
نوع مقاله : (W.O.S) ISI دارای رتبه
عنوان مقاله : Experimental and optimization of mechanical properties of epoxy/nanosilica and hybrid epoxy/fiberglass/nanosilica composites
نویسندگان : S. Feli
M. Mahdipour Jalilian
محل چاپ یا ارائه : Journal of Composite Materials
سال انتشار : 2016
چکیده مقاله :
In this paper, the effect of addition of nanosilica on mechanical properties of pure epoxy and epoxy/fiberglass composite has been investigated. The epoxy/nanosilica composites and epoxy/fiberglass/nanosilica hybrid composites have been fabricated, and the Young’s modulus, tensile strength, yield stress and elongation at break have been determined by simple extension tests. The results show that by addition of 1 wt% of nanosilica in both types of composites, Young’s modulus, yield stress and tensile strength decrease and elongation at break increases. By increasing the nanosilica content, the Young’s modulus, yield stress and tensile strength increase and elongation at break decreases. Also, imperialist competitive algorithm is employed to model the mechanical properties as fourth degree polynomial functions. The accuracy of polynomial is maximized and coefficients are obtained. The results show 25.66%, 56.87% and 45.84% improvement in Young’s modulus, yield stress and tensile strength of pure epoxy, respectively. Also, 12.9%, 24.83% and 12.85% improvement in Young’s modulus, yield stress and tensile strength of epoxy/fiberglass composites, has been observed, respectively.

نوع مقاله : (W.O.S) ISI دارای رتبه
عنوان مقاله : Predicting the combined effect of TiO2nanoparticles and welding input parameters on the hardness of melted zone in submerged arc welding by fuzzy logic
نویسندگان : Masood Aghakhani, Mohammad Reza Ghaderi, Maziar Mahdipour Jalilian, Ali Ashraf Derakhshan
محل چاپ یا ارائه : Journal of Mechanical Science and Technology
سال انتشار : 2013
چکیده مقاله : Submerged arc welding (SAW) is a highquality arc welding process used in heavy industries for welding thick plates. In this process, selecting appropriate values for the input parameters is required for high productivity and cost effectiveness. A very important weld quality characteristic affected by welding input parameters is the hardness of melted zone (HMZ). This paper reports the applicability of fuzzy logic (FL) to predict HMZ in the SAW process which is affected by the combined effect of TiO2 nanoparticles and welding input parameters. The arc voltage, welding current, welding speed, contact tiptoplate distance, and TiO2 nanoparticles were used as input parameters and HMZ as the response to develop FL model. A fivelevel fivefactor central composite rotatable design (CCRD) was used in the experiments to generate experimental data. Experiments were performed, and HMZs were measured. The predicted results from FL were compared with the experimental data. The correlation factor value obtained was 99.99% between the measured and predicted values of HMZ. The results showed that FL is an accurate and reliable technique for predicting HMZ because of its low error rate.

نوع مقاله : خارجی غیر ISI معتبر
عنوان مقاله : Optimization of GMAW Process using Imperialist Competitive Algorithm
نویسندگان : Masood Aghakhani, Maziar Mahdipour Jalilian, Alimohammad Karami, Mahyar Mahdipour Jalilian
محل چاپ یا ارائه : Applied Mechanics and Materials
سال انتشار : 2012
چکیده مقاله : In Gas Metal Arc Welding (GMAW) process, one of the main goals is to reach high depth of penetration as a characteristic of quality. This requires high amount of input heat. On the other hand high amount of input heat causes the increase in dimensions of heat affected zone (HAZ) which is not desirable. In this paper, an objective function including both depth of penetration of weld bead and the width of heat affected zone namely F = (HAZ+t) / (P+t) has been considered where, HAZ, P, and t denote the width of heat affected zone, the depth of penetration, and thickness of test pieces respectively. A five level five factor rotatable central composite design was used to collect the data for depth of penetration and width of heat affected zone. After collecting the data, the regression equation of objective function was obtained as a function of wire feed rate, welding voltage, nozzletoplate distance, welding speed and gas flow rate using least squares method. Then the objective function (f) was minimized by using the Imperialist Competitive Algorithm. One can be sure that the width of HAZ will decrease and the depth of penetration will increase due to minimization of the objective function. The computational result demonstrates that the proposed optimization algorithm is quiet effective in minimizing the objective function. The result shows that in order to obtain higher depth of penetration and lower width of heat affected zone at the same time, wire feed rate, arc voltage and nozzletoplate distance must be at their lowest levels while welding speed and gas flow rate should be at their highest levels.

