جستجوی مقالات مرتبط با کلیدواژه "روش تاگوچی" در نشریات گروه "مکانیک"

The global population increase and the depletion of fossil fuel reserves, along with environmental changes caused by the rising demand for renewable energy, have turned the sustainable, adequate, and cost-effective supply of these resources into a significant challenge. The current study examines the power generation cycle based on geothermal and solar energy, aiming to optimize operational procedures, increase efficiency, and reduce energy production costs. This study utilizes EES software for exergy and exergy-economic analysis and employs the Taguchi optimization method to identify optimal operational conditions. Results show that, under optimal conditions, this system can increase the first law efficiency by up to 17% compared to the average and reduce the total exergy destruction by up to 50%. Furthermore, the results indicate that the evaporator connected to the solar collector and the condenser temperature are the main factors affecting the efficiency of the first and second laws, reducing exergy destruction, and the cost rate of exergy destruction

In this study, a novel absorber design is presented to enhance performance over the conventional polymer variant in car bumpers. The new absorber adopts a sandwich structure with aluminum foam shells and a polymer foam core. Finite Element Method (FEM) and Abaqus software were employed, conforming to the E.C.E-R042 standard. Analysis indicates density has a more significant impact on performance than thickness. Across sandwich configurations, both maximum von Mises stress and plastic strain were significantly reduced compared to the polymer absorber. The maximum impact force, within a specified shell density range, was lower than the polymer counterpart. The optimal structure for maximum impact force, von Mises stress, and the plastic strain was determined using the Taguchi method. The selected item: sandwich absorber, 25mm shell thickness, and 225 kg/m³ density.

In this paper, the effect of including SiC nanoparticles in the weld zone on the maximum shear strength of friction stir lap welded 7075 aluminum alloy is investigated, both experimentally and numerically. This objective is carried out by studying the effects of rotational and transverse speeds, tilt angle, the shape of the tool and the penetration depth. The numerical investigation is based on developing an FE model by means of Deform and ABAQUS to simulate the welding procedure, which results are verified by the experimental findings. Experimental procedure is designed based on Taguchi method. The verification of the developed FE model shows that the simulation results are in proper agreement with the experimental findings. In general, including SiC nanoparticles in the weld zone can increase the maximum shear strength up to 24%, compared to the case of where the specimens are welded without SiC. Furthermore, applying the threaded tapered tool leads to higher shear strength in comparison with the squared shape tool, i.e., the strength of the specimens welded by threaded tapered tool are 4 to 5% higher without SiC inclusion and 4 to 7.5% higher with SiC, compared to the same case welded by squared tool. In addition, while the rotational speed has the highest influence on the findings, the tilt angle does not affect the results that much.

In the present study, the sensitivity of particle dispersion within a room to the spatial position of the inlet and outlet air register was investigated using the Taguchi method and analysis of variance. For this purpose, 86400 particles with a size of 1µm were uniformly injected from the inlet register into the room at equal time intervals. Different positions for the inlet register (32 positions) and outlet register (4 positions) on the ceiling and floor of the room were considered. Subsequently, the behavior of the particles, as well as the particle deposition and dispersion within the room over a 60-second time period, were examined using the multi relaxation time lattice Boltzmann method. By employing the Taguchi method and L16 orthogonal arrays, the required number of experiments was reduced by 1/8. All specified experiments which suggested by orthogonal array are simulated, and the number of suspended particles in the room were measured. Following the experiments, the effects of each parameter on the output of the problem were determined based on a factor called the signal-to-noise (S/N) ratio and analysis of variance. According to the obtained results, the longitudinal position of the inlet register had the highest impact on the number of suspended particles in the room, accounting for 84.42% contribution. Additionally, the vertical position of the outlet register had the least impact, contributing only 0.16%.

In the process of molding parts using the plastic injection molding method, it is key essential to apply appropriate parameters in order to produce a qualified product. The purpose of this paper is to choose helpful production parameters and optimize them for molding eight different parts made from Polyetherimide. In the beginning, based on the previous research and the capabilities of Mold Flow software, appropriate process parameters were chosen. These parameters were: melt temperature, mold surface temperature, packing pressure and coolant inlet temperature. The simulations in Mold Flow software were done based on Taguchi’s L25 orthogonal array. Afterward, the critical and comparable results including: volumetric shrinkage, sink mark, warpage and the percentage of frozen volume in parts were exported from the simulations. Eventually, the optimizations were made based on these results by applying the gray relational analysis. The optimizing results show that in all distinguishing coefficients of the gray relational analysis (0.1 to 0.9), the melt temperature was 360 °c, the mold surface temperature was 140 °c, the packing pressure was 100% of the injection pressure and the coolant inlet temperature was 12.5 °c lower than the mold surface temperature of the most optimized ones. Also based on the ANOVA results, in all difference indices, parameters of melt temperature and packing pressure were respectively the most effective.

