考虑表面粗糙度及摩擦热的冷挤压模具磨损模型研究

基于Archard磨损模型,提出了考虑表面粗糙度及摩擦热的修正Archard冷挤压模具磨损模型,对DEFORM 3D V6.1进行二次开发,将该修正的磨损模型嵌入有限元软件模拟真实冷挤压成形过程,进行了挤压过程中冲头及凹模的磨损分析,得到了冲头及凹模磨损最严重的区域。通过对比分析,研究了模具表面形貌、摩擦热及相对滑动速度对模具磨损量的影响,计算结果表明,使用修正的磨损模型预测模具寿命与试验结论具有较好的一致性。该考虑表面粗糙度及摩擦热的修正Archard冷挤压模具磨损模型,能较好地预测冷挤压模具磨损的情况,有利于更好地预测冷挤压模具使用寿命及失效时间。     

金属热成形中考虑界面摩擦及传热的模具磨损模型研究

基于Archard磨损模型,提出了考虑接触面摩擦及传热的修正Archard磨损模型,对DEFORM 3D V6.1进行二次开发,将该修正的磨损模型嵌入有限元软件模拟真实挤压成形过程,分别在坯料的初始温度、模具的预热温度、接触界面传热效应、成形速度等不同条件下对热挤压模具的磨损量进行计算,结果表明,该修正Archard磨损模型能较好地预测热成形模具磨损情况、模具失效及模具寿命。     

基于静态间隙杆模型的曲柄滑块机构磨损分析

磨损是导致机械设备和机械零部件失效的主要原因之一,磨损与系统动力学响应的耦合对机构的性能均有重要影响。基于一种转动副反力的简化求解模型,进行了一系列的参数研究。结合达朗贝尔原理对曲柄滑块机构进行动力学建模,利用Winkler弹性地基模型获取界面的接触压力分布,使用Archard模型计算间隙副的磨损深度,建立了含间隙曲柄滑块机构的磨损与动力学耦合分析框架;通过与有限元(FEM)方法的比较发现,该磨损计算耦合模型不但具有相当的求解精度,而且在计算效率方面有质的提升。     

涂层导轨

本文在机床导轨的修复方面和提高机床导轨表面耐磨性能措施上,提出了一种“涂层导轨”工艺方法。它与普通机床导轨相比,具有含油性能高、耐磨耐腐性能好,适用于机床导轨局部磨损和划伤拉毛部位的修复、热变形影响也很小和技术经济效果好等特点。“等量磨损涂层导轨”是国内外从未提出的一种新的“涂层导轨”方法。采用此方法后,将大大地提高了机床导轨精度的保持性和导轨的使用寿命。本文还较为详细地介绍了“涂层导轨”的等离子喷涂工艺和“涂层导轨”的磨削加工工艺,同时还模拟机床导轨在实际使用过程中的磨损状况,进行了耐磨性能试验,其结果表明:“涂层导轨”的耐磨性能比普通导轨要提高一倍,进一步论证了“徐层导轨”的优越性。     

精冲模具磨损及对制件棱边质量的影响

基于精密冲裁的加工过程,选用DEFORM-2D有限元软件建立出其精密冲裁模型,利用Archard磨损理论对冲裁模具的磨损量等进行了预测,并采用简化刃口与磨损刃口两种形式对精密冲裁进行模拟,系统地揭示出模具特征点上的磨损深度值、制件棱边质量的变化,以及不同刃口磨损状态下板料等效应变、静水应力分布的变化规律.对进一步规范模具更换周期,进而优化模具结构具有重要意义.     

基于Archard磨损理论的滑动导轨磨损率预测模型研究

以机床滑动导轨副典型工况下的载荷和速度为变量因素,采用正交实验设计方法,进行销盘磨损实验,研究滑动导轨副在干摩擦条件下的磨损规律。参照经典的Archard磨损公式对实验数据进行回归并修正,得出相应的磨损率的回归公式。将该回归公式和Archard公式计算结果与实验数据进行对比,得出该回归公式能更好地预测导轨副的磨损率。     

销-盘试验的热-应力-磨损耦合模拟研究

销-盘磨损试验涉及复杂的热-应力-磨损耦合现象。基于广义Archard磨损模型和商用有限元软件ABAQUS,开发模拟销-盘磨损试验过程中热-应力-磨损耦合模拟分析的顺序耦合方法。分析销-盘试验的瞬态温度场,将温度场作为热载荷分析摩擦副的应力-磨损耦合问题;分析过程中考虑温度对摩擦副材料的力学和热学性能的影响以及广义Archard磨损系数和摩擦因数对温度和接触压力的依赖性。热传导分析考虑摩擦生热、销-盘接触传热、各个表面与空气之间的强制对流换热、自然对流换热以及热辐射。将该方法用于销-盘磨损试验的模拟,得到温度场、接触压力和磨损量的演变过程,揭示温度场对接触和磨损的影响规律,仿真结果与试验结果吻合良好。     

