共查询到20条相似文献,搜索用时 187 毫秒
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针对目前金属切削仿真存在的精度问题,提炼了典型数值仿真算法及其耦合过程的“平衡”本质问题,揭示了典型数值仿真算法中产生温度—应力耦合以及温度—热物理属性耦合的本质原因。建立了影响Fe-Cr-Ni不锈钢切削仿真精度的3个仿真模型,包括本构模型、热物理属性模型和摩擦模型,并进行正交切削试验验证了仿真模型的准确性。同时,进行切削仿真试验,利用仿真结果分别说明了本构模型、热物理属性模型和摩擦模型对仿真结果的显著影响,分析了仿真过程中分别由本构模型以及热物理属性模型驱动的温度—应力耦合以及温度—热物理属性耦合作用,并依据两个耦合作用讨论了切削过程的鲁棒性。 相似文献
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高强度钢板热成形热、力、相变数值模拟分析 总被引:3,自引:0,他引:3
在已建立的高强度钢板热成形热、力、相变多场耦合本构模型和板料、水冷模具相互耦合的接触热传导模型基础上,基于自主开发的商业化金属成形CAE软件KMAS(King-Mesh analysis system)构建热成形热、力、相变耦合的非线性、大变形静力显式数值模拟模块。对典型U形高强度钢板的热成形过程进行数值模拟分析;计算板料与模具相互耦合的温度场变化规律,并将钢板组织相变释放的潜热考虑其中;将温度场计算结果引入热成形热、力、相变多场耦合的本构方程和静力显式有限元列式中,计算钢板等效应力和组织相变分布变化规律。通过钢板温度场以及马氏体转变量数值模拟结果与试验结果的一致性对比,验证建立的多场耦合本构模型和KMAS热成形仿真模块的正确性和有效性。 相似文献
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在已建立的高强度钢板热成形热、力、相变多场耦合本构模型和板料、水冷模具相互耦合的接触热传导模型基础上,基于自主开发的商业化金属成形CAE软件KMAS(King-Mesh analysis system)构建热成形热、力、相变耦合的非线性、大变形静力显式数值模拟模块.对典型U形高强度钢板的热成形过程进行数值模拟分析;计算板料与模具相互耦合的温度场变化规律,并将钢板组织相变释放的潜热考虑其中;将温度场计算结果引入热成形热、力、相变多场耦合的本构方程和静力显式有限元列式中,计算钢板等效应力和组织相变分布变化规律.通过钢板温度场以及马氏体转变量数值模拟结果与试验结果的一致性对比,验证建立的多场耦合本构模型和KMAS热成形仿真模块的正确性和有效性. 相似文献
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基于MARC平台的连续铸轧热力耦合分析 总被引:8,自引:1,他引:8
综合考虑辊套与铸轧板的弹塑性变形对温度场和应力场的影响,建立了铝带坯双辊连续铸轧过程的二维动态热力耦合计算模型;通过热模拟试验得出了纯铝高温流变本构关系和接触热阻计算模型;在MARC有限元分析软件平台上开发了粘塑性材料本构用户子程序URPFLO.F和接触表面传热系数用户子程序UHTCON.F;采用更新的拉格朗日方法(UL法)进行分析,得出铝带坯连续铸轧过程温度场和应力场的分布。实例计算表明,所得结果与实测结果相吻合,模型和子程序能够很好地应用于连续铸轧过程的计算与研究。 相似文献
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Yong Heack Kang Nam Jin Kim Byung Ki Hur Chong Bo Kim 《Journal of Mechanical Science and Technology》2002,16(3):344-353
A reliable computational heat transfer model has been investigated to define the heat transfer characteristics of a spray column direct contact heat exchanger, which is often utilized in the process involving counterflows for heat and mass transfer operations. Most of the previous studies investigated are one-dimensional unsteady solutions based on rather fragmentary experimental data. Development of a multidimensional numerical model and a computational algorithm are essential to analyze the inherent multidimensional characteristics of a direct contact heat exchanger. The present study has been carried out numerically and establishes a solid simulation algorithm for the operation of a direct contact heat exchanger. Operational and system parameters such as the speed and direction of working fluid droplets at the injection point, and the effects of aspect ratio and void fraction of continuous fluid are examined thoroughly as well to assess their influence on the performance of a spray column. 相似文献
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Some advances and applications in quadratic programming method for numerical modeling of elastoplastic contact problems 总被引:2,自引:0,他引:2
H.W. Zhang W.X. Zhong C.H. Wu A.H. Liao 《International Journal of Mechanical Sciences》2006,48(2):176-189
