Orthogonal Test Table Research Articles

Stress and strain analysis and parameter optimization of pipe truss tower connection of super-large tower crane based on FEM

Clamping bushing structure is an internode connection mechanism designed for the standard section of tubular truss tower. In this paper, the clamping bushing structure of the connecting mechanism of super-large tower crane is taken as the research object, a three-dimensional model of clamping bushing structure is established and imported into ABAQUS, and its multi-body contact model is further constructed to study the contact and bearing relationship of the structure under multiple working conditions, and the accuracy of the calculation results of the model is verified by the experimental stress test under tensile working conditions. In addition, this study is based on the control variable method, and through the design of orthogonal test table, the influence degree of five variable parameters of clamping bushing on the bearing capacity of the structure is investigated. Finally, through the range analysis, the optimal horizontal combination of variables and parameters of clamping bushing structure is obtained, and the optimal matching relationship between the shape of the tower connecting mechanism and the bearing capacity is obtained. The results show that, compared with the original model, the stress concentration at the most dangerous section of the optimized joint and the bushing is obviously alleviated, in which the stress peaks of the upper and lower joints are kept below 500 MPa, and the stress peaks of the bushing groove are also reduced to between 573 and 722 MPa. Moreover, the designed and optimized lower joint can reduce the maximum equivalent plastic strain of the joint root circumference by 56.05% under the original maximum tensile condition, and the overall distribution trend of equivalent plastic strain is more uniform, and a more reliable structural design is obtained, which plays an important guiding role in the design, optimization and analysis of the connecting mechanism of the tower body of large tower crane.

Heat transfer enhancement of power-law fluid in a solar-driven pretreatment system for microalgae hydrothermal liquefaction

In this article, the flow and heat transfer performance of microalgae slurry in a solar-driven rectangular absorption tube with embedded vortex generators were studied by data optimization analysis and numerical simulation. The orthogonal test design method was used to establish an orthogonal test table by changing the shape, height, spacing, and fluid flow rate of the vortex generator to determine the optimal combination of various factors. Then the response surface analysis method was used for further optimization analysis. Eventually, the flow and heat transfer performance of microalgae slurry were studied numerically, and the optimal data were verified. The results show that the optimal comprehensive heat transfer performance (PEC) is delivered by the cylindrical vortex generator with height of 9 mm and spacing of 28 mm when the inlet velocity of microalgae slurry is 0.02 m/s. It can be seen that the data analysis method combined with numerical simulation can optimize the experimental process parameters and save the cost of the engineering design process, effectively and practically.

Design and Optimization of Intelligent Algae Interception Equipment for Rivers based on Orthogonal Analysis and Finite Element Analysis

This paper describes the process of designing an intelligent algae deterrent device that can stop algae and clean water, and the mechanical analysis and optimization of the key force parts of the device. The design of the equipment includes the design of the main structural frame and the transmission mechanism. The optimization process is mainly based on the orthogonal analysis experimental method, and ANSYS is used as the main calculation tool. The maximum stress of the chain is taken as the experimental result, the length of the tooth rake, the chain material and the transmission power are taken as three factors, and three levels are set for each factor, and a four-factor three-level orthogonal test table is selected. Finally, the optimized parameter values were obtained by simulated annealing algorithm, and reducing the self-weight of the equipment reduces the probability of resonance and enhances the stability of the system, It has some reference significance to the development research, structure design and optimization of intelligent algae interception equipment for river cleaning.

