多层刚架的分析——无剪力分配法

1.单跨多层刚架的计算图1(a)所示,单跨多层刚架,其中任一层柱AB、ab的角变位移方程为 M,。=41,。乡, 2‘,。6。一61月。刀,。(a) M。月=41,。8。 Zf月。0,一6‘,。刀,。(b) M。。=4iaoo。 Ziaoo。一61。。口,。(e) M。。=41。。8。 Zfaoo。一6‘a。刀,。(d)、少、.了(e(fQ,。61月刀(夕, 0。)一气竺刀ABQ。。一争‘“· “‘,-12fa、刀,B式中,￡=El/h,刀二J/h,J为柱两端的相对线位移. 横梁月a两端无相对线位移,其角变位移方程为MA一4‘“·OA十“‘A·e·不M。搜=4f通a夕。 Zf刀。0月,(1)尸.尸.尸_广毛·尸l_}BPO。5尸 由图1(b)的…     

日本液体炸药应用初探

日本正在研制的液体炸药具有以下优点: 比较安全。文中所涉及的炸药基本上均无臭,无毒,无刺激性,不挥发,冲击和摩擦感度很低,操作容易,使用安全。 性能可靠。液体炸药的起爆和传爆性能良好,起爆的临界直径可小于3～4毫米,用6~n或8~n雷管便可稳妥起爆。液体炸药各部位的成份和密度十分均匀。 便于运输。许多液体炸药的原材料单独都很钝感,使用前可分别运至现场或用泵输送到现场。 装药容易。可采用注入的方式装填,便于实现机械化和自动化。     

变形协调方程、应力函数与应变函数注记

在弹性力学,户,六个变形协调方程可以写成不协调量几J为零的形式,即L 11三。22,33 。33,22一2 023,23=0L22三。3:,,1一 。11,33一2 031,31=0L33三。lx,:2 。:2,11一2 012,xZ=0L 12三。323一 。31,32一。33,12一c12,33=OL23三。13,12 。12,一3一ell,23一。23,11=0L31三。2123 。23,21一。22,31一。31,22=0、1.!11.、f,tl、es.2(2)这六、产、J护no J4/‘、了r、、、少‘j声比d六h了t、J硬、上式可缩写为: L*s=0此处及以下,i,了=1、2、3.显然,么,二乌*,所以(2)式只有六个不同的方程式,个式子亦即下列81个方程中不同的六个式子: c、了,*, …     

格式要求

(句末括号内是相关的国家标准)1.题名:不超过20个汉字,中英对照,反映论文内容,包含尽可能多的关键词。避免非公知的字符和长的公式。(GB 7713)2.作者:中文及拼音(姓前名后,均不缩写)。国外作者按国际惯例。(GB/T 16159)3.作者单位:中英对照,数码编号与作者的上标一致,单位全称,所在省市及邮政编码,英文中加国家名。4.作者简介:第一作者的姓名,职称,最高学位,研究方向,Email。     

格式要求(句末括号内是相关的国家标准)

<正>1.题名:不超过20个汉字,中英对照,反映论文内容,包含尽可能多的关键词。避免非公知的字符和长的公式。(GB 7713)2.作者:中文及拼音(姓前名后,均不缩写)。国外作者按国际惯例。(GB/T 16159)3.作者单位:中英对照,数码编号与作者的上标一致,单位全称,所在省市及邮政编码,英文中加国家名。4.作者简介:第一作者的姓名(出生年-),性别,民族,籍贯,职称,最高学位,研究方向,Email。     

润滑材料研讨会中心发言题目目录

1.合成润滑脂的发展动向,颜志光,一评化工厂合成润滑油脂研究所。2.国外润滑油(脂)的发展动向与展望,欧风,石化总公司情报所。3.齿轮润滑油及其应用,李英,兰州炼油厂。2524·柴油机的使用及其作用机理,马汉卿,北京东方红炼油厂研究所。5·发展边界润滑添加剂提高节能效果,高大德、韦淡平,石油化工科学院。6.节能油情况简介,范煜,中国科学院兰州化学物理研究所。7.极压抗塔剂,张宝真,武汉海军工程学院。8.固体润滑的发展与展望,党鸿辛,中国科学院兰州学物理研究所。9.润滑旋I面与界面化学的几个问题,薛群基,中国科学院兰州化学物理研究所。1…     

地震预报中的某些力学问题

地震是一种灾害性自然现象。在一次大地震发生时,可造成房倒屋塌、山崩地裂和大量人畜伤亡。但是,地震的规律是可知的,“人定胜天”,人是可以战胜自然的。因此,要加强地震预报工作。本文讨论地震预报中的某些力学问题。由于问题较复杂,所以下面的讨论是极其初步的。     

