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金属切削加工中航空铝合金板材的本构模型 总被引:4,自引:0,他引:4
针对金属切削加工中材料的高温度、高应变、高应变率数据难以获取,无法建立动态本构模型这一技术难题,提出基于有限元模拟和"单因素"流动应力公式计算的联合建模策略.由"单因素"流动应力公式反复计算与模拟应变率对应的流动应力,基于新的流动应力有限元模拟迭代的进行并追求模拟值与实验结果的一致,获取能反映切削材料力学性能的"三高"数据和流动应力数据.数据分析表明,应变率对流动应力具有强化作用,温度对流动应力具有弱化作用,稳态变形后,各应力-应变曲线都变为一条趋于与应变坐标轴平行的直线.根据影响规律选取Zerilli-Armstrong经验模型,采用非线性回归分析建立起航空铝合金板材在铣削加工中的动态本构模型.最后进行实验验证,证明了该本构模型的正确性. 相似文献
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为弥补现有航空钛合金切削加工本构模型研究的不足,提出基于正交切削理论的材料本构模型构建方法。根据正交切削理论建立剪切区内应力、应变、应变率、温度以及二维切削力的数学模型,开发以剪切区长度和厚度比值为迭代变量的建模技术,结合动态压缩力学性能实验(SHPB实验)和直角铣削实验,通过对各变形参数的数学求解,建立航空钛合金切削加工本构模型。在此基础上,进行材料本构模型的分析和实验验证。结果表明:航空钛合金材料在切削加工中具有明显的应变硬化特性、温度敏感特性和应变率敏感特性;钛合金随着应变率的增大,流动应力的增量逐渐减小,材料的应变率敏感性降低。 相似文献
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从细微晶粒层面考虑了跨晶界切削、切削颤振等问题,基于晶界硬化效应的霍尔-佩奇定律和常规金属切削本构模型,建立了一种包含材料晶粒平均粒径的微细切削本构模型。通过仿真和切削力试验,对模型的系数进行了修正。研究结果表明,晶粒平均粒径在0.07~0.20 mm时,晶界强化效应较为明显,当晶粒平均粒径超过0.20 mm时,微细切削本构模型对切削力的预测趋势逐渐趋近于常规金属切削本构模型。且随着晶粒平均粒径的增大,常规金属切削本构模型与微细切削本构模型的预测差值逐渐减小。试验数据与理论数据对比验证了微细切削本构模型的准确性。 相似文献
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镍铝青铜材料因具有较高的强度、耐磨损及优异的抗应力腐蚀特性而广泛用于螺旋桨的制造中。为了建立其在高应变率条件下的本构关系,提出一种切削加工过程中Johnson-Cook模型参数辨识的新方法。该方法综合了SHPB动态压缩实验、可预测切削力模型及直角切削实验。首先,根据SHPB实验得到镍铝青铜在不同应变率和温度下的真实流变应力-应变曲线;然后,建立关于预测流变应力和实验流变应力的目标函数,将SHPB实验辨识的本构参数作为初值,采用PSO算法反演得到最终的本构参数;最后,对可预测切削力模型和有限元仿真获得的切削力进行对比,验证了所辨识参数的准确性。 相似文献
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总结了金属增材制造材料本构模型的获取方法,从准静态试验、热压缩试验、动态试验、硬度等效及微观组织模拟5个方面归纳了金属增材制造材料本构模型获取的研究成果。在此基础上,分析了目前存在的问题,并对未来的发展方向进行了展望。结果表明,通过准静态力学试验、热压缩试验及动态力学试验获取的本构模型可以反映材料宏观的力学性能,但无法反映材料的非均质特性;硬度等效本构模型可以体现一定的非均质性,但准确性无法得到保证;基于微观组织的本构模型对材料的性能表征较为全面,但目前仍处在探索阶段。随着计算机技术和增减材复合制造技术的发展,开发具有一定物理意义、考虑增材成形材料微观组织分布的本构模型获取方法将是未来主要的发展方向。 相似文献
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This paper presents a unified mathematical model which allows the prediction of chatter stability for multiple machining operations with defined cutting edges. The normal and friction forces on the rake face are transformed to edge coordinates of the tool. The dynamic forces that contain vibrations between the tool and workpiece are transformed to machine tool coordinates with parameters that are set differently for each cutting operation and tool geometry. It is shown that the chatter stability can be predicted simultaneously for multiple cutting operations. The application of the model to single-point turning and multi-point milling is demonstrated with experimental results. 相似文献
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Analysis of the inverse identification of constitutive equations applied in orthogonal cutting process 总被引:1,自引:0,他引:1
J. Pujana P.J. Arrazola R. MSaoubi H. Chandrasekaran 《International Journal of Machine Tools and Manufacture》2007,47(14):2153-2161
Flow stress identification of work-piece materials for its use in machining operation simulation models has been long treated. The interest in defining the flow stress in an easy and fast way without using complicated dynamic characterization tests leads to analyse the inverse identification of flow stress employing cutting operations. This paper presents a revision of different aspects concerning the inverse algorithms applied to the primary shear zone (PSZ). It also presents a new approach for studying material's behaviour on the secondary shear zone (SSZ) where experimentally measured temperatures have been included in the inverse algorithm. Two steels, 42CrMo4 and 20NiCrMo5 are employed and finite element method (FEM) simulations are carried out in order to evaluate the usefulness of the calculated flow stress laws and proposed algorithm. 相似文献
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通过表面层理论和金属晶体塑性变形原理解释微细薄板材料在塑性变形中产生尺寸效应的内在机理。引入尺度参数,对经典的Hall-Petch公式进行修正,建立基于表面层模型理论的尺度依赖材料模型。利用所建立的材料模型分析微细薄板厚度及其晶粒尺寸对材料成形流动性能的影响。在晶粒尺寸一定的情况下,随着微细薄板厚度的减小,材料流动应力逐渐降低;晶粒尺寸越大的微细薄板,其流动变形的尺寸效应现象越明显。利用不同厚度的不锈钢和纯铜箔材的微细薄板拉伸真应力-应变曲线对所建立的材料模型进行验证,计算结果与实验结果比较吻合,验证了所建立的材料模型的合理性。 相似文献
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Takashi Matsumura Eiji Usui 《International Journal of Machine Tools and Manufacture》2010,50(5):467-473
