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A new 3D plastoelastohydrodynamic lubrication model for rough surfaces

Friction 2024年第6期12卷 1176-1193页

作者： Shengyu YOU jinyuan tang Qiang WANG State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South UniversityChangsha 410083China

Plastoelastohydrodynamic lubrication of rough surfaces(R-PEHL)is a cutting-edge area of research in interface fluid-structure coupling *** existing R-PEHL model calculates the elastic-plastic deformation of rough surface by the Love equation in a semi-infinite space smooth surface,which deviates from the actual ***,it is an innovative work to study the exact solution of elastic-plastic deformation of rough surface and its influence on the solution results of R-PEHL *** this paper,a new contact calculation model of plastoelastohydrodynamic lubrication(PEHL)with three-dimensional(3D)rough surface is proposed by integrating numerical method of EHL and finite element *** new model eliminates an original error introduced by the assumption of semi-infinite space in contact calculation,providing wide applicability and high *** the given rough surfaces and working conditions,the study reveals that:(1)the oil film pressure calculated by the new model is lower than that of the smooth surface in semi-infinite space by 200–800 MPa;(2)the Mises stress of the new model is 2.5%–26.6%higher than that of the smooth surface in semi-infinite space;(3)compared with the semi-infinite space assumption,the rough surface plastic deformation of the new model is increased by 71%–173%,and the local plastic deformation singularity may appear under the semi-infinite space assumption;(4)the plastic deformation caused by the first contact cycle on the rough surface of the new model accounts for 66.7%–92.9%of the total plastic deformation,and the plastic deformation of the semi-infinite space accounts for 50%–83.3%.This study resolves the contradiction between the smooth surface assumption and the rough surface in the existing R-PEHL model,establishing a solid logic foundation for the accurate solution of R-PEHL model.

关键词： rough surface plastoelastohydrodynamic lubrication(PEHL) asperity plastic deformation semi-infinite space

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High-precision simulation and experimental verification of residual stress and surface topography of cylindrical surface shot peening

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CHINESE JOURNAL OF AERONAUTICS 2024年第9期37卷 535-559页

作者： Zhao, Jiuyue tang, jinyuan Liu, Huaming Zhang, Huiyun Li, Xin Ding, Han Cent South Univ State Key Lab Precis Mfg Extreme Serv Performance Changsha 410083 Peoples R China Cent South Univ Coll Mech & Elect Engn Changsha 410083 Peoples R China

Shot peening is commonly employed for surface deformation strengthening of cylindrical surface part. Therefore, it is critical to understand the effects of shot peening on residual stress and surface topography. Compared to flat surface, cylindrical surface shot peening has two significant features: (i) the curvature of the cylindrical surface and the scattering of the shot stream cause distributed impact velocities; (ii) the rotation of the part results in a periodic variation of the impact velocity component. Therefore, it is a challenge to quickly and accurately predict the shot peening residual stress and surface topography of cylindrical surface. This paper developed a high-precision model which considers the more realistic shot peening process. Firstly, a kinematic analysis model was developed to simulate the relative movement of numerous shots and cylindrical surface. Then, the spatial distribution and time-varying impact information was calculated. Subsequently, the impact information was used for finite element modeling to predict residual stress and surface topography. The proposed kinematic analysis method was validated by comparison with the discrete element method. Meanwhile, 9310 high strength steel rollers shot peening test verified the effectiveness of the model in predicting the residual stress and surface topography. In addition, the effects of air pressure and attack angle on the residual stress and surface topography were investigated. This work could provide a functional package for efficient prediction of the surface integrity and guide industrial application in cylindrical surface shot peening.