This paper reviews briefly some advances and applications in parametric quadratic programming (PQP) method for numerical modeling of elastoplastic contact problems. The parametric variational principle (PVP) and the corresponding finite element model for numerical simulation of 3D elastoplastic frictional contact problems with isotropic/anisotropic (orthotropic) friction law are presented. The finite element software JIFEX is then developed with the application-oriented concept for nonlinear analysis of complex structures in general purposed engineering. Some typical engineering applications such as compressor impeller and the railway wheel/rail contact analysis are shown to illustrate the potential of the software developed. 相似文献
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The thermal contact conductance problem is an important issue in studying the heat transfer of engineering surfaces,which has been widely studied since last few decades,and for predicting which many theoretical models have been established.However,the models which have been existed are lack of objectivity due to that they are mostly studied based on the statistical methodology characterization for rough surfaces and simple partition for the deformation formats of contact asperity.In this paper,a fractal prediction model is developed for the thermal contact conductance between two rough surfaces based on the rough surface being described by three-dimensional Weierstrass and Mandelbrot fractal function and assuming that there are three kinds of asperity deformation modes:elastic,elastoplastic and fully plastic.Influences of contact load and contact area as well as fractal parameters and material properties on the thermal contact conductance are investigated by using the presented model.The investigation results show that the thermal contact conductance increases with the increasing of the contact load and contact area.The larger the fractal dimension,or the smaller the fractal roughness,the larger the thermal contact conductance is.The thermal contact conductance increases with decreasing the ratio of Young’s elastic modulus to the microhardness.The results obtained indicate that the proposed model can effectively predict the thermal contact conductance at the interface,which provide certain reference to the further study on the issue of heat transfer between contact surfaces. 相似文献
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高速干切滚齿工艺消除了切削油/液的使用,是一种绿色高效的齿轮制造工艺。切削热伴随着高速干切滚齿工艺全过程且区别于传统湿式滚切工艺,是造成干切滚刀磨损和机床热变形的重要因素,直接影响制造成本和加工精度。根据干切滚刀周期性断续传热特性,综合考虑切削热在切屑、工件、干切滚刀、冷却介质以及滚齿机床加工空间的传递规律,提出将高速干切滚齿工艺系统切削热的发生与传递全过程划分为三个阶段的研究思想,从关系模型和热传递方程两个层面建立了高速干切滚齿工艺系统切削热全过程传热模型,包括切削接触界面热传递、切削区域热传递和机床加工空间热传递三个阶段的模型,然后基于工艺仿真试验对所建模型进行了应用研究,揭示了高速干切滚齿工艺系统的切削热在工件、干切滚刀、切屑中的动态变化规律,最后通过试验验证了模型的有效性。 相似文献
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P. M. M. Vila Real C. A. M. Oliveira J. T. Barbosa 《International Journal of Mechanical Sciences》2004,46(2):245-261
The finite element method is used to model the thermomechanical behaviour of ductile cast iron using metallic moulds. Heat conduction is assumed for the heat transfer analysis and an elasto-viscoplastic model is employed to predict the development of thermal stresses and strains. Special finite elements with coincident nodes are used to model the heat transfer and the mechanical contact at the metal–mould interface. The local heat transfer coefficient between the casting and the mould may be dependent on the air-gap formation. The latent heat evolution effect is modelled by the use of the enthalpy method. An iterative procedure is required to take into account the material and the contact non-linearity. A real casting has been modelled and numerical results are compared with the experimental measurements. 相似文献
