共查询到19条相似文献,搜索用时 218 毫秒
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《锻压技术》2015,(10)
短行程内高压成形机具有合模速度快、主缸行程小、快速建立合模力和生产效率高等优点。为了降低应力的脉动幅值,提高机架的疲劳寿命并保证内高压成形件的精度,短行程内高压成形机的本体结构采用预应力组合框架结构。因此首先通过传统材料力学的方法,对承载横梁进行强度和刚度的理论校核,横梁的最大主应力和最大变形挠度均在许用范围内。通过数值模拟,分析了满载时机身的应力分布、变形挠度、立柱的横向相对偏移量以及横梁与立柱接合面的形态。结果表明:机身的等效应力不超过100 MPa,最大变形挠度为0.184 mm·m-1,立柱横向偏移量为0.49 mm,最大纵向缝隙为0.02 mm。机身结构的强度和刚度均符合设计要求。 相似文献
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《组合机床与自动化加工技术》2017,(9)
以开放式铝材构件加工设备为研究对象,对整机结构进行了静动态特性分析及其优化设计。分析了考虑切削力情况下整机静力变形情况与各部件变形量占系统总变形量的百分比、找出了系统静刚度的薄弱环节;通过整机模态分析获得了前6阶固有频率及振型,找出了整机动态特性薄弱环节;对薄弱环节——横梁及滑枕进行了优化。为研究此类加工设备静动态特性及其结构优化设计提供理论基础,有助于提升窄长铝材构件加工质量,促进相关行业发展。 相似文献
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为了研究在各种误差源综合作用的条件下,FDM桌面3D打印机挤出机头相对于热床的定位精度情况,通过蒙特卡洛法对其定位精度进行评估。根据多刚体系统理论,建立3D打印机的拓扑结构模型;基于仪器精度理论,对误差向量进行综合分析,分析步进电机在运动过程中,各种误差源在x,y,z方向引入的误差向量,建立3D打印机的误差传递模型;通过蒙特卡洛法对在各种误差源综合作用的情况下打印机挤出机头的定位精度进行仿真计算。结果表明:在置信概率95%情况下,挤出机头相对于热床在x,y,z 3个方向上的定位输出及其扩展不确定度分别为x=(70±0.099)mm,y=(50±0.100)mm,z=(20±0.518)mm。该方法可用于分析影响定位精度的主要因素,进行误差补偿,提高定位精度;也可应用到精密仪器设计中用于精度分配计算,合理分配多刚体结构各环节的精度指标。 相似文献
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工程机械倾翻保护结构(ROPS)轻量化是其安全设计的发展趋势,对轻量化改制后某轮式装载机ROPS进行侧向加载,通过贴应变片方法对其时域变形进行研究分析。实验结果表明:ROPS横梁与立柱各减薄5 mm后,改用Q345B材质和加强焊缝连接可满足ISO3471侧向加载要求和能量吸收标准。侧向加载力达到标准值时,能量值为标准值的30%,能量值达到标准值时侧向承载极限为标准值的1.4倍;横梁(W)中心位置靠近加载区域先进入塑性变形区,两侧变形呈近似对称分布;横梁(L)出现塑性铰呈近似S型变形;立柱(Z)靠近加载端位置先进入塑性变形,中心以下部位不会发生塑性变形,刚度远比横梁大。 相似文献
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基于有限元分析的现场铣床横梁结构优化 总被引:7,自引:1,他引:6
针对在加工中由于横梁部件刚度不足在工件表面产生波纹状刀痕的情况,使用三维软件Solidworks以及有限元分析插件CosmosWorks对现场铣床进行建模和静、动态性能的分析,依据横梁振动相对变形的振型和幅值,以及机床的工作环境和机床设计的结构力学理论,提出了对横梁的几项改进建议,通过有限元分析其性能有较大提高,并通过模态实验进行验证,将实测值与理论值对比可知,改进后横梁具有较好的静、动态性能,证明横梁结构的优化设计是可行的. 相似文献
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采用双丝CO2气体保护焊方法焊接30 mm厚Q690D钢板全尺寸液压支架顶梁.基于温度热源和热弹塑性算法对局部顶梁结构焊接变形进行计算,获得焊接固有应变,然后将固有应变施加在全尺寸壳单元顶梁模型上进行弹性计算,最终得到液压支架顶梁结构的焊接变形.结果表明,结合小结构模型的热弹塑性法和大结构固有应变法,能高效预测大型结构的焊接变形且能保证一定精度,预测的液压支架顶梁焊接变形结果与试验结果符合较好;液压支架顶梁的焊接变形主要为角变形,且两侧分布不对称. 相似文献
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Jui-Pin Hung Yuan-Lung LaiChing-Yuan Lin Tzu-Liang Lo 《International Journal of Machine Tools and Manufacture》2011,51(9):731-739
The prediction of machining stability is of great importance for the design of a machine tool capable of high-precision and high-speed machining. The machining performance is determined by the frequency characteristics of the machine tool structure and the dynamics of the cutting process, and can be expressed in terms of a stability lobe diagram. The aim of this study is to develop a finite element model to evaluate the dynamic characteristics and machining stability of a vertical milling system. Rolling interfaces with a contact stiffness defined by Hertz theory were used to couple the linear components and the machine structures in the finite element model. Using the model, the vibration mode that had a dominant influence on the dynamic stiffness and the machining stability was determined. The results of the finite element simulations reveal that linear guides with different preloads greatly affect the dynamic behavior and milling stability of the vertical column spindle head system. These results were validated by performing vibration and machining tests. We conclude that the proposed model can be used to accurately evaluate the dynamic performance of machine tool systems designed with various configurations and with different linear rolling components. 相似文献