关键词： Shot peening Cylindrical surface 9310 high strength steel High-precision modeling Residual stress Surface topography FATIGUE BEHAVIOR ROUGHNESS INTEGRITY STRENGTH HARDNESS STEEL

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考虑多场耦合作用的航空薄辐板齿轮热处理后辐板车削变形研究

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机械传动 2024年第6期48卷 100-108,116页

作者：唐成唐忠威陶琪唐进元中国航发中传机械有限公司湖南长沙410200 中南大学机电工程学院湖南长沙410083 中南大学极端服役性能精准制造全国重点实验室湖南长沙410083

薄辐板齿轮拥有质量轻、结构与受力相匹配等诸多优点,常应用于航空航天等重要场合。然而,薄辐板齿轮本身的刚度较小,工艺过程复杂且涉及应力场、温度场等多个物理场的耦合作用,难以对其进行精确变形及加工精度的控制与预测。以薄辐板齿... 详细信息

薄辐板齿轮拥有质量轻、结构与受力相匹配等诸多优点,常应用于航空航天等重要场合。然而,薄辐板齿轮本身的刚度较小,工艺过程复杂且涉及应力场、温度场等多个物理场的耦合作用,难以对其进行精确变形及加工精度的控制与预测。以薄辐板齿轮件为研究对象,针对齿轮辐板的热处理及车削加工工艺过程,建立了零件的工艺参数与其应力场间的映射模型,并通过试验验证了该模型的正确性;基于该模型,分析了不同的工艺参数、工艺路线以及零件的装夹方式等对航空薄辐板齿轮辐板的热处理后车削加工变形的影响,明确并优化了导致零件产生变形的主要因素。

关键词：多物理场耦合航空齿轮薄辐板车削仿真变形控制

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外泌体在肝内胆管癌中的作用

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临床肝胆病杂志 2024年第1期40卷 181-186页

作者：唐晋元杨陈凤麟梁冬乐罗雨豪西南医科大学附属医院肿瘤科四川泸州646000 廊坊市人民医院肿瘤科河北廊坊065000

肝内胆管癌(ICC)是一种特殊类型的肝癌,其早期临床症状不典型,大多数患者初诊时已处于中晚期。由于缺乏有效的分子标志物和治疗手段,ICC患者5年生存率极低。外泌体是一种细胞分泌的囊泡,包含蛋白质、RNA、脂质等,是细胞间通讯的重要载... 详细信息

肝内胆管癌(ICC)是一种特殊类型的肝癌,其早期临床症状不典型,大多数患者初诊时已处于中晚期。由于缺乏有效的分子标志物和治疗手段,ICC患者5年生存率极低。外泌体是一种细胞分泌的囊泡,包含蛋白质、RNA、脂质等,是细胞间通讯的重要载体。近期研究显示外泌体在ICC发生发展过程中扮演重要角色,本文就外泌体在ICC中的诊断、治疗作用及其机制进行综述,并展望外泌体的治疗前景与潜在的临床应用。

关键词：胆管上皮癌外泌体诊断治疗学

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弧齿锥齿轮喷丸表面微观形貌仿真与试验验证

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机械传动 2024年第8期48卷 97-103页

作者：廖祥贵吴昊唐进元赵久越中国航发中传机械有限公司湖南长沙410200 中南大学极端服役性能精准制造全国重点实验室湖南长沙410083

喷丸强化工艺能在弧齿锥齿轮表面及次表面引入残余压应力场,提高其疲劳寿命;但工程应用中经常出现不适当的喷丸参数,导致齿轮表面粗糙度显著增加,影响了齿面制造质量。为了准确预测与调控喷丸后齿轮表面微观形貌及表面粗糙度,基于离散... 详细信息

喷丸强化工艺能在弧齿锥齿轮表面及次表面引入残余压应力场,提高其疲劳寿命;但工程应用中经常出现不适当的喷丸参数,导致齿轮表面粗糙度显著增加,影响了齿面制造质量。为了准确预测与调控喷丸后齿轮表面微观形貌及表面粗糙度,基于离散元和有限元耦合的方法,提出了一种弧齿锥齿轮齿面喷丸工艺仿真计算方法,表面粗糙度预测与实测误差在20%以内,表明仿真预测方法具有准确性。基于该方法,以某弧齿锥齿轮为研究对象,研究了不同喷丸工艺参数与喷丸后齿面微观形貌的关联规律。研究结果表明,①随着喷丸时间增加,齿面三维粗糙度Sa先显著增加后缓慢下降;②当喷丸时间为50 s时,在本文的工艺参数下能达到满覆盖率;③弹丸速度与弹丸直径对齿面粗糙度均有较大的影响,但弹丸直径的影响更为显著。研究工作为喷丸后弧齿锥齿轮表面的微观形貌准确数值模拟与预测提供了方法基础,为合理制定喷丸工艺参数提供了技术参考。

