Orthogonal Array Experiment Research Articles

A prediction model for the rockslide-generated wave amplitude under the condition of bedrock mass breakup

Landslides along coastlines and rivers can cause landslide-generated waves and pose a threat to the offshore banks, navigation vessels and coastal buildings. The maximum amplitude of the landslide-generated wave, which is strongly related to the size and geometry of the landslide and gradually decreases with the increase of the propagation distance, is one of the important indexes to evaluate the secondary hazard caused by landslides. The fragmentation of rockslide has an influence on the effect of rockslide on water body. This study proposes a relationship between the maximum rockslide-generated wave amplitude and the number of fragmentation blocks which is defined to present different degrees of landslide bedrock mass breakup. The computational fluid dynamics (CFD) numerical method is used to simulate the whole process of landslide and wave propagation. The orthogonal array experiment algorithm is used to design the numerical simulation schemes. The Gauss-Newton algorithm is adopted to analyze the results and elect the optimal model with the strongest correlation. A series of conducted physical model experiments prove the applicability and accuracy of the optimal model. This optimal numerical model can offer a reference for rockslide-generated wave analysis when considering bedrock mass breakup.

Design and optimization of nylon coated display unit cabin

The purpose of this research was to develop a method of optimization that may be applied to the existing layout of the display cabinet at the grocery store in order to make it more functional. This method can be applied to either continuous or discrete design variable values, depending on the context. It is also possible to take into account a large number of different design variables. As finite element analysis (FEA) is a common analysis tool for engineers, an optimization procedure was developed in order to reach the objective by combining the orthogonal array experimentation technique with FEA. This was done in order to create the best possible solution. In order to produce a combined optimised design for the purpose of reducing the amount of material used and the associated costs, topology, topography, and size optimization were all performed. The aim is not necessarily to obtain the actual optimum value, if such a thing even exists; rather, the objective is to devise a more practical approach that will, with a reasonable amount of effort, produce a result that is close to the optimum.

Cross-linking of polyvinyl alcohol-g-methionine with bisacrylamide and optimization of its swelling response using taguchi method

A hydrophilic macromolecular network is synthesized by crosslinking of grafted polyvinyl alcohol methionine with bisacrylamide (PVAMB). Firstly, polyvinyl alcohol (PVA) was chemically modified by grafting methionine onto its backbone using persulphate initiator. Secondly, the crosslinking of grafted polymer was carried out using N, N’ - Methylene bisacrylamide. The crosslinked macromolecule was characterized by UV Visible spectroscopy, FTIR spectroscopy, X-ray diffraction. The thermal behaviour of the crosslinked polymer was analysed using thermogravimetric analyser. The thermal stability of the polymeric network was found to be stable up to 400 °C. To optimize the performance and quality of the synthesized cross-linked polymer, Taguchi L-9 orthogonal array of experiments were designed with the factors such as weight of the hydrogel, pH, time of exposure and temperature using Qualitek-4 software. The studies revealed that PVAMB retains water molecules in their network to a greater extent in neutral solution. Also the swelling behaviour of the cross-linked polymer was investigated in various physiological solutions.

STUDY ON THE INFLUENCE OF ZINC-COATED WIRE MATERIAL ON 3D PROFILE MACHINING OF INCONEL 825 ALLOY USING WEDM PROCESS

The experimental analysis carried out in this paper aimed at the selection of optimal machining conditions for the 3D profile machining of Inconel 825 alloy using Wire Electrical Discharge Machining (WEDM). It was noticed that the 3D profile machining of Inconel 825 alloy using WEDM process has not been performed and reported so far by the researchers in this domain to the best of our knowledge. As the machining of Inconel 825 alloy is difficult using the conventional machining processes, nontraditional machining is generally used. As the material is conductive, the WEDM process is suitable to machine this material. The effects of input factors such as wire material, pulse on-time, pulse off-time, peak current, wire tension and gap voltage on the material removal rate (MRR), surface roughness (SR) and dimensional shift (DS) have been investigated using [Formula: see text] mixed-level orthogonal array of experiments. The DS value for every machining condition has been predicted and inputted into the CNC system as the wire offset value to enhance the dimensional accuracy of the product. The parametric analysis has been done by Minitab software. Analysis of variance (ANOVA) has been used to find the significant parameters affecting surface quality. The regression equations have also been formulated to study the adequacy of the model. Multi-response optimization based on the Gray Relational Analysis has been employed and the results that optimize the MRR and SR simultaneously have been suggested. SEM images have been taken on the machined surfaces to compare the surface finish on the specimens.