Surface roughness is one of the most important characteristics in nanomachining products. One of the parameters that always has a great impact on the surface quality is the forces caused by the nanocutting process. In this research, using molecular dynamics simulation in LAMMPS software, the process of dynamic nano ploughing of single-crystal copper workpiece by a diamond tool is investigated. The effect of parameters of dynamic nano- ploughing process such as depth of cut, amplitude and frequency of cutting tool vibration on cutting force and surface roughness has been investigated by calculating average roughness. Also, in order to more closely examine the effect of parameters and their interaction on each other, Taguchi method has been used to design experiments. The simulation results show that the characteristics of cutting depth, amplitude and frequency of cutting tool vibration have the greatest effect on surface smoothness and cutting forces, respectively. Based on the presented results, it has been determined that the surface roughness can be improved in different machining conditions based on the selection of parameters, and it is necessary to check their conditions together well before selecting these parameters. Also, using Taguchi method, the optimal values of dynamic ploughing parameters were obtained to achieve the best surface smoothness and the lowest cutting force in certain dimensions as described by DOC=2.5 , R=0.1 and ω=50 KHz.

In this research, hydrothermal performance of boehmite alumina nanofluid based on water in a cylindrical heat sink with helical minichannels is investigated numerically. The design factors were selected at four levels including the helix angle of minichannels, the Reynolds number, the nanoparticles shape and volume fraction of nanoparticles. To perform sensitivity analysis of design factors, the Taguchi method with L16 orthogonal array and statistical analysis of variance are used.The Nusselt number, the Fanning friction factor and the total thermal performance factor were computed as the output parameters. The obtained results showed that the helix angle of minichannels and the nanoparticles shape have a vital role in the Nusselt number and the Fanning friction factor with the sum of the contribution ratios of the two factors 85.21% and 96%, respectively. Also, the helix angle of minichannels has a 47.93% contribution in the total thermal performance factor.The optimal combination for the Nusselt number and the total thermal performance factor is acquired as A1B4C4D4. Overall, the helical minichannel with boehmite alumina nanofluid can be useful as a preferred cooling for the cylindrical heat sources.

Due to the development of using composite pipes and fittings in transmission lines and refineries of petrochemical and gas industries, knowledge of mechanical behavior and their optimal design in working conditions is essential. In this study, by using the Taguchi experimental design method, a numerical model is presented to investigate the behavior of composite pipes, made of glass fibers and different resins, against impact loads due to drop weight at different operating temperatures. The pipes are produced with three types of epoxy resins, vinyl ester and polyester and have been tested in the temperature range of -15o C to 100 °C. In order to evaluate the model, the results of the numerical model in different cases are compared with experimental ones and the effect of each of the control factors on the mechanical response of the pipe is evaluated. The results show that the pipe with epoxy resin and temperature of 100 °C has the best performance against impact load and also with increasing ambient temperature, the load carrying capacity of the pipe decreases and the impact time of the impactor increases.

Achieving the minimum thinning and required forming force is one of the main purposes in the manufacturing of sheet products using the hydroforming process. This paper investigates forming of the copper sheet using the hydrodynamic deep drawing assisted by radial pressure via the design of experiment method and finite element (FE) analysis. Firstly, the necessary experiments have been designed using the Taguchi design of experiment method. In this design, maximum fluid pressure, punch velocity, the friction coefficient between punch and sheet, the friction coefficient between die and sheet, the gap between blankholder and die, punch nose radius, die entrance radius, and prebulge pressure were considered as input variables and thinning ratio and punch force considered as response functions. Then, designed experiments were performed using an experimental verified FE model and the desired results were obtained. Finally, the optimum levels of input variables were obtained using the Taguchi optimization method and the confirmation experiments were performed using the FE simulation. Results show that the punch nose radius and die entrance radius are the essential parameters on the thinning ratio. Also, the maximum fluid pressure is the most effective parameter on the punch force.

