子午线轮胎振动特性实验研究

利用振动实验模态分析的方法，建立了自由悬置和接地状态下轮胎的振动特性模态测试与分析系统，通过轮胎径向激振测试信号的数据处理与分析，提取了各阶的频率及其径向模态振型，分析了轮胎的模态参数随充气压力、负荷变化的规律，为实验方法的研究和轮胎结构设计及车辆的动力性能分析提供指导。     

低频振动场对HDPE性能的影响

利用低频熔体振动注射成型技术获得自增强高密度聚乙烯。实验结果表明,采用振动注射成型工艺,试样屈服拉伸强度由26.5MPa提高到36.1MPa;试样的芯层中可获取沿流动方向生成的串晶或行式排列的片晶结构;压力振动注射有利于分子在(110)晶面择优取向,使结晶更加完善;振动注射提高了试样的结晶度,芯层结晶度最大提高了10.2%。     

Crack formation and self-healing behavior during the drying of alumina gels: Experimental studies

The high shrinkage of alumina gels during the drying process leads to cracks. In this work, the behavior of four alumina gel formulations was experimentally studied following two drying procedures: (i) at ambient temperature and ambient humidity, outside a convective dryer and (ii) inside the dryer, allowing the application of different conditions of temperature and humidity. During the experiments, the observations in real time showed shrinkage of gels and the formation of cracks on them due to drying. Two of the gels displayed a capacity for self-healing, requiring numerical treatment of pictures to distinguish the closure of cracks due to shrinkage from those due to self-healing. The results show the precise determination of shrinkage steps, the estimation of the “shrinkage diffusivity” and proved that the manifestation of the chemical reaction is responsible for self-healing, activated by both applied temperature conditions and residual water of gels. Additional in situ investigations at microscopic scale using an environmental scanning electronic microscope corroborate the self-healing phenomenon noticed at macroscopic scale.     

合成气压缩机低压缸振值高原因分析

本文叙述了辽河化肥厂合成气压缩机低压缸入口处振值居高不下的分析过程及处理手段。     

塔器防振用声波扰流器的实验研究

随着化工设备大型化的发展,塔器的风诱导振动现象日益引起人们的广泛关注。针对此问题,设计了一种新型的扰流减振装置,即正弦声波扰流器,并依据涡致振动理论对声波的扰流减振原理进行了分析。对设计的扰流器进行了风洞实验,研究了扰流器的参数变化对扰流效果的影响。结果表明:声波扰流器能够有效减振,其原理是声波干扰使得漩涡脱落频率降低并且脱落的漩涡由单一频率变成多频混杂状态,破坏了共振锁定现象;声波扰流器的安装高度和数目增加,减振效果增强;扰流器的频率和波动速度在一定范围内增加,减振效果增强。研究结果为塔器防振措施中扰流器的设计与工程应用提供了参考和依据。     

Experimental study on the packing of uniform spheres under three-dimensional vibration

Densification of mono-sized sphere packings under three-dimensional (3D) vibration is experimentally studied. The effects of an operational condition, such as vibration amplitude and frequency and feeding method, on packing density are systematically investigated. The results indicate that the dense packings can be achieved by proper control of both vibration amplitude and frequency. The feeding method plays an important role in densification. Higher packing densities can be obtained when the number of particles fed per batch is less than one layer. Packing density decreases with increasing number of particles fed per batch, but keeps constant when the number of particles per batch is larger than three layers. Through the extrapolation on packing density obtained from different sized containers, the maximum packing density is 0.69 for the total feeding method and 0.74 for the batch-wise feeding under the present experimental condition. The formation of ordered structure is discussed based on the particle interlayer diffusion.     

Experimental and numerical analysis on fatigue durability of single-lap joints under vibration loads

Fatigue is one of the most common yet complicated failures that can cause damage to mechanical structures. Structural adhesively bonded joints are not exempt from this deleterious phenomenon and have to be assessed under vibration loads. In this work, fatigue characteristics of single-lap joints (SLJ) made of steel and carbon fibre reinforced plastic (CFRP) laminates under vibration loads are primarily investigated by experiments. The aim of this work is to analyze the changes in the ultimate load of the SLJ under vibration loads. The experimental results showed that SLJ will face cohesive failure after the uniaxial tensile loading test. In addition to the increase of vibration cycles, the ultimate load and failure displacement gradually decrease. In order to model the adhesive between joint components and simulate the damage propagation, a new traction–separation law called the embedded process zone (EPZ) and a damage factor are introduced and developed within the framework of cohesive zone Modeling (CZM) techniques. Meanwhile, the stress variations in the adhesive layer of SLJ in different vibration cycles are researched using the finite element method in ABAQUS.     