Optimization Process Parameter on Wear Characterization of Al6061 and AlSi10Mg Alloy Manufactured by Selective Laser Melting

In this research, wear optimization, hardness, and density were investigated for an AlSi10Mg alloy made by selective laser melting (SLM), and also an additive SLM process simulation was carried out. The quality and performance of the additive manufactured (AM) parts depends on the build orientation. A model based on an L9 orthogonal array of Taguchi design experiments was created to perform the wear characterization for the Al6061 and AlSi10Mg alloys. However, the wear and mechanical properties of the AlSi10Mg alloy showed better results than the 6061-cast alloys. Finally, the optimal process parameters at low wear rate and frictional force were found at a load of 20 N, a sliding speed of 200 rpm, and a time of 5 minutes. The obtained result at optimal parameter a low wear is 90 micrometers, and the frictional force was 3.6 N. The laser energy density was calculated based on the given process parameter as 150 J/mm3. The hardness of the SLM-AlSi10Mg alloy Vickers was measured for AlSi10Mg as 126±5 HV and Al6061 as 98±5 HV because of the very fine microstructure and fine distribution of the Si phase in AlSi10Mg SLM parts. The highest density achieved was 99.6% (2.660 g/cm3) and obtained defect-free components.

Impact of stir-squeeze casting process parameters on tensile strength of hybrid aluminium matrix composite

Aluminium metal matrix composite with higher tensile strength is made using a hybrid stir-squeeze casting technique. The hybrid technology combines the desirable features of uniform reinforcement particle distribution in the base matrix through stir casting and refined microstructure, minimizing porosity and enhanced mechanical properties via squeeze casting process. The composite was made from A356 aluminium alloy reinforced with Molybdenum disulfide (MoS2) and wheat husk ash (WHA). A356 alloy has a wide range of engineering applications, with MoS2 increasing wear resistance and WHA particles providing major technological and economic benefits. Taguchi L16 orthogonal array experiments are applied to optimize the stir-squeeze casting parameters (stirring speed, mould temperature, squeeze time squeeze pressure, pouring temperature) for achieving better tensile strength of the composites. The identified significant factors for the stir-squeeze casting process are stirring speed, squeeze pressure, and squeeze time. The optimum stir-squeeze casting condition increased the composite's tensile strength by 23.72%. The squeeze pressure of 125 MPa was noted that to eliminating these porosities and gives better grain refinement in the microstructure. The fractured tensile test specimen indicated the brittle and ductile mode of fracture.

Study on the recycling of ceramic polishing slag in autoclaved aerated foam concrete by response surface methodology

In this study, the mechanical performance and thermal insulation properties of autoclaved aerated foam concrete (AAFC) with ceramic polishing slag (CPS) were investigated using chemical foaming technology at a density of 500 kg/m3. An orthogonal experimental array and the response surface methodology analysis were used to optimize the mix proportion of CPS slurry, cement, and lime content, and XRD, SEM, TG, and MIP were employed to study the microstructure and composition of the AAFC. The AAFC with the maximum compressive strength, minimum thermal conductivity, and cement consumption was obtained using the quadratic model of the response surface methodology analysis. The minimum thermal conductivity reached 0.1032 W/m·K, and a compressive strength value of 4.03 MPa was obtained for the mixtures with the CPS slurry, cement, and lime at 2804, 226.2, and 234 kg/model, respectively. The results of the microstructure development show that with an increase in CPS slurry, the compressive strength is significantly enhanced. This might be due to a sufficient hydration reaction with a proper water content. The Si and Al in the CPS react with the calcareous material and C–S–H gels to form tobermorite, thus promoting the compressive strength. In addition, the MIP indicates that the micropore (10–50 mm) content of the AAFC has a significant correlation with thermal conductivity, while macropores (>500 mm) have a significant relationship with compressive strength.

