共查询到19条相似文献,搜索用时 531 毫秒
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基于有限元分析的二轴柔性滚弯过程影响因素的研究 总被引:2,自引:0,他引:2
利用弹性介质对钣金件进行二轴柔性滚弯成形是一种先进的钣金制造工艺,将弹性介质(聚氨酯橡胶)的冲压优势和传统滚弯原理结合,成为钣金成形领域的一个新的发展方向。本文利用有限元软件MARC建立二轴柔性滚弯过程的有限元分析模型,成功的模拟了板料滚弯成形及回弹的加工过程,对工件滚弯成形过程的主要影响因素进行了分析,给出了压入深度、柔性层厚度、刚性滚轴半径、材料性能与回弹后曲率半径的关系。分析结果表明,有限元模拟对滚弯过程的工艺参数选取有着一定的指导意义。 相似文献
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型材变曲率滚弯过程有限元模拟 总被引:2,自引:0,他引:2
采用大型有限元分析软件ANSYS建立了型材滚弯成形弹塑性有限元模型,成功地完成了型材变曲率滚弯过程的数值模拟,数值模拟结果与生产实际情况符合较好。利用有限元模型,分析了变曲率型材零件滚弯成形后的残余应力分布,研究了滚弯成形后型材剖面角度的变化,可以为实际生产过程中参数的选择和滚弯工装的设计提供有力的帮助。 相似文献
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《机械制造与自动化》2017,(5):42-44
柔性滚弯成形技术主要用于制造形状多样化、生产批量小的复杂薄壁曲面制件,广泛运用于飞机、船舶、火箭等运载工具。总结了柔性滚弯成形技术在国内外的研究现状,介绍了刚性辊滚压橡胶垫的单轴柔性滚弯成形技术;刚性辊和柔性辊相互作用或者双柔性辊相互作用的双轴柔性滚弯成形技术;可弯曲、可调节的三柔性辊相互作用的曲面连续成形技术。对新型工艺技术的基本原理以及工艺特点进行了分析和总结。 相似文献
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回弹是由工件在卸载后的弹性变形引起的。板料成形过程中为了控制成形件的最终形状,必须进行回弹设计优化。准确预测回弹对于板料成形过程的模具设计非常重要。降低回弹模拟结果与试验结果的偏差是设计过程中的难题。基于NUMISHEET’02的自由弯曲标准考题考虑板材与模具间的接触演变过程,建立了一个有限元模型来预测回弹。采用一个常规的优化方法对有限元分析中的材料和单元模型进行了分析,研究发现不同模型对回弹结果有较大影响。模拟结果与参考文献中的试验结果比较表明了模型的正确性和可行性。 相似文献
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回弹是空间弯管成形的主要成形缺陷。为了预测和补偿空间弯管成形中的回弹,通过编写用户幅值子程序(UAMP),将有限元法应用于空间弯管的成形和回弹分析,提出了一种从仿真结果中提取管材中心线的方法。通过圆柱螺线形弯管成形的仿真计算,建立了管材回弹前后中心轴线曲率、挠率的关系。提出了一种基于求解曲线基本方程的空间弯管模具型面补偿方法,论述了曲线几何补偿的数学依据。通过对曲率和挠率(均为非常值)曲线进行补偿计算和成形仿真,对该方法进行了验证。结果表明该方法能够有效补偿回弹误差,保证弯管精度。 相似文献
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Daniel Lepadatu Ridha Hambli Abdessamad Kobi Alain Barreau 《The International Journal of Advanced Manufacturing Technology》2005,27(1-2):40-47
The aim of this work includes the springback optimisation of bending processes using the concept of experimental design and
response surface methodology (RSM).
The optimisation method includes two phases. The first involves the objective function prediction using design of experiments
and response surface method, while the second is an optimisation process using a FORTRAN gradient algorithm.
Springback of sheet parts during bending processes is simulated using finite element model (FEM) including damage evolution
effects within the sheet. The numerical simulation of the damage evolution has been modelled by means of continuum damage
approach. The Lemaitre damage model, taking into account the influence of triaxiality, has been implemented into ABAQUS/Standard
code in order to predict the external fibres rupture evolution during the process and the material characteristics changes
after bending. The simulation included die corner radius and punch-die clearance as the main variables. 相似文献
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在平截面和平面弯曲等假设条件下,建立了可适用于纵向拼焊板V形小曲率自由弯曲回弹的解析预测模型。在自由弯曲卸载阶段,该模型引入了两母板间相互作用的弯矩,基于单一母板求解了拼焊板回弹后的弯曲角。利用解析模型分析了不同工艺参数对拼焊板V形自由弯曲力和回弹后弯曲角度的影响规律,确定了影响拼焊板V形自由弯曲力和卸载后回弹角的主要影响因素。 相似文献
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Stress and residual stress distributions in bending are important in calculating springback and loading capacity of a sheet-metal bending part. Great differences have been found in springback prediction with the same input (benchmark problems) among different researchers. In order to find out the root cause of these differences, stress and residual stress calculation methods in plane strain bending are briefly reviewed or developed. The influence of deformation theory and incremental theory, repeating bending, unbending and re-bending, cyclic material models and springback calculation methods on the stress or residual stress distributions are examined and shown to be large. This emphasizes the importance of careful selection of these variables in a simulation model in addition to other general input variables, such as material properties, tool geometry and friction condition. This fact also helps to explain the great differences among different research results, and presents a challenge to both the programmers and the users of finite element packages. 相似文献
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Ti-6Al-4V钛合金材料在弯曲成形过程中会产生较大的回弹,其弹性模量对回弹影响较大,但以往研究均未考虑材料塑性应变变化过程中弹性模量的变化。以Ti-6Al-4V钛合金为对象,进行了材料的单轴拉伸实验和循环加载-卸载实验,以揭示材料各向异性参数及材料弹性模量随塑性应变变化的规律,在此基础上建立了Ti-6Al-4V钛合金变弹性模量数学模型。基于YLD2000-2D屈服准则及变弹性模量和Mises各向同性两种不同的本构模型,对常温下Ti-6Al-4V钛合金板材的五点弯曲过程进行了数值模拟,为了验证数值模拟结果,进行了常温下Ti-6Al-4V板材的五点弯曲实验,结果显示,前者显著提高了Ti-6Al-4V钛合金弯曲回弹预测精度,预测精度相比后者提高了31.18%。 相似文献
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The Element Bending Group (EBG) method, previously introduced for two-dimensional (2-D) problems, was developed to introduce an approximate bending stiffness in 3-D membrane, static-implicit, rigid-viscoplastic FEM programs. Inter-element stiffness with respect to change in mesh curvature was evaluated by assuming a standard linear variation of engineering strain through the thickness, without adding degrees of freedom to a membrane model. A constant curvature was utilized for the EBG in the plane normal to the edge common to the two elements in order to calculate bending forces and stiffnesses. Patch tests were conducted to evaluate the performance of this new technique when applied to standard problems, and good accuracy was obtained. The technique was then evaluated in three case studies (each with significant bending deformation). The EBG technique was found to approximate the real bending stiffness, thus enhancing the stability of membrane models and allowing simulation of bending-sensitive configurations, at much reduced computation times compared to standard shell approaches. However, well-developed wrinkling and springback cannot be handled adequately by this method because of mesh-orientation dependence and approximate 3-D bending stiffness. 相似文献