低灰高热值煤泥制备水煤浆试验研究

研究了山西某矿煤泥制备高浓度煤泥水煤浆可行性,从煤泥成浆性分析到影响因素都做了详细的试验研究,并结合单因素试验,设计正交试验,得出制备高浓度优质水煤浆的最佳工艺条件：添加剂用量0．16％,温度35℃,搅拌强度1200rpm,搅拌时间25min。在最佳条件下,可以制得浓度为69％,粘度为911．30mPa·s,发热量为20．60MJ／kg的一级水煤浆,符合GB／T 18855—2002水煤浆技术标准。     

基于振动混流原理的油页岩风选除尘技术研究

为解决油页岩干馏后页岩油中粒径0.2 mm以下粉尘、杂质难分离而影响油品质的问题,试验利用风选选煤系统,对干馏前的油页岩进行风选除尘处理,通过调节风量大小以及更换风选筛网的形式,研究了不同条件下风选试验系统的除尘效果。试验结果表明:油页岩风选除尘试验系统能够完成选煤条件,除尘效率可达91%以上;风选效果因筛选条件不同而有所不同,在本试验条件下,筛网类型为10 mm×10 mm方孔筛,对应风量值为4 767.2 m~3/h时除尘效率达到最大值。     

Effect of vibration on rheology of polymer melt

In this article, under shearing vibration and pressure vibration, the rheological behavior of HDPE, ABS, and PS melts and the mechanical properties of molded parts are studied. The experimental results show that, under the vibration condition, the apparent viscosity of the polymer melt decreases with an increasing of the vibration frequency and amplitude applied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1587–1592, 2002     

Experimental and theoretical study on the agglomeration arising from fluidization of cohesive particles—effects of mechanical vibration

A novel technique that can prevent the disruption of agglomerates when sampling the agglomerates from a fluidized bed has been developed and has been applied to the investigation of the agglomeration behaviour of cohesive particles during fluidization with and without mechanical vibration. A new model for the prediction of agglomerate size has also been established on the basis of the energy balance between the agglomerate collision energy, the energy due to cohesive forces and the energy generated by vibration. The accuracy of the model is tested by comparing the theoretical results with the experimental data obtained both in the present work and in the literature. Effects of gas velocity and mechanical vibration on agglomeration for two cohesive (Geldart group C) powders in fluidization are examined experimentally and theoretically. The experimental results prove that mechanical vibration can significantly reduce both the average size and the degree of the size-segregation of the agglomerates throughout the whole bed. However, the experiments also reveal that the mean agglomerate size decreases initially with the vibration intensity, but increases gradually as the vibration intensity exceeds a critical value. This suggests that the vibration cannot only facilitate breaking the agglomerates due to the increased agglomerate collision energy but can also favour the growth of the agglomerates due to the enhanced contacting probability between particles and/or agglomerates. Both the experimental and theoretical results show that a higher gas velocity leads to a smaller agglomerate size.     

冻融环境下透水性生态混凝土试验研究

目前透水性生态混凝土受冻时的孔隙结构、破坏形式等尚不明确.本文通过制备出透水性生态混凝土,利用快速冻融方法分别测试并分析了添加不同掺合料的透水性生态混凝土试件的各项指标变化,采用图像处理方法探索了试件在冻融条件下孔隙率、孔径的变化规律,分析了透水性生态混凝土的破坏现象.试验结果表明添加粉煤灰提高透水性生态混凝土的抗冻性优于硅粉;受冻时孔隙平均半径0 ～5 mm的孔隙增幅达37％,孔隙不断变大,可达35 mm;三种开裂形式中以中间开裂为主,混凝土破坏由裂缝的发展导致,而出现裂缝的原因是受被挤压的未冻水压力和水结冰的膨胀压力影响.     

Study of failure behaviors of rigid polyurethane foam treated under thermal and vibration conditions by experiment and numerical simulation

Failure mechanism of rigid polyurethane foam (RPUF) treated under different conditions was studied by means of experiments and numerical simulation. Thermal degradation mechanism of RPUF under different temperatures was characterized by thermogravimetric analysis-Fourier transform infrared spectrometry coupled with gas chromatography–mass spectrometry (TG-FTIR-GC–MS) in air and nitrogen atmosphere, respectively. And the vibration failure mechanism of RPUF was analyzed by finite element analysis (FEA) and extended finite element method (XFEM). The experimental results indicated that the failure mode in nitrogen was the broken of carbamate groups, and in air was the broken of carbamate groups and the radical decomposition of ether groups. Numerical simulation suggested that there was vibration stress concentration in the center of foam prism, which was easy to produce sliding and opening fatigue cracks during random vibration.     