关键词：弧齿锥齿轮喷丸强化微观形貌离散元方法有限元方法

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Prediction and Minimization of the Heat Treatment Induced Distortion in 8620H Steel Gear:Simulation and Experimental Verification

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Chinese Journal of Mechanical Engineering 2022年第6期35卷 207-218页

作者： Wen Shao Mohan Yi jinyuan tang Siyuan Sun State Key Laboratory of High Performance Complex Manufacturing College of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083China

The considerable heat treatment induced runout value in the end face of the automobile main reducer gear is always dimensionally out of *** directly affects the dimensional accuracy,the grade of carburized and hardened gears,and the post-quenching manufacturing *** this study,three dimensional numerical models were developed to simulate the carburizing-quenching process of gear based on the multi-field coupling theory using DEFORM *** results indicated that the ununiform cooling rate of the gear caused by the asymmetry of the web structure would result in the ununiform distribution of martensite,leading to the large runout value at the end face of the ***,a novel method was proposed to minimize the heat treatment induced runout *** was found that the heat treatment induced runout value could be effectively controlled by the addition of a compensation ring and the support of a rod *** experiments showed that the average runout value of the gear end face before and after the proposed heat treatment method were about 0.023 mm and 0.059 mm respectively,which was in good agreement with the simulated *** novel approach proposed in this study led to a reduction of the gear runout value by 70.0%‒76.9%compared to that of the original heat treatment process,which may serve as a practical and economical way to predict and minimize the heat treatment induced distortion in drive gear.

关键词： Distortion Carburizing-quenching Numerical simulation Heat treatment 8620H steel gear

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A Comparative Study on Asperity Peak Modeling Methods

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Chinese Journal of Mechanical Engineering 2021年第4期34卷 137-150页

作者： Wei Zhou Daiyan Zhao jinyuan tang Jun Yi Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-Cut Material Hunan University of Science and TechnologyXiangtan 411201China State Key Laboratory of High Performance Complex Manufacturing Central South UniversityChangsha 410083China

The peak identification scheme based method(three-point definition)and the spectral moments based method(spectral moment approach)are both widely used for asperity peak modeling in *** discover the differences between the two methods,a great number of rough surface profile samples with various statistical distributions are first randomly generated using *** the distribution parameters of asperity peaks are calculated for the generated samples with both *** obtained results are compared and verified by *** variation rules of the differences between the two methods with statistical characteristics of rough surfaces are *** explain for the discovered differences,the assumptions by spectral moment approach that the joint distribution of surface height,slope and curvature is normal and that the height distribution of asperities is Gaussian,are *** results show that it is unreasonable to assume a joint normal distribution without inspecting the correlation pattern of[z],[z′]and[z′′],and that the height distribution of asperities is not exactly Gaussian before correlation length of rough surface increases to a certain extent,20 for instance.

关键词： Surface topography Roughness Surface analysis Asperity peak Random process model

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Evaluation of contact fatigue risk of a carburized gear considering gradients of mechanical properties

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Friction 2020年第6期8卷 1039-1050页

作者： Wei WANG Huaiju LIU Caichao ZHU jinyuan tang Chenxu JIANG State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400030China State Key Laboratory of High Performance Complex Manufacturing Central South UniversityChangsha 410083China College of Aerospace Engineering Chongqing UniversityChongqing 400044China

Carburized gears are widely used in geared machines such as wind *** fatigue problems occur in engineering practice,reducing reliabilities of *** fatigue failures are related to many factors,such as gradients of mechanical properties of the hardening *** this work,an elastic-plastic contact model of a carburized gear is developed based on the finite element method to evaluate contact fatigue failure risk,considering variations in hardness and *** Dang Van multiaxial equivalent stress is calculated via Python coding within the Abaqus *** gradient of yield strength along the depth from case to core is *** concept of local material fatigue failure risk is defined to evaluate the probability of pitting *** effects of design factors,such as the case hardening depth(CHD),surface hardness,and contact pressure on fatigue failure risk,are *** the CHD increases or the surface hardness decreases,the risk of deep spalling failure *** increase in surface hardness leads to a decreased risk of pitting failure,while the variation in CHD hardly affects the pitting failure risk.

