基于ANSYS的双螺杆磨浆机传动系统主轴的有限元分析

在分析双螺杆磨浆机传动系统主轴系统且计算出系统所受载荷的基础上,利用有限元分析软件ANSYS完成传动系统主轴零部件静态有限元应力和应变分析,得到主轴零件在受载情况下的应力应变图,并对各种支撑情况进行了研究,提出合理的径向轴承布置方案。     

虚拟仪器技术的应变测试系统设计

测试一辆自行车遭遇正面冲撞时,车架横梁、斜梁、竖梁等关键部位的受力大小以及不同部位冲击力之间的相互关系。将应变测试数据处理结果与理论分析的结论进行对比。通过在自行车三个梁的关键部位粘贴应变片,分析三个梁的变形方式。同时比较各处受力峰值之间的时间差,最后判断车架断裂危险情况。文章以虚拟仪器LabVIEW为平台开发了应变测试系统,实现了多通道数据采集和存储管理,实时显示自行车冲撞受力过程的波形,实时显示应变量值。     

基于编码器的织机主轴回转不匀检测方法

在分析编码器测量转速误差的基础上,提出了一种可有效提高测试精度的软件方法,并应用虚拟仪器测试技术开发一种基于编码器的织机主轴回转不匀的测试系统.介绍了系统的组成、工作原理及测试方法,并结合测试结果指出,该系统操作简便、快捷,测试精度高.     

经编电子送经系统的滞后响应

为减少由开、停机过程中经纱张力波动引起的经编停车横条织疵,通过实验测试经编机电子送经系统在开、停机过程中主轴与经轴电动机的运动曲线。分析认为：开、停机过程中送经系统经轴电机滞后于主轴运动,开机时滞后时间随着主轴转速的升高而减小,滞后角度逐步增大;停机时滞后时间随着主轴转速的降低而变化不大,滞后角减小,引起经纱张力呈现“正常→偏松状态下的松、紧变化→较紧状态下的松、紧变化→正常”的波动。同时,还对主控制器性能、系统控制程序、伺服控制模式、送经伺服性能、伺服参数设置和主轴编码器等影响经编送经系统滞后的主要因素进行了讨论。     

毛纤维与梳针的摩擦角分析及测试

本文分析了毛纺用载面为圆形、椭圆形、方形的三种梳针在梳理毛纤维时毛纤维的运动情况、受力情况,计算了毛纤维与梳针的摩擦角.分别对羊毛、山羊绒、安哥拉兔毛、牦牛毛与弹性针布钢针、金属针布针齿的摩擦角进行了测试.结果表明:毛纤维与梳针的摩擦角基本呈正态分布,但同类毛纤维的摩擦角随纤维直径变细而增大.     

Wildman的电子选针人造毛皮圆纬机

美国Wildman 公司制造了一种生产提花毛皮的Maxi—Pile 12E型圆纬机,配有电子机械联合式的选针装置。这种机器的隔距有10、12和14之分,简径24吋,12个成圈系统,针筒转速25转/分;毛绒高度可在3/8～4吋范围内调节。选针动作是由选针器来完成,它们的踵部受选针装置的执行机构作用。在单独选针时,每个单元花纹的最     

碾米机主轴系统临界转速的计算

基于有限元方法对碾米机主轴的临界转速进行了研究。根据碾米机主轴系统结构,确定了转子系统的主要组成部分,并采用二维弹簧‐阻尼单元对轴承进行建模。给定0、500、1000、1500和2000 r／min 5种工作转速,对转子动力学进行分析,得到了坎布尔图,从而确定了主轴的临界转速为725 r／min。这意味着当工作转速达到725 r／min附近时,主轴会达到共振状态。因此应当尽量避免主轴在此转速附近工作。如果工作转速超过了此速度,那么在启动时应当尽快通过此转速,以避免较大的振动而引起的零部件的破坏。该方法对于采用有限元方法计算碾米机主轴系统的临界转速有较好的参考作用。     

