bluuebunny/crossref_metadata_2025 huggingface dataset:
A Predictive Model of Dimensional Deviation Based on Regeneration PSO-SVR with Cutting Feature Weight in Milling
Authors: Yao Hang , Luo Bin , Li Jing , Zhang Kaifu , Cao Zhiyue
Published: November 2021

Support vector regression (SVR) optimized by particle swarm optimization (PSO) has low predictive accuracy and premature convergence in milling. To solve this problem, A PSO-SVR model combined with the cutting feature weight was proposed in this paper. Firstly, basing on the SVR, the feature weight was integrated with the kernel function, and added the premature judging to the PSO to improve the global searching ability. Secondly, the mathematical model composed of the cutting force, temperature and cutting vibration was built based on the datasets obtained by experiment. The covariance was calculated to get the characteristic weights of process parameters, which promoted the incremental data in turn. Finally, the predictive model of the dimensional deviation was established based on the promoted PSO-SVR and the result was compared with the general PSO-SVR. The accuracy of the predictive model reached 97.5%. And compared with the predictive model of the general PSO-SVR without feature weighting, the dimensional deviation predictive accuracy and generalization ability of the regeneration PSO-SVR predictive model with feature weighting was improved by 37.75% and 24.5%.
Numerical Simulation Analysis of Flow and Heat Transfer in Medium Temperature Boiler
Authors: Sun Na , Yang Hexu
Published: November 2021

Waste heat recovery by waste heat boiler is one of the important means to utilize secondary energy, which is widely used in metallurgical industry. However, due to the great influence of production technology and other factors in industrial process, it brings many difficulties to waste heat utilization. Based on the structural parameters and operating parameters of the waste heat boiler, combined with the basic principles of fluid mechanics, the numerical calculation model of the waste heat boiler is established. The flow field and temperature field inside the waste heat boiler are studied and analyzed by numerical simulation method, which provides the necessary basis for its structural optimization.
A New Method of Manufacturing Hollow Shafts via Flexible Skew Rolling
Authors: Cao Xiaoqing , Wang Baoyu , Guo Wei , Ju Zhidong
Published: November 2021

The existing rolling process of large and long axle parts, such as the cross wedge rolling (CWR) process, requires special molds and larger equipment. Flexible skew rolling (FSR) hollow shafts with mandrel is a near net-shape rolling technology which can achieve the diversified production of rolled parts without special molds. It has significant advantages such as small equipment tonnage, small die size, low rolling load, simple process adjustment, and especially suitable for multi-variety and small-batch production. This paper proposes hollow train shafts formed by FSR with mandrel. Reasonable parameters were selected for experiments, and the forming process was calculated by finite element (FE) software. The experimental results are consistent with the simulation results, indicating that the FE model is reliable. The rolling force and rolling torque are analyzed by simulation. Finally, the microstructure of different positions of the rolled-piece is analyzed, and the microstructure of the rolled part is refined. It is provide a feasible scheme for the rolling of large hollow shaft parts.
Strategy and Technique of High Efficiency Balancing in Field for Turbo-Generator Units with Large Capacity
Authors: Cai Wenfang , Lu Songyuan , Wu Zhengfeng , Ying Guangyao , Wu Wenjian
Published: November 2021

Abstract.This paper aims at the high efficiency of field balancing for turbo-generator with large capacity currently, and introduces the strategies and key techniques of the rotor system balancing with practical cases of power plant in field. The acquisition, analysis and former processing of the original vibration data for balance calculation are included. Furthermore, they involve complete measuring points and conditions, accurate judgment for the types of unbalance exciting force and selection of stable vibration data, all these could reduce the blindness of balancing effectively. The strategies and techniques also contain the determination for axial plane of unbalance by the modal method, then the optimal steps and the plane of adding weight are chosen during the implementation of balancing. Besides, this paper also introduces the analysis and selection of influence coefficients and the phase of trial weight, these can help determine the final correction weight accurately in order to guarantee the balancing process prompt and efficient. Meanwhile, the restriction of practical location for adding weight and construction period of maintenance and production for the units should be considered during the high efficiency balancing in field. These strategies and techniques of high efficiency balancing have practical application value in promoting the technology of field balancing for turbo- generator units with large capacity.
Analysis on Leakage Characteristics of Labyrinth Piston Clearance in Reciprocating Labyrinth Compressor
Authors: Huang Rui , Cheng Junming , xia Tian , Feng Quanke
Published: November 2021

In this paper, the piston clearance leakage model in reciprocating labyrinth compressor is established, and the leakage characteristics of labyrinth piston are analysed. The results show that in the labyrinth entrance section, the gas velocity decreases greatly, and the throttling effect is the most obvious. In the middle section of the labyrinth, the flow velocity descending gradient decreases. In the exit section, the flow rate begins to increase. When the labyrinth clearance is less than or equal to 0.1 mm, the clearance changes has little effect on the leakage. When the clearance is greater than 0.1 mm, the leakage increases rapidly with the clearance increasing. When the piston operates eccentrically, the leakage will increase by 1.5 ∼ 2 times compared with the non-eccentric operation. Therefore, the eccentric operation of the piston should be avoided as much as possible and the clearance should be reduced.
The Analysis of a Generator Shaft Crack Cause by Torsional Vibration due to SSR
Authors: Cai Wenfang , Ying Guangyao , Li Weijun , Wang Zaihua
Published: November 2021

