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Dry Grinding of Titanium Alloy Using Brazed Monolayer cBN Wheels Coated with Graphite Lubricant

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Transactions of Nanjing university of Aeronautics and Astronautics 2014年第1期31卷 104-110页

作者：陈燕丁兰英傅玉灿苏宏华吴杰徐九华徐鸿钧 college of mechanical and electrical engineering Nanjing University of Aeronautics and Astronautics college of engineering Nanjing Agricultural University

The purpose of this study is to investigate the effect of graphite lubricant on the dry grinding performance of Ti-6Al-4Valloy,using graphite-coated,brazed monolayer,cubic boron nitride(cBN)*** monolayer cBN wheels both with and without a coating of polymer-based graphite lubricant are fabricated and subsequently compared for grinding performance based on measurements of grinding temperature,surface microstructure and *** terms of grinding temperature,considerable improvement in dry grinding performance of titanium alloy is achieved using coated brazed monolayer cBN wheels,with 42%—47%reduction in grinding temperature as opposed to uncoated *** grinding force ratio with the coated wheels is observed to remain between 1.45to1.85despite material removal rates reaching up to 1 950mm3/*** tangible change in ground titanium surface microstructure is noted as a result of grinding with the graphite coated wheels as opposed to the uncoated ones.

关键词： grinding graphite lubricant Ti-6Al-4V grinding temperature grinding force ratio

Improvement of mechanical Properties of Wood-Plastic Composite Floors Based on the Optimum Structural Design

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Acta Mechanica Solida Sinica 2016年第4期29卷 444-454页

作者： Yang Zhang Ping Xue Yun Ding Mingyin Jia Jianchen Cai Xiaoming Jin college of mechanical and electrical engineering Beijing University of Chemical Technology college of mechanical engineering Quzhou University

A study is carried out on the structural design of wood-plastic composite floors. The geometric parameters of the cavities, the structure, and the means to optimize the performance of these light boards are investigated. Various structural parameters of the boards, such as size, shape, and the pattern of cavities are also studied. The optimal structure can be determined by calculation and analysis of the strength, stiffness, weight and cost of the material. A finite element model for the mechanical analysis of wood-plastic composite floors is established; and the results are used to verify the strength criteria under bending deformation, which is the most common loading condition of flooring board.

关键词： wood plastic composite cavities flooring board optimal structure the finite element model

Low Cycle Fatigue and Strengthening Mechanism of Cold Extruded Large Diameter Internal Thread of Q460 Steel

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Chinese Journal of mechanical engineering 2016年第3期29卷 556-563页

作者： MIAO Hong MEI Qing YUAN Jingyun ZHENG Zaixiang JIN Yifu ZUO Dunwen college of mechanical engineering Yangzhou University college of mechanical and electrical engineering Nanjing University of Aeronautics and Astronautics

large diameter internal thread of high-strength steel（LDITHSS） manufactured by traditional methods always has the problems of low accuracy and short life. Compared with traditional methods, the cold extrusion process is an effective means to realize higher accuracy and longer life. The low-cycle fatigue properties of LDITHSS are obtained by experiments, and the initiation and propagation of fatigue cracks are observed by scanning electron microscope（SEM）. Based on the mechanical properties, surface microstructure and residual stress, the strengthening mechanism of cold extruded large diameter internal thread（LDIT） is discussed. The results show that new grains or sub-grains can be formed on the surface of LDIT due to grain segmentation and grain refinement during cold extrusion. The fibrous structures appear as elongated and streamlined along the normal direction of the tooth surface which leads to residual compressive stress on the extruded surface. The maximum tension stress of LDIT after cold extrusion is found to be 192.55 k N. Under low stress cycling, the yield stress on thread increases, the propagation rate of crack reduces, the fatigue life is thus improved significantly with decreasing surface grain diameter and the average fatigue life increases to 45.539×10~3 cycle when the maximum applied load decreases to 120 k N. The low cycle fatigue and strengthening mechanism of cold extruded LDIT revealed by this research has significant importance to promote application of internal thread by cold extrusion processing.

