Mohammad Riahi, Mohammad Sedighi and Hassan Rahmanian
The paper aims to design a process to mechanize traditional chasing and repoussé which is the art of creating an artistic pattern on a sheet metal by making high and low points…
Abstract
Purpose
The paper aims to design a process to mechanize traditional chasing and repoussé which is the art of creating an artistic pattern on a sheet metal by making high and low points through utilization of hammer and chisel. In scientific literature, it is a kind of incremental sheet metal forming.
Design/methodology/approach
In the designed process, a magnetic actuator is used as a hammer which converts electric energy into kinetic reciprocal impact energy, and hammering sequence is completely controlled via the designed software. The sheet is bound not to move easily. Then, a hammering mechanism is connected to the numerical control machine. As the magnetic hammer is moved gradually along the defined path, the sheet is chased gradually by controlling the consecutive impacts. Different methods of test sheet entanglement are also discussed to reduce noise and undesired deformations of sheet, and indents are also clarified.
Findings
The designed mechanism enables the user to form desired art patterns faster with more precision via the automated process. The hammering sequence is controlled via computer successfully. The designed magnetic actuator could be commercialized easily. Experiments show that the pitch under sheet is the best. Typical art patterns are chased successfully.
Originality/value
In incremental sheet metal punching, there was no control on hammering sequence before. In this process, the designed magnetic hammer is quite controllable. Also, it is easily attached to the computerized numerical control (CNC) and is suitable for commercial use. Furthermore, the stuff under sheet was not taken into consideration before.
Details
Keywords
Ji-Huan He, Fei-Yu Ji and Hamid Mohammad-Sedighi
The purpose of this paper is to demonstrate that the numerical method is not everything for nonlinear equations. Some properties cannot be revealed numerically; an example is used…
Abstract
Purpose
The purpose of this paper is to demonstrate that the numerical method is not everything for nonlinear equations. Some properties cannot be revealed numerically; an example is used to elucidate the fact.
Design/methodology/approach
A variational principle is established for the generalized KdV – Burgers equation by the semi-inverse method, and the equation is solved analytically by the exp-function method, and some exact solutions are obtained, including blowup solutions and discontinuous solutions. The solution morphologies are studied by illustrations using different scales.
Findings
Solitary solution is the basic property of nonlinear wave equations. This paper finds some new properties of the KdV–Burgers equation, which have not been reported in open literature and cannot be effectively elucidated by numerical methods. When the solitary solution or the blowup solution is observed on a much small scale, their discontinuous property is first found.
Originality/value
The variational principle can explain the blowup and discontinuous properties of a nonlinear wave equation, and the exp-function method is a good candidate to reveal the solution properties.
Details
Keywords
Ahmed E. Abouelregal, Marin Marin, S.S. Saskar and Abdelaziz Foul
Understanding the mechanical and thermal behavior of materials is the goal of the branch of study known as fractional thermoelasticity, which blends fractional calculus with…
Abstract
Purpose
Understanding the mechanical and thermal behavior of materials is the goal of the branch of study known as fractional thermoelasticity, which blends fractional calculus with thermoelasticity. It accounts for the fact that heat transfer and deformation are non-local processes that depend on long-term memory. The sphere is free of external stresses and rotates around one of its radial axes at a constant rate. The coupled system equations are solved using the Laplace transform. The outcomes showed that the viscoelastic deformation and thermal stresses increased with the value of the fractional order coefficients.
Design/methodology/approach
The results obtained are considered good because they indicate that the approach or model under examination shows robust performance and produces accurate or reliable results that are consistent with the corresponding literature.
Findings
This study introduces a proposed viscoelastic photoelastic heat transfer model based on the Moore-Gibson-Thompson framework, accompanied by the incorporation of a new fractional derivative operator. In deriving this model, the recently proposed Caputo proportional fractional derivative was considered. This work also sheds light on how thermoelastic materials transfer light energy and how plasmas interact with viscoelasticity. The derived model was used to consider the behavior of a solid semiconductor sphere immersed in a magnetic field and subjected to a sudden change in temperature.
Originality/value
This study introduces a proposed viscoelastic photoelastic heat transfer model based on the Moore-Gibson-Thompson framework, accompanied by the incorporation of a new fractional derivative operator. In deriving this model, the recently proposed Caputo proportional fractional derivative was considered. This work also sheds light on how thermoelastic materials transfer light energy and how plasmas interact with viscoelasticity. The derived model was used to consider the behavior of a solid semiconductor sphere immersed in a magnetic field and subjected to a sudden change in temperature.
Details
Keywords
Mohammad Majid Fouladgar, Ahmad Borumand Kakhki, Alireza Nasr Esfehani and Mohammadsadegh Sedighi
This paper aims to propose a policy prioritization framework in view of a layered scenario building along with key stakeholder analysis and has been applied in a case study to…
Abstract
Purpose
This paper aims to propose a policy prioritization framework in view of a layered scenario building along with key stakeholder analysis and has been applied in a case study to determine the priority of Iran environmental policies at the horizon of 2030. A creative framework that covers future scenarios and allows for a more accurate and intelligent policy assessment and prioritization.