Abstract.This paper introduces the serious crack accident of the rotor of a 600 MW turbo-generator unit in Vietnam, which leads to the rotor scrapped. After excluding the material and design reasons, it is considered that the electrical torque is the possibility. Through the operation parameters and theoretical calculation of the unit, the fault reason is positioned as Sub-synchronous resonance. The most important criterion is that the vibration of Unit 1 increases simultaneously with that of Unit 2, which is physically isolated from Unit 1. Further theoretical calculation shows that the natural frequencies of torsional vibration are 13.74 Hz, 26.23 Hz and 30.30 Hz, which are complementary to the grid frequency at that time cause of the change of grid structure.
Reliability Analysis on Domestic Special CNC Machine Tools Based on Weibull Distribution
Authors: Shi Zhanghu , Zhao Xi , Zhang Huang , Sun Hailong , Zeng Chao , Lei Pei , He Xiaoxu , Xia Fengqin
Published: November 2021

Mean time between failures (MTBF), regarded as an important target to evaluate the performance of machine tool, is widely applied in analysis of reliability, especially in reliability model building. Taking Huazhong CNC HNC-848C Complex Machine Tool as research object, this paper conducted censored test to collect MTBF data during a period of 226 days. Based on the data and presupposed Weibull reliability model. Parameters of the model were estimated by least square method. Graph test Method and Kolmogorov-Smirnov Method are implemented to perform the hypothesis test on obtained parameters, which provides evaluation on MTBF of complex machine tool with theoretical basis and data reference.
Optimal Design of Brake Disc Structures for Brake Squeal Suppression
Authors: Pan Gongyu , Liu Zhikang , Xu Qizhao , Chen Lin
Published: November 2021

Aiming at the brake squeal problem of automobile disc brakes, an optimization design method of brake disc structure based on the weighted brake squeal tendency coefficient is proposed. This method is based on the brake squeal complex modal finite element model of a certain disc brake. Based on the validity of the model verified by the bench test, the single-sided disc surface height of the brake disc, the height of the radiating rib, the elastic modulus and the disc are selected. The four key structural parameters of the cap height are used as design variables. Taking the weighted braking squeal tendency coefficient proposed in this paper as the optimization target, the response surface method and the central composite test design are combined to construct a weighted braking squeal tendency coefficient response surface model, and use multi-island genetic algorithm to optimize the model. The results show that the optimization design method proposed in this paper can greatly improve the optimization efficiency while effectively reducing the screaming tendency of the disc brake in the full frequency band, so as to achieve the purpose of improving the NVH performance of the disc brake and improving the comfort of the car.
Numerical Simulation of Acoustic Scattering by a Cylinder Based on the Enhanced Optimized Scheme
Authors: Yuan Siqi , Ma Ruixuan , Wu Conghai , Zhang Shuhai
Published: November 2021

The enhanced optimized scheme we developed in the early work is employed to simulate the scattering of acoustic waves from a two-dimensional cylinder by solving the Euler equations. The numerical results of a benchmark problem are found to be in excellent agreement with the exact solution. Our numerical results show that when acoustic waves propagate through a cylinder, the acoustic scattering results in a spatial redistribution of the acoustic energy as well as an alteration of the phase of the waves. The directivities of the scattered fields change significantly for the different length ratios of acoustic wavelength to the radius of the cylinder.
Research on Intelligent Control and Integration Technology for Visual Inspection of TEC Components
Authors: Cai Zhishan , Chen Jiangwei , Yan Shaobin , Li Shizhan , Liao Tingdi
Published: November 2021

Technical schemes such as uniform TEC component feeding, posture adjustment, multi-station positioning, and communication between upper and lower machines were designed. The opto-electromechanical integration mechanism was integrated by software to realize the detection of TEC component surface defects, and qualified TEC components were separated from unqualified TEC components by blow sieving. Adopt ARM MCU for real-time control; Image recognition adopts the machine vision deep learning platform based on linux to learn and recognize the TEC components, and sends the results to the lower computer for sieving. The accuracy of triggering the camera to take pictures is 99.9%, which provides a guarantee for capturing and processing images accurately. The accuracy of blow sieving is over 99.9%, which can meet the sieving requirements. The electrical control system of the whole machine can meet the motion control requirements of detection.
Development and Test of Rubber Wheel Full Hydraulic Drill in Coal Mine
Authors: Chen Fenglei , Xu Pengbo , Wang Song , Zhong Zicheng
Published: November 2021

