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Elastic/crystalline viscoplastic finite element (FE) analyses were carried out to asses the drawability of three kinds of BCC steel sheets, such as mild steel, dual-phase steel and high-strength steel, in the cylindrical cup deep drawing processes. In this study, the crystal orientations were obtained by X-ray diffraction and orientation distribution function (ODF) analyses. The measured ODF results have revealed clearly different textures of sheets, featured by orientation fibers, skeleton lines and selected orientations in Euler angle coordinate space, which can be related to the plastic anisotropy. An orientation probability assignment method, which can be categorized as an inhomogenized material modeling, was used in this FE modeling. The orientations were determined from the measured ODF and assigned to FE integration points one by one. Numbers of integration points, which represent crystallites and can rotate individually, are employed to represent textures of the sheet metals for taking account of the initial and evolutional plastic anisotropy without introducing Taylor or Sachs homogenization assumption. The FE analyses showed how the fiber textures affect the strain localization and earing in the deep drawing operation. It was confirmed by comparison with experimental results that this FE code could predict the extreme strain localization and earing with good accuracy and assess the sheet drawability. 相似文献
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The conventional fracture mechanics parameters KIC and/or JIC are used as fracture toughness criteria necessary for the start of crack propagation under plane strain conditions. These criteria are defined only for small-scale yielding or infinitesimal deformation, though actual fractures involve large plastic deformation. Hence, measurement of fracture resistance during crack propagation is difficult with the conventional parameters.Estimating the mechanical conditions around the propagating crack tip is very useful for reducing damage during accidental fracture. Therefore, establishing a criterion for crack propagation with large-scale yielding is very important for not only science fields but also some industrial fields. For fractures with large-scale yielding, micro- or mesoscale damage processes in the crack tip vicinity have to be considered.In this study, Gurson's constitutive model for void occurrence and growth was introduced into the finite element method to discuss failure behavior in the crack tip vicinity. Fast crack propagation behavior under high-speed deformation was simulated using the moving finite element method based on the Delaunay automatic triangulation. The excellent far-field integral path independence of the T* integral was verified for pure mode I fast crack propagation and non-straight crack propagation under mixed mode conditions. The void growth conditions near the crack propagation path were evaluated. 相似文献
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基于ANSYS番茄翻秧机机架的有限元分析 总被引:5,自引:1,他引:4
番茄翻秧机是番茄收获机械化中的关键机构,番茄翻秧机机架的设计是整个机械的关键部件。用Pro/E建立了番茄翻秧机机架的实体模型,并利用有限元分析软件ANSYS10.0对机架进行三维有限元分析,获得了机架的变形特征及应力分布情况。在合理简化模型,正确加载与约束下,用大量的计算机处理的应力值进行比较,对方案进行优化并作出评价。 相似文献
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Junjie Ye Yumin He Xuefeng Chen Zhi Zhai Youming Wang Zhengjia He 《Mechanical Systems and Signal Processing》2010,24(2):379-393
In this paper, a new method is presented to identify crack location and size, which is based on stress intensity factor suitable for pipe structure and finite element method of second generation wavelets (SGW-FEM). Pipe structure is dispersed into a series of nested thin-walled pipes. By making use of stress intensity factor of the thin-walled pipe, a new calculation method of crack equivalent stiffness is proposed to solve the stress intensity factor of the pipe structure. On this basis, finite element method of second generation wavelets is used to establish the dynamic model of cracked pipe. Then we combine forward problem with inverse problem in order to establish quantitative identification method of the crack based on frequency change, which provides a non-destructive testing technology with vibration for the pipe structure. The efficiency of the proposed method is verified by experiments. 相似文献
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摩擦驱动系统中正压力的大小直接影响系统的位移分辨率,为了获得稳定的、连续可调的正压力,提出了一种新型的基于压电陶瓷驱动的柔性四杆型可调预压装置,可以得到(0~500)N的可计算机控制的正压力输出.并基于有限元分析的方法,系统地分析了铰链的各个几何参数对预压装置的静、动态特性的影响,对预压装置的设计参数进行了优化. 相似文献
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基于有限元的腰绳系统设计方法 总被引:1,自引:1,他引:1
腰绳是减小履带起重机起臂过程中臂架挠度的重要构件之一,根据这种柔性系统力学复杂性的分析,提出了基于有限元的腰绳系统设计方法,通过实例表明腰绳作用的有效性及方法的合理性. 相似文献
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Design of interference fits via finite element method 总被引:3,自引:0,他引:3