Design/methodology/approach
The general environmental policies of the Islamic Republic of Iran are evaluated, and observation policies in social area were identified. Causal layered analysis (CLA) is applied for policy prioritization based on layered probable scenarios and key stakeholder role consideration. The Multiple-criteria decision-making (MCDM) is also used for ranking General Environmental Policies by the technique for order of preference by similarity to ideal solution (TOPSIS).
Findings
Four uncertainties were obtained in different layers based on the CLA analysis, resulting in the creation of four main scenario and 16 discrete scenarios. Finally, Iran’s environmental policies were prioritized given the probable scenarios and the centralized policies on the social and political domains. The proposed model will be effective in policy-making in multilateral atmosphere to prioritize policies and alternative macro-strategies.
Originality/value
This paper shows that foresight and especially developed scenarios provide intelligent, efficient and effective planning and policy-making, and in addition to illustrating surrounding changes and probable future imagery, it generates common understanding and inter-subjective knowledge by increasing participation of various officials and stakeholders.
Details
Keywords
Muhammad Nadeem and Ji-Huan He
The purpose of this paper is to find an approximate solution of a fractional differential equation. The fractional Newell–Whitehead–Segel equation (FNWSE) is used to elucidate the…
Abstract
Purpose
The purpose of this paper is to find an approximate solution of a fractional differential equation. The fractional Newell–Whitehead–Segel equation (FNWSE) is used to elucidate the solution process, which is one of the nonlinear amplitude equation, and it enhances a significant role in the modeling of various physical phenomena arising in fluid mechanics, solid-state physics, optics, plasma physics, dispersion and convection systems.
Design/methodology/approach
In Part 1, the authors adopted Mohand transform to find the analytical solution of FNWSE. In this part, the authors apply the fractional complex transform (the two-scale transform) to convert the problem into its differential partner, and then they introduce the homotopy perturbation method (HPM) to bring down the nonlinear terms for the approximate solution.
Findings
The HPM makes numerical simulation for the fractional differential equations easy, and the two-scale transform is a strong tool for fractal models.
Originality/value
The HPM with the two-scale transform sheds a bright light on numerical approach to fractional calculus.
Details
Keywords
Bahador Bahrami, Mohammad Reza Mehraban, Seyed Saeid Rahimian Koloor and Majid R. Ayatollahi
The purpose of this study is to develop an efficient numerical procedure for simulating the effect of printing orientation, as one of the primary sources of anisotropy in…
Abstract
Purpose
The purpose of this study is to develop an efficient numerical procedure for simulating the effect of printing orientation, as one of the primary sources of anisotropy in 3D-printed components, on their fracture properties.
Design/methodology/approach
The extended finite element method and the cohesive zone model (XFEM-CZM) are used to develop subroutines for fracture simulation. The ability of two prevalent models, i.e. the continuous-varying fracture properties (CVF) model and the weak plane model (WPM), and a combination of both models (WPM-CVF) are evaluated to capture fracture behavior of the additively manufactured samples. These models are based on the non-local and local forms of the anisotropic maximum tangential stress criterion. The numerical models are assessed by comparing their results with experimental outcomes of 16 different configurations of polycarbonate samples printed using the material extrusion technique.
Findings
The results demonstrate that the CVF exaggerates the level of anisotropy, and the WPM cannot detect the mild anisotropy of 3D-printed parts, while the WPM-CVF produces the best results. Additionally, the non-local scheme outperforms the local approach in terms of finite element analysis performance, such as mesh dependency, robustness, etc.
Originality/value
This paper provides a method for modeling anisotropic fracture in 3D-printed objects. A new damage model based on a combination of two prevalent models is offered. Moreover, the developed subroutines for implementing the non-local anisotropic fracture criterion enable a reliable crack propagation simulation in media with varying degrees of complication, such as anisotropy.
Details
Keywords
This study aims to introduce a modern higher efficiency predictor–corrector iterative algorithm.
Abstract
Purpose
This study aims to introduce a modern higher efficiency predictor–corrector iterative algorithm.
Design/methodology/approach
Furthermore, the efficiency of new algorithm is analyzed on the based on Chun-Hui He’s iteration method.
Findings
In comparison with the current robust algorithms, the newly establish algorithm behaves better and efficient, whereas the current existing algorithm fails or slows in the considered test examples.
Practical implications
The modified Chun-Hui He’s algorithm has great practical implication in numerous real-life challenges in different area of engineering, such as Industrial engineering, Civil engineering, Electrical engineering and Mechanical engineering.
Originality/value
The paper presents a modified Chun-Hui He’s algorithm for solving the nonlinear algebraic models exist in various area.
Details
Keywords
Mingyang Liu, Guangjun Gao, Huifen Zhu and Chen Jiang
The purpose of this paper is to investigate the feasibility of solving turbulent flows based on smoothed finite element method (S-FEM). Then, the differences between S-FEM and…
Abstract
Purpose
The purpose of this paper is to investigate the feasibility of solving turbulent flows based on smoothed finite element method (S-FEM). Then, the differences between S-FEM and finite element method (FEM) in dealing with turbulent flows are compared.
