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Partial Surface Damper to Suppress Vibration for Thin Walled Plate Milling

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 632-643页

作者： Jiahao SHI Qinghua SONG Zhanqiang LIU xing ai key laboratory of high efficiency and clean mechanical manufacture of ministry of education shandong universityJinan 250061China school of mechanical engineering shandong universityJinan 250061China

The material removal rate and required work- piece surface quality of thin-walled structure milling are greatly limited due to its severe vibration, which is directly associated with the dynamic characteristics of the system. Therefore, the suppression of vibration is an unavoidable problem during milling. A novel partial surface damping method is proposed to modify the mode of the thin walled cantilever plate and to suppress vibration during milling. Based on classical plate theory, the design criterion is analyzed and configuration of the partial surface damper is introduced, in which viscoelastic plate and constraining plate are attached to the surface of the plate to increase the system＇s natural frequency and loss factor. In order to obtain the energy expression of the cutting system, the Ritz method is used to describe the unknown displacements. Then, with Lagrange＇s equation, the natural frequency and loss factor are calculated. In addition, the plate is divided into a finite number of square elements, and the regulation of treated position is studied based on theoretic and experimental analysis. The milling tests are conducted to verify its damping performance and the experimentalresults show that with treatment of partial surface damper, the deformation of the hare plate is reduced from 0.27 mm to 0.1 mm, while the vibration amplitude of the bare plate is reduced from 0.08 mm to 0.01 mm. The proposed research provides the instruction to design partial surface damper.

关键词： Partial surface damper Milling process Thin-walled plate

A novel stability prediction approach for thin-walled component milling considering material removing process

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Chinese Journal of Aeronautics 2017年第5期30卷 1789-1798页

作者： Jiahao SHI Qinghua SONG Zhanqiang LIU xing ai Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of Education Shandong University Ji'nan 250061 China School of Mechanical Engineering Shandong University Ji'nan 250061 China

The milling stability of thin-walled components is an important issue in the aviation manufacturing industry, which greatly limits the removal rate of a workpiece. However, for a thin-walled workpiece, the dynamic characteristics vary at different positions. In addition, the removed part also has influence on determining the modal parameters of the workpiece. Thus,the milling stability is also time-variant. In this work, in order to investigate the time variation of a workpiece＇s dynamic characteristics, a new computational model is firstly derived by dividing the workpiece into a removed part and a remaining part with the Ritz method. Then, an updated frequency response function is obtained by Lagrange＇s equation and the corresponding modal parameters are extracted. Finally, multi-mode stability lobes are plotted by the different quadrature method and its accuracy is verified by experiments. The proposed method improves the computational efficiency to predict the time-varying characteristics of a thin-walled workpiece.

关键词： Material removal effect Multi-mode Stability Thin-walled workpiece Vibration

Measurement of gear tooth dynamic deformation using dynamic speckle photography

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Chinese Science Bulletin 1998年第6期43卷 514-518页

作者： Jianfeng Li xing ai Zhiren Tian Shandong Univ Technol Jinan 250061 Peoples R China

A new method of measuring gear tooth dynamic deformation is proposed. Dynamic speckle photographs of the rotating gear tooth have been achieved by combining the pulsed ruby laser with the out-syn-signal. Double speckle patterns of the whole mesh period of gear tooth are obtained by accurate time delay of the ruby laser. Gear tooth dynamic deformation of the whole mesh period is achieved using the automatic image processing. Testing results show that the trends of gear tooth deformation coincides with the calculation by the finite element method. The success of this new trying provides a new technique for the measurement of gear tooth dynamic deformation.

关键词： pulsed ruby laser dynamic speckle photography image process gears deformation.

Bonding mechanism and performance of ceramic coatings by sol-gel process

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Chinese Science Bulletin 2000年第14期45卷 1291-1296页

作者： Yuanchun Chen xing ai Chuanzhen Huang Shandong Univ Technol Dept Mech Engn Jinan 250061 Peoples R China

Thin alumina coatings were prepared on carbide tools to enhance their wear-resistant ability by dip coating from an aluminum alkoxide solution. The coating eventually obtained was perfectly integrated, without any macroscopic defect, and showed good performance in turning medium carbon steel, which presented a novel and promising coating method for cutting tools. The coating morphology before and after heat treatment was examined with the aid of a scanning electron microscope (SEM). The composition of coating and interface layer as well as the crystal structure of coating was characterized by X-ray diffraction (XRD). The elemental distribution near the interlayer was analyzed by electron probe microanalysis (EPMA).

关键词： coated tools sol-gel method cemented carbide ceramic coating.

High temperature creep mechanisms of a single crystal superalloy: A phasefield simulation and microstructure characterization

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Progress in Natural Science:Materials International 2020年第3期30卷 366-370页

作者： Ronghai Wu Yunsong Zhao Yanfei Liu xing ai School of Mechanics Civil Engineering and Architecture Northwestern Polytechnical University Beijing Institute of Aeronautical Materials AECC Sichuan Gas Turbine Establishment AECC Hunan Aviation Power Plant Research Institute

The high temperature creep behavior of a single crystal Ni-based superalloy was studied by combined experimental and numerical methods. The creep test results showed that the creep curves exhibited a three-stage feature. The qualitative explanations for each stage of the creep curves were carried out based on the microstructure characterizations of γ/γ′ phases and dislocations. An elastoplasticity incorporated phase-field model was developed to provide quantitative understanding on directional coarsening(rafting) of γ′ phase. The simulation results showed that the directionality of γ′ coarsening was induced by both dislocation activity in γchannels and elastic inhomogeneity between γ and γ’ phases, therein the dislocation activity played a major *** findings provide new insights into the design of novel single crystal superalloys with improved creep properties.