Enzymatically synthesized γ-[Glu](n≥1)-Gln as novel calcium-binding peptides to deliver calcium with enhanced bioavailability

Novel γ-[Glu](n≥1)-Gln-Ca chelates were prepared by using γ-[Glu](n≥1)-Gln (mixture peptides containg γ-Glu-Gln, γ-Glu-Glu-Gln, γ-Glu-Glu-Glu-Gln, γ-Glu-Glu-Glu-Glu-Gln, γ-Glu-Glu-Glu-Glu-Glu-Gln) which were synthesized by glutaminase. Based on single factor and orthogonal array experiments, the optimal calcium-chelation conditions were as follows: 30 min chelation at 70 °C; peptide concentration, 0.15 g/mL; mixture peptides-to-calcium mass ratio, 25:1. The particle size of chelates was 743.6 ± 64.2 nm and the chelates appeared stable neutral molecular entities with 91.33% of chelation rate and 35.2 mg/g of calcium, also with higher thermostability. Chelated calcium ions might be surrounded by coordination bonds linking to two or more connecting points: oxygen atoms (carboxyl oxygen, hydroxyl oxygen and oxygen of peptide bonds) and nitrogen atoms (amino nitrogen). The chelates could be used for food/nutraceutical applications, as no toxicity at 0.125–10 mg/mL and enhanced efficiency in calcium release (releasing percentage over 85% at pH 8.0), transport and uptake compared with CaCl2 were detected in Caco-2 cells.

Encapsulation of Bacillus pumilus G5 from polyvinyl alcohol‑sodium alginate (PVA-SA) and its implications in improving plant growth and soil fertility under drought and salt soil conditions

Drought and salt stresses adversely affect the growth and yield of plants in agricultural production. Bacillus pumilus, an important plant growth-promoting bacterium, play a significant role in improving plant tolerance to abiotic stresses. In this study, B. pumilus G5 were immobilized in polyvinyl alcohol‑sodium alginate (PVA-SA) microbeads and then applied on the Pharbitis nil under drought and salt stresses by pot experiment. Orthogonal array experiments showed that the optimal immobilization conditions of PVA-SA immobilized G5 microbeads were adsorbent 6.0%, PVA: SA 1:1 (3.0%), CaCl2 4.0%, and bacterium: embedding agent (PVA-SA) 3:4; And the G5 microbeads produced at the optimal condition exhibited better cultivable bacteria count, encapsulation rate, expansion rate and mechanical strength. Pot experiment showed that G5 microbeads significantly increased the length and diameter of root and stem, and dry weight of P. nil during experimental stage under drought and salt stress. G5 microbeads also increased the total cultivable bacteria population, the activities of invertase (INV), urease (URE), phosphatase (PHO) and catalase (CAT), and the contents of available nitrogen (AN) and available phosphorus (AP) in the rhizosphere soil of P. nil. Therefore, our study obtained the optimal process of G5 microbeads, and confirmed its effect on improved plant growth and soil chemical and biological properties of P. nil. Thus it can be used as sustainable tool for eco-friendly bio-inoculants at salinity soil within arid and semi-arid areas.

Machinability study on Al7075/Al2O3-SiC hybrid composites

In the present research, the effects of volume fraction of SiC+Al2O3 particles and aging temperature on the machinability of stir-casted Al7075 metal matrix composites (MMC) have been investigated. The hybrid composites were fabricated using the liquid metallurgy route. Al7075 was reinforced with different wt. % of SiC (3%, 6%, and 9%) and Al2O3 (2%, 4%, and 6%) which were used to fabricate the hybrid metal matrix composites. The samples were aged at different temperatures (140 ºC, 160 ºC, and 180 ºC) for 4 h and cooled at furnace temperature (27 ºC). The machinability of hybrid metal matrix composites was studied by carrying out L27 orthogonal array experiments. Three process parameters were selected, such as 0.2 mm/min of the depth of cut, 0.1 mm/min of feed rate, and 1500 rpm of spindle speed. The obtained results indicate that the surface roughness and machining force of MMCs increase with an increase in weight percentage of Al2O3/SiC and decrease with the increase in aging temperature. Optimum machining force and surface roughness were obtained at 2% Al2O3 + 3 % SiC and 180°C of aging temperature.

