共查询到20条相似文献,搜索用时 9 毫秒
1.
Jih-Hua Chin Shou-Der Sheu 《The International Journal of Advanced Manufacturing Technology》2007,32(3-4):229-237
Deep hole drilling has been studied mainly experimentally in the past. Recently, some theories using beam or column equations
have been proposed, which involved complicated mathematical efforts. This work analyzed deep hole drilling by a finite element
model (FEM). Results of modal analysis on the established FEM were compared with results from Euler beam equations. Further
analysis showed that the FEM could also predict straightness deviation as did the column equation. In addition, FEM could
analyze the effects of variable support distance which neither beam nor column equation could. Other analysis results are
also presented. The results in this study showed the strength and weakness of the FEM. 相似文献
2.
残余应力对航空整体结构件加工变形的影响分析 总被引:9,自引:0,他引:9
基于理论计算和有限元模拟,研究了毛坯的初始残余应力对大型整体结构件数控加工变形的影响,对单向 应力作用的矩形截面梁在剥层过程中的变形挠度值进行了求解。结果表明,理论解与有限元计算值是一致的。面 向工程应用,采用ABAQUS有限元软件模拟了残余应力对隔框类整体结构件加工变形的影响,并进行了试验验证。 有限元仿真结果与试验数值非常吻合。最后,根据工件加工变形的有限元模拟结果,提出了提高整体结构件制造 精度的工艺措施。 相似文献
3.
The shaft behavior of BTA deep hole drilling tool 总被引:1,自引:0,他引:1
Jih-Hua Chin Chi-Ti Hsieh Li-Wei Lee 《International Journal of Mechanical Sciences》1996,38(5):461-482
This paper is a study on the shaft behavior of BTA deep hole drilling tool. The dynamics of tool shaft are often taken to be that of a second order lumped mass system for other cutting processes. This simplification does not apply for deep hole drilling because of its shaft length and the fact of fluid coupling. This paper constructed the general equations of motion for the pipe-like fluid conveying tool shaft of deep hole drill. The proposed general equations can be reduced to different specific forms of former works. Solutions for lateral and longitudinal motions were given. Series of experiments were designed and performed. Comparisons between theoretical and experimental results confirmed the validity of the constructed equations. The studies disclosed build the knowledge about the tool shaft and pave the way for future research concerning the correlation between the tool shaft and cutting process taking place on the cutting head. 相似文献
4.
深孔镗削是提高深孔加工精度的一种方法,它能校正己有孔上的缺陷,如圆度误差、直线度误差,从而获得良好的几何精度和表面粗糙度。深孔镗削的加工方式、运动形式、镗刀的轨迹方程和对镗削的受力分析是深孔镗削加工中各不稳定因素的渊源,在深孔镗削过程中,运用合适的镗削方式可以减小切削系统的振动。针对多刃均布式深孔镗刀,在推镗和拉镗方式下进行受力分析,并利用PRO/E建立镗杆几何模型并生成中性几何文件,通过ANSYS有限元法,计算出推镗和拉镗时镗杆产生的挠度以及最大应力应变曲线,将二者结果进行比较,证明在细长管时拉镗加工的优势。 相似文献
5.
Compared with grinding, hard turning may induce a relatively deep compressive residual stress. However, the interactions between the residual stress profile and applied load and their effects on rolling contact stresses and strains are poorly understood, and are difficult to measure using the current experimental techniques due to the small-scale of the phenomena. A new 2-D finite element simulation model of bearing rolling contact has been developed, for the first time, to incorporate the machining-induced residual stress profile instead of only surface residual stresses. Three cases using the simulation model were assessed: (a) measured residual stress by hard turning, (b) measured residual stress by grinding, and (c) free of residual stress. It was found that distinct residual stress patterns hardly affect neither the magnitudes nor the locations of peak stresses and strains below the surface. However, they have a significant influence on surface deformations. The slope and depth of a compressive residual stress profile are key factors for rolling contact fatigue damage, which was substantiated by the available experimental data. Equivalent plastic strain could be a parameter to characterize the relative fatigue damage. The magnitudes of machining-induced residual stress are reduced in rolling contact. The predicted residual stress pattern and magnitude agree with the test data in general. In addition, rolling contact is more sensitive to normal load and residual stress pattern than tangential load. 相似文献
6.
《Measurement》2014
A deep hole or oblique hole diameter measuring system was introduced, a cylindrical capacitive probe with effective measurement electrode was adopted to measure the diameter by measuring the clearance between the probe electrode and the measured hole, and it has no measurement force by measuring in non-contact mode. And then, we obtain the precision diameter measurement system for straight holes. By using the measurement system in oblique hole, we can see that with the increase in the hole depth, the measurement results are basically approaching stable value. 相似文献
7.
A thermo-elastic–viscoplastic model using explicit finite element code Abaqus was developed to investigate the effect of sequential cuts and tool–chip friction on residual stresses in a machined layer. Chip formation, cutting forces and temperature were also examined in the sequential cuts. The affected layer from the first cut slightly changes the chip thickness, cutting forces, residual strain and temperature of the machined layer, but significantly affects the residual stress distribution produced by the second cut. Residual stress is sensitive to friction condition of the tool–chip interface. Simulation results offer an insight into residual stresses induced in sequential cuts. Based on simulation results, characteristics of residual stress distribution can be controlled by optimizing the second cut. 相似文献
8.