Design/methodology/approach
The stabilization scheme, the streamline-upwind/Petrov-Galerkin stabilization is coupled with stabilized pressure gradient projection in the fractional step framework. The Reynolds-averaged Navier-Stokes equations with standard k-epsilon model are selected to solve turbulent flows based on S-FEM and FEM. Standard wall functions are applied to predict boundary layer profiles.
Findings
This paper explores a completely new application of S-FEM on turbulent flows. The adopted stabilization scheme presents a good performance on stabilizing the flows, especially for very high Reynolds numbers flows. An advantage of S-FEM is found in applying wall functions comparing with FEM. The differences between S-FEM and FEM have been investigated.
Research limitations/implications
The research in this work is limited to the two-dimensional incompressible turbulent flow.
Practical implications
The verification and validation of a new combination are conducted by several numerical examples. The new combination could be used to deal with more complicated turbulent flows.
Social implications
The applications of the new combination to study basic and complex turbulent flow are also presented, which demonstrates its potential to solve more turbulent flows in nature and engineering.
Originality/value
This work carries out a great extension of S-FEM in simulations of fluid dynamics. The new combination is verified to be very effective in handling turbulent flows. The performances of S-FEM and FEM on turbulent flows were analyzed by several numerical examples. Superior results were found compared with existing results and experiments. Meanwhile, S-FEM has an advantage of accuracy in predicting boundary layer profile.
Details
Keywords
Muhammad Nadeem, Ji-Huan He and Asad Islam
This study aims that very lately, Mohand transform is introduced to solve the ordinary and partial differential equations (PDEs). In this paper, the authors modify this…
Abstract
Purpose
This study aims that very lately, Mohand transform is introduced to solve the ordinary and partial differential equations (PDEs). In this paper, the authors modify this transformation and associate it with a further analytical method called homotopy perturbation method (HPM) for the fractional view of Newell–Whitehead–Segel equation (NWSE). As Mohand transform is restricted to linear obstacles only, as a consequence, HPM is used to crack the nonlinear terms arising in the illustrated problems. The fractional derivatives are taken into the Caputo sense.
Design/methodology/approach
The specific objective of this study is to examine the problem which performs an efficient role in the form of stripe orders of two dimensional systems. The authors achieve the multiple behaviors and properties of fractional NWSE with different positive integers.
Findings
The main finding of this paper is to analyze the fractional view of NWSE. The obtain results perform very good in agreement with exact solution. The authors show that this strategy is absolutely very easy and smooth and have no assumption for the constriction of this approach.
Research limitations/implications
This paper invokes these two main inspirations: first, Mohand transform is associated with HPM, secondly, fractional view of NWSE with different positive integers.
Practical implications
In this paper, the graph of approximate solution has the excellent promise with the graphs of exact solutions.
Social implications
This paper presents valuable technique for handling the fractional PDEs without involving any restrictions or hypothesis.
Originality/value
The authors discuss the fractional view of NWSE by a Mohand transform. The work of the present paper is original and advanced. Significantly, to the best of the authors’ knowledge, no such work has yet been published in the literature.
Details
Keywords
Sinan Obaidat, Mohammad Firas Tamimi, Ahmad Mumani and Basem Alkhaleel
This paper aims to present a predictive model approach to estimate the tensile behavior of polylactic acid (PLA) under uncertainty using the fused deposition modeling (FDM) and…
Abstract
Purpose
This paper aims to present a predictive model approach to estimate the tensile behavior of polylactic acid (PLA) under uncertainty using the fused deposition modeling (FDM) and American Society for Testing and Materials (ASTM) D638’s Types I and II test standards.
Design/methodology/approach
The prediction approach combines artificial neural network (ANN) and finite element analysis (FEA), Monte Carlo simulation (MCS) and experimental testing for estimating tensile behavior for FDM considering uncertainties of input parameters. FEA with variance-based sensitivity analysis is used to quantify the impacts of uncertain variables, resulting in determining the significant variables for use in the ANN model. ANN surrogates FEA models of ASTM D638’s Types I and II standards to assess their prediction capabilities using MCS. The developed model is applied for testing the tensile behavior of PLA given probabilistic variables of geometry and material properties.
Findings
The results demonstrate that Type I is more appropriate than Type II for predicting tensile behavior under uncertainty. With a training accuracy of 98% and proven presence of overfitting, the tensile behavior can be successfully modeled using predictive methods that consider the probabilistic nature of input parameters. The proposed approach is generic and can be used for other testing standards, input parameters, materials and response variables.
Originality/value
Using the proposed predictive approach, to the best of the authors’ knowledge, the tensile behavior of PLA is predicted for the first time considering uncertainties of input parameters. Also, incorporating global sensitivity analysis for determining the most contributing parameters influencing the tensile behavior has not yet been studied for FDM. The use of only significant variables for FEA, ANN and MCS minimizes the computational effort, allowing to simulate more runs with reduced number of variables within acceptable time.