The cutting force and the chip flow direction in peripheral milling are predicted by a predictive force model based on the minimum cutting energy. The chip flow model in milling is made by piling up the orthogonal cuttings in the planes containing the cutting velocities and the chip flow velocities. The cutting edges are divided into discrete segments and the shear plane cutting models are made on the segments in the chip flow model. In the peripheral milling, the shear plane in the cutting model cannot be completely made when the cutting point is near the workpiece surface. When the shear plane is restricted by the workpiece surface, the cutting energy is estimated taking into account the restricted length of the shear plane. The chip flow angle is determined so as to minimize the cutting energy. Then, the cutting force is predicted in the determined chip flow model corresponding to the workpiece shape. The cutting processes in the traverse and the contour millings are simulated as practical operations and the predicted cutting forces verified in comparison with the measured ones. Because the presented model determines the chip flow angle based on the cutting energy, the change in the chip flow angle can be predicted with the cutting model. 相似文献
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From the basic mechanics of orthogonal metal cutting toward the identification of the constitutive equation 总被引:1,自引:0,他引:1
N. Tounsi J. Vincenti A. Otho M. A. Elbestawi 《International Journal of Machine Tools and Manufacture》2002,42(12)
This paper proposes a methodology to identify the material coefficients of constitutive equation within the practical range of stress, strain, strain rate, and temperature encountered in metal cutting. This methodology is based on analytical modeling of the orthogonal cutting process in conjunction with orthogonal cutting experiments. The basic mechanics governing the primary shear zone have been re-evaluated for continuous chip formation process. The stress, strain, strain rate and temperature fields have been theoretically derived leading to the expressions of the effective stress, strain, strain rate, and temperature on the main shear plane. Orthogonal cutting experiments with different cutting conditions provide an evaluation of theses physical quantities. Applying the least-square approximation techniques to the resulting values yields an estimation of the material coefficients of the constitutive equation. This methodology has been applied for different materials. The good agreement between the resulting models and those obtained using the compressive split Hopkinson bar (CSHB), where available, demonstrates the effectiveness of this methodology. 相似文献
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Development of a thermomechanical cutting process model for machining process simulations 总被引:1,自引:0,他引:1
A thermomechanical model for cutting processes is presented. The deformation in the shear zone is represented using Johnson-Cook material model. The rake contact is modeled using sticking and sliding zones, and their lengths are also predicted. The parameters of the material model and the friction coefficient on the rake are directly identified from a few number of orthogonal cutting tests. The model can predict cutting forces, shear angle and stress, pressure distribution and contact lengths on the rake face and temperature distribution. The application of the model to common operations such as turning and multi-axis milling is also presented with experimental verification, and satisfactory results are obtained. 相似文献
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《Journal of Materials Processing Technology》2006,171(1):1-9
In this study, a thermal analysis model is developed to determine temperature distribution in orthogonal metal cutting using finite elements method. The model calculates the temperature distribution as a function of heat generation. The heat generation was introduced in the primary deformation zone, the secondary deformation zone and along the sliding frictional zone at the tool–chip interface, as well. The location and shapes of these zones was determined based on the literature work done so far and the model results. The temperature dependency of material properties was included in the model. A series of thermal simulations have been performed, and the value and location of maximum temperature have been determined for various cutting conditions. The comparison of the simulations with earlier works gave promising trend for the presented model. The thermal aspects of metal cutting as a result of the model findings were discussed. 相似文献
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《CIRP Annals》2019,68(1):273-276
The flow model in metal cutting is applied to cold forging for forming a H-shaped double cup by moving the bottom of an ironed cup to a predetermined position. In the proposed process, the cutting flow occurs between the internal corners of the upper cup and the lower cup and the tool pressure is lower than half of the plasticity coefficient of the cup material. Products are formed without defects when the ratio of the depth of cut to the bottom thickness of the cup is larger than the critical value related to the corner radius of the ironed cup. 相似文献