Modeling for a small-hole drilling process of engineering plastic PEEK by Taguchi-based neural network method

Engineering plastics have specific properties in strength, hardness, impact resistance, and aging persistence, often used for structural plates and electronic components. However, the holes made by the drilling process always shrink after the cutting heat dispersion due to their high thermal expansion coefficient. Drilling parameters must be discussed thoughtfully especially in the small-hole fabrication to acquire a stable hole quality. This study developed parameter models by the Taguchi-based neural network method to save the experimental resources on the drilling of engineering plastic, polyetheretherketone (PEEK). A three-level full-factorial orthogonal array experiment, L27, was first conducted for minimizing the thrust force, hole shrinkage in diameter, and roundness error. In terms of the network modeling, four variables were designated to the input layer neurons included the three drilling parameters (spindle speed, depth of peck-drilling, feed rate) and the thrust force detected, and that of the output layer neurons were two hole characteristics of diameter shrinkage and roundness. The models were trained by a stepped-learning procedure to expand the network’s field information stage by stage. After three stages of training, the models developed can provide precise simulations for the network’s training sets. For the non-trained cases, the prediction accuracy of the hole’s characteristics discussed was below 1 μm in the drilling of a 1-mm-diameter hole.

Experimental and statistical study on the effects of fused filament fabrication parameters on the tensile strength of hybrid PLA/Wood fabricated parts

Fused filament fabrication (FFF) also referred to as fused deposition modeling (FDM) is the most extensively used among all the additive manufacturing (AM) technologies due to its low cost, ease of use and variety of materials commercially available. An FFF printer generates a 3-dimensional object by extruding a stream of heated and semi-melted thermoplastic material, which is deposited onto layer upon layer, working from the bottom up. The literature study reveals that primary attributes of FFF parts like surface texture, mechanical strength, surface roughness, and dimensional accuracy depend on crucial process-related parameters and, therefore, should be set appropriately. This study focuses on the effects of several FFF parameters on the ultimate tensile strength (UTS) of a 3D-printed organic, biocompatible PLA with wood flour. Taguchi’s design involving orthogonal array experiments runs was applied to fabricate the test specimens (according to ASTM D638-10 type I one) and obtain the results corresponding to stress-strain curves and the ultimate tensile strength (UTS). The independent FFF parameters examined are layer thickness (LT), nozzle temperature (NT), raster deposition angle (RDA) and printing speed (PS). The results obtained are further analyzed by implementing standard statistical analyses like contour plots emphasizing 2-way interactions and analysis of variance. Full quadratic models were obtained and proved of high accuracy in terms of predicting the results for the response of UTS. The statistical results are supported with micrographs of failure sections and validated by comparing them with previous studies performed on pure PLA material. Moreover, evaluation experiments were performed to validate the results.

Multi-axis stiffness and road contact characteristics of honeycomb wheels: A parametric analysis using Taguchi method

Three-dimensional finite element (FE) models of a non-pneumatic wheel (NPW) with three different honeycomb cell angles are developed and verified to investigate their multi-axis stiffness and road contact characteristics. The experiment designs based on L8(27) and L9(34) orthogonal arrays are subsequently formulated to identify influential design factors affecting the wheel response measures and their nonlinear effects. The multi-axis stiffness of the NPW are strongly influenced by the spokes design parameters, although the yaw stiffness is mostly affected by the tread parameters. The road contact properties, however, are dominantly affected by the annular beam and tread design parameters. The results from these experiment designs are effectively used to establish guidance for design tuning of the NPW for realizing desirable stiffness and road contact properties. A L16(215) orthogonal array experiment is further formulated to study the interactions among the influential design factors in view of the multi-axis stiffness and road contact responses of the wheel. The results showed negligible contributions due to interactions among the design factors. It is shown that the NPW design parameters can be tuned to achieve multi-axis stiffness properties comparable to those of the pneumatic tires.