In order to solve the problem of moving rig quickly and reducing labor intensity in the mine face with trackless transportation conditions, a solution of rubber wheel drill which meets the working conditions is put forward. The drilling rig adopts the configuration of double power and double system, the power comes from the engine when moving, to achieve walking, steering, braking and temporary stability, relocation and transfer of high efficiency and flexibility, the power comes from the motor when drilling, to achieve rotation, feed and auxiliary Angle adjustment, safe and pollution-free construction. After the assembly and debugging of the whole machine, ground simulation test and underground industrial test were carried out on the rig. The test results show that the rig has strong maneuverability, one person can complete the moving walking, the maximum walking speed is 20km/h, and the steering is flexible and the braking is safe. The maximum depth of drilling hole construction is 318m, the target area hit rate reaches 77.8%, the working performance is stable, the hydraulic system is stable, and all parameters meet the design requirements. The equipment provides new technical equipment for the mine drilling construction with trackless transportation conditions.
Research on Automatic Control Method of Motor Current in Distribution Network Based on Bionic Algorithm
Authors: Yuan Wei , Liu Fan , Chen Quanzhi , Ye Pengfei
Published: November 2021

Due to the problems of multi-parameter identification and processing in traditional approach of current-predicting, it is difficult to control PMSM in practical complex environments. In this paper, a predictive current control method based on improved extended observer is proposed, whose mathematical model based on extended state observer is also established. Because of the problem of multi-parameter setting in ESO, the flower pollination algorithm is used to adjust the parameters with the fitness function of minimum absolute error of ESO input and output. To verify the stability of PMSM system based on predicted current control with improved ESO, MATLAB/SIMULINK is used to build the simulation model. And the results show that the control strategy can predict the accurate current ofdq, and the PMSM based on this method can output the desired current, determining the stable operation of the system.
Method for Determining the Boundary Condition of Heat Transfer in Mold for Slab Casting
Authors: Guo Junli , Zou Jin , Yang Changlin , Lu Deping , Sun Lefei
Published: November 2021

The calculation of temperature field in the mold is important for the study of solidification process of liquid steel. In order to calculate the accurate temperature field of slab in the mod, the boundary condition of heat transfer in the mold should be determined before the calculation of slab temperature. In this paper, the relationship among the average heat transfer coefficient in the mold, the physical properties of steel, the cast condition and the cooling condition is derived according to the energy conservation equation and the Fourier law of heat conduction. Furthermore, the method for determining the parameters related to the formula of boundary heat flux is introduced. Results indicate that the average heat transfer coefficient in the mold ranges from 450 to 2000 W·(m2oC)−1 for conventional caster with a casting speed ranging from 0.8 and 1.8 m·min-1. The average heat transfer coefficient increases with the increase of casting speed. Besides, the casting speed has an effect on the parameters in the formula of calculating boundary heat flux, which indicates that the casting speed and the cooling condition should be taken into consideration for determining parameters related to the formula of calculating surface heat flux in the mold.
Design and Research on Shell Breaking Mechanism
Authors: Bao Jinfeng , Li Xiang
Published: November 2021

For the large demand but low acquisition efficiency of the black olive kernel, the automatic assembly line instead of the traditional artificial olive kernel, automatically complete the shell breaking and kernel, kernel screening. Based on the design requirements of kernel extraction, we determine the overall structure of the olive kernel machine. Focus on analyzing material conveying device and cutting and shell breaking device, in the pipeline design, mainly use vibration disc, linear feeder, sprocket conveyor, pneumatic pressure device and linear screening machine and other institutions. Furthermore, three machining-sized molds were designed for the irregularities of the olive core. Finite element analysis showed that the design organization are reasonable.
Design and Research of Bearing Reliability Test Bed Based on Multi-Dimensional Vibration Loading
Authors: Wang Yanzhong , Shiyuan E
Published: November 2021

Rolling bearings are widely used in aviation, aerospace and other important fields, and their reliability is greatly affected by external vibration excitation during service. Due to the large volume and high cost of the combined structure of shaking table and test chamber, this paper designed a dynamic reliability test bed specially for rolling bearings to study the influence of external vibration excitation with different directions, frequencies and amplitudes on vibration signals and service life of rolling bearings. The test bed is loaded with external excitation by means of electromagnetic shakers in two directions, and the flexible material is used to realize the displacement of the test chamber under two external excitation directions at the same time. The bearing vibration loading life test carried out by this test bed has important guiding significance for the design of rolling bearing. The experimental results show that the test bed can apply axial and radial vibration loads of 1-800Hz sinusoidal waveform, and the vibration acceleration can reach 1g, which can simulate the effect of actual working conditions.
Research on Simulation Based Dynamic Scheduling Strategy of the Logistics Distribution System for Assembly Lines in Engineering Machinery
Authors: Rao Youfu , Chen Zhihuang , Fang Weikang , Guan Zailin
Published: November 2021

The objective of designing a logistics system for assembly production planning should be accurate, efficient distribution, and low cost. It is difficult to use mathematical methods to solve the design of logistics distribution route planning for a given layout of assembly lines which often be restricted. We take the logistics distribution system for actual assembly lines of engineering machinery as the research object, and analyze its current status. And we build a 3D simulation model of the corresponding scene, and use a variety of logistics scheduling methods to optimize the logistics distribution system. Considering the congestion strategy characteristics of some distribution channels, adjustment strategy of time window is proposed, and a dynamic scheduling strategy of congestion is designed. Combined with the simulation tests, we analyze and optimize the solution suitable for the actual assembly lines. The results show that our strategy had better performance than other common scheduling strategies. And the proposed strategy could optimize the material distribution system of assembly lines, reduced the number of vehicles and the cost of the enterprise.
Effects of Oxygen Vacancies on Dielectric Properties and Relaxor Behavior of Ba(ZrxTi1-x)O3 Ceramics
Authors: Li Xiang , Sun Zheng , Zhang Yuan , Huang Dianchen , Hu Jitao
Published: November 2021