Research on Forming Quality of GH4169 Superalloy Multi-Step Hollow Turbine Shaft by Three-roll Skew Rolling

Abstract: This paper innovatively proposes a three-roll skew rolling process for flexible forming of hollow turbine shaft, which solves the problems of long manufacturing process and low material utilization of hollow turbine shaft, the core component of aeroengine. Simufact.Forming 14.0 (SF) numerical simulation software was used to establish the finite element model of two-pass three-roll skew rolling of the GH4169 superalloy turbine shaft. The effects of process parameters on the outer diameter error, roundness error and wall thickness uniformity of the rolled piece were investigated by single factor experiments. A five-factor three-level orthogonal test was designed to explore the optimum process parameters by ' comprehensive scoring method'. The results show that the optimal process parameters are that the first pass roll rotating speed is 40 rad/min, the first pass axial speed is 15 mm/s, the second pass roll rotating speed is 50 rad/min, the second pass axial speed is 25 mm/s, and the billet preheating temperature is 1000ºC. The axial velocity of the second pass has the greatest influence on the test results, while the rotational speed of the second pass has the least influence. Under the optimal parameter combination simulation experiment, the outer diameter error, outer roundness error and wall thickness standard deviation are 0.151 mm, 0.121 mm and 0.034 mm, respectively, which are better than the results in the orthogonal test table. The research results provide a theoretical basis for realizing flexible, economical and high-quality forming of hollow turbine shaft by three-roll skew rolling.

Investigating the Effects of Recycled Micropowder and Aggregate on the Properties of Cement Stabilization of Crushed Aggregate (CSCA)

The recycled powder produced in the process of crushing concrete and brick waste (C&BW) into recycled aggregate will cause environmental pollution. To realize the green full recycling of concrete and brick waste, the cement stabilization of crushed aggregate (CSCA) containing recycled brick-concrete composite micropowder (RBCP) and recycled brick-concrete composite aggregate (RBCA) is proposed. In this paper, RBCP, recycled brick-concrete composite fine aggregate (RBCFA), and recycled brick-concrete composite coarse aggregate (RBCCA) were the recycled materials from C&BW. The orthogonal test table was used to analyze the effects of the three recycled materials on the compaction characteristics, mechanical properties, and shrinkage behavior of CSCA at different dosages. The effects of RBCP, RBCCA, and RBCFA on the properties of CSCA are studied by variance analysis methods. On this basis, the micromorphology and the interface transition zone (ITZ) were studied for CSCA and the cement stabilization of crushed aggregate with RBCP, RBCFA, and RBCCA through scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), and the mechanism was revealed. The results indicate that the addition of RBCP and RBCA can increase the optimal water content while decreasing the optimal dry density of CSCA, and the influence of RBCCA on the optimal water content is greater than that of RBCFA. Three optimal composite replacement systems for CSCA, including 20% RBCP/20%RBCFA/40%RBCCA, are proposed and have the best mechanical and antishrinkage performance through the range analysis. Furthermore, the variance analysis test results show that RBCCA and RBCFA have the most significant effect on the compressive strength and shrinkage strain properties, while RBCP has the most significant effect on the bending tensile strength. It is found that RBCP played a filling effect and pozzolanic activity in the strength formation of CSCA. The SEM/EDS test shows that the CSCA with recycled materials produced the Ca/Si ratio in the interfacial zone between the cement paste and aggregate lower than the CSCA without recycled materials, the largest decline 52.83%. The research results of this paper can provide the potential application of RBCP and RBCA.

Characteristics analysis and optimization design of bridge crane based on improved particle swarm optimization algorithm

Large redundant metal structures have high stability with large cost. An excellent mechanical structure should have the lower weight when satisfying its stability. Aiming at the large redundancy of the main beam metal structure of the double-beam bridge crane, the paper extracts six important parameters to determine its quality, and the corresponding value is set. The orthogonal test table is designed to calculate the strength and stiffness. In order to avoid resonance, the fixed vibration frequency and excitation frequency are calculated. The experimental results are fitted to obtain the six parameters of the quality, strength, stiffness, and natural frequency. Moreover, particle swarm optimization algorithm is used to solve the multi-objective optimization mathematical model with the design quality as the goal and the stiffness, strength, and easy resonance interval as constraints. In view of the long calculation time and poor convergence of particle swarm optimization algorithm, a module that limits the particle forward speed is added and the generation conditions of particles are redefined. The improved particle swarm algorithm shows that the first-order vibration frequency of the main beam increases from 18 Hz to 27.55 Hz. It improves the stability of the overall structure and avoids resonance with the motor frequency. Under the condition of satisfying the stability of the main beam, the quality of the main beam is reduced from 1.23 tons to 0.53 tons, with a reduction of 6%.