Measurement of residual stress in thick section composite laminates using the deep-hole method 总被引:2,自引:0,他引:2
M.G. Bateman O.H. Miller T.J. Palmer C.E.P. Breen E.J. Kingston D.J. Smith M.J. Pavier 《International Journal of Mechanical Sciences》2005,47(11):1718-1739
The deep-hole method is a method of measuring residual stress in large metallic components. In this paper, an extension to the deep-hole method is described to allow the residual stresses in thick section composite laminated plates to be evaluated. The method involves first drilling a small hole through the laminate perpendicular to the surface. The material around the hole is then machined away, resulting in a change in diameter of the hole due to the release of residual stress. This change in diameter is measured and used to calculate the residual stress. The calculation requires the evaluation of coefficients that depend on the properties of the composite. In this work, the finite element method is used to evaluate these coefficients. Using this method, the residual stresses in a 22 mm thick carbon/epoxy composite plate are measured and reported. 相似文献
9.
为满足多元化需求的用户对数控深孔加工机床的个性化要求,提出了一种基于知识重用的数控深孔加工机的快速设计方法。选用规则推理(RBR)与实例推理(CBR)两种方式相结合的混合推理技术进行数控深孔加工机床知识重用的研究。基于知识重用理论,根据数控深孔加工机床结构和功能的设计要求对其进行模块划分,建立数控深孔加工机床模型库。使用Visual Basic 6.0(VB)对Solid Works 2010进行二次开发,选择Access为数据库,研究快速设计系统,实现数控深孔加工机床快速化设计。 相似文献
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The state of a surface region after machining is definitely affected by cutting parameters, such as cutting speed, feed rate, tool nose radius, tool rake angle and the presence of a cutting fluid, which plays a major role in determining friction at the tool–chip interface. The aim of the present study is to develop a finite element model based on the general-purpose nonlinear finite element code MSC.Marc by MSC.Software Corporation. This software is capable of simulating the cutting process of low-pressure turbine disks of aircraft jet engines from its very beginning to steady-state conditions. Basically, the present analysis is a coupled thermo-mechanical dynamic-transient problem, based on the update Lagrangian formulation; no pre-defined path is given for the separation of the chip from the workpiece, since material deformation occurs as a continuous indentation performed by the rigid tool. In addition to the cutting parameters, the main inputs in this analysis are material constitutive data, the friction coefficient at the toolchip interface and the cutting tool temperature. All the relevant variables, like stresses, strains, temperatures, chip shape and residual stresses, are predicted in a wide range of cutting conditions. The results from the model are compared to some basic theories of metal cutting and to an experimental study, concerning orthogonal cutting of steel AISI 316L. Concerning the specific case of turning process of nickel alloy Inconel 718 low-pressure turbine disks, the calculated residual stress are compared to experimental measurements from real machined disks. 相似文献
14.
在分析难加工材料切削特性的基础上,针对高温镍基合金的深孔加工,设计一种在普通车床上使用麻花钻头进行深孔加工的工艺装备和工艺方法,提高了工作效率,并取得了良好的效果。 相似文献
15.
残余应力应变释放系数的有限元分析 总被引:1,自引:1,他引:0
通过建立16Mn残余应力盲孔法有限元分析模型,模拟出孔边应力、应变的变化情况.揭示了残余应力引起的孔边应力、应变变化情况与应变释放系数A、B值之间的关系,并用孔边应力、应变的有限元运算结果计算出A、B值.通过应变计中点应变法、应变计中点应力法和平均应变法三种方法去标定和修正应变释放系数,通过对三种方法的比较表明,三种方法的计算结果与实验结果相符.且计算精度较高.证实了残余应力有限元模拟的准确性和A、B值标定和修正方法的多样性. 相似文献
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振动切削深孔加工初始偏差对孔直线度误差的影响 总被引:3,自引:0,他引:3
构建了振动切削深孔加工钻杆在轴向振动、振动切削力和切削液流体力影响下的多跨动力学有限元模型。引入自由模态综合技术,将钻杆线性自由度的特征模态进行缩减,仅保留具有非线性动力特征的模态,从而可有效降低耦合系统自由度数,减小计算量。利用该缩减后的模型,研究了辅助支撑位置和加工深度与孔直线度误差的作用关系,获得了孔直线度随初始偏差量变化的规律,为大跨度振动切削深孔加工机床的精度设计和加工误差分析提供了依据。通过试验与数值计算结果的对比,验证了所提出方法的有效性与准确性。 相似文献
18.
针对不锈钢、钛合金材料的深孔加工问题 ,分析了难加工材料的切削特性。从刀具设计及工艺方面 ,对高效深孔钻削进行了研究 ,并实际进行了切削试验 ,取得了较为满意的加工效果 相似文献
19.
深孔钻削过程中的超声监测系统 总被引:1,自引:0,他引:1
由于深孔在封闭或半封闭的状况下进行,钻头的走偏情况无法直接观察,以致于无法保证产品的加工质量,采用工控机、PLC和超声检测技术相结合,设计深孔在线超声监测系统,根据壁厚可以实时检测刀具的走偏情况,为深孔加工提供重要理论依据。 相似文献
20.
孔挤压强化可以显著提高机械连接的疲劳强度。采用有限元方法建立了孔挤压强化轴对称模型,得到了孔壁残余应力分布状态,建立了孔壁残余应力和孔径、板件厚度、挤压强化过盈量等工艺参数之间的关系曲线。结果表明,周向残余应力和孔径、挤压强化过盈量之间为对数关系,和板件厚度之间为线性关系;径向残余应力和孔径、挤压强化过盈量之间为对数关系,和板厚(以2.5mm为分界线)之间为线性关系,为孔挤压强化效果的定量化认识奠定了基础。 相似文献