By comparing the structure, dielectric and electrical conduction properties of sintered Ba(Zr0.15Ti0.85)O3 ceramics (short as BZT15) annealed in air and oxygen atmosphere was conducted to explore the impact of oxygen vacancies (OVs) on them. The dielectric properties of the samples were studied as changing with temperature (260–400K) in the scope of frequency from 100 Hz to 100 kHz. A typical relaxor behavior was observed in BZT15 and the relaxor behavior was enhanced after oxygen annealing treatment, which confirmed that the relaxation process was connected with the OVs inside ceramics. The value of activation energy was calculated to be 1.76 eV, 1.79eV, and 1.85 eV for as-prepared, air and oxygen annealed samples, respectively. Besides, the dielectric relaxor behavior was found to be associated with the conductivity originated from the dipolar conduction and long-distance movement of doubly ionized OVs. More interestingly, compared with other ferroelectric materials, the higher activation energy of BZT15 ceramics revealed a weaker concentration of OVs for such dielectric materials.
Experimental and Numerical Study on Long-Life and Progressive Damage in Laminates in Open-Hole Compression Tests
Authors: Dai Zongmiao , Liu Liu , Lu Shaojuan , Li Wangnan , Liang Guijie , Wang Jingyang , Zhong Zhicheng , Peng Xuefeng
Published: November 2021

The strength theory design accuracy of carbon fiber reinforced plastics (CFRP) composite structures are integral to CFRP composite structures product weights along with production costs. In order to further improve the CFRP composite structure strength theory design accuracy in this paper, it developed an ATM/SIFT analysis method by combining strain invariant failure theory (SIFT) and Accelerated testing methodology (ATM). The developed implementation scheme of ATM/SIFT includes: three parts of accelerating material strength test, component strength main curve characterization, structures life prediction, among which the material life prediction is achieved by using Python code to customize user material subroutines (VUMAT), through secondary development on the ABAQUS platform. Based on the developed ATM/SIFT method, it analyzed the compressive gradual failure mechanism and life of IM600/TDE-85 composite laminated plates open pore structures. Finally, it predicted the long-term static load compression life of IM600/TDE-85 composite laminate open-hole structures by using ATM/SIFT method and compared this prediction results with test results.
Formability Difference between TC4 Titanium Alloy Hollow Shaft and AISI 1045 Steel Hollow Shaft Formed by Cross Wedge Rolling with a Mandrel
Authors: Feng Pengni , Wang Baoyu , Yang Cuiping , Zhang Huibo
Published: November 2021

Production of TC4 alloy hollow shaft formed by cross wedge rolling (CWR) can meet the needs of the lightweight structures in aviation field. Different from the steel, the formability of TC4 alloy is sensitive to deformation temperature. In this work, the formability difference of TC4 alloy hollow shaft and AISI 1045 steel hollow shaft formed by CWR with a mandrel was studied numerically and experimentally. The results show that the influence of temperature on TC4 alloy flow stress is larger than that of 1045 steel, and the peak stress of TC4 alloy at 900 °C is close to that of 1045 steel at 1050 °C. For the hollow shafts of two materials, the ellipticity increases with increasing the inner hole diameter. For the same size of thin-walled billets, the forming quality of TC4 alloy at 900 °C is better than that of 1045 steel at 1050 °C. The CWR temperature range of TC4 alloy is narrower than 1045 steel. The increase of the initial deformation temperature can significantly increase the ellipticity of TC4 alloy and the appropriate forming temperature range of CWR TC4 alloy hollow shaft should be lower than 950 °C. Moreover, the rolling force and torque of TC4 alloy hollow shaft are smaller than that of 1045 steel when CWR hollow billet with the same dimensions.
Preparation of IC21 Spherical Powders by PREP Process
Authors: Wang Qingxiang , Zhen Zhu , Liang Shujin
Published: November 2021

The IC21 spherical powders with main content of Ni3Al were successfully manufactured by the high speed plasma rotating electrode process (HS-PREP). The powders particle size distribution fitted the mixed spraying model well. The chemical contents changes after melting were detected. The microstructure of the IC21 powders was formed by cellular crystal on the surface and dendrite inside, which was a typical PREP powder. The morphologies and properties of the irregular powders were also analyzed which indicated that the composition segregation and oxides inclusion of the electrode were the main reason for the formation. However, its proportion was less than 0.5%, which would not affect the additive manufacturing. The fundamental powder particle size distribution data for different rotating speeds was measured. The morphology and properties result show that the PREP could support qualified IC21 spherical powders with significant powder yields.
Finite Element Analysis on Behavior of Reinforced Hollow High Strength Concrete Filled Square Steel Tube Short Columns under Axial Compression
Authors: Yang Z J , Li X , Li G C , Peng S C
Published: November 2021