Simulation Study of a New Magnetorheological Polishing Fluid Collector Based on Air Seal

Inverted magnetorheological (MR) polishing device mainly use a magnetic sealing ring to collect polishing fluid. This collection method wears the wheel surface of the polishing wheel, affects the surface accuracy of the polishing wheel, and introduces machining error. In order to reduce this wear and improve recovery efficiency, a new type of collector using an air seal is proposed in this paper. Furthermore, testing method using six factors and a three-level orthogonal test table is used to study the structural parameters of the new collector. The flow fields affected by the different structural parameters were simulated, and the corresponding collection efficiency was analyzed. The results show that the air nozzle diameter has the greatest impact on the fluctuation value of the collector outlet flow, followed by the airflow velocity and nozzle spacing. Moreover, the structural parameters obtained from the orthogonal test were optimized using the control variable method. The minimum flow fluctuation and maximum flow at the collector outlet can be obtained when the nozzle diameter is 2.5 mm and the nozzle airflow velocity is 31 m/s.

Numerical Simulation and Experimental Validation of Squeeze Casting of AlSi9Mg Aluminum Alloy Component with a Large Size.

The squeeze casting process for an AlSi9Mg aluminum alloy flywheel housing component was numerically simulated using the ProCAST software, and orthogonal simulation tests were designed according to the L16 (4) 5 orthogonal test table to investigate the alloy melt flow rule under four factors and four levels each of the pouring temperature, mold temperature, pressure holding time and specific pressure, as well as the distributions of the temperature fields, stress fields and defects. The results showed that the flywheel housing castings in all 16 test groups were fully filled, and the thinner regions solidified more quickly than the thicker regions. Hot spots were predicted at the mounting ports and the convex platform, which could be relieved by adding a local loading device. Due to the different constraints on the cylinder surface and the lower end surface, the solidification was inconsistent, the equivalent stress at the corner junction was larger, and the castings with longer pressure holding time and lower mold temperature had larger average equivalent stress. Shrinkage cavities were mainly predicted at mounting ports, the cylindrical convex platform, the peripheral overflow groove and the corner junctions, and there was also a small defect region at the edge of the upper end face in some test groups.

E-M calculation model and its application of calculating deformation in a new tunnel orthogonally undercrossing an existing tunnel

A new tunnel orthogonally undercrossing an existing tunnel at a close distance inevitably affects the deformation of the existing tunnel. Analytical calculation methods of the deformation of an existing tunnel orthogonally undercrossed by a new tunnel remain underdeveloped. Based on the principles of the equivalent layer method and mirror method, a new calculation model (E-M calculation model) for the vertical deformation of an existing tunnel undercrossed by a new tunnel in multi-layered strata is proposed, and the accuracy of the model in calculating the vertical deformation of the existing tunnel is verified by on-site monitoring data and numerical simulation. An L25(56) orthogonal test table is designed to conduct a sensitivity analysis on the parameters that affect the vertical deformation of the existing tunnel. The diameter of the new tunnel D2, the burial depth of the existing tunnel H1 and the distance between the new tunnel and the existing tunnel ΔH are the main factors affecting the deformation of the existing tunnel. Among them, ΔH mainly affects the shape of the settlement curve of the existing tunnel. The settlement of the existing tunnel Uz has a quadratic correlation with the diameter of the new tunnel D2 and a linear correlation with the burial depth of the existing tunnel H1. The major influence zone of the existing tunnel undercrossed by the new tunnel is -i < x < i (i is between 6.33 m and 8.35 m, and × is the distance to the tunnel axis), while the minor influence zone is an uncertain range. For safety, the area of the major influence zone can be appropriately enlarged in practical engineering applications.