نوع مقاله : خارجی غیر ISI معتبر
عنوان مقاله : Prediction of Weld Bead Dilution in GMAW Process using Fuzzy Logic
نویسندگان : Masood Aghakhani, Maziar Mahdipour Jalilian , Alimohammad Karami
محل چاپ یا ارائه : Applied Mechanics and Materials
سال انتشار : 2012
چکیده مقاله : Gas metal arc welding is one of the most important arc welding processes used in manufacturing and repair. In this process selecting appropriate values for process variables is essential in order to decide upon metal transfer and subsequently control the heat input into the workpiece from which reliable predictions could be made about the metallurgical, mechanical properties and performance of the welded joints. In this paper, the welding dilution in gas metal arc welding of ST37 steel has been predicted by fuzzy logic. A five level five factor rotatable central composite design was used to collect the welding data and the weld dilution was modeled as a function of wire feed rate, welding voltage, nozzletoplate distance, welding speed and gas flow rate.

نوع مقاله : خارجی غیر ISI معتبر
عنوان مقاله : Modeling of Weld Dilution in Gas Metal Arc Welding Process using Taguchi’s Design of Experiments
نویسندگان : Masood Aghakhani, Ehsan Mehrdad, Ehsan Hayati, Maziar Mahdipour Jalilian, Arash Karbasian
محل چاپ یا ارائه : Applied Mechanics and Materials
سال انتشار : 2012
چکیده مقاله : Gas metal arc welding is a fusion welding process which has got wide applications in industry. In order to obtain a good quality weld, it is therefore, necessary to control the input welding parameters. In other words proper selection of input welding parameters in this process contribute to weld productivity. One of the important welding output parameters in this process is weld dilution affecting the quality and productivity of weldment. In this research paper using Taguchi method of design of experiments a mathematical model was developed using parameters such as, wire feed rate (W), welding voltage (V), nozzletoplate distance (N), welding speed (S) and gas flow rate (G) on weld dilution. After collecting data, signaltonoise ratios (S/N) were calculated and used in order to obtain the optimum levels for every input parameter. Subsequently, using analysis of variance the significant coefficients for each input factor on the weld dilution were determined and validated. Finally a mathematical model based on regression analysis for predicting the weld dilution was obtained. Results show that wire feed rate (W),arc voltage (V) have increasing effect while Nozzletoplate distance (N) and welding speed (S) have decreasing effect on the dilution whereas gas Flow rate alone has almost no effect on dilution but its interaction with other parameters makes it quite significant in increasing the weld dilution.

نوع مقاله : خارجی غیر ISI معتبر
عنوان مقاله : Application of Imperialist Competitive Algorithm in Optimizing the Width of Heat affected Zone in GMAW Process
نویسندگان : Masood Aghakhani, Maziar Mahdipour Jalilian, Mohammad Mehdiabadi, Mahyar Mahdipour Jalilian and Alimohammad Karami
محل چاپ یا ارائه : International Journal of Modeling and Optimization
سال انتشار : 2011
چکیده مقاله : In Gas Metal Arc Welding (GMAW) process, one of the main goals is to reach minimum width of Heat affected Zone (HAZ) as a characteristic of quality. A five level five factor rotatable central composite design was used to collect the data for width of HAZ. After collecting the data, the regression equation of width of HAZ was obtained as a function of wire feed rate, welding voltage, nozzletoplate distance, welding speed and gas flow rate using least squares method. Then the cost function (width of HAZ) was minimized by using the Imperialist Competitive Algorithm. The computational result demonstrates that the proposed optimization algorithm is quite effective in minimizing the cost function. The result shows that in order to obtain lower width of HAZ, wire feed rate and welding voltage must be at their lowest levels while nozzletoplate distance, welding speed and gas flow rate should be at their highest levels.