关键词： large diameter internal thread cold extrusion low cycle fatigue strengthening fatigue resistance

A novel LS-SVM control for unknown nonlinear systems with application to complex forging process

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Journal of Central South university 2017年第11期24卷 2524-2531页

作者： FAN Bin LU Xin-jiang HUANG Ming-hui School of mechanical and electrical engineering Central South University college of mechanical and electrical engineering Hunan City University

A novel LS-SVM control method is proposed for general unknown nonlinear systems. A linear kernel LS-SVM model is firstly developed for input/output(I/O) approximation. The LS-SVM control law is then derived directly from this developed model without any approximation and assumption. It further proves that the control error is fully equal to the LS-SVM modeling error. This means that a desirable control performance can be achieved because the LS-SVM has been proven to have an outstanding modeling ability in the previous studies. Case studies finally demonstrate the effectiveness of the proposed LS-SVM control approach.

关键词： unknown system inverse control input/output approximation LS-SVM control linear kernel

Analysis and performance test on dynamic seed corn threshing and conveying process with variable diameter and spacing

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International Journal of agricultural and Biological engineering 2023年第2期16卷 259-266页

作者： Fei Dai Yiming Zhao Yuanxiang Liu Ruijie Shi Shanglong Xin Qiufeng Fu Wuyun Zhao college of mechanical and electrical engineering Gansu Agricultural UniversityLanzhou 730070China Jiuquan OK Seed Machinery Co. Ltd.Jiuquan 735000GansuChina

In order to further reduce the damage rate in threshing seed corn,a seed corn threshing testbed with variable diameter and spacing that can realize dynamic adjustment of parameters,such as feed quantity,rotating speed of the threshing device,threshing spacing of the threshing units,was designed in this *** software of finite element analysis ANSYS Workbench was applied to do modal analysis on the threshing axis designed for variable diameter and spacing of seed *** first 8 orders of natural frequencies were distributed in 201.12-1640.20 Hz,with corresponding vibration amplitude in 5.86-27.04 mm,showing reasonable structural design of the threshing axis,which could realize effective seed corn threshing and *** element method was applied to do simulation analysis on the seed corn threshing and conveying process with variable diameter and *** the condition of different feed quantity,different rotating speed of the thresher,the moving speed of corn clusters and contact force among clusters were measured through simulation,and the working characteristics of the threshing testbed for low-damage and dynamic threshing and conveying of seed corn with variable diameter and spacing were *** performance test results of the testbed of seed corn with variable diameter and spacing showed that,when the rotating speed of the threshing axis was 190-290 r/min,feed quantity was 1.80-3.80 kg/s,the damage rate of seed corn was 0.32%-0.63%,threshing rate was 99.20%-99.82%,and content impurity rate was 4.23%-5.86%,the mass of threshed corn grains first increased and then decreased along the axial *** test verification process was in line with the simulation results;thus,the test results could satisfy the requirements in design and actual operation.

关键词： seed corn threshing device with variable diameter and spacing threshing and conveying process performance test

Optimal Design of Multiple Stresses Accelerated Life Test Plan Based on Transforming the Multiple Stresses to Single Stress

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Chinese Journal of mechanical engineering 2014年第6期27卷 1125-1132页

作者： GAO Liang CHEN Wenhua QIAN Ping PAN Jun HE Qingchuan college of mechanical and electrical engineering Sichuan Agricultural University Zhejiang Province's Key Laboratory for Reliability Technology of mechanical & electrical Products Zhejiang Sci-Tech University

For planning optimum multiple stresses accelerated life test plans, a commonly followed guiding principle is that all parameters of the life-stress relationship should be estimated, and the number of the stress level combinations must be no less than the number of parameters of the life-stress relationship. However, the general objective of an accelerated life test（ALT） is to assess thep-th quantile of the product life distribution under normal stress. For this objective,estimating all model parameters is not necessary, and this will increase the cost of test. Based on the theoretical conclusion that the stress level combinations of the optimum multiple stresses ALT plan locate on a straight line through the origin of coordinate, it is proposed that a design idea of planning the optimum multiple stresses ALT plan through transforming the problem of designing an optimum multiple stresses ALT plan to designing an optimum single stress ALT plan. Moreover, a method of planning the optimum multiple stresses ALT plan which can avoid estimating all model parameters is established. An example shows that, the proposed plan which only has two stress level combinations could achieve an accuracy no less than the traditional plan, and save the test time and cost on one stress level combination at least; when the actual product life is less than the design value, even the deviation of the model initial parameters value is up to 20%, the variance of the estimation of thep-th quantile of the proposed plan is still smaller than the traditional plans approximately 25%. A design method is provided for planning the optimum multiple stresses ALT which uses the statistical optimum degenerate test plan as the optimum multiple stresses accelerated life test plan.