Academics are interested in solar energy for water purification because it is easily accessible. In this investigation, a stepped solar still was constructed and tested experimentally in Arak. Using the Taguchi design of experiment approach, it was determined how the five input parameters-saline water flow rate, device angle, absorber plate color, number, and spacing of distilled water-conducting threads in each row-affected the amount of freshwater production as the output variable. This research is unique in that it uses plastic threads to create channels on the cover glass surface that lead distilled water to the freshwater tank. In addition, the simultaneous study of the effect of input parameters is one of the innovations of this research. The results showed that when the input saline water flow rate was 50 ml/min, the device angle was 40°, the absorber plate was black, the number of water-conducting threads in each row was 2, and the row spacing was 8 mm, the greatest freshwater output of 1975 ml/m2 was produced. Also, by using two water-conducting threads in each row and spacing them 8 mm apart, the amount of water produced per unit of surface area was increased.

The wavy channels increases the performance of thermal apparatuses and decreases the their size. The design parameters of wavy-plate heat exchangers are the pitch, height, thickness, length of channel and wave-length and wave-amplitude. In the present syudy, to optimum the performance of wavy-plate heat exchangers, a Taguchi method is utilized for 25 models in five levels. Thermal-hydraulic performance of the models is investigated using an appropriate 3D-CFD simulation. Then, the variance analysis is applied to detect the optimum values and more effective parameters on heat transfer rate and pressure drop. The results indicated that the most effective geometrical parameters on f factor and the criterion of evaluating performance j/f is wavy amplitude. The wavy-amplitude on j factor has the most influence in the laminar regime, but its importance is gradually reduced at higher Reynolds numbers and the importance of pitch is increased. The wavelength is the second effective characteristic for j, f, and j/f factors in all Reynolds numbers.

Surface roughness is one of the most important features in nanoscale machining. Due to the use of nanometer-sized products for use in assemblies that require extremely high accuracy at a fraction of a nanometer, care must be taken in selecting machining parameters that affect the surface roughness. In this study, using molecular dynamics simulations, the machining of a single-crystal copper workpiece by diamond tools with different geometries has been investigated and the final surface roughness has been calculated. The effect of machining parameters such as cutting depth and cutting speed along with parameters related to tool geometry such as rake angle, relief angle and tip radius on surface roughness have been investigated with average roughness (R_a) and root mean square (RMS) measuring instruments. In order to study more precisely the effect of parameters and their interaction with each other, Taguchi method has been used to design experiments. The simulation results show that both the average roughness and root mean square parameters predict the greatest effect on the surface roughness of the workpiece due to the depth of cutting. Based on the presented results, it has been determined that the surface roughness can be improved in different machining conditions based on the selection of parameters, and it is necessary to carefully examine their conditions together before selecting these parameters. Using the Taguchi method, the optimal values of cutting parameters to achieve the best surface roughness in specified dimensions are described as

The purpose of this study was to predict the optimal conditions of machining parameters including tool coating method, cutting speed, advancement rate, and cutting depth to minimize tool flank wear in AISI 4140 hardened steel machining, with PVD and CVD coated tools. In recent years, the trend towards cutting tool coating technology has increased with increasing cutting speed and advancement rate. These tools are coated using two different physical vapor deposition (PVD) and chemical vapor deposition (CVD). The L18 orthogonal array was designed by Taguchi experiments and the signal-to-noise ratio (S/N) was used to optimize the parameters. Analysis of variance (ANOVA) was also used to determine the importance of effective parameters. Finally, the validation test was performed using the Taguchi optimization method to validate and show the effectiveness of this method. The results showed that the tool with PVD coating has the best performance for minimum tool wear. Also, cutting speed was the most important parameter affecting tool wear. The results of the confirmation test showed that the Taguchi method is a reliable and successful method for optimizing machining parameters for minimum tool wear in AISI 4140 high-speed steel turning.

In this study, heat transfer of nanofluid in a channel with an externally–applied magnetic field and a porous obstacle is simulated and discussed. To simulate the flow field inside the obstacle, the Darcy–Brinkman–Forchheimer model is implemented in the LBM method. Thereafter, effects of influencing parameters on the heat transfer rate are analyzed utilizing the experimental design method. The results show that the nanoparticles type has the greatest effect on the heat transfer with the contribution ratio of 62.79%. The second and the third parameters are the obstacle size and the Reynolds number, with the contribution ratios of 20.71% and 7.58%, respectively. The contribution ratios of the Hartmann number and the nanoparticles fraction are estimated about 3%. However, it is found that in this problem, the influences of the porosity, type, and the Darcy number of the obstacle on the mean Nusselt number are almost negligible.

This research aims to improve aerodynamic performance of a radial gas microturbine from input to output, so that the best case can be selected. In this work, ANSYS CFX software was used. First, using one-dimensional model, different states were investigated and the best mode was selected. Then, by solving the governing equations, the efficiency of the designed turbine was obtained. This work combines computational work and experimental design to find the best blade profile for optimal operation. The geometrical parameters of rotor blade were considered as variable factors. Four levels were selected for each factor according to Credential references. According to the number of parameters and the number of levels determined, the appropriate orthogonal table can be selected and again numerically simulated with CFX software. The optimally designed rotor offers the highest efficiency and power output compared to the original rotor, such that the output power of the designed rotor is increased by 7.3%.