نوع مقاله : خارجی غیر ISI معتبر
عنوان مقاله : Modeling the Free Convection Heat Transfer in a Partitioned Cavity by the Use of Fuzzy Logic
نویسندگان : T. Yousefi, A. Karami, S. Mahmudinejad, M. Mahdipour Jalilian and M. Ahmadi
محل چاپ یا ارائه : International Journal ofModeling and Optimization
سال انتشار : 2011
چکیده مقاله : In this paper fuzzy logic method has been used to model and predict the experimental results of steady free convection heat transfer in a partitioned cavity with adiabatic, horizontal and isothermally vertical walls and an adiabatic partition. Experiments covered Rayleigh number ranging from 1.5×105 to 4.5×105 and the angle of the partition with respect to horizon from 0° to 90°. Results indicate that, at a constant angle of the adiabatic partition, the average Nusselt number and consequently heat transfer increases with the increase of Rayleigh number and at a constant Rayleigh number, the maximum and minimum heat transfer occurs at the partition angle of 45° and 90°, respectively. Velocity contours from a commercial code, Fluent, has been used to analyze the variation of heat transfer in the cavity. A fuzzy inference system named Mamdani was used to expect the output membership functions to be fuzzy sets. It has been shown that fuzzy logic is a powerful tool for predicting the experiments, due to its low error. The average error of fuzzy predictions with respect to experimental results was found to be 0.37% for this study.

نوع مقاله : خارجی غیر ISI معتبر
عنوان مقاله : Fuzzy Logic to Model the Free Convection Heat Transfer from Horizontal Isothermal Cylinders Arranged in Vertical and Inclined Arrays
نویسندگان : Ehsan Rezaei, Alimohammad Karami, Tooraj Yousefi, Masood Aghakhani, and Maziar Mahdipour Jalilian
محل چاپ یا ارائه : International Journal of Modeling and Optimization
سال انتشار : 2012
چکیده مقاله : This paper highlights the application of fuzzy logic to predict the free convection heat transfer from horizontal isothermal cylinders arranged in vertical and inclined arrays. Experiments included cylinder spacing (centertocenter) varying from 2 to 5 times the cylinder diameter and horizontal spacing ranging from 0 to 2 times the cylinder diameter in inclined array. Also, Rayleigh number based on the cylinder diameter varied from 10 3 to 3×10 3. It was observed that the increase of cylinder spacing in vertical and inclined array and horizontal spacing in inclined array results in heat transfer increase from the array. Moreover, it was shown that, fuzzy logic is a powerful technique used for predicting the heat transfer due to its low error rate. The average error of fuzzy technique as compared with experimental data was found to be 0.081 % for this study.

نوع مقاله : (W.O.S) ISI دارای رتبه
عنوان مقاله : Three Dimensional Solution of Low Velocity Impact on Sandwich Panels with Hybrid Nanocomposite Face sheets
نویسندگان : S Feli, M Mahdipour Jalilian
محل چاپ یا ارائه : Mechanics of Advanced Materials and Structures
سال انتشار : 2017
چکیده مقاله : In this paper, a threedimensional solution based on Fourier's series and Generalized Differential Quadrature (GDQ) method is presented to model the low velocity impact on sandwich panels with hybrid nanocomposite face sheets. The Navier's equations are derived and displacements are substituted by their corresponding Fourier's series. The contact force is considered as a Fourier's series of impactor displacement and deflection of contact point. To verify the theoretical model experiments are performed on a polyurethane foam cored sandwich panel with epoxy/wovenfiberglass/nanosilica hybrid nanocomposite face sheets. Contact force and lateral displacement of contact point histories are compared with theoretical model.

نوع مقاله : (W.O.S) ISI دارای رتبه
عنوان مقاله : Theoretical model of lowvelocity impact on foamcore sandwich panels using finite difference method
نویسندگان : S Feli, M Mahdipour Jalilian
محل چاپ یا ارائه : Journal of Sandwich Structures & Materials
سال انتشار : 2016
چکیده مقاله : In this article, a threedimensional solution based on the Fourier’s series and finite difference method has been presented to study the lowvelocity impact on sandwich panels with foam core and composite face sheets. The Navier’s equations are derived and displacements are substituted by their corresponding Fourier’s series and three partial differential equations with coefficients of Fourier’s series are obtained. The contact force has been considered as a Fourier’s series of impactor displacement and deflection of top face sheet. Also, the model is verified by experiments performed on sandwich panel with epoxy/wovenfiberglass composites, face sheets and polyurethane foam core, and other researchers’ works. The history of contact forces and lateral displacement of contact point has been obtained experimentally and compared with theoretical model. Finally, the effects of impact energy and geometrical parameters including inplane dimension ratio, core thickness, and face sheet thickness on contact force and lateral deflection histories have been investigated.