离散型最小二乘法分析薄板强度

本文使用了加权残数法中的离散型最小二乘法,分析了薄板弯曲强度问题。所选择的试函数是一个双重的幂级数,事先既不满足薄板定解微分方程式,亦不满足边界条件。所以分析方法属于混合法。所有残数方程,一律化为无量纲形式。权函数一般取为一,用此法计算固定的或简支的正方形板,位移与内力最大的误差小于1％。所编计算机通用程序较同问题有限元程序简单,计算时间很少,准备工作量很少。此法方便、准确、迅速、通用性大,适合用于计算机使用及误差可知可控等,有较多优点。     

格式要求

正(句末括号内是相关的国家标准)1.题名:不超过20个汉字,中英对照,反映论文内容,包含尽可能多的关键词。避免非公知的字符和长的公式。(GB 7713)2.作者:中文及拼音(姓前名后,均不缩写)。国外作者按国际惯例。(GB/T 16159)3.作者单位:中英对照,数码编号与作者的上标一致,单位全称,所在省市及邮政编码,英文中加国家名。4.作者简介:第一作者的姓名,职称,最高学位,研究方向,Email。     

简单起重机具的力学原理

滑车、绞车、千斤顶、扒杆、缆索吊车等常用简单起重机具,在铁路施工中,对解决起重运输、节省人力、缩短工期有重要的作用。本章着重介绍这些起重机具的力学原理。在修正主义教育路线统治时期,这些内容很少写入力学教材,或者零星的有一些,也不大结合实际。学生学完力学课以后,有的人连扒杆也不知道,更不会分析和应用。这种状况必须改变。起重机具的种类和形式繁多,这里将只讨论铁路施工中几种常见起重机具的力学原理,并力求简明实用,尽量减少烦琐的数学推导。希望通过这一章的学习,初步掌握基本原理和应用方法,从而更好地发挥机具的作用,为多快好省地建设社会主义服务。     

AN EXPERIMENTAL STUDY OF PAPER FLUTTER

An experimental study was conducted in order to clarify the phenomenon of paper flutter. Flutter speed was measured in wind tunnel tests for sheet paper and web paper of various materials, sizes and tensions. The relationships between flutter speed, rigidity, mass ratio and tension were clarified from a large data set. The flutter boundaries were obtained in the form of dimensionless flutter speed and mass ratio for the case of sheet paper, and dimensionless flutter speed, mass ratio and tension parameter for the case of web paper. The flutter mode and air-flow around fluttering paper were investigated by visualization tests.     

送纸机构纸张控制方程及卡纸现象数值分析

卡纸现象是打印机和复印机送纸机构常见故障之一,广泛存在于各种介质的传送系统中．为解决该问题,需要研究纸张在送纸机构中的运行规律和受力特点．根据送纸机构的原理,建立纸张在辊轮间运动的计算模型,并推导这一过程中的纸张运动方程．理论推导表明机构的材料与尺寸对卡纸有影响;同时,利用多体动力学分析软件RecurDyn,建立送纸机构仿真分析模型,研究送纸机构运行状态并分析在纸张脱离辊轮后各个因素对卡纸现象的影响,获得纸张与导板间不同的摩擦系数、主动辊轮转速、纸张模量及厚度变化对机构运动影响的规律;最后对比了实验与仿真的扭矩结果,来验证仿真方法的可靠性．结果表明,在纸张被辊轮夹持阶段,纸张运动主要受机构材料和尺寸影响;在纸张脱离辊轮后,纸张运动主要受摩擦力和接触力的影响,并发现随着纸张与导板间摩擦系数的增加、辊轮转速的减小、纸张模量及厚度的变大,机构中容易发生卡纸现象．研究结果可为解决卡纸故障提供指导．     

Modelling of Fluid/Paper Interaction in the Application Nip of a Film Coater

This paper describes a model for the penetration of fluid into a moving paper web in the application nip of a film coater. One-dimensional and two-dimensional solution methods are developed and compared. The two-dimensional model is solved using a Galerkin finite element method with a free surface algorithm. The depth of fluid penetration into the paper web increases with increase in applied pressure, paper permeability and exposure time. The fluid penetration depth decreases as the porosity or solution viscosity increases. The functional relationship among these variables depends on the profile of the pressure applied at the surface of the paper sheet. For the case of uniform paper permeability and no air compression in the web, the two-dimensional model gives similar results to the one-dimensional model.     

Comments on “Design of sampled data state estimator for Markovian jumping neural networks with leakage time-varying delays and discontinuous Lyapunov functional approach”

This paper first points out some fatal errors in the paper (Nonlinear Dyn 73:1367–1383, 2013). Then the main results of the above paper are corrected with some suitable modifications. The new feedback gain matrix is used to prove the estimation of the neuron states through numerical simulations with the same examples as discussed in the above paper.     