Hollow concrete-filled steel tubular (CFST) member is mainly adopted in power transmission and transformation structures, but when it is used in the superstructure with complex stress, the hollow CFST member has a low bearing capacity and is prone to brittle failure. To improve the mechanical performance of hollow CFST members, a new type of reinforced hollow high strength concrete-filled square steel tube (RHCFSST) was proposed, and its axial compression performance was researched. 18 finite element analysis (FEA) models of axially loaded RHCFSST stub columns were established through FEA software ABAQUS. The whole stress process of composite columns was studied, and parametric studies were carried out to analyze the mechanical performance of the member. Parameters of the steel strength, steel ratio, deformed bar and sandwich concrete strength were varied. Based on the simulation results, the stress process of members can be divided into four stages: elastic stage, elastoplastic stage, descending stage and gentle stage. With the increase of steel strength, steel ratio, the strength of sandwich concrete and the addition of deformed bars, the ultimate bearing capacity of members also increases. Additionally, the increment of those parameters will improve the ductility of the member, except for the sandwich concrete strength.
Design and Mechanical Properties of a New Clamp-Type Carbon Fiber Materials Tension Anchoring System
Authors: Wang Xianwei , Liu Bo , Hu Shengyong , Bao Longsheng
Published: November 2021

Carbon fiber materials are widely used in bridge reinforcement techniques, while conventional carbon fiber material tensile anchoring equipment produces a large prestressed loss. This paper analyzes the deficiencies of existing tensile anchoring systems at home and abroad, summarizing the cause of prestressed losses, and combining with existing anchoring systems, a new type of clamp type carbon fiber cloth tension anchoring system is proposed. The amount of deformation of the anchoring system is reduced by about 20%, which in turn reduces the system prestress loss caused by the system deformation. The ABAQUS finite element analysis software is used to numerically simulate the thickness of the tension anchor system and the force of the fixture at different inclination angles. Compare the experimental measurement data, under consideration of the mechanical properties of the system, making errors, and installation convenient prerequisites, the mechanical properties of the system are optimal when the thickness of the fixed plate is 30mm and the clamp tilt angle is 5 °.
Experimental Study on Statistic Failure Properties of Composite Considering Temperature Effect
Authors: Liu Zhun , Zhao Xiaoning , Liu Xuanxiu , Song Lei , Nie Qing
Published: November 2021

Advanced composite has been widely used in many fields with high mechanical performance requirements. Aim to characterize the reliability of composite, a statistic failure model was established based on Weibull distribution. Strength tests at various temperatures were conducted under tensile, compressive and in-plane shear loading conditions. As the temperature rises from 25 °C to 180°C, the strengths at different loading conditions reduces by nearly 60% except that the longitudinal tensile one reduces by only 16%. Equivalent strength at reference temperature was obtained based on time-temperature superposition principle. Then, the model parameters were determined with transferred test data using the median rank method, and statistic characterizations of different strength properties were further studied. Results show that the failure probability of composite is independent of temperature. Among all the strengths, the longitudinal compressive strength possesses the smallest shape parameter and correlation coefficient R of the fitting result, which means the strongest randomness of failure.
An Experimental Study on High Temperature Corrosion of TP347H Stainless Steel in Molten Chloride and Sulfate
Authors: Yu Weixin , Chu Xi , Zhang Huihui , Shen Yue , Tao Kangning , Li Jueyan
Published: November 2021

The corrosion resistance of TP347H stainless steel was evaluated by measuring mass loss in molten salt at 500-650°C. The corrosion mechanism was characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results show that the corrosion resistance of TP347H stainless steel increases with the increase of corrosion temperature. When the temperature is below 600°C, TP347H mainly generate low-stable FexOy, and the oxides such as Fe2O3, Fe3O4, Ni1.43Fe1.7O4 and NiFe2O4 are dissolved with the increase of temperature. NbO with higher stability is formed on the surface at 650 °C, which help Cr2O3 and NiO retain for a longer time. Mn-containing compounds on the surface further improve corrosion resistance of TP347H. The corrosion of TP347H stainless steel is mainly intergranular corrosion, and the temperature range of corrosion is consistent with the melting range of alkali metal chloride. Therefore, the molten alkali metal chloride plays a decisive role in the corrosion of TP347H stainless steel.
Effect of Mg Doping on SnO2 Energy Band and Power Conversion Efficiency of Dye-Sensitized Solar Cells
Authors: Yang Hao , Fan Hao , Duan Junhong
Published: November 2021

In this work, Mg-doped SnO2 materials with different molar ratios were synthesized by hydrothermal method. Based on the UV-Vis study, band gap (Eg) of the Mg-doped SnO2 is adjusted from 3.76 eV to 3.65 eV via 3 at% concentrations. Results of photovoltaic measurement for dye-sensitized solar cells (DSCs) based on Mg-doped SnO2 film as photoanode indicate that the doping of Mg ions can improve the open-circuit voltage (V
oc) of the DSCs, while the electric current density (J
sc) of the DSCs is almost unchanged. The cells were measured at 3 days intervals within 24 days after fabrication. Power conversion efficiency (PCE) of 3 at% Mg-doped SnO2 DSCs increases step by step and achieves 4.38% as the cell is tested after 18 days. Electrochemical impedance spectroscopy (EIS) analysis shows that Mg doping enhances light collection, increased the number of photogenerated electrons and inhibits charge recombination.
Effect of P + Sr + RE Ternary Compound Modification on Microstructure of Eutectic Al-13wt%Si Alloy
Authors: Liu Shibin , Wang Jing , Xu Jianwei , Meng Xiangcai
Published: November 2021