关键词： Creep mechanism Dislocation activity Phase-field method Single crystal superalloy

Adaptive mechanisms of Ardisia crenata *** along an elevational gradient on Gaoligong Mountain,Southwest China

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Journal of Mountain Science 2023年第3期20卷 765-778页

作者： ai xing-mei LI Yu XIE Huan ZHAO Cai-bao College of Landscape Architecture and Horticulture Sciences Southwest Forestry UniversityKunming 650224China Southwest Research Center for Engineering Technology of Landscape Architecture(State Forestry and Grasslan Administration) Southwest Forestry UniversityKunming 650224China

Plants overcome environmental stress by generating metabolic ***,it is crucial to understand the physiological mechanisms of plant responses to changing *** crenata *** has an important ornamental and medicinal *** reveal the impact of elevational gradient on the habitat soil and plant physiological attributes of this species,we collected root topsoil(0–20 cm)and subsoil(20–40 cm)samples and upper leaves at the initial blooming phase,in a survey of six elevations at 1,257 m,1,538 m,1,744 m,1,970 m,2,135 m,and 2,376 m,with 18 block plots,and 5sampling points at each *** decreases with an increase in elevation,and soil variables,and enzymatic activities fluctuated in both the topsoil and subsoil,with all of them increasing with elevation and decreasing with soil *** analysis was conducted to explore the correlation between the distribution of *** *** along the elevational gradient and soil nutrients and enzyme activities,the soil properties were mainly affected by p H at low elevations,and governed by total phosphorus(TP)and available nitrogen(AN)at high *** levels of chlorophyll,carbohydrates,and enzymatic activity except for anthocyanin in this species showed significant variation depending on physiological attributes evaluated at the different collection *** decline in chlorophyll a and b may be associated with the adaptive response to avoid environmental stress,while its higher soluble sugar and protein contents play important roles in escaping adverse climatic conditions,and the increases in activities of antioxidant enzymes except peroxidase(POD)reflect this species’higher capacity for reactive oxygen scavenging(ROS)at high *** study provides supporting evidence that elevation significantly affects the physiological attributes of *** *** on Gaoligong Mountain,which is helpful for understanding plant adaptation strategies and the plastic

关键词： Ardisia crenata var.bicolor Adaptive distribution Elevation Gaoligong Mountain Plant physiological trait Soil physicochemical properties

Plastic Flow Modeling of Ti-5 Al-2 Sn-2 Zr-4 Mo-4 Cr Alloy at Elevated Temperatures and High Strain Rates

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Journal of Wuhan University of Technology(Materials Science) 2015年第3期30卷 611-616页

作者：王宝林 ai xing 刘战强 LIU Jigang School of Mechanical &Automotive Engineering Qilu University of Technology Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of Education School of Mechanical Engineering Shandong University

The true stress-sWain relationships of Ti-5A1-2Sn-2Zr-4Mo-4Cr（TC17） alloy with a wide range of strain rates were investigated by tmiaxial quasi-static and dynamic compression tests, respectively. Quasi- static compression tests were carried out with Instron 8874 test machine, while dynamic compression tests were performed with the split Hopkinson pressure bar （SHPB） which was installed with heating device and synchro- assembly system. The dynamic mechanical behaviors tests of TC17 were carded out from room temperature to 800 ℃ at intervals of 200 ℃ and at high sWain rates （5 500-1 9200 s-l）. The stress-strain curves considering temperature-sWain rate coupling actions were obtained. The Johnson-Cook constitutive model was developed through data fitting of the stress-sWain curves. The material constants in the developed constitutive model can be determined using isothermal and adiabatic stress-strain curves at different strain rates. The Johnson-Cook constitutive model provided satisfied prediction of the plastic flow stress for TC17 alloy.

关键词： Ti-5A1-2Sn-2Zr-4Mo-4Cr SHPB stress-strain curve high temperature high strain rate dynamic constitutive relationship

Cutting tool materials for high speed machining

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Progress in Natural Science:Materials International 2005年第9期15卷 777-783页

作者： LIU Zhanqiang** and ai xing(School of Mechanical Engineering, Shandong University, Jinan 250061, China) School of Mechanical Engineering Shandong University Jinan 250061 China

High speed machining (HSM) is one of the emerging cutting processes, which is machining at a speed significantly higher than the speed commonly in use on the shop floor. In the last twenty years, high speed machining has received great attentions as a technological solution for high productivity in manufacturing. This article reviews the developments of tool materials in high speed machining operations, and the properties, applications and prospective developments of tool materials in HSM are also presented.

关键词： tool materials high speed machining.

Stress Field Analyses of Functionally Gradient Ceramic Tool by FEM

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Journal of Materials Science & Technology 2001年第4期17卷 466-468页

作者： Ning FAN , xing ai and Jun ZHAO Department of Mechanical Engineering, Shandong University,Jinan 250061, China Dept. of Mech. Eng. Shandong Univ. Ji'nan 250061 China

The cutting properties of the functionally gradient ceramic cutting tools relate closely to the gradient distribution. A cutting model of the functionally gradient ceramic tool is firstly designed in the present paper... 详细信息

关键词： Stress Field Analyses of Functionally Gradient Ceramic Tool by FEM Tool