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管形件毛坯展开长度的探讨 总被引:1,自引:0,他引:1
通过一个弯曲零件的两种不同成形方法,说明弯曲件的毛坯展开长度不仅与弯曲半径R、材料厚度t、弯曲系数K有关,而且还与弯曲件的成形机理、弯曲方法、模具结构等诸因素有关。 相似文献
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为了提高管材自由弯曲成形技术的加工精度,针对平面弯管加工精度的成形参数开展精确预测工作,通过建立成形参数预测模型的方法使弯曲半径和弯曲角的实验值与设计值一致。首先,建立有限元仿真模型并通过管材加工实验进行修正,采用优化后的仿真模型建立预测的样本数据库,以有限元仿真得到的弯曲半径和弯曲角作为输入,以弯曲半径和弯曲角的设计值作为输出,结合BP神经网络和灰狼优化算法搭建成形参数预测模型。结果显示,改进后的PGWO-BP神经网络预测的弯曲半径和弯曲角的最大误差不超过2%,同时利用该预测模型开发了管材精确成形的工艺参数确定软件。 相似文献
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基于Ansys ls-dyna及Ls-prepost的对同曲率弯管连续二次弯曲进行数值模拟。利用Ansys ls-dy na软件,基于多弯曲模组,实现弯管的二次弯曲。在弯管的成形过程中,观察弯管的成形变化,包括弯管最外侧的减薄率及内侧的增厚率,同时在二次弯曲建模网格划分过程中,采用自适应网格技术,更加贴近实际地反映成形中应力应变的变化。在Ls-prepost中进行后处理,观察管壁减薄率等的变化。弯管的同曲率连续弯曲数值模拟结果有助于工程实际的应用,同时有限元方法有助于促进对弯管弯曲成形的研究。 相似文献
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板带金属不均匀压下面内弯曲成形机理的研究 总被引:7,自引:0,他引:7
本文建立了不均匀压下刚塑性硬化板带面内弯曲变形过程的上限模型。该模型可以用于预估板带面内弯曲半径,预选成形参数。此外还以LF21M及L4M冷轧板为试验材料进行了试验研究,试验实测结果不仅有助于阐明该过程的成形机理,还可以检验所建立的数值模型的精度。 相似文献
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研究了多层微细通道平行流式换热器的绕弯成形过程。基于绕弯成形机理和LS-DYNA软件平台建立了多层换热器的有限元模型,并通过实验的方法,研究了换热器层数和弯曲力矩之间的关系及换热器和翅片的变形情况,验证了有限元模型的可靠性。利用验证过的有限元模型,分析了不同的翅片形状及弯曲半径对换热器成形质量的影响。研究结果表明,随着换热器层数的增加,弯曲力矩呈线性增加;对于不同形状的翅片,三角形翅片更适合微细通道平行流式换热器的弯曲成形;在一定范围内,较大弯曲半径更有利于换热器的弯曲成形。 相似文献
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A finite element algorithm is presented for simulating the mould filling process. The incompressible, Navier-Stokes equations are solved by the Galerkin finite element method. The metal front is tracked by the pseudo-concentration approach which is a variant of the volume of fluid (VOF) method. The finite element algorithms and the special techniques implemented to ensure that the predicted filling pattern is realistic are discussed. The proposed algorithm has been tested on a bench mark mould filling problem13 and the results demonstrate the ability of the finite element method to model such flow phenomena. Results presented for various Reynolds numbers throw light on the complexities involved and the factors to be considered while attempting to model mould filling problems realistically. 相似文献
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J. ChenK. Chandrashekhara C. MahimkarS.N. Lekakh V.L. Richards 《Journal of Materials Processing Technology》2011,211(2):245-255
Cold rolling is used to eliminate void defects in cast materials thus improving the material performance during service. A comprehensive procedure is developed using finite element analysis and neural network to predict the degree of void closure. A three-dimensional nonlinear dynamic finite element model was used to study the mechanism of void deformation. Experiments were conducted to investigate void closure during the cold flat rolling process. Experimental results are compared to the three-dimensional finite element predictions to validate the model. The void reduction predictions from finite element analysis are in good agreement with experimental findings. Plastic strain, principal stress distribution around the void and void reduction ratio are presented for various case studies. As finite element simulation is time-consuming, a back-propagation neural network model is also developed to predict void closure behavior. Based on the correlation analysis, the reduction in sheet thickness, the dimension of the void and the size of the rollers were selected as the inputs for the neural network. The neural network model was trained based on results obtained from finite element analysis for various simulation cases. The trained neural network model provides an accurate and efficient procedure to predict void closure behavior in cold rolling. 相似文献
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运用有限元方法研究了高温超导体的电磁响应特性。给出了基于磁场强度的高温超导体电磁响应特性公式体系,建立了二维有限元模型,并采用带状几何结构进行了模型的验证。还研究了不同几何结构超导体的交流响应和磁相互作用力。研究表明,本模型正确地反映了高温超导体的宏观电磁响应特性,并且具有较好的扩展性。 相似文献
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将广义模块化设计应用到液压机预应力机架的有限元分析中,提出了广义有限元模块和广义有限元模块接口的概念.阐述了ANSYS软件中有限元模块数据库的建立方法、有限元模块装配成整机分析模型的具体装配方法和预紧力载荷的模拟方法,用ANSYS参数化设计语言编制了组装有限元模块、预紧单元法施加预紧力和施加问隙导向约束的通用程序模块.最后以45 MN液压机预应力机架的有限元分析为例,详细说明了广义模块设计中分析环节的实施过程和此类液压机设计的注意事项,为同类机架的设计提供了参考和指导. 相似文献