Studies of interference fits in ring gear-wheel connections show that the traditional design method based on thick-wall cylinder theory has some limitations. Application of the finite element method (FEM) for the three-dimensional stress analysis of interference fitted connections gives more complete and accurate results than the traditional method. An improved design method utilizes two safety factors, λs and λp, providing a new approach for evaluating the quality of interference fits. A tolerancing method utilizing the Imax and Imin curves provides a quantitative guideline for interference fit design. The selective assembly method combined with the FEM-based method for interference fit design provides an effective approach to achieve more reliable interference-fitted connections and more precise assembly with lower manufacturing cost. 相似文献
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基于有限单元法的热风阀阀体模态和谐响应分析 总被引:2,自引:1,他引:2
采用有限元分析软件ANSYS对热风阀阀体进行了模态分析和谐响应分析。给出了阀体前4阶的固有频率和振型,并得出了前四阶固有频率下激振力和动应力问的关系。该分析方法和结论为阀体的消除焊接残余应力振动时效工艺提供了理论依据。 相似文献
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This paper presents a finite element based methodology for obtaining pressure dependent friction laws from experimental tribometer tests on rubber-metal contacts. Tribometer tests are simulated for analyzing the area of contact and obtaining an approximation to the contact pressure distribution in the test. The proposed methodology will be applied to the evaluation of experimental results from tribometer tests run in flat on flat and flat on cylinder configurations, for which flat and cylindrical countermaterials have been produced with very similar surface morphologies and, therefore, theoretically the same pressure-dependent friction law. 相似文献
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基于虚拟样机与有限元技术的自卸车举升机构设计 总被引:3,自引:0,他引:3
运用虚拟样机技术对自卸车举升机构的位置布置进行设计,在完成对举升机构零部件的形位参数设计后,对举升机构零部件三角板进行受力分析,结合有限元技术,对三角板进行了最大载荷工况下的结构应力分析。验证举升机构零部件的设计合理,提出举升机构新的设计方法。 相似文献
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Experimental based finite element simulation of cold isostatic pressing of metal powders 总被引:3,自引:0,他引:3
M. Szanto W. Bier N. Frage S. Hartmann Z. Yosibash 《International Journal of Mechanical Sciences》2008,50(3):405-421
The present work addresses the various ingredients required for reliable finite element simulations of cold isostatic pressing (CIP) of metal powders. A plastic constitutive model for finite deformation is presented and implemented into an explicit finite element (FE) code. The FE implementation is verified so that numerical errors (both temporal and spatial errors) are kept under control. Thereafter, uniaxial die compaction experiments are performed required for determining the material parameters in the constitutive model. Subsequently they are applied for the simulation of a “complex” CIP process. The experimental observations of the complex CIP process were used to validate the overall method by comparing the FE results (final dimensions and average relative density) to the experimental observations. The numerical results (final dimensions and relative density) are in good agreement with the experimental observations. 相似文献
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Numerical analysis of projection welding on auto-body sheet metal using a coupled finite element method 总被引:1,自引:1,他引:0
W.-F. Zhu Z.-Q. Lin X.-M. Lai A.-H. Luo 《The International Journal of Advanced Manufacturing Technology》2006,28(1-2):45-52
A comprehensive finite element method employing a subroutine to link up submodules of commercial code ANSYS is proposed to
perform analysis of projection welding in quantitative detail. In order to solve the complexity due to dynamic changes in
heat and electrical current flow paths, as well as temperature-dependent material properties, information about contact interfaces
and the geometry of the projection areas have been taken into account. By updating parameter information among these submodules
in an incremental manner, a truly thermal-electrical-mechanical coupled numerical analysis is realized for projection welding
simulation. A case study of an automotive door assembly welding process is carried out and a series of experiments is conducted
to confirm the validity of the newly developed method. The agreement between the experimental and numerical results is satisfactory,
indicating that the incrementally coupled finite element method may be suitable for projection welding research. Finally,
future work to extend this method in optimizing projection welding process design is also presented. 相似文献
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S. H. Chung J. H. Lee H. S. Chung S. M. Hwang 《International Journal of Mechanical Sciences》2000,42(5):965
A new approach to process optimal design in non-steady forming of porous metals is presented. In this approach, the optimal design problem involving diverse objective functions and design variables is formulated on the basis of the finite element process model, and a derivative-based approach is adopted as the solution technique. The process model, the formulation for process optimal design, the schemes for the evaluation of the design sensitivity, and an iterative procedure for optimization are described in detail. The validity of the schemes for the evaluation of the design sensitivity is examined by performing a series of numerical tests. The capability of the proposed approach is demonstrated through application to a selected design problem. 相似文献