对胶印机刚性滚筒与弹性滚筒间压力的研究

对刚性滚筒与弹性滚筒间的压力进行了研究。以胶印机印刷滚筒为例,从油墨附着和印刷机精度的角度分析确定了印刷滚筒包衬的压缩变形量和滚筒挠度的计算方法,然后通过压缩变形量计算横截面上的最大印刷压力、任意点印刷压力和总印刷压力,以便在印刷设计和使用中控制最佳参数。     

配重平衡对印刷滚筒动态特性影响分析

印刷滚筒是完成图文转移的关键部件,其性能直接影响到图文转移质量。本研究以某型号平版胶印机橡皮滚筒为对象,基于PRO/E软件平台进行三维建模,利用有限元分析软件ANSYS Workbench对其进行了考虑重力和惯性力的动态挠度建模分析。仿真分析结果表明:重力对滚筒母线的旋转精度有一定影响,但平衡配重并不能减少其动态挠度。     

基于有限差分法的印刷滚筒挠度计算

以单张纸胶印机橡皮滚筒为研究对象,将其简化为变截面简支梁模型,利用有限差分法和Matlab对其在印刷压力作用下的挠曲变形情况进行编程计算,得到相应的挠变曲线,为印刷滚筒的挠度计算和合理设计提供了思路。     

滚筒配重工艺及其影响研究分析

以某机型平版胶印机橡皮布滚筒为对象,基于PRO/E软件平台和有限元软件ANSYS WORKBENCH,对其进行了考虑重力和惯性力的动态挠度建模分析。仿真分析结果表明:不同的平衡配重方案具有不同的动态挠度响应,而且有的差异很大。     

滚筒混合机工作模型建立与模糊优化设计

文章首先建立滚筒混合机关于功率、物料滞留时间和生产率的数学模型;其次通过建立的数学模型并结合模糊优化方法建立混合机各个关键参数与混合机生产率相关联的模糊优化模型;最后通过国产某型号滚筒混合机的实际运行数据和建立的工作模型进行对比,验证模型的准确性,并利用建立的模糊优化模型对该型号混合机进行优化设计。     

滚筒烘丝机内烟丝滞留时间模型的建立及数值模拟

为深入研究滚筒烘丝机内部加工过程,提升卷烟产品品质,通过对烟丝在滚筒烘丝机内的运动过程进行分析,建立了滚筒烘丝机内烟丝滞留时间模型,并通过数值模拟分析了理论模型随各工艺参数的变化规律。结果表明:烟丝滞留时间随着滚筒转速、半径和倾角的增大而减小;与滚筒烘丝机的长度成正比关系;随着滚筒内介质风速的增大略有减小。各工艺参数对烟丝滞留时间的影响大小依次为倾角半径转速长度风速。通过试验验证了滚筒转速与烟丝滞留时间的变化规律,试验结果与数值模拟结果具有较好的一致性。该模型能够准确预测滚筒烘丝机内烟丝滞留时间,有助于加强烘丝过程控制,提高制丝加工品质。     

基于接触力学的圆柱滚子轴承刚度对印刷压力的影响分析

以对开胶印机使用的轴承NNU4922-S-K-M-S为研究对象,基于接触力学理论,计算圆柱滚子轴承的静态载荷分布及刚度,分析了静态载荷分布及刚度与径向游隙、外加径向载荷的关系;利用有限元软件ANSYS建立压印滚筒模型,分析圆柱滚子轴承静态刚度对压印滚筒挠度的影响.研究表明:随着游隙的增大,最大负荷增大,轴承刚度减小,滚筒变形量增大,其结果是引起印刷压力下降.     