Used Al-13wt%Si alloy was as raw material, the influence mechanism of Al-Sr, Al-P and Al-RE ternary compound modifier was studied by casting technology. The effects of P, Sr and RE modification on Al-13wt% Si were studied by metallographic microscope, scanning electron microscope and X-ray. The effects of the addition order and amount of modifier on the microstructure of Al-13wt% Si were investigated The results show that compared with a single modifier, P + RE + Sr ternary composite modifier has more obvious modification effect on eutectic silicon in Al-13%Si alloy: the microstructure of different morphology can be obtained by using different amount and order of adding modifier. When the amount and order of modifier are 0.5wt%Sr, 0.7wt%P, 1.5wt%RE,the eutectic silicon with small size and uniform distribution can be obtained. Eutectic silicon consists of 70 μm, the slender lamella is refined to 5 μm.
A Strain Rate Dependent Progressive Damage Model for Carbon Fiber Woven Composites under Low Velocity Impact
Authors: Hu Xueyao , Tang Jiaojiao , Xiao Wei , Qu Kepeng
Published: November 2021

A progressive damage model was presented for carbon fiber woven composites under low velocity impact, considering the strain rate sensitivity of both mechanical properties and failure mechanisms. In this model, strain rate dependency of elastic modulus and nominal strength along in-plane direction are considered. Based on the Weibull distribution, stiffness progressive degradation is conducted by introducing strain rate dependent damage variables for distinct damage modes. With the model implemented in ABAQUS/Explicit via user-defined material subroutine (VUMAT), the mechanical behavior and possible damage modes of composites along in-plane direction can be determined. Furthermore, a bilinear traction separation model and a quadratic stress criterion are applied to predict the initiation and evolution of interlaminar delamination. Comparisons are made between the experimental results and numerical simulations. It is shown that the mechanical response and damage characteristics under low velocity impact, such as contact force history and delamination, are more consistent with the experimental results when taken the strain rate effect into consideration.
Fatigue Modeling for Carbon Fiber/Epoxy Laminated Composites Considering Voids’ Effect
Authors: Liu Haolong , Su Xuming , Kang Hongtae
Published: November 2021

In this article, experimental tests under static tensile loadings and tension-tension cyclic loadings were conducted for T300/924 unidirectional laminated composites at different porosity levels. On the basis of the experimental tests, a physical-based residual stiffness model for porous CFRP composites was put forward. The present model describes the deterioration of composites under cyclic loading in perspective of the initiation and propagation of cracks in the matrix, and is capable of capturing the effect of voids on fatigue behaviors of the composites. Lastly, the stiffness degradations of laminates with different void contents under various stress levels were predicted, and the predicted stiffness reduction as well as fatigue life of the material agreed well with the experimental data.
Effect of Magnesium on Corrosion Resistance of Galvalume Coating
Authors: Ding Z L , Zhang J , Jiang S M , Zhang Q F
Published: November 2021

In order to improve the performance of Galvalume coating, the expected microstructure and the better property could be obtained by adding 1∼3% Magnesium into Galvalume coating (55%Al-Zn). In this paper, effect of magnesium on the corrosion resistance of 55%Al-Zn coating was studied. The morphology and microstructure of coatings, polarization curve and surface corrosion of two different kinds of samples were analysed by SEM, EDS, electrochemistry workstation and salt spray test. The results show that the numbers of surface spangles by adding 2% magnesium are not changed obviously; the corrosion resistance of 55% Al-Zn-2%Mg coating becomes much better.
Preparation, Microstructure and Electrical Conductivity of LATP/LB Glass Ceramic Solid Electrolytes
Authors: Luo Jiajia , Zhong Yang , Chen Guohua
Published: November 2021

The Li2O-Al2O3-TiO2-P2O5 system glass ceramic solid electrolytes were prepared by adding Li3BO3 (LB) frits. The phase composition, microstructure and electrical properties of glass ceramics were investigated by using X-ray diffraction, scanning electron microscopy and AC impedance spectroscopy. The results show that the principal crystalline phase of all glass ceramic samples was LiTi2(PO4)3. The grain sizes of glass ceramic sample increase with the increase of sintering temperature. When the additive amount of LB is 1wt %, the glass ceramic solid electrolyte sintered at 950 oC shows the highest room-temperature ionic conductivity of 1.9×10−4 S.cm−1, which can be expected to be used in solid-state lithium-ion batteries.
Corrosion Behavior of 7075 and 2A12 Aluminum Alloys in Different Water Environments
Authors: Wu Zhipeng , Wang Shan , Zhen Nan
Published: November 2021