Effect of test parameters on the stability of fabric shape retention indexes increase recovery testing

Fabric shape retention is a crucial property that impacts the durability and usability of fabric and which needs a convenient and accurate evaluation method. In the previous research, the automated crease recovery testing method was used to obtain fabric crease recovery information and evaluate the property of shape retention. Based on the previous research, an orthogonal test method was adopted to investigate the effect of different test parameters on the stability of shape retention detection in this paper. First, three factors, that of sample size, pressure, and pressure time, and three different levels of each factor were determined by the L9(34) orthogonal test table. Next, the fabric shape retention indexes were detected by nine different test schemes, and the comprehensive score of shape retention index standard deviation was obtained as the evaluation criterion of the orthogonal test results. Finally, the optimal test scheme was determined by visual analysis and variance analysis. The results show that the sample size has a certain effect on the stability of shape retention indexes, while the pressure time and the pressure have no significant influence. The optimal test scheme is that the sample size is 30 cm × 30 cm, the pressure time is 60 s, and the pressure is 40 N. The test result measured by the optimal test parameters reveals excellent stability when the vertex angle standard deviation is 2.0°, the height standard deviation is 0.06 cm, and the shape retention area standard deviation is 0.16 cm2. This paper provides an experimental basis for improving the accuracy of fabric shape retention evaluation method.

Design optimization of a shell and tube heat exchanger with staggered baffles using neural network and genetic algorithm

A shell and tube heat exchanger with staggered baffles (STHX-ST) is designed by integrating the features of both segmental and helical baffles, which produces a helical flow in the shell side. This work studies the effect of different parameters on the performance of the STHX-ST through numerical analysis. Shell inner diameter, tube outer diameter, baffle cut, baffle spacing, and baffle orientation angle are the design parameters. Multi-objective optimization using genetic algorithm (GA) is carried out to maximize the heat transfer rate while minimizing the pressure drop. The objective functions for optimization are approximated using artificial neural networks (ANNs). The training data for ANNs are simulated from CFD analysis as per the Taguchi orthogonal test table. The optimal solution obtained from the Pareto front has a maximum heat transfer of 154555 W for a minimum pressure drop of 88083.86 Pa.

Orthogonal optimum design of parameters of flux used for low carbon bainitic steel

L8 (27) orthogonal test table is applied to design eight kinds of flux, and arranged with SiO2, ZrO2 and TiO2 as three factors. The microstructure, morphology and mechanical properties of low carbon bainitic steels are investigated by means of optical microscope, scanning electron microscope, transmission electron microscope, tensile testing machine and instrumented drop weight impact tester with oscilloscope. The results indicate that the optimum composition rate is as follows: 20% SiO2, 10% ZrO2, and 6% TiO2, and the interaction between ZrO2 and TiO2 is obvious. The microstructure of deposited metal of low carbon bainitic steel is mainly formed by acicular ferrite and granular bainite. The acicular ferrite is paralleled distribution, and plenty of fine sheet Martensitic–Austenitic constituents are dispersing, which can hinder crack propagation and improve strength and toughness. The impact energy is up to 109.7 J at − 20 °C, and the ratio of brittle fracture termination load to maximum impact load is 0.378, ensuring excellent crack arrest toughness.

Effects of the Impeller Blade with a Slot Structure on the Centrifugal Pump Performance

An impeller blade with a slot structure can affect the velocity distribution in the impeller flow passage of the centrifugal pump, thus affecting the pump’s performance. Various slot structure geometric parameter combinations were tested in this study to explore this relationship: slot position p, slot width b1, slot deflection angle β, and slot depth h with (3–4) levels were selected for each factor on an L16 orthogonal test table. The results show that b1 and h are the major factors influencing pump performance under low and rated flow conditions, while p is the major influencing factor under the large flow condition. The slot structure close to the front edge of the impeller blade can change the low-pressure region of the suction inlet of the impeller flow passage, thus improving the fluid velocity distribution in the impeller. Optimal slot parameter combinations according to the actual machining precision may include a small slot width b1, slot depth h of ¼ b, slot deflection angle β of 45°–60°, and slot position p close to the front edge of the blade at 20–40%.