Suppression of diamond tool wear in machining of tungsten carbide by combining ultrasonic vibration and electrochemical processing

As an important ceramic material, tungsten carbide (WC) is utilized as the typical mold in precision glass molding, which has replaced conventional grinding and polishing to provide a highly replicative process for mass manufacturing of optical glass components. Ultra-precision grinding, which is time consuming and has low reproducibility, is the only method to machine such WC molds to high profile accuracy. Although diamond turning is the most widely used machining method for fabrication of optical molds made of metals, diamond turning of WC is still considered challenging due to fast abrasive wear of the diamond tool caused by high brittleness and hardness of WC. Ultrasonic vibration cutting has been proven to be helpful in realizing ductile-mode machining of brittle materials, but its tool life is still not long enough to be utilized in practical diamond turning of optical WC molds. In the current study, a hybrid method is proposed to combine electrochemical processing of WC workpiece surface into the diamond turning process. Cutting tests on WC using poly-crystalline diamond tools were conducted to evaluate its effect on improvement of tool wear and surface quality. Validation cutting tests using single crystal diamond tools has proven that the proposed hybrid method is able to significantly reduce the diamond tool wear and improve the surface quality of machined ultra-fine grain WC workpiece compared to ultrasonic vibration cutting without electrochemical processing.     

振动时间、比压等参数对炭阳极质量影响的研究

通过采用动态过程优化程序,对预焙阳极成型参数(振动时间、振动频率、振动比压、激振力和振幅)进行优化,探索出一套适宜多品种预焙阳极均质生产的方法。     

液压脉振塑化过程振动参数对LDPE性能的影响

采用新型液压脉振式注塑机成型低密度聚乙烯(LDPE)标准试样,测试成型过程整机能耗及试样的拉伸强度、密度等,探讨塑化过程中振动频率和振幅对制品性能的影响.实验发现,保持其他工艺参数不变,施加振动后,试样拉伸强度最大提高6.1%,密度增大3.3%,熔点向高温移动1.7℃,整机的加工能耗约降低6.8%,且呈现一定的变化规律.     

Effect of low‐frequency melt vibration on HDPE morphology

BACKGROUND: A low‐frequency vibration‐assisted injection‐molding (VAIM) device was developed to explore the morphology of high‐density polyethylene (HDPE) injection moldings. Scanning electron microscopy, wide‐angle X‐ray diffraction and differential scanning calorimetry were used to characterize structure‐property relationships of final products prepared under different VAIM processing conditions (vibration frequency and vibration pressure amplitude) with conventional injection molding for comparison. RESULTS: It was found that increasing the vibration frequency at constant vibration pressure amplitude was beneficial for obtaining ‘shish‐kebab’ structures in the core region of VAIM specimens, and increasing the vibration pressure amplitude at constant vibration frequency was a prerequisite for achieving HDPE specimens with large‐scale lamellas, more pronounced orientation and high crystallinity. CONCLUSION: Both preferred orientation lamellas and increased crystallinity allow one to obtain strong injection moldings with the application of the melt vibration technique. Copyright © 2009 Society of Chemical Industry     

电动机振动原因分析及处理方法

结合设备检修的实际经验分析了电动机振动产生的原因、振动的测定和处理方法,通过剖析电动机的振动的原因使化工岗位人员和设备检修人员能充分了解电动机产生振动的过程、特点和处理方法,为保证化工设备的安全生产提供了宝贵的经验.     

减振用高性能阻尼硅橡胶的制备和应用

该文以橡胶减振性能为出发点,通过阴离子开环共聚的方法,成功地将苯基侧链引入聚硅氧烷结构中,制成了一种减振用高阻尼硅橡胶。通过对比苯基硅橡胶、甲基乙烯基硅橡胶、氯化丁基橡胶等三种橡胶的阻尼性能和减振性能,进一步研究了橡胶的阻尼性能与减振效果的关系。实验结果表明,所制备的阻尼硅橡胶在较宽温度内具有良好的阻尼性能,是一种性能优良的减振用阻尼材料。     

聚合物动态加工过程中温度压力及振动的测量分析

基于虚拟仪器软件平台LabVIEW,开发了对聚合物电磁动态加工过程中温度压力以及振动振幅与频率进行实时监测与分析的仪器。实际使用表明,该仪器具有界面友好、测量精度高、分析功能强、操作方便的特点,稳定性和实用性好,可以用于对聚合物加工过程时的材料性能研究。