The corrosion of 7075 and 2A12 aluminium alloys are studied in three types of water, including freshwater lake water, salt lake water and saline lake brine in the Qinghai-Tibet Plateau region. The samples are immersed into the different water for different time, which are divided into four types of 30d, 60d, 90d and 120d. After undergoing dry and wet cycle immersion corrosion under natural conditions, it can be concluded that the two aluminum alloy samples have more serious corrosion in freshwater lakes, and 2A12 aluminum alloy is more corrosion resistant than the 7075 aluminum alloy. The corrosion is mainly pitting, accompanied by crevice corrosion and galvanic corrosion. Cl
− can pass through the passivation film on the surface of the samples to form pitting pits, while the dissolved Al
3+ in the matrix and

S

O
4

2
−

in the water can form stable Al
2(SO
4)3 ▪ xH
2
O, which plays a certain protective role for the sample.
Experiment and Research on Calculation Methods on Flexural Mechanical Behaviors of Non-Metallic Reinforced ECC Beams
Authors: Li Yang , You Yicai , Zhou Xiaoyong
Published: November 2021

Engineered cementitious composites (ECC) has high tenacity and the characteristics of strain hardening. In the bending test, ECC beams equipped with carbon fiber reinforced polymer (CFRP) in the tensile region show good deformation ability and bending ability. In this paper, the constitutive models of ECC and CFRP materials are established by uniaxial tensile compression test. Based on the plane section supposition, the analysis theory of bending capacity of cross section for ECC beams with non-metallic reinforcement is proposed. The calculation results are compared with the four-point bending test results. The results show that: (1) ECC beams with non-metallic reinforcement reflect the advantages of the two materials, and have strong deformation capacity before bending failure. (2) The calculation results based on the theory of flexural capacity of normal section are in good agreement with the experimental results, and the maximum error is less than 4%. The research results can provide the basis and reference for the calculation analysis and practical application of non-metallic reinforced high toughness material structure.
Research Progress on Microstructure Characterization of Silicon Carbide Fibers
Authors: Zhang Xingjian , Cai Zixi , Fan Jinjuan , Liu Changkui , Ye Jinfa
Published: November 2021

Ceramic matrix composites have excellent properties such as high temperature resistance and oxidation resistance, and have good application prospects in the hot end parts of engines. In ceramic matrix composites, the microstructure composition of silicon carbide fibers determines their macroscopic properties. Therefore, this article takes silicon carbide fiber as the research object, summarizes the existing SiC fibers structure, composition, and morphology characterization methods, compares the development and advantages and disadvantages of XRD, SEM, TEM and other testing equipment analysis, and proposes The problems of sample preparation, surface defects and internal structure changes in the microstructure characterization of silicon carbide fibers are discussed, which provides a reference for the preparation of high-performance SiC fibers and the improvement of their characterization work.
Architecture of a Spatial Disorientation Platform and Serious Game
Authors: Castañeda Claudia , Sánchez Natalia , Aviles Oscar F. , Mauledoux Mauricio
Published: November 2021

In recent years there have been several applications for the study of stabilometric mainly in the analysis of disorder, using mechanical structures of one or two degrees of freedom. An architecture of a stabilometric platform is proposed, which can acquire data through a virtual environment, in this case, a Snowboarding environment, since this sport provides greater balance, increases flexibility and strength in the muscles, and strengthens the lower limbs since it can have a displacement movement in one direction. Thanks to this environment, an architecture is proposed to execute several applications, focused on balance rehabilitation. As a result of this proposal, mathematical models were made by applying the Euler Lagrangian theory, and architecture was obtained that can acquire data in real-time, allowing to visualize this data through a sensor, which shows the position of the person with its respective movement. Also, with the implementation of the Self-Assessment Manikin (SAM) a preliminary study was conducted with 10 people in which 70% presented a discussion of different errors in the design and development stage in the virtual environment, also, 10% of the study population showed greater spatial disorientation to one side of the platform. Thanks to this, it was possible to modify the virtual environment and obtain a more efficient response by implementing this method. As future work, it is proposed to develop variable control systems on the platform and a trajectory variation in the virtual environment.
Model-based motion simulation of delta parallel robot
Authors: Makwana Mahesh A , Patolia Haresh P
Published: November 2021

For a parallel configuration of a robot manipulator, the solution of Forward Kinematics (FK) is tough compared to Inverse Kinematics (IK). This paper presents the model-based motion planning of a delta parallel robot in Simulink’s SimScape environment. A model was developed and simulated for motion study. The developed model has been simulated to solve the FK of the parallel manipulator and to check its efficacy. First, a helix curve has been planned within the reachable workspace. Then IK was solved to extract angular positions of the biceps. Obtained angular positions then fed to SimScape model to run a simulation. The path taken by the end effector of the system calculated by simulation is in good approximation to the planned helix path. Further, visual simulation and motion analysis of delta parallel robot can be performed by Model-based simulation and solves mechanical design as well control system design problems. Experimental study also shows that the circular path designed for experiment is well followed in real time simulation.
Design and Analysis of the Spray-Painting Robot for tall statues and monuments
Authors: Shah Darshita , Dave Jatin , Detharia Dipen , Majithiya Ashish
Published: November 2021