Research on the Properties of Low Temperature and Anti‐UV of Asphalt with Nano‐ZnO/Nano‐TiO2/Copolymer SBS Composite Modified in High‐Altitude Areas

Strong ultraviolet light and low‐temperature are the typical environmental characteristics in high‐altitude areas. The performance of SBS‐modified asphalt in the above environmental characteristics needs further study. To improve the resistance ultraviolet (UV) ageing and low‐temperature performance of copolymer‐ (SBS‐) modified asphalt, an SBS‐modified asphalt containing nano‐ZnO and nano‐TiO2 is proposed. In this paper, nano‐ZnO, nano‐TiO2, and SBS were used as modifiers with the silane coupling agent (KH‐560) as the nanomaterial surface modification. The orthogonal test table was used to analyse the effects of the three modifiers on the physical properties of modified asphalt at different dosages. On this basis, the physical properties, low‐temperature properties, and ageing indices (carbonyl index and sulfoxide index) were studied for base asphalt, SBS‐modified asphalt, nano‐ZnO/SBS‐modified asphalt, and nano‐ZnO/nano‐TiO2/SBS composite‐modified asphalt before and after photoaging. The content changes of characteristic elements (Zn and Ti) in the nano‐ZnO/nano‐TiO2/SBS composite‐modified asphalt before and after ageing were studied by scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), and the UV ageing mechanism was revealed. The results indicate that two nanoparticles show the best compatibility with asphalt after surface modification and can improve the binding ability between SBS and base asphalt. The orthogonal test analysis shows that nano‐ZnO has a highly significant effect on the low‐ and high‐temperature performance of the nano‐ZnO/nano‐TiO2/SBS composite‐modified asphalt, and nano‐TiO2 has a significant effect on the high‐temperature performance. Three optimal composite‐modified systems for base asphalt including 4% nano‐ZnO/1.5% nano‐TiO2/3.2% SBS were proposed and had the best antiaging ability. Compared with the sulfoxide index, the carbonyl index changed most obviously before and after ageing. Additionally, the results reveal that nano‐TiO2 has a good absorption effect at a wavelength of 365 nm (ultraviolet light), while nano‐ZnO is liable to photolysis, and its activity decreases at this wavelength.

Investigation of the effect of humidity at both electrode on the performance of PEMFC using orthogonal test method

Abstract Under the vehicle working conditions, operating temperature and relative humidity (RH) of gas supplies have an important influence on the performance and durability of PEMFC. In this paper, the influence of hydrogen RH, air RH, operating temperature and air stoichiometric ratio on the performance of PEMFC was studied with the help of 5 factors and 4 levels orthogonal test table. The fifth factor was set to be empty to carry out the variance analysis. Using variance analysis method, the influence degree of random errors on the experiments was analyzed. The credibility of the experimental results was verified along with the polarization curve and the electrochemical impedances spectroscopy (EIS) results. The experiment results show that the most important factor which affects the performance of PEMFC is air stoichiometric ratio, followed by air RH, and then the operating temperature. The effect of hydrogen RH on PEMFC performance is minimal and negligible. Low hydrogen RH can be used during operation to reduce energy consumption of auxiliary system.