关键词： multiple stresses accelerated testing optimum design test planning

Diving control of underactuated unmanned undersea vehicle using integral-fast terminal sliding mode control

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Journal of Central South university 2016年第5期23卷 1085-1094页

作者：严浙平于浩淼侯恕萍 college of Automation Harbin Engineering University college of mechanical and electrical engineering Harbin Engineering University

The problem of diving control for an underactuated unmanned undersea vehicle(UUV) considering the presence of parameters perturbations and wave disturbances was *** vertical motion of an UUV was divided into two noninteracting subsystems for surge velocity control and *** stabilize the vertical motion system,the surge velocity and the depth control controllers were proposed using backstepping technology and an integral-fast terminal sliding mode control(IFTSMC).It is proven that the proposed control scheme can guarantee that all the error signals in the whole closed-loop system globally converge to the sliding surface in finite time and asymptotically converge to the origin along the sliding *** a unified control parameters for different motion states,a series of numerical simulation results illustrate the effectiveness of the above designed control scheme,which also shows strong robustness against parameters perturbations and wave disturbances.

关键词： integral-fast terminal sliding mode control depth control underactuated unmanned undersea vehicle

Optimization and field experiment of an adjustable device for sugar beet digger

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International Journal of agricultural and Biological engineering 2021年第6期14卷 68-74页

作者： Fangyan Wang college of mechanical and electrical engineering Qingdao Agricultural UniversityQingdao 266041China

The harvesting operation,which affects the energy consumption and application performance,usually determines the harvesting effect and production quality of the *** adjustable sugar beet excavation device was designed to put the excavation equipment into practice by reducing harvest *** device is composed of an excavation disc,hub,pedestal,threaded rod,adjustable nut,boom,mounting seat,leak proof disc,*** theoretical analysis,it was found that the excavation disc and the adjustment mechanism,which determine the excavation space and loading condition of the device,are important to the excavation *** parameters of the excavation disc were selected according to the growth status of sugar beet and the requirements of excavation space,with 340 mm as the radius of the excavation disc and 7.5°as the edge angleθ.The adjustment mechanism parameters were selected to change the operating parameters(inclination angleβand deflection angleγ)*** the theoretical and experimental preliminary research,the key components structure and parameters of the excavation device were *** Central Composite Design(CCD)method,the regression equation was established,with rotation angleα,opening angleεand excavation depth h as factors,and break rate,loss rate and excavation resistance as performance *** influence of factors on performance indexes was *** optimized parameter combination is:35.37°of rotation angle,15.08°of opening angle and 135.20 mm of the excavation *** verified that the adjustable excavation device worked stably and achieved smooth excavation without *** test indexes improved,with 0.6%of break rate,1.1%of loss rate and 2312.8 N of the excavation *** satisfied the requirement for beet harvest quality,and is roughly consistent with the optimization *** research results can provide reference for the research on mechanized harvesting technology and equipment of sugar beet.

关键词： sugar beet excavation harvest parameter optimization

Study of LED array fill light based on parallel particle swarm optimization in greenhouse planting

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Information Processing in Agriculture 2019年第1期6卷 73-80页

作者： Feifei He Lihua Zeng Dongming Li Zhenhui Ren college of mechanical and electrical engineering Hebei Agricultural UniversityBaoding 071001China

agricultural productivity is crucial to the *** output and quality of crops have a direct impact on people’s daily lives and a country’s food and ***,harvesting high-quality crops efficiently and maximizing yield per unit area are the most important goals pursued by *** an important parameter of plant growth,light intensity is one of the important factors that affects plant growth and development,morphological establishment and accumulation of functional chemical *** light intensity cannot meet the plant’s needs,the optimal light intensity or uneven light distribution will have a greater impact on plant growth and *** paper aims to address the optimal plant light intensity *** paper presents an expert system technology database storing the empirical value of real-time light intensity values and compares it with a parallel particle swarm optimization algorithm to identify the optimal locations where LED lights need to be turned on and where drive circuit lit LED arrays need to be situated,to identify the number of LED fill lights and to solve light intensity optimization problems.

关键词： Particle swarm optimization Greenhouse Fill light Expert system LED