机床导轨结合部的有限元模型

基于结合面特性参数，提出了机床导轨结合部特性仿真分析的有限元方法，通过该方法可以建立机床整机性能分析的有限元模型。给出了导轨结合部上反映界面连接特性的六结点接触单元的刚度矩阵，并将其与通过实验获得的结合面特性参数联系起来，通过实例建立了机床整机分析模型。整机刚度的实验结果与计算结果的比较，证实了该方法的有效性。     

基于修正Archard理论的螺旋锥齿轮锻造模具寿命预测

基于修正的Archard理论,采用弹塑性有限元模型对螺旋锥齿轮热锻成形的模具磨损进行了模拟仿真,分别从齿模齿顶的过渡圆弧半径、模具热处理硬度、模具的预热温度以及锻造成形速度四个方面对模具易磨损位置的磨损量进行计算,采用正交试验优化设计方法分析各工艺因素对模具寿命的影响规律,确定最优的工艺参数进行锻造试验。试验结果表明,使用提出的预测模具寿命的方法估算的模具寿命与试验结论具有较好的一致性。     

微动工况下柱面不同因素对平面磨损显著性的分析

为了研究二维柱面不同参数对平面磨损形貌的影响,基于改进的Archard磨损方程,建立二维柱面—平面微动磨损模型,并通过对比Hertz接触理论,验证了有限元模型的正确性。运用正交试验技术设计试验方案,对在不同因素下平面的磨损轮廓进行了数值模拟,并分别从平面的磨损宽度和磨损深度分析了柱面半径、柱面材料弹性模量、泊松比三个参数对平面磨损轮廓的影响。对平面磨损轮廓的影响因素显著性分析表明:柱面材料的弹性模量最大,柱面半径次之,柱面材料的泊松比最小。     

Statistical investigation of die wear in metal extrusion processes

The aim of this paper is the statistical process control analysis of the tool wear evolution during metal extrusion process for better understanding the principal causes that generate the variability of such a complex phenomenon. The wear prediction is carried out using finite element simulation including the Archard wear model. The tool wear modeling is presented briefly as well as the response surface methodology. The study is based on the application of the central composites designs and allows for the analysis of the response (wear) sensitivity of the tool. The statistical investigation of the process makes it possible to study the influence of each process parameter on the response sensitivity.     

涡旋压缩机动涡旋盘端面摩擦副多转速下磨损影响分析

针对涡旋压缩机工作过程中动涡旋盘端面在常见工况下因表面磨损过大导致气体泄漏问题,以某型号涡旋压缩机为研究对象,建立动涡旋盘端面摩擦副受力分析模型,分析作业过程中动涡旋盘端面受载荷变化情况;利用有限元数值模拟得到动涡旋盘在典型工况下不同转速时端面摩擦副动态接触应力变化云图,在端面磨损实验机上测得动涡旋盘常用材料QT400磨损系数,通过修正Archard磨损模型并结合有限元磨损仿真计算出在不同转速下QT400的磨损深度值,并根据材料PV值原理设计实验方案分析QT400的磨损机制。结果表明：动涡旋盘转速越快,接触应力值较大的区域磨损深度值越大：材料磨损机制主要为疲劳磨损,随着载荷增大磨损机制不断向黏着磨损转化,并伴随有少量的磨粒磨损,该研究对涡旋压缩机动涡旋盘结构改进具有一定的参考价值。     

基于动力学特性的挖掘机工作装置端面摩擦副间隙磨损机理研究

机械动力装备中常因为作业工况恶劣导致关节端面摩擦副间隙处磨损严重,为了探讨关节端面摩擦副间隙处作业过程中磨损变化行为及作用机理,以某型号挖掘机为例,基于动力学模拟分析两种典型工况下得到动臂关节处动态载荷数据基础上,利用有限元数值模拟技术并修正Archard磨损模型计算得出端面摩擦副间隙处磨损深度与磨损次数的关系,在端面磨损试验机上验证两种工况下关节间隙处耐磨垫片磨损变化过程,在扫描电镜下观察磨损后的表面形貌分析磨损作用机理。结果表明：两种工况下,磨损区域均为环形区域;偏载工况磨损主要与接触应力值大小和偏载角度有关,磨损过程中表面产生锥刺凹坑和交叉犁沟等,磨损机制由疲劳磨损向黏着磨损转化,同时伴随有少量的磨粒磨损;满载启动回转工况磨损主要与接触碰撞程度有关,磨损形式主要为黏着磨损与磨粒磨损。此分析方法对工程机械行业分析其它动力装备关节摩擦副和工程应用具有较好的参考价值。     

Numerical and experimental analyses of punch wear in the blanking of copper alloy thin sheet

This research on punch wear resulting from the blanking of copper alloy thin sheet has been conducted by means of experimental and numerical analyses. Firstly, the experimental method has consisted in measuring punch worn profiles from replicas, and secondly in obtaining the wear coefficient by using a specific tribometer. The numerical modelling of blanking process has been developed with the finite element method to compute the mechanical fields necessary to calculate wear. Thus, the Archard formulation for abrasive wear has been programmed to compute the wear depth and the resulting punch geometry. Finally the simulation results of wear prediction have been compared to experimental ones.     

