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在不同变形温度(275~350℃)和应变速率(5~25s~(-1))下,采用单道次大变形量(80%)轧制ZK60镁合金,研究了变形温度和应变速率对合金显微组织和拉伸性能的影响。结果表明:随着变形温度的升高和应变速率的增大,合金的再结晶体积分数增加;当变形温度不高于300℃时,随着应变速率的增大,再结晶晶粒尺寸先减小后增大,抗拉强度先增后降,伸长率增大;而当温度高于300℃时,再结晶晶粒尺寸先增大后减小再增大,抗拉强度先降低后增大再降低,伸长率增大;在温度300℃,应变速率10s~(-1)下轧制后,所得ZK60镁合金板的拉伸性能最好,抗拉强度和伸长率分别为358 MPa,21.5%。 相似文献
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为分析不同摩擦系数对地铁列车曲线碰撞的影响,以某4节编组地铁列车为研究对象,建立其有限元模型。设计了动摩擦系数在0.05~0.5之间变化的6种碰撞工况,从碰撞能量转化、车辆点头姿态和车轮抬升量等方面,对地铁列车碰撞结果进行了详细的对比分析。研究结果表明,随着摩擦系数的提高,轮轨间滑移能逐渐增大,车体结构变形吸收的总内能变化不大,而防爬吸能装置和头车前端结构吸收的能量逐渐减少;碰撞能量转化、车辆点头姿态和车轮抬升量等增大或减小的趋势随摩擦系数的提高而逐渐变缓。 相似文献
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通常对冷轧过程的润滑进行分析时,不考虑热效应。但实际生产和实践中发现,当速度较大或者轧制变形量比较大时界面热效应不可忽略。采用综合考虑冷轧润滑过程中轧件表面热量的产生和传导关系,推导出轧件以及润滑膜的温升计算模型,并通过二辊轧制纯铝板的实验来进行验证和说明。结果表明:冷轧润滑过程中,轧件的温升随着轧制速度和压下率的增大而增大,压下率对轧件温升的影响大于轧制速度的影响;对轧件温升起主要作用的是塑性变形热,在轧制变形区内轧件的温度随着变形的增大而增大,并且在最大变形处附近轧件的温度达到最大;润滑膜的温升主要受到轧件表面温升的影响,润滑膜温度随着轧制压下率的增大而升高,当轧制压下率和轧制速度较小时,润滑膜的温度变化不是很明显。 相似文献
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针对目前大多汽车厂商没有控制螺栓的摩擦系数,联接可靠性差的问题,通过对控制摩擦系数前后的微车常用的电镀锌高强度螺栓进行拧紧实验和不同摩擦系数的螺栓进行横向振动实验,并从控制扭矩系数稳定性、扭矩转化率、防松脱等方面分析了摩擦系数对螺栓联接性能的影响。结果表明:随着摩擦系数的散差减小,扭矩系数的散差减小;随着摩擦系数的增大,螺栓的防松性能越好,但是扭矩转化率越低。控制螺栓的摩擦系数能控制扭矩系数的稳定性,提高摩擦防松的稳定性。 相似文献
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新型等通道转角模具挤压AZ91D镁合金的数值模拟 总被引:1,自引:0,他引:1
设计了一种新型的等通道转角挤压模具外形并推导出了在该模具中变形工件上分布的等效应变的理论公式.基于该公式,采用3D有限元分析技术,分析了平值的变化对工件变形的应变分布和挤压所需的最大载荷的影响.模拟的平均等效应变值和理论值非常吻合,ψ=40°时,工件上的等效应变分布最为均匀;ψ的增大将导致最大载荷的逐渐减小,且下降的幅度越来越小. 相似文献
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Counter-roller spinning (CRS), where the mandrel is replaced by rollers, is an effective means of manufacturing large-sized, thin-walled, cylindrical parts with more than 2500 mm diameter. CRS is very complex because of multi-axis rotation, multi-local loading along the circumference, and radial-axial compound deformation. Analytical or experimental methods cannot fully understand CRS. Meanwhile, numerical simulation is an adequate approach to investigate CRS with comprehensive understanding and a low cost. Thus, a finite element (FE) model of CRS was developed with the FORGE code via meshing technology, material modeling, determining the friction condition, and so on. The local fine mesh moving with the roller is one of highlights of the model. The developed 3D-FE model was validated through a CRS experiment by using a tubular blank with a 720 mm outer diameter. The developed 3D-FE model of CRS can provide a basis for parameter optimization, process control, die design, and so on. The data on force and energy predicted by the 3D-FE model can offer reasonable suggestions for determining the main mechanical parameters of CRS machines and selecting the motors. With the predicted data, an all-electric servo-drive system/machine with distributed power was designed in this work for CRS with four pairs of rollers to manufacture a large-sized, thin-walled, cylindrical part with 6000 mm diameter. 相似文献
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针对超导极向场(Poloidal field, PF)超导导体外方内圆的结构特点,以ABAQUS软件分析为手段,采用四辊轮缩径成形工艺对导体缩径成形进行研究。对缩径成形原理、变形区金属的流动规律和横截面受力情况进行理论分析,设计四道次成形工序,并通过拉伸试验获得导体材料316L不锈钢的应力应变曲线。数值模拟结果表明导体缩径过程中应力应变分布不均匀,最大应力出现在接触位置后端,应变集中在四个圆角部位,符合金属流动最小阻力定律。在分析软件中测量变形后导体的截面尺寸,在规定的使用范围之内。在自主设计的成形机上进行试验,取5个不同截面测量尺寸并取平均值,所得结果与模拟结果相近,符合导体尺寸要求,验证了该成形方案的可行性。 相似文献
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应用Pro/E 3.0建立辊轴的三维模型,并应用ANSYS建立有限元模型,求得辊轴在工作条件下的压力分布,变形状态。结果显示了辊轴在稳定工作状态下的应力应变状态。 相似文献
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The article deals with findings of experimental research on the running-in process of steel pieces with rollers that harden the contact strength. The hardening effectiveness of steel pieces physically simulates the bearing strain process, the physical and mechanical properties of the surface layer and its microstructure, and the diffusion of chemical elements by surface deformation using the chemical microanalyzer. The method and technology of running-in steel pieces of complex profile with the wedge roller and the device for the process implementation are developed. The findings are demonstrated for the adaptation of novel technology to production. 相似文献
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不锈钢复合板冷轧过程有限元模拟 总被引:1,自引:0,他引:1
研究了双金属复合板中不锈钢复合板的冷轧生产工艺,并用大型有限元软件ANSYS模拟了不锈钢复合板的冷轧过程。建立了包括上下辊、轧件在内的二维模型,采取适当的加载和约束条件,对不锈钢复合板的冷轧做了模拟,最后得出了不同压下条件下,轧制变形区域内应力应变分布情况。并分析出不锈钢复合板首道次的压下条件,这与冷轧带钢厂不锈钢复合板实际的生产工艺条件是一致的。 相似文献
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Experiments with pairs of rollers of different hardnesses designed to assess the effect of hardness difference on surface durability and surface failure are described. Sliding-rolling contact fatigue tests were performed with combinations of thermally refined, through-hardened and induction-hardened 0.45% C steel rollers. The mode of failure is discussed in relation to the hardness difference between the rollers and the presence of residual stresses. The effect of hardness on the modulus of elasticity was also examined. An empirical equation was devised to describe the relationship between the rolling contact fatigue limit under hertzian stress and the surface hardness. 相似文献
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