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粗糙表面分形接触模型的研究进展 总被引:4,自引:0,他引:4
工程表面具有分形特征,利用分形参数对表面形貌进行表征不受仪器分辨率和取样长度的影响。2个粗糙表面之间的接触行为对摩擦、磨损、润滑、密封和传热等均有着重要的影响,因而一直是摩擦学研究的重要课题之一。基于表面的分形特性而建立的接触模型,可使表面接触的分析结果具有确定性和唯一性。介绍分形表面形貌的Weierstrass-Mandelbrot函数生成方法并给出利用MATLAB程序生成的分形曲线和曲面,分析和评述近二十年来分形接触模型中单个微凸体的接触行为、接触面积分布与真实接触面积、接触变形方式与接触载荷以及总的真实接触面积与接触载荷之间的关系等方面的研究情况,并简单列举分形接触模型在机械学科中的应用情况。指出结合分形理论对表面接触行为进行研究是接触理论发展的必然趋势,为摩擦学研究提供新的思路。 相似文献
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针对角接触球轴承在高速运转时因温度过高而导致失效的问题,对其热特性进行了研究。在研究中,建立角接触球轴承的有限元模型,应用热力学理论计算轴承的生热率和对流换热系数,进行热特性有限元分析,得到角接触球轴承在2000 r/min转速时的温度场。所做研究为通过润滑冷却系统控制角接触球轴承温升提供了技术参考。 相似文献
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《Wear》1987,119(1):63-76
Two versions of the principle of minimum potential energy for the frictionless adhesive contact between a smooth-surfaced elastic and a smooth-surfaced rigid body are set up. The non-variational first-order equalities equivalent to the variational principles are given, as well as a condition for stability. They lead to the conclusion that in the case of isotropy the intensity of the inverse square root singularity of the surface traction at the edge of contact is a constant composed of the material constants of the bodies. This property appears to be a powerful tool in solving special problems, notably in the case of the Hertz problem where it is shown that, except in the axisymmetric case, the contact area is not elliptic.Although the theory has been set up for the contact of an elastic body with a rigid body, the theory is easily extended to cover the contact of two elastic bodies as well. 相似文献
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J. M. P. Martins D. M. Neto J. L. Alves M. C. Oliveira L. F. Menezes 《The International Journal of Advanced Manufacturing Technology》2016,87(5-8):1797-1811
Heat flow across the interface of solid bodies in contact is an important aspect in several engineering applications. This work presents a finite element model for the analysis of thermal contact, which takes into account the effect of contact pressure and gap dimension in the heat flow across the interface between two bodies. Additionally, the frictional heat generation is also addressed, which is dictated by the contact forces predicted by the mechanical problem. The frictional contact problem and thermal problem are formulated in the frame of the finite element method. A new law is proposed to define the interfacial heat transfer coefficient (IHTC) as a function of the contact pressure and gap distance, enabling a smooth transition between two contact status (gap and contact). The staggered scheme used as coupling strategy to solve the thermomechanical problem is briefly presented. Four numerical examples are presented to validate the finite element model and highlight the importance of the proposed law on the predicted temperature. 相似文献
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恒热流加热条件下烧蚀过程的解 总被引:1,自引:0,他引:1
对恒热流加热条件下物体表面的烧蚀过程进行近似理论分析计算.烧蚀过程中的烧蚀界面位置随时间移动,其位置未知且是解的-部份,在移动的界面上须满足能量平衡条件.将烧蚀过程分为物体的预热使加热表面达到熔解温度阶段和开始烧蚀阶段,分别对两阶段的温度场进行理论分析,利用移动界面上的能量平衡条件,建立烧蚀移动界面的运动控制方程.该方程是一阶非线性常微分方程,通过数值计算得到在不同热流条件下烧蚀界面的移动规律.利用该方程可方便地确定任意时刻的烧蚀进度,可为烧蚀过程的控制提供理论依据. 相似文献