Fabrication of Polyether–Ether–Ketone Foams with Superior Properties and Mitigated Weld Lines by Microcellular Injection Molding

Polyether–ether–ketone (PEEK) as an engineering plastic with excellent mechanical properties requires strict processing conditions. Introducing microcells in PEEK parts is beneficial for reducing the material cost and improving their tenacity. Herein, foamed PEEK parts are fabricated using microcellular injection molding with supercritical nitrogen as the blowing agent. Using optimum processing conditions obtained from orthogonal array experiments based on finite‐element simulation, the foamed PEEK parts achieve a 10% average weight reduction and display a typical sandwich structure with an average cell size of 30 μm in the core region. The cell size is larger, whereas the cell density and skin layer thickness are smaller in the region near the gate than the region far from the gate. The foamed PEEK parts show a slight drop in the tensile modulus and tensile strength but a significant improvement in the elongation at break when compared with the solid parts. Moreover, the foamed PEEK parts with weld lines exhibit less reduction in tensile properties than the solid counterparts, attributed to their tighter interfacial adhesion at the weld line. This study successfully produces foamed PEEK parts with high weight reduction and ductility and provides insights into the weld line mitigation through microcellular injection molding.

Optimization of Machining Parameter in CNC Turning of Aluminium Alloy by Taguchi’s Orthogonal Array Experiment

Optimization of Machining Parameter in CNC Turning of Aluminium Alloy by Taguchi’s Orthogonal Array Experiment

Study on the particle interaction in a hydrocyclone classifier with multi-component feed blend at a high solids content

In mineral processing circuits, the feed to hydrocyclone consists of different density particle system at varying degrees of liberation and sizes, leading to a multi-component system. These different density components' interaction affects the separation in the hydrocyclones, particularly at high feed solids concentrations. In this work, an attempt is made to account for bi-component particle interaction in a hydrocyclone at different feed solids concentrations (10–50 wt%). For classification experiments, pure silica and pure magnetite components were utilized as a ratio of 1:1 in the feed mixture. Customized orthogonal array experiments were carried out using three-spigot and pressure level for 3″ and 4″ hydrocyclones. Components' grade efficiency curves and the performance parameters (d50; Rf; Rs;α;β) were estimated and analysed using the Whiten Equation. The cut-size and beta parameter of the mixture and individual components witnessed to increase with increasing feed solids concentration. Suspension rheology and hindered settling rate studies were carried out to understand the influence of the fine and coarse particle interaction on the performance of the hydrocyclone processing bi-component mixture at different feed solids concentrations. The enhanced viscous flow at the conical region attributes the crowding effect and the dense medium effect near apex zone, and consequential coarse and fines inflections are observed. The lighter particle displacement in the presence of heavier component is further supported by the locus of maximum volume fraction and equilibrium position from the numerical analysis.

Optimization based methodology to design metal hydride reactor for thermal storage application

A metal hydride based thermal energy storage system offers high energy density, provides longer storage time and requires less storage space compared to either conventional or phase change material based thermal energy storage systems. However, the design of such system is considered significantly complex. In this study, Taguchi method coupled with grey relational analysis was used to optimize the design parameters i.e. diameter of helical tube (dh), major diameter of helical tube (dm), number of turns of helical tube (N) and velocity of heat transfer fluid (Vf) for the helical tube heat exchanger embedded inside metal hydride reactor for thermal energy storage application. These parameters were optimized subjected to achieve maximum reaction fraction (C0) and maximum outlet temperature of heat transfer fluid (To). The performance of all experiments in the orthogonal array which were used for Taguchi and Grey relational analysis were evaluated by 3-D numerical simulations performed in commercial software COMSOL 5.3a. This methodology used is significantly computationally efficient as the number of required simulations reduced by 90% as compared to the conventional parametric study-based methodology. The required number of simulations reduced from 81 to 9 with the use of proposed methodology. Further, the added advantage of this methodology is, it enables to estimate an optimized level of the parameters by considering all the objective functions (C0, To) simultaneously. Lastly, the performance of the optimally designed systems was compared with all the orthogonal array experiments and it was found out that the optimized system designs were found to have better performance considering the objective parameters i.e., C0 and To as compared with the other experiments of the orthogonal array.