花键微动磨损和损伤累积的耦合机制及寿命预测

渐开线花键联轴器在航空领域应用广泛，花键在复杂工况下往往达不到预期寿命，其中花键轴不对中对花键服役寿命产生较大影响。基于有限元方法建立了高效的花键三维仿真模型，分析内外花键轴偏斜0.3°时花键各齿载荷分布规律，基于Archard磨损模型计算接触区域各节点的磨损深度，并基于ABAQUS的UMESHMOTION子程序和Arbitrary Lagrangian-Eulerian技术更新网格，采用Brown-Miller和Smith-Watson-Topper临界平面准则充分考虑花键齿面和齿根区域的应力状态差异，并拟合花键循环寿命、最大磨损深度与磨损系数之间的关联规律，采用试验方法测试表面磨损形貌，验证模型的有效性，为花键联轴器的设计和校核提供指导依据。结果表明：磨损演化逐渐改变初始应力集中区域的几何形状，从而减少了应力集中效应，提高了花键剩余寿命。当磨损系数较大时，花键以磨损失效为主，当磨损系数较小时，花键以疲劳裂纹萌生失效为主。     

Finite element simulation and experimental validation of fretting wear

A finite element-based method is presented for simulating both the fretting wear and the evolution of fretting variables with number of wear cycles in a cylinder-on-flat fretting configuration for application to aeroengine transmission components. The method is based on a modified version of Archard’s equation and is implemented within a commercial finite element code. Fretting tests are employed to determine the coefficient of friction (COF) and the wear coefficient applicable to the contact configuration and loading conditions. The wear simulation technique is incremental in nature and the total simulation time has been minimised via mesh and increment size optimisation. The predicted wear profiles have been compared with profilometer measurements of fretting test scars.     

Study on microstructure wear reduction performance and life prediction of unfolding wheel

The unfolding wheel for testing steel ball is apt to wear. Manufacturing microstructure at its surface is a method to reduce wear. Firstly, friction and wear experiments were conducted with load and microstructure area as variables. The friction coefficients and wear mass of the specimens were measured. The friction and wear performance of the microstructure surface is studied by analyzing the data trend of friction coefficient and wear mass. Then, the mechanism on wear resistance of microstructure surface is analyzed. The mathematical model of wear is deduced based on the Archard wear model. The finite element simulations of wear of microstructure surface and smooth surface were conducted through ANSYS software respectively. Finally, the equation relationship between the unfolding wheel life and the number of wear is established by fitting the data from the simulation results using MATLAB. The predicted result shows that the unfolding wheel life of the microstructure surface is about 26.5 % longer than that of the smooth surface.

     

基于“差分”磨损模型的车削刀具磨损仿真预测研究

研究表明,切削过程中的刀具磨损与刀面温度、刀/屑和刀/工界面的接触压力及相对滑动速度等切削过程变量有关,借助于有限元分析法可对这些切削过程变量进行仿真预测。基于“差分”磨损模型,提出了一种对切削过程中刀具轮廓磨损变化的预测方法,以硬质合金刀具切削AISI1045材料为例,介绍了该方法的原理和实施步骤,并对刀具前后刀面磨损的预测结果进行了试验验证,分析了预测结果与试验结果存在误差的原因。     

A study on die wear prediction for automobile panels stamping based on dynamic model

A new method for the prediction of die wear is established by studying the wear characteristics of automobile panels stamping dies. This method takes into account the contact pressure, the change of wear coefficient and material hardness along the thickness direction of the treatment layer. In order to obtain the relationship of wear coefficients with contact pressures and die hardness, a new kind of friction wear device is designed, which can simulate the wear environment of the blank-die interface in practical stamping. With this equipment, the dynamic wear coefficient considered the contact pressure and die hardness is obtained. Based on finite element software LS-DYNA, the prediction of die wear is achieved by using the dynamic coefficient and the continuously update of wear surface by means of the move of nodes. Based on wear at the feature line of an engine hood outer panel, the relationship between wear depth and stamping times is established. Comparing the prediction results of the new method and the traditional Archard method with the practical wear condition, the results show that the die life prediction method used in this study is closer to the practical condition; moreover, the accuracy is obviously higher than the traditional Archard method.