基于神经网络和遗传算法的锭子弹性管性能优化

为得到减振弹性管对下锭胆的支承弹性和锭子高速运动下的稳定性等性能的最优匹配效率,依据减振弹性管的等效抗弯刚度及底部等效刚度系数公式,利用MatLab数值分析软件构建弹性管抗弯刚度和底部挠度数学模型。首先,结合Isight优化软件基于径向基神经网络构建其近似模型,且使精度达到可接受水平,并以模型的关键结构参数弹性模量、螺距、槽宽、壁厚为设计变量,结合遗传算法对弹性管抗弯刚度和底部挠度进行多目标优化设计,得到Pareto最优解集和Pareto前沿图,确定出减振弹性管结构工艺参数的优化方案。通过对优化数据进行分析发现,该方案在保证减振弹性管弹性的同时,其底部振幅明显减弱。     

6HP-150型核桃破壳机

简单介绍了核桃破壳机的结构特点， 主要参数的确定， 对核桃分级滚筒的运动参数， 几何参数以及挤压破壳滚筒的参数进行了分析， 最后给出了整机参数。     

基于BIM技术的地铁车站照度分析应用

BIM技术具有可视化及参数化的特点,文章通过创建参数化的照明灯具BIM模型,结合照度分析软件进行地铁车站的站厅、站台区域照度的实时分析优化,大幅度提高照明效率,减少能源浪费,提供了BIM技术与照度分析软件结合利用的一种方法。     

Increase in Regain during Vacuum-steaming

The importance of lateral pressure in the tension and bending behaviour of yarns and fabrics is discussed. To determine the lateral pressure between fibres, a specific model is considered, that of a filament helically wound around a cylinder. The equations governing the equilibrium of the filament are derived and both account for the helical geometry of the filament and allow for the variation of the helix angle. The filament is assumed to possess both bending and torsional rigidities. The special case of constant helix angle yields expressions for the lateral-force intensity as a function of the tension in the filament, bending and torsional rigidities, bending curvature, and torsion. Specific examples are considered to show the relative contributions of the bending and torsional rigidities to the lateral force     

压力容器大开孔补强结构强度的有限元分析

运用压力面积法和有限单元法计算分析了一模型容器筒体上受内压的大开孔补强结构 ,用极限分析法求出其极限载荷和设计载荷 ,并用分析设计法进行了验证。通过比较和分析可知 ,压力面积法由于没有考虑弯曲应力的限制 ,用于大开孔补强设计有时是不可靠的 ,在工程实践中压力容器大开孔补强结构应有较大的安全系数 ,有限单元法对于大开孔补强设计是合理和安全的     

织物折皱回复角的计算

利用标准固体单元和滑块并联组成的模型,在织物摩擦约束力偶与其弯曲曲率成正比的假设下,对织物的弯曲和折皱回复进行了分析,并用纯弯曲实验得到的数据计算出织物的模型参数,从而计算出织物在不同时刻的回复角,平纹织物的理论预期与实测结果符合较好。     

特种高线压辊(缸)壳横向内力的分析计算

随着造纸及整饰设备向高速、宽幅、强化过程的方向发展,包括:高冲量压榨辊、宽压区压榨辊、热压榨辊、光泽压榨缸、抗挠辊、可控挠度辊等各种特殊结构、大直径、高线压辊(缸)的设计已成为现代造纸设备发展突出的关键技术之一。为进行这类辊的纵横向综合强度分析和刚度计算,导出了辊(缸)壳的横向内力(弯矩、拉力、剪力)计算式,绘制了弯、拉、剪力系数计算图,为高线压辊(缸)的横向内力分析、计算提供了直观、方便的工具。     

Predicting bending rigidity of woven fabrics using adaptive neuro-fuzzy inference system (ANFIS)

Predictability of the bending rigidity of cotton plain-woven fabrics from their structural parameters has been investigated using an adaptive neuro-fuzzy inference system (ANFIS) approach. A set of cotton grey fabrics meant for apparel end use was desized, scoured, and relaxed. The fabrics were then conditioned and tested for bending properties. Fabric weight, fabric thickness, and fabric cover constituted the input parameters for the model, whereas overall bending rigidity of the fabric was the single output parameter. Fabric data-set has been modeled using ANFIS and its prediction potential is compared with that of an artificial neural network (ANN) model. A sensitivity analysis was also carried out to investigate the robustness of developed model. Results show that the learning capability of the ANFIS model is superior and its generalization ability is slightly better than that of a standalone ANN model.     