关键词： carburized gear multiaxial stress hardness gradient pitting spalling

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New analytical model of elastic-plastic contact for three-dimensional rough surfaces considering interaction of asperities

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Friction 2022年第2期10卷 217-231页

作者： Yuqin WEN jinyuan tang Wei ZHOU Lin LI Caichao ZHU State Key L aboratory of High Performance Complex Manufacturing Central South University.Changsha 410083.China Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-Cut Material Hunan University of Science and TechnologyXiangtan 411201China State Key Laboratory of Mechanical Transmission Chongqing UniversityXiangtan 400044China

The contact calculation of three-dimensional real rough surfaces is the frontier field of tribology and surface *** this study,we consider the interaction and elastic-plastic deformation characteristics of asperities and further,propose an analytical contact calculation method for rough surfaces considering the interaction of *** on the watershed algorithm,the rough surface is segmented and the asperities are reconstructed into *** to the height relationship between the asperities,the definition of the deformation reference height of the matrix between each couple of asperities is ***,the calculation formula of the substrate deformation is provided according to the local contact pressure considering the elastic-plastic deformation of the asperity,and the contact state under a specific load is determined using the iterative correction *** results correspond with those of finite element numerical calculation and the study reveals the following:(1)compared with the results obtained without considering the asperity interaction,contact area,distance,and stiffness will be reduced by 6.6%,19.6%,and 49.5%,respectively,when the influence of asperity interaction is considered;(2)the interaction of the asperities has the greatest influence on the surface contact distance and *** the same load,the existence of asperity interaction will reduce the contact distance,area,and stiffness;(3)considering the interaction of the asperities,the higher asperity will bear more load,but it will simultaneously reduce the contact of the surrounding area and increase that of the distant *** calculation method proposed in this study has the advantages of high calculation efficiency and accuracy,thus,providing the calculation basis and method for subsequent studies on service performance of rough surfaces,such as the calculation of contact stiffness and fatigue performance analysis of rough surfaces.

关键词： calculation method contact analysis interaction of asperities rough surface

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Tribological behavior of coated spur gear pairs with tooth surface roughness

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Friction 2019年第2期7卷 117-128页

作者： Huaiju LIU Heli LIU Caichao ZHU Peitang WEI jinyuan tang State Key Laboratory of Mechanical Transmissions Chongqing University State Key Laboratory of High Performance Complex Manufacturing Central South University

Coating is an effective way to reduce friction and wear and to improve the contact-fatigue lives of gear components, which further guarantees a longer service life and better reliability of industrial machinery. The fact that the influence coefficient linking the tractions and stress components could not be expressed explicitly increases the difficulty of coated solids contact analysis. The complicated tribological behavior between tooth surfaces influenced by lubrication and surface roughness further adds difficulty to the coated gear pair contact problems. A numerical elastohydrodynamic lubricated(EHL) contact model of a coated gear pair is proposed by considering the coupled effects of gear kinematics, coating properties, lubrication, and surface roughness. The frequency response function and the discrete convolute, fast Fourier transformation(DC-FFT) method are combined to calculate the surface deformation and the subsurface stress fields at each meshing position along the line of action(LOA). The Ree-Eyring fluid is assumed to incorporate the non-Newtonian effect, which is represented in the generalized Reynolds equation. Influences of the ratio between the Young's modulus of the coating and the substrate on the contact performance, such as pressure, film thickness, tooth friction coefficient, and subsurface stress field, are studied. The effect of the root mean square(RMS) value of the tooth surface roughness is studied by introducing the roughness data, deterministically measured by an optical profiler.

关键词： coating gear elastohydrodynamic lubrication (EHL) surface roughness

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