经编机启停过程中的闭环送经控制特性

在阐述基于闭环控制的经编电子送经系统结构的基础上,文章主要研究了闭环送经控制系统在经编机启停过程中主轴转速的变化对经轴送经的影响,并对送经系统在启停过程中的经轴滞后于主轴运动和经纱张力变化进行了测试与分析。根据测得的经编机启停过程中经轴电机响应性能和送经张力变化规律,设计了一种经编机启停过程中的送经补偿方法,可显著提高经编机启停过程中送经张力的平稳性,进而改善经编产品品质。     

高速经编机梳栉横移运动的优化设计

为改善梳栉横移运动,减小横移冲击,通过分析梳栉横移运动的工艺特性,运用机械运动学理论,选用适合高速凸轮机构的组合正弦加速度运动规律作为梳栉横移驱动曲线,研究影响横移运动特征值的4个因素：织针针距、横移针距数、经编机主轴转速和横移允许主轴转角。分析结果表明,可通过增大横移允许主轴转角的方法来优化横移运动,即在确保横移安全可靠的条件下导纱针横移提早起始点,延后结束点,增长实际横移时间,从而显著改善高速经编机梳栉横移的运动性能。     

BG2327转子式刨花干燥机主轴寿命分析

对BG2327转子式刨花干燥机主轴进行了受力分析及疲劳强度校核,分析主轴疲劳破坏的因素;提出了提高主轴使用寿命的有效方法,并根据设计计算确定主轴尺寸。     

Finite element analysis of penetration force for needle during tufting process

Tufted carpet is one of the most used carpets. The penetration force of needle is an important factor in tufting process. Few know how to calculate the penetration force during the tufting, although the principle is one of the least understood processes. This paper presents our research on using finite element method (FEM) to study the penetration force of needle during tufting. In this study, the model is developed using ABAQUS software, and the material properties of nonwoven fabric are approximately modeled by linear elastic orthogonal anisotropic continuum. The required engineering constants were obtained from experimental test. A user-defined subroutine VUMAT for characterizing the constitutive relationship of the orthogonal anisotropy nonwoven fabric and the damage evolution was compiled and connected with a commercial software package ABAQUS/Explicit to calculate the penetration force. At the same time, needle penetration force was tested by sensor mounted on needle bar of tufting machine. It was found that there is an approximate agreement of the penetration force between FEM calculations and experimental results. The reasonable agreement proves the validity of finite element analysis model, which could be used to calculate the impact response of the needle penetration stress precisely. The finite element model has been verified experimentally and can be used to study the influence of the key tufting parameters such as the backing material properties and the needle geometry on penetration force, which is vital for designing needle and driving mechanism.     

基于柔性多体系统的经编机梳栉摆动机构动力学分析

 梳栉摆动机构作为经编机的主要关键机构之一,直接影响了经编机的高速运行性能。本文仿真分析了梳栉转轴在低速运行时约束反力的变化情况,并借助ADAMS以及Nastran分析软件建立了经编机梳栉传动机构的柔性多体动力学模型,分析了经编机高速运行时的动态响应,得出了在高速运行时梳栉允许横移时间角改变的程度;在不同转速下导纱针针尖位置的偏差程度和变化趋势;梳栉传动机构振动的变化趋势及其原因。     

Momentary measurement of force exerted on individual fork needles in random-velour needling

Random-velour needling can be regarded as a modified technique of conventional needling process. This modified technique results in the occurrence of fundamental changes in initial orientation of fibers within the preconsolidated fibrous assembly. As the consequence of these changes a dual fibrous structure comprising base and pile layer is created. It is evident that momentary analysis of forces exerted on fork needles is vitally important in the design of both needle and machine. In this research, momentary forces experienced by individual fork needles were precisely measured. A novel force measuring system enabling the momentary sensing of the forces was designed and developed. The results were analyzed by purposely written MATLAB-based software hereafter named as force analyzing software. Results showed that fork needle experiences various forces due to its vibration and inertia and also frictional resistances offered by preconsolidated fibrous assembly and brush conveyor during a complete needling cycle. Furthermore, fork needle is subjected to an additional force due to contact of fork needle with fibers of preconsolidated fibrous assembly during dwell of needle board at the bottom dead center. It is concluded that total force on the fork needle includes contact and noncontact components. Quantification of results showed that, noncontact forces are due to fork needle vibration and inertia. These comprise significant proportion of total force experienced by individual fork needles. Magnitudes of these forces are strongly dependent on stroke frequency of the needle board. It was found that contact component of the total force is dominated by preconsolidated fibrous assembly characteristics.     