Modelling crease recovery behaviour of woven fabrics

Crease recovery behaviour is an important property of fabrics for apparel applications. A theoretical model is developed in which the fabric is represented by an elastic element and a frictional element. The frictional restraint is assumed to be proportional to the square root of the curvature of the fabric during deformation. An energy method is applied to the study of crease recovery behaviour of the fabric. Equations of crease recovery work and crease recovery force as a function of curvature are derived. Two basic parameters are needed to characterise the fabric in the crease recovery model: the bending rigidity and bending hysteresis of the fabric; both are readily measured in a pure bending test. Good agreement is observed between experimental data and theoretical predictions for wool/polyester blended and worsted fabrics.     

基于混合韦伯分布的碳纤维针刺毡结构表征

为研究碳纤维针刺毡的结构并对其参数化表征,基于混合（Weibull）分布分析了3种碳纤维针刺毡的结构参数。对碳纤维针刺毡的纤维长度分布进行了拟合,并分析了造成纤维长度分布规律不同的原因。采用纯弯梁模型模拟碳纤维在针刺毡中的弯曲状态,并对弯曲参数进行了统计分析。结果表明,采用混合Weibull分布模型分析碳纤维针刺毡的内部结构,可真实反映参数指标的分布规律。无论是纤维长度还是纤维的弯曲参数,拟合曲线都有较高的拟合度。此外,采用纯弯梁模型模拟弯曲的碳纤维,不仅可以模拟纤维在针刺毡中的弯曲形貌,还可以将测量结果用于碳纤维针刺毡的参数化建模。     

织物的弯曲性能

用线性粘弹理论对织物在小弯曲变形情况下的弯曲性能作了分析。假定织物的弯曲行为是粘弹性的,具有内摩擦约束,内摩擦弯矩与弯曲曲率成正比。织物流变模型由标准线性固体模型和一个摩擦元件并联组成。通过分析曲率周期性变化时的弯曲行为,建立了弯曲性能与模型参数之间的关系。利用实验所得到的模型参数对表征织物弯曲性能的指标进行计算,理论计算与实验结果相符。     

MEASURING MILK GELIFICATION BY MEANS OF AN INSTRON UNIVERSAL TESTING MACHINE OPERATING IN DYNAMIC MODE1

This note describes a simple method to measure the kinetics of milk coagulum formation using an Instron Universal Testing Machine operating in dynamic mode. Coaxial cylinder geometry is used, applying to the internal cylinder a vertical periodical motion of 2 mm amplitude and constant speed of 1 cm/min. The flow conditions are similar to that applied in a sliding rheometer. The experiment can be equated to a periodical stress growth experiment as coagulation proceeds. Data produced according to this technique provides information on the kinetic parameters which characterize the kinetic model currently used to describe milk coagulation     

Predicting the thermal inactivation of bacteria in a solid matrix: simulation studies on the relative effects of microbial thermal resistance parameters and process conditions

A combined mathematical model for predicting heat penetration and microbial inactivation in a solid body heated by conduction was tested experimentally by inoculating agar cylinders with Salmonella typhimurium or Enterococcus faecium and heating in a water bath. Regions of growth where bacteria had survived after heating were measured by image analysis and compared with model predictions. Visualisation of the regions of growth was improved by incorporating chromogenic metabolic indicators into the agar. Preliminary tests established that the model performed satisfactorily with both test organisms and with cylinders of different diameter. The model was then used in simulation studies in which the parameters D, z, inoculum size, cylinder diameter and heating temperature were systematically varied. These simulations showed that the biological variables D, z and inoculum size had a relatively small effect on the time needed to eliminate bacteria at the cylinder axis in comparison with the physical variables heating temperature and cylinder diameter, which had a much greater relative effect.