Thermex is a thermo-mechanical process which is used as an in-line operation after rolling process. By using this process, the yield strength of the rebar reaches to at least 500 MPa. Due to the importance of using high-strength rebars, in the present study, the influences of the process parameters on the rebar’s mechanical properties are investigated using experimental techniques. Considering four effective factors including water flow rate, Thermex pressure, rolling speed and different furnace temperatures, standard tensile tests were performed. The required experiments according to Taguchi method were designed and then the effect of mentioned parameters on the mechanical properties (yield strength, ultimate strength and ductility) of the rebar was studied. Statistical investigation includinf signal to noise (S/N) ratio and analysis of variance (ANOVA) showed that all the mentioned parameters have s significant influence on the mechanical properties. Based on the results, the optimal values of the parameters were determined to achieve optimal conditions of strength and ductility.

Nowadays, in different industries, especially in the automotive industry, the use of lightweight materials such as aluminum alloys has been increased in order to reduce the weight of parts and fuel consumption. These alloys have low formability at room temperature. To overcome this problem, forming at elevated temperatures is proposed. In this paper, formability of 5052 aluminum alloy sheet under hydrodynamic deep drawing assisted by radial pressure process has been studied at warm condition. Initially, after analyzing the effect of geometric parameters on thickness distribution and punch force, the effect of temperature, fluid pressure and punch speed on thickness distribution, punch force and limiting drawing ratio (LDR) were investigated. Also, the effects of forming temperature and punch speed on the minimum thickness of the workpiece were studied using Taguchi method. Based on the obtained results, higher temperature in warm isothermal and non-isothermal states leads to decrease and increase in the part thickness, respectively while higher punch speed helps in thickness improvement. It was found that the LDR increases with increasing temperature in non-isothermal state and with decreasing temperature in isothermal condition. In addition, increase in fluid pressure leads to a higher LDR.

Fiber-reinforced thermoplastic composites have drawn much attention due to higher toughness in comparison with thermosets. Polycarbonate is of particular concern because of low weight, high thermal and impact resistance. In this paper, effect of manufacturing parameters such as temperature, pressure and time on mechanical properties of Polycarbonate/Glass laminate is investigated using Taguchi method. In order to evaluate effects of various parameters, an experimental design planned using L9 orthogonal array with three level of time, pressure and temperature with the help of Minitab software. For this, composite beams having arrangement [0]8 were produced in film staking procedure in a hot-pressing apparatus. The 3-points bending tests were carried out to assess manufacturing quality. Comparison of flexural modulus and flexural strength of various specimens were made and the results are commented upon and discussed. Results show that the temperature of 215 Celsius degree results higher mechanical properties than other temperatures because of preventing resin degradation and adequate viscosity. Furthermore, results indicated that the time factor was more significant, than time and pressure, on curing quality. Optimum values of factors such as time, pressure and temperature to achieve higher flexural modulus and flexural strength are determined using analysis of Signal to Noise Ratio (SNR).

Dry electrical discharge machining is a sustainable machining process that is used gas medium such as air or Nitrogen instead of liquid dielectric mediums that are mainly based on oil derivation. In the current research, first each of three main responses including material removal rate (MRR), surface roughness (Ra) and radial overcut (ROC) have been optimized considering the effects of six main input factors including current (I), pulse on time (Ton), duty factor (D), spindle rotational speed (N), gas pressure (P) and the gas type.. Regarding the input factors, there are five quantitative and one qualitative input factor (gas type). So, in addition of air as most common dielectric medium, Nitrogen and mixture of Argon and air have been investigated as the other input factors of this parameter. The main purpose of this study is the multi objective optimization of dry electrical discharge machining responses by using the Grey relational analysis based on the Taguchi method. The results of this optimization method show the optimized level at I=12A, Pulse on time (Ton)=100 s , Duty factor (D) =66, Gas Pressure (P) = 3 bar and Spindle rotational speed (N)= 300 rpm and Nitrogen as the dielectric medium. The confirmation experiment at the optimized level by this method depicts that the optimized level has the maximum grey grade, hence it confirms the accuracy of the optimized level by Grey Relational Analysis method.. Also, regarding the equal weights of responses and considering the same effects of the surface roughness and radial over cut that both of them have the smaller the better characteristics, the optimization results in more effect on these responses in comparison with material removal rate.