Study on Output Voltage Ripple Coefficient of DC Charger Based on Orthogonal Test

DC chargers output high voltage, large current during their charging process, which inevitably produce and carry a lot of ripple. The ripple will not only damage performance of electric vehicle battery, but also cause current distortion at AC side. Therefore, studies on output voltage ripple coefficient of DC charger are important. In this paper, we consider the condition that the structure of DC charger is fully established, and take AC input voltage, DC output voltage and DC output current as the three main parameters. Then orthogonal test method and matrix analysis method are introduced successively, through orthogonal test table, range analysis and matrix calculations, the optimal combination status when DC chargers produce the minimum ripple coefficient is studied. Results show that when AC input voltage, DC output voltage reach up to maximum and DC output current reach up to median, output voltage ripple coefficient of RMS and peak-peak value of DC charger reach to the minimum value simultaneously. Finally, validity and reliability of the analysis results are verified through the traditional test method.

Influence of SiO2/MoS2/graphite content on the wear properties of PTFE composites under natural seawater lubrication

The polytetrafluroethylene (PTFE) mixed with different particles, such as SiO2, MoS2, and graphite, were prepared by using cold briquetting and hot sintering technologies. In order to investigate the influence of different mixture ratios of particles on the wear properties of PTFE composite under natural seawater lubrication, 10 different samples were designed through orthogonal test table and evaluated using an MMU-5 G wear tester. For comparison, the wear experiments of pure PTFE were also carried out under the same conditions. Moreover, the 3D profiles and depth variations of wear scars of PTFE composites were observed by a laser scanning confocal microscope. Results showed that the addition of SiO2, MoS2, and graphite can greatly improve the wear resistance of PTFE under seawater lubrication. In particular, 10% SiO2, 15% MoS2, and 15% graphite filled with PTFE composite possesses the best wear resistance. And a synergistic effect is found for the combination of SiO2, MoS2, graphite, and seawater, which effectively prevents the slipping of PTFE from matrix, increases the adhesion resistance, decreases the friction energy, further results in lower wear rate and little damage on the surface of the PTFE composites.

An effective method for fabricating microchannels on the polycarbonate (PC) substrate with CO2 laser

This paper proposes an effective processing method for fabricating microchannels on the polycarbonate (PC) substrate with CO2 laser. The width of microchannel has close relationship with CO2 laser parameters including laser power, laser moving velocity, and length of microchannel. In order to optimize the width of the microchannel, the orthogonal experiment method is successfully applied in this experiment with L9(33) orthogonal test table. Then, the optimal machining parameters are obtained and a verified experiment is confirmed. Finally, the optimal microcahnnels on the PC can be obtained with the presented process parameters.

Experimental Study on Matrix Wear Resistance of Bionic Coupling Bits

Bionic coupling bit has much advantage, such as high drilling efficiency and long life. In order to research on the matrix wear resistance of bionic coupling bit, based on the bionic coupling theory, 9 samples were designed and processed according to orthogonal test table, and then the abrasion ratio of each sample was tested. With extreme difference analysis method the test data was analyzed, the results showed that the non-smooth shape has an important impact on wear resistance of matrix, and the primary factor is non-smooth ratio, and then diameter of bionic unit and diamond concentration. The optimal combination is A1B2C3 that is non-smooth 9%, pit diameter 1.5mm and diamond concentration 125%.

Study on Optimal Scheduling Methods of Urban Drainage Pumping Stations Based on Orthogonal Test

An optimal scheduling method of urban pumping stations was proposed to cut down the energy cost.Using this method, pumping stations in the drainage area were divided into groups,and the scheduling period was divided into several computation periods,and several operation schemes were fixed in each group. In each computation period, groups were regarded as test objects,and operation schemes as test levels, and scientific tests were carried out with the help of orthogonal test table. Choosing the ratio of drainage volume and power consumption as the objective function, the best theoretical operation scheme should be found out through the orthogonal analysis.Using the unsteady flow model to calculate each river water level, and if each river water level was within the allowable variation amplitude, then the scheme was optimal and feasible; otherwise, adjust the test level according to the main-to-secondary sequence to obtain the optimal operation scheme. Taking 20-year frequency storm in one region of Shanghai city as a study case, total electric power consumption could be reduced more than 1/4 with the optimal scheduling method compared with the traditional one.