The painting on tall structures, statues, monuments and buildings is dangerous task for humans. Robotics finds its applications in operations, which are repetitive, hazardous, and dangerous. The aim of the present work is to design a manipulator for spray painting on surfaces of tall monuments, statues and structures. The robot can be installed on a crane platform for lifting and operated from the ground. A lightweight and compact design is desired that can be easily accommodated within the space of the crane. A Revolute-Revolute-Revolute-Prismatic (RRRP) type Robotic arm is developed and analysed for this application. By establishing the rigid body tree model in Robotics System Toolbox, the numerical model of direct and inverse kinematics using Homogenous Matrix Transformation is prepared in MATLAB. Using the spray patch method and offline programming method, the spray model is prepared in Solid woks to obtain trajectory waypoints. A B-spline path is generated through these waypoints. At each waypoint, joint displacement variables are calculated using an inverse kinematic model. An air-less spray gun is selected and attached with a robot. Controlled motion algorithm for spray painting operation on a circular surface were obtained with simulation results. A smooth trajectory for performing spray painting is obtained.
Jumping robot: A pneumatic jumping locomotion across rough terrain
Authors: Dilip R , Karthik Milan R , Vajrangi Arpit , Chavadi Karthik S , Puneeth A S
Published: November 2021

This paper presents a jumping mechanism using pneumatic actuators adopted in a traditional robotic vehicle’s frame. This is a skeleton for future development on this technology. This is a simple mechanism to overcome obstacles on its way in a robotic vehicle. As we know a traditional wheeled robotic vehicle can not over come an obstacle on ease as it doesn’t have an effective mechanism or it might take an other alternative long route to reach the target. This mechanism has an effective design to overcome obstacles comparing to the traditional robot vehicles. So this model has a higher mobility, flexibility and rapidity. This design has a new type of locomotion to it that is jumping along with wheeled movement which is not present in a traditional robot. This mechanism works from the real time information from the sensors. There are 4 double acting cylinders placed at equidistant from each other and mass distribution of the whole model has been equally divided and each cylinder has the same load. These 4 cylinders are pneumatically actuated as compressed air as source. When these cylinders are actuated there is rapid pressurizing which causes the jump. These cylinders are actuated when the relay receives signal from the sensor module that there is an obstacle ahead. As we know there are many kind of locomotion of robots are been developed these days like wheeled, tracked, crawling, walking and so on but all these robots have difficulty in overcoming obstacle on their way, if it is modified to overcome obstacle too their would be a complex design which in this model is not the case as it has a very simple design. This mechanism is designed to take over rough terrains and uneven and unknown terrains. As a overall outcome we were able to make the robot overcome the obstacles on its way in its unique way.
Design and simulation of disaster mitigation robot using machine vision
Authors: Avinaash M , Andrew D , Visnu S , Abrar M , Seenu N
Published: November 2021

The goal is to provide a robust mobile robot to assist recures in their operation by providing real time surveillance, remote operation as well autonomous operation. The mobile robot is capable of mapping using a LIDAR, this provides a map of the disaster zone which is then used to assess and provide a path planning for the most efficient rescue for the Mobile robot as well as the Rescuers. The built-in gas sensor reads the concentration of gases in the area, providing data on the environment in the disaster zone. The use of high definition cameras combined with Artificial Intelligence based image classification provides an edge in autonomous traversing and search and rescue. Disaster mitigation is an extremely dangerous task for the rescuers, a mobile robot such as LV-01 can be the difference between life and death.
AI powered IoT based Real-Time Air Pollution Monitoring and Forecasting
Authors: Mani Geetha , Viswanadhapalli Joshi Kumar , Sriramalakshmi P
Published: November 2021

Air is one of the most fundamental constituents for the sustenance of life on earth. The consumption of non-renewable energy sources and industrial parameters steadily increases air pollution. These factors affect the welfare and prosperity of life on earth; therefore, the nature of Air Quality in our environment needs to be monitored continuously. This paper presents the execution and plan of Internet-of-Things (IoT) based Air Pollution Monitoring and Forecasting utilising Artificial Intelligent (AI) methods. Also, Online Dashboard was created for real-time monitoring of Air pollutants (both live and forecasted data) through ‘firebase’ from the Google cloud server. The air pollutants like Carbon Mono Oxide (CO), Ammonia (NH3), and Ozone (O3) layer information are collected from IoT-based sensor nodes in Vijayawada Region. Time Series modelling techniques like the Naive Bayes Model, Auto Regression Model (AR), Auto Regression Moving Average Model (ARMA), and Auto-Regression Integrating Moving Average Model (ARIMA) used to forecast the individual air pollutants aforementioned. The data collected from the IoT sensor node with a time frame is fed as input features for training the model, and optimised model parameters are obtained. The obtained model parameters are again verified with new unseen data for time. The performances of various Time Series models are validated with the help of performance indices like Mean Absolute Error (MAE) and Root Mean Square Error (RMSE). The machine learning algorithm flashed in Raspberry Pi-3. It acts as an edge computing device. The current air pollutants data and forecasted data are monitored for the next 4 hours through an online dashboard created in an open-source firebase from Google cloud service.