An Investigation of the Penetration Force Profile of the Sewing Machine Needle Point

The distributions of the tangential and radial stresses acting on the yam of a fabric during sewing as the sewing needle is inserted into the fabric have been discussed by means of the mechanical principles of elasticity. The influence on the needle penetration force caused by the shape of the cross section and the profile curve at the needle point has also been investigated. It is suggested that five parameters. i.e., the mechanical properties of the textile material k, the variation ratio y' of the needle radius, the contacting arc length θ. the frictional coefficient μ and the sewing machine speed v are the main factors that determine the penetration force of the sewing needle. The variation ratio y', or the slope at any point of the needle profile, is the most important factor for needle design. Depending on the analysis of the forces acting on the needle surface, an optimum profile curve has been obtained. If this curve is used as a new sewing needle profile, the penetration force can possibly be reduced by up to 20%.     

电脑刺绣机针杆机构质心轨迹研究

以电脑刺绣机针杆机构为研究对象 ,推导了针杆机构质心位置矢量方程 ,在针杆机构位移分析的基础上 ,研究了针杆机构质心轨迹线图 ,求出了质心速度、加速度和惯性力大小 ,为改进针杆机构设计提供了理论基础。     

基于结构拓扑优化的绣花机压脚与针杆机构结构优化

针对高速绣花机的压脚机构及针杆机构加速度突变引起的过度柔性冲击和运动失衡问题,首先通过机构运动学求解绣花机压脚及针杆机构运动规律。进一步基于结构拓扑优化的独立、连续、映射的方法,采用有限元技术将离散变量因子转为连续函数,再通过映射反映在部件的子域(单元)有无上进行零件优化,对产生过度柔性冲击的主要部件进行受力分析,划分不同网格区域形成不同子域(单元),用拓扑变量来定义各子域中的质量因素,在质量平衡的基础上减少产生柔性冲击的主要部件质量。工程实例表明,该方法使结构设计满足轻质要求,可达到降低柔性冲击的效果。     

工业缝纫机气浮针杆的柔性联接装置

由于滑槽座导轨副的配合间隙等原因的存在,使得通过刚性连接柱传给工业缝纫机针杆的作用力造成其运动方向偏移。设计了一种工业缝纫机气浮针杆的柔性联接装置,采用柔性铰链弹性变形产生微小角位移来非平行输出微位移,用以减弱滑块受到刚性干扰传递给针杆而造成的运动影响,运用ANSYS对其变形及强度进行了校核与分析。结果表明:ANSYS分析结果与理论设计计算对比验证了设计结构与强度的合理性;该柔性联接装置结构简单,定位精度高,可以有效地解决刚性传递的干扰,实现精密微位移定位,为今后精密微位移机构的研究提供了很好的研究方法和指导。     

多针头静电纺丝工艺过程探讨

借助于Maxwell电场仿真模拟软件和具体实验研究了针头间距和针头数量对静电纺运动射流所处电场分布以及纤维最终沉积形态的影响。结果表明,随着针头间距的增加,电场相互干扰程度减弱,得到的环形纤网会由椭圆形向圆形转变。在多针头静电纺丝工艺中,靠中排布的针头得到的纤网与边缘针头对应的纤网的外观存在明显差别。基于此结果,设计了钢带式多针头连续静电纺丝装置,此装置可以通过调整针头排布并配合钢带旋转制备出不同幅宽和不同规格的均匀纳米纤维网。     

电脑刺绣机针杆机构力矩分析

 针对电脑刺绣机横梁振动影响刺绣质量,易断线的问题,从减少针杆机构出发,根据角动量定理,推导针杆机构的振动力矩计算公式,分析针杆机构在力平衡与力不平衡2种状态下的振动力矩。以MATLAB为编程计算工具,详细计算了针杆机构振动力矩,绘制了振动力矩曲线图。计算结果表明：配重后实现力平衡的针杆机构,不但不能减轻横梁的振动,反而会引起横梁剧烈振动。计算所得数据可用于针杆机构的改进设计。