纸页受力微损伤演化过程的声发射及多元统计特征

纸页受载后的损伤断裂行为涉及其使用性能,对其损伤断裂过程的研究不仅有助于揭示纸页破坏行为的物理本质,而且有助于对纸页质量及其生产、加工工艺作出更加科学合理的评定。本文基于声发射(Acoustic Emission,AE)实验研究纸页内部微损伤演化过程,给出了评估纸页宏观损伤断裂性能的定量描述方法。首先,根据AE信号与微损伤事件之间存在本质上的关联性,通过采集和观测纸页试样受载过程中的AE信号来研究纸页损伤断裂的基本特征;其次,针对所采集AE信号的数据量大、蕴含信息丰富导致数据分析和处理困难的特点,本文采用多元随机变量的分析方法。利用概率熵和Andrews曲线法等统计分析手段对AE数据展开研究分析,并最终利用一条损伤状态轨迹曲线实现了对纸页微损伤演化过程的完整宏观描述。结果表明,纸页微损伤演化过程呈现明显阶段性变化特征;Andrews曲线的聚类结果有效地区分了不同损伤阶段的相似性和差异性,同时,不同损伤阶段中纸样的微观形貌观测提供了实验性的证据。本文以一种典型的牛皮箱板纸为试件,验证了上述方法的有效性。     

无损残余应力测量及其新技术

简述及比较了主要的残余应力无损测量技术，重点为磁力法，并介绍一台新的磁力仪MAPS，且对MAPS及传统磁力仪作了比较，同时以X射线及中子衍射得到的结果验证了MAPS的可靠性，也介绍了文献上较少见的火车钢轨残余应力分布图。     

Thermographical Analysis of Paper During Tensile Testing and Comparison to Digital Image Correlation

The thermal response in paper has been studied by thermography. It was observed that an inhomogeneous deformation pattern arose in the paper samples during tensile testing. In the plastic regime a pattern of warmer streaks could be observed in the samples. On the same samples digital image correlation (DIC) was used to study local strain fields. It was concluded that the heat patterns observed by thermography coincided with the deformation patterns observed by DIC. Because of its fibrous network structure, paper has an inhomogeneous micro-structure, which is called formation. It could be shown that the formation was the cause of the inhomogeneous deformations in paper. Finite element simulations was used to show how papers with different degrees of heterogeneity would deform. Creped papers, where the strain at break has been increased, were analysed. For these paper it was seen that an overlaid compaction of the paper was created during the creping process. During tensile testing this was recovered as the paper network structure was strained.     

Nonlinear imbibition influence on the hygro-mechanical bending response of paper due to its interaction with water

The bending response analysis of a piece paper as a result of its interaction with water is studied to provide a better understanding of the problem that is dominated by water imbibition into paper. Three phenomenon that take simultaneously place are considered in this model: (i) water imbibition (ii) swelling of fibers and (iii) the softening effect on paper due to the water penetration. The water penetration into paper is modeled including the nonlinear imbibition phenomenon into paper. Numerical solution of the problem is carried out using MatLab^®. The influence of the nonlinear imbibition on the bending response is studied. The proposed model is more accurate and provides a better understanding of the problem compared to previous models presented in earlier works. Moreover, the formulation requires only four parameters to characterize the hygro-mechanical bending response of paper. Finally, the results show a good agreement with the experimental measurements reported in the literature.     

A note of hybrid GR-SVM for prediction of surface roughness in abrasive water jet machining: a response

This paper is the responses for a note submitted by Dr. Antoni Wibowo based on the article entitle “Hybrid GR-SVM for prediction of surface roughness in abrasive water jet (AWJ) machining”. The author of the note pointed out some problems in the original paper. The paper presented a proposed hybridization approach of grey relational analysis and support vector machine in predicting surface roughness (Ra) in AWJ machining. We deny all the claims given by Dr. Wibowo based on the justifications stated in this paper.     

Experiments on tension measurement in manufacturing processes

Today's demand to preserve energy, to optimally utilize limited resources and to still increase quality calls for more-precise measurements in virtually all manufacturing processes. One such field is the measurement of tension in, for instance, paper machines, printing presses, machines for the manufacturing of rubber, plastics, fabrics, etc. Newspaper-printing presses produce today an impressive number of paper breaks. Measurement of the web tension at critical positions could give an early warning when the tension in the paper is growing to dangerous values. In a paper macnine, it is necessary to introduce webtension measurements at many positions to optimize quality, to prevent paper breaks and to reduce wear. Measurements have been carried out with a particular force transducer that can be easily built into an existing, as well as a new machine. Several installations, mainly in paper machines and newspaper-printing presses, show that

- the number of paper breaks are drastically reduced

- a more-uniform quality of the paper can be achieved

- the lifetime of machine parts, such as wires and felts, can be increased.