based on Trial Inspections. Innovative design has been employed for the code into P2P networks using diverse weighted EDW code to be fitting into optical CDMA relevance applications. A new developed relation for EDW code is presented, the relation is based on studying and experimenting the effect of input transmission power with code weight, and the relation developed using numerical analysis method. This relation makes the estimation for the system input power needed more efficient. The results of the code has been explained by eye diagram and parametric illustrations from the simulated results. The result shows a magnificent performance of the code during high number of users and weight. On the other hand, the relation developed for power measurement helps to prevent power loss and consumption

Genetic folding for solving multiclass SVM problems

Genetic Folding (GF) algorithm is a new class of evolutionary algorithms specialized for complicated computer problems. GF algorithm uses a linear sequence of numbers of genes structurally organized in integer numbers, separated with dots. The encoded chromosomes in the population are evaluated using a fitness function. The fittest chromosome survives and is subjected to modification by genetic operators. The creation of these encoded chromosomes, with the fitness functions and the genetic operators, allows the algorithm to perform with high efficiency in the genetic folding life cycle. Multi-classification problems have been chosen to illustrate the power and versatility of GF. In classification problems, the kernel function is important to construct binary and multi classifier for support vector machines. Different types of standard kernel functions have been compared with our proposed algorithm. Promising results have been shown in comparison to other published works

Investigation the nonlinear optical properties of silver nanoparticles using femtosecond laser

© 2020 Published under licence by IOP Publishing Ltd. In this research, the fabrication of silver nanoparticles and experimental nonlinear response (NLO). The fabrication of the silver nanoparticles has been done using E-Beam evaporation on a glass substrate (Ag-NPs) and investigation of their nonlinear optical response (NLO). The silver nanoparticles was evaluated by optical spectrum (UV-Vis) that shows localized surface Plasmon band at 375 nm. The experiment shows the nonlinear absorption and nonlinear refraction effect of silver nanoparticles, the silver nanoparticles is analysed by Z-Scan technique using a femtoseconds laser with 800 nm wavelength. The result shows the nonlinear absorption (NLA) is at 4.8710-4cmW-1, while (NLR) is at 7.9410-9cmW-1