Application of orthogonal array experiment to the design of a digital video

Quality improvement is a continuous process which applies a systematic way to the analysis of practical performance of products or services and execution of efforts to improve performance and enhance customers’ satisfaction. Digital-video products have been seen their applications in various fields for the past decade. The digital video work under study in the present article is a 30-second two-dimensional digital video, involving three chronological scenes. This digital video work was submitted to a design competition in Taiwan and was rated by the referees at the sixth place in the design competition, which indicates that its watching quality could be further improved. To upgrade the watching quality of this digital video, the orthogonal-array experimental approach is applied, where four controllable factors and one uncontrollable factor are identified and the L9 orthogonal array is employed. Ten persons are randomly selected to evaluate the planned nine versions of the digital video. In the aspect of data analysis, the larger-the-better signal-to-noise ratio is used to integrate the scores from evaluators. Based on the results of data analysis, the optimal design conditions for our digital video should possess the following attributes: fuzzy conversion mechanism from the first scene to the second scene, dark blue words in the last scene, light yellow background color in the last scene, and three pages to include all of information in the last scene.

Design of metal hydride reactor with embedded helical coil using optimization methods

Metal hydride offers an efficient and cost-effective method to store hydrogen. In this study, Taguchi method coupled with grey relational analysis was used to optimize the design parameters i.e., diameter of helical tube (dh), major diameter of helical tube (dm), number of turns of helical tube (N) and velocity of heat transfer fluid ( V f ) for the helical tube heat exchanger embedded inside metal hydride bed to achieve minimum desorption time (td) for 80% desorption and minimum outlet temperature (T0) of heat transfer fluid (HTF). The performance of all experiments in the orthogonal array used for Taguchi and Grey relational analysis was evaluated by 3-D numerical simulations performed in commercial software COMSOL 5.3a. This stepwise methodology is significantly computationally efficient as the number of required simulations reduced by 90% as compared to the traditional parametric study-based methodology. Further, this methodology enables to estimate an optimized level of the parameters by considering all the objective functions (td, T0) simultaneously. Later, the performance of the optimally designed systems was compared with the orthogonal array experiments and it was found out that the optimized system designs have better performance in terms of the objective parameters i.e., td and T0 when compared with the other experiments of orthogonal array. These optimized systems will then be used for refrigeration and cooling applications.

Integration of data envelopment analysis and Al-Refaie and Al-Tahat model in Taguchi method for the optimisation of additives in expansive soil treatment

ABSTRACT The effectiveness of the incorporation of data envelopment analysis (DEA) and Al-Refaie and Al-Tahat (AA) model to solve the intrinsic multiple response problem in Taguchi optimisation method was assessed in this study. Charnes, Cooper and Rhodes model, which is a variant of the DEA method, was employed in the optimisation of additives for expansive soil treatment. The additives, which were sawdust ash (SDA), quarry dust (QD) and Portland cement (CM), were assigned various levels in the designed Taguchi mixed level L18 (6^1 × 3^2) orthogonal array experiment. SDA was assigned six levels while CM and QD were assigned three levels each. Multiple responses, which included the unconfined compressive strength, California bearing ratio and differential free swell, were determined with the designed experiment and later optimised concurrently with the DEA and AA model. Optimum combination of the additives (20% SDA + 20%QD + 5% CM) obtained with the models and validated by performing confirmatory tests on the soil admixed with it proved that DEA and AA model can be integrated in Taguchi method to optimise multiple responses simultaneously. Finally, scanning electron microscope of the expansive soil treated with the optimum combination of additives revealed the formation of cementation compound in the mixture.