轻质多孔结构在机床工作台中的应用研究

将轻质多孔结构应到高速立式加工中心的工作台结构中,设计出了一种新型的机床工作台—多孔结构工作台,与原工作台相比多孔结构工作台的总质量减少了16.337kg,从而减小了高速加工过程中产生的惯性力,并对两种不同结构的工作台分别进行了静力学分析和模态分析。分析结果表明:多孔结构工作台比原工作台的最大静变形减小了20.9%,并且多孔结构工作台的前6阶固有频率平均增加87.33Hz,最大增加了191.56 Hz;说明将多孔结构应用到机床工作台中的方法是有效的,这将为改变传统的工作台筋板设计提供一种新的思路。     

DVG850立式加工中心工作台结构优化

对DVG850高速加工中心工作台,设计了2丝母座工作台和2丝母座轻质多孔结构工作台,用Pro/e软件建立三维模型。利用ANSYS Workbench进行有限元分析。与原工作台比较,结果显示2丝母座工作台静刚度和动态性能提高。但质量略有增加。采用轻质多孔结构代替筋结构的2丝母座轻质多孔结构工作台,比原工作台质量减少17.36kg,同时静刚度、动态性能提高。又分析并给出了丝母座中心与工作台中心距离L对工作台质量、最大变形和固有频率的影响曲线,为其进一步的设计与研究提供了理论参考。     

轻质多孔结构在机床工作台的应用与研究

以DVG850高速加工中心工作台为研究对象,将轻质多孔结构应用到该工作台结构中,设计出正方形和正三角形两种轻质多孔结构,利用ANSYS Workbench进行有限元分析,与原工作台相比,轻质多孔结构的工作台可以大幅度提高工作台的刚度和抗振性能,同时还减轻工作台的质量;再对相同条件下的正方形孔结构和正三角形孔结构的性能进行比较得出:正三角形轻质多孔结构静、动态特性优于正方形孔,还比正方形孔结构的质量轻。另外,对性能优越的正三角轻质多孔结构工作台进行了谐响应分析,分析结果与模态分析一致。     

基于ANSYS Workbench的DVG850工作台拓扑优化

以DVG850高速立式加工中心工作台为例,利用SolidWorks软件强大的三维实体设计功能,精确地实现了工作台的三维建模,通过专有程序接口将模型导入到ANSYS Workbench软件中。利用ANSYS Workbench有限元分析软件的静力学分析功能,对工作台进行静力学分析,并根据计算结果校核了工作台的静刚度。应用ANSYS Workbench中的拓扑优化模块对工作台结构进行改进。改进后的工作台保持了原结构的静刚度,但质量却比原方案减少23.2kg。     

泡沫铝填充结构机床工作台结构优化设计

为了最大限度地提升泡沫铝填充结构机床工作台的轻质性和静、动态性能,对前期设计的该结构工作台进行优化设计。优化设计过程中设定工作台的总体质量最小为目标函数,铸铁层外壳的厚度尺寸为优化变量,工作台的最大应力和最大变形量为约束条件。然后对优化前后的泡沫铝填充结构机床工作台的静、动态特性进行有限元仿真分析,对其质量进行计算,并将两种结构工作台的静、动态特性和质量进行比较。结果表明,优化后的泡沫铝填充结构机床工作台的轻质性和高静、动态性能更显突出。     

数控铣床工作台有限元分析及结构改进

为了分析数控铣床工作台在工况下的变形情况、应力大小是否符合设计要求,通过SolidWorks软件建立了工作台的三维模型,并将上述模型导入ANSYS Workbench中并建立了工作台有限元分析模型,对工作台在铣削工况和钻削工况下分别进行了有限元分析。结果表明,工作台在钻削工况下变形量过大,超过了最大变形量设计要求,需要对工作台进行结构改进。改进后的工作台在铣削工况下的最大变形量下降12.14%,最大等效应力应力下降18.98%,钻削工况下最大变形量下降13.19%,最大等效应力应力下降23.02%,满足了设计要求,研究结果为数控铣床工作台或其他类似产品的结构设计提供了一种思路和方法。     

VX380T数控加工中心工作台拓扑分析及多目标参数优化设计

为使VX380T数控加工中心工作台同时具有优越的静、动态性能和轻量化特点。利用拓扑分析的方法研究工作台截面的最佳载荷传递路径,依据拓扑分析结果设计了工作台的加强筋布局。将新结构工作台的整体质量和最大频响幅值为目标函数,以各加强筋的结构参数为设计变量,以原始工作台的静态性能和前3阶固有频率为约束条件进行多目标参数优化设计。对参数优化后工作台的质量、静动态性能进行对比分析,结果表明,其质量减轻了12.19%的同时,其静动态性能也得到了显著提高,证明了优化设计的可行性和有效性。     

立式加工中心滑座结构改进及性能分析

以DVG850高速立式加工中心滑座为研究对象,以轻质多孔结构为基础对原模型进行改进,运用Pro/E造型软件建立滑座的模型,用ANSYS Workbench有限元分析软件对滑座进行静力学分析、模态分析,得出:改进后的轻质多孔结构滑座的静刚度和抗振性能优于原模型,而且还减轻了质量。再通过对轻质多孔结构的滑座进行拓补优化,在满足静刚度和抗振性能的前提下质量进一步减少,与原模型相比质量减少19.08kg。滑座性能提高,同时为滑座及其他类似结构的进一步设计与研究提供了参考依据。     

DVG850工作台静、动态特性分析及结构改进

以DVG850高速立式加工中心工作台为例,利用ANSYS Workbench软件对工作台进行静力学分析和模态分析,根据分析结果了解了其静、动态特性.应用ANSYS Workbench中的拓扑优化模块对工作台结构进行拓扑优化,根据优化结果对其进行结构改进,改进后的工作台保持了原结构的静态特性,动态特性有所提高,质量却比原结构减少23.2kg.     

PCB数控钻床工作台的结构分析与优化

随着印刷电路板(PCB)钻孔精度要求的提高,对由直线电机驱动的工作台提出了多孔结构设计的新思路。论文对比分析了原有工作台的结构(加强筋结构)和改进后的工作台蜂窝结构。结果表明,多孔蜂窝结构在静力学分析和模态分析都优于原结构。同时,在此基础之上,对蜂窝结构进行参数优化,参数优化后的机床工作台更加的轻量化和高比刚度。将蜂窝结构运用到机床工作台中,提高PCB数控钻床的加工精度和效率有很好的效果,具有重要的工程实际意义。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.     

Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking

This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern...     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.