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Y. Yang J. Muñoa Y. Altintas 《International Journal of Machine Tools and Manufacture》2010,50(9):834-842
Chatter is more detrimental to machining due to its instability than forced vibrations. This paper presents design and optimal tuning of multiple tuned mass dampers (TMDs) to increase chatter resistance of machine tool structures. Chatter free critical depth of cut of a machine is inversely proportional to the negative real part of frequency response function (FRF) at the tool–workpiece interface. Instead of targeting reduction of magnitude, the negative real part of FRF of the machine is reduced by designing single and multiple TMD systems. The TMDs are designed to have equal masses, and their damping and stiffness values are optimized to improve chatter resistance using minimax numerical optimization algorithm. It is shown that multiple TMDs need more accurate tuning of stiffness and natural frequency of each TMD, but are more robust to uncertainties in damping and input dynamic parameters in comparison with single TMD applications. The proposed tuned damper design and optimization strategy is experimentally illustrated to increase chatter free depth of cuts. 相似文献
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介绍了马鞍形曲线自动焊接系统的工作原理、插补算法及软件实现.系统通过x,y,z三轴联动,控制焊枪实现马鞍形曲线焊缝的自动焊接.在基于角度逼近的平面圆弧插补算法的基础上,分析了马鞍形曲线空间几何特点,根据x,y,z三坐标的空间几何关系设计了一个插补决策.算法利用焊枪对马鞍形曲线焊缝在xOz平面内投影轨迹的回转联动y轴运动来拟合马鞍形曲线,从而解决了马鞍形曲线焊缝的自动焊接问题.由该算法实现的程序结构简单,易于实现,而且运行效率高,插补出的曲线均匀且误差小. 相似文献
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某加工中心的部件横梁刚度不足,致使被加工的工件的表面产生波纹状刀痕。针对上述情况,首先使用Solidworks建模,然后导入有限元分析软件abaqus中,对该横梁进行静、动态性能的分析,根据分析结果,首先调整边界约束条件,然后依据横梁的结构尺寸参数对其质量影响的灵敏度分析报告,以及该加工中心所属厂方的改进要求,对横梁的结构尺寸参数进行调整,调整后的模型再次导入abaqus中分析,依据分析结果,重复调整尺寸参数,直至横梁的刚度和质量均达到预期要求。 相似文献
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Qiang Wang Song Zhang Chun-Hua Zhang Chen-Liang Wu Ling Ren Jian-Qiang Wang Jiang Chen 《金属学报(英文版)》2018,31(1):19
Direct laser metal deposition is a kind of advanced rapid manufacturing technology, which can produce near net shape parts by depositing metal powders layer by layer. This study demonstrates fabrication, the anisotropy of mechanical properties and hardness of a graded steel. The characteristics of constituent phases, microstructure, mechanical anisotropy, and microhardness were investigated using electron backscatter diffraction, optical microscopy, tensile test machine, and microhardness tester. It was found that the graded steel is dense and free of cracks. The crystal structures of the as-built samples evolved in three grades from fcc structures to fcc+bcc structures and then to bcc+fcc structures. Samples in x and z directions showed obvious mechanical anisotropy. The samples machined in x direction showed higher strength and lower elongation than those machined in z direction due to the presence of lack-of-fusion pores and the higher metallurgical bonding between layers in the x direction. The microhardness of the as-built samples increased along the cross section from the substrate(159.7 HV) to the top surface(545.4 HV). 相似文献