基于LS-DYNA的修枝机跌落仿真分析

目的寻找修枝机整机跌落时的易破损部件,以便针对易损部件设计更合理的结构和缓冲防护包装。方法基于Hypermesh和LS-DYNA软件对修枝机水平跌落、竖直侧向跌落这2种极限工况进行仿真分析。结果在2种工况下,旋转管均会发生应力集中,出现破损,影响修枝机使用寿命。结论在今后的产品设计中,要重点对旋转管的结构进行优化设计;在运输过程中,要着重针对旋转管部件设计合理的运输包装防护结构。     

锂电池运输包装设计与跌落仿真分析

目的 文中以深圳市某科技公司新型动力锂离子电池为研究对象,为其设计缓冲运输包装。方法 结合相关测试标准运用仿真软件ANSYS Workbench对锂电池及其包装件进行跌落仿真分析,并结合跌落试验结果以验证仿真模型的可靠性。结果 裸机跌落时,外壳等效应力最大值为720.41 MPa,超过硬质铝合金的许用应力325 MPa,外壳将会发生破裂;电芯的等效应力最大值为363.4 MPa,超过铝的许用应力280 MPa,可导致电芯损毁;锂离子电池运输包装件跌落仿真结果显示,外壳、电芯、散热板、PCB板等各部件的最大等效应力值较裸机跌落时分别降低了73.66%、39.82%、38.65%、81.70%,且其等效应力的最大值均未超过对应材料的屈服强度。结论 综合变形云图及实验结果,采用EPP泡沫和BC瓦楞纸箱的锂离子电池运输包装结构具有较好的防护效果,能够满足抗冲击强度要求。     

液晶显示器缓冲垫绿色设计及有限元分析

目的设计绿色环保的液晶显示器缓冲衬垫,并对其受跌落冲击时的缓冲效果进行有限元分析。方法采用瓦楞纸板折叠成形的方式对液晶显示器的缓冲衬垫进行绿色设计。在ABAQUS有限元软件中建立液晶显示器和缓冲衬垫的实体模型,通过有限元软件模拟液晶显示器运输过程中角跌落的冲击响应,分析缓冲衬垫的缓冲效果。结果角跌落冲击过程中,等效应力云图表明衬垫跌落角处变形较大,应力集中,显示器跌落角处最大应力达到1.293 MPa,但未超过材料的屈服极限。冲击加速度计算结果表明,以1 m的高度跌落时,显示器上易损件的最大冲击加速度为748 m/s2,未超过液晶显示器的许用脆值。结论瓦楞纸板折叠成形的环保缓冲衬垫满足缓冲包装要求,能有效保护显示器抵抗跌落冲击。     

平板玻璃运输包装设计及保护性能分析

目的采用瓦楞纸箱内衬聚氨酯泡沫衬垫设计平板玻璃运输包装,通过仿真分析检验设计的合理性与可行性。方法采用Creo parametric软件建立运输包装件模型,采用Ansys Workbench软件对模型进行仿真分析,完成静态堆码载荷仿真、模态仿真、随机振动仿真,并利用LS-DYNA与Ansys Workbench进行联合模拟跌落仿真。结果将瓦楞纸箱与木箱运输包装形式的仿真结果进行对比分析,得出相同静应力作用下,瓦楞纸箱包装的最大响应应力最小且分布均匀;随机振动过程中,虽然瓦楞纸箱相对于木箱形变量较大,但避免应力集中情况且满足变形限度要求;跌落过程中,瓦楞纸箱相对于木箱传递到平板玻璃的作用力较小,且避免了应力集中现象。结论综合分析结果,瓦楞纸箱加聚氨酯缓冲衬垫的运输包装形式设计合理,能够在运输过程中更好保护平板玻璃的安全,设计方案可行。     

某型号锂电池全纸化包装件跌落仿真分析

目的 验证锂离子电池全纸化运输包装件的防护性能。方法 依据锂离子电池的产品特性、流通环境以及包装防护等多方面要求，选用合适的纸质包装材料得到全纸化的包装方案，选用仿真分析软件对包装件进行跌落模拟，得到其应力、应变等相关数据。结果 由跌落仿真分析可知，最大应力出现在外壳上盖凸台位置，其应力值为346.06 MPa，超过外壳最大许用应力值(325 MPa)，外壳发生破损。锂电池包装件跌落时，外壳等效应力值为1.211 MPa，仿真得到的应力值均未超过材料的许用应力，不会发生损坏。结论 该包装结构能够在运输过程中吸收大部分的冲击能量，能很好地保护内部产品不受损伤，具有良好的防护性能。     

真空平板玻璃托盘集装包装系统设计与跌落测试验证

目的 对真空平板玻璃进行托盘集装包装系统设计,并进行跌落仿真测试,验证包装方案的可靠性。方法 提出运输包装设计五步法。第1步产品及流通环境调研,得到相关信息;第2步包装方案设计及建模,选用瓦楞纸板、胶合板、EVA泡沫和捆扎带等包装材料,利用SolidWorks软件进行三维建模,建立各跌落工况下的几何模型;第3步有限元模型建立,对各包材选用合适的材料模型,并利用试验测得相关性能参数,在所建几何模型的基础上进行接触设置、网格划分和载荷设置;第4步有限元模型可靠性验证,对模型进行实际试验和相应仿真测试,两者结果对比分析;第5步多工况下仿真测试,涉及跌落、冲击、振动等。结果 展示最具代表性的角、面和棱跌落仿真测试与相应试验结果,最大误差小于10%,验证了有限元模型的可靠性。进一步展示了跌落下各块玻璃的响应加速度,其中峰值加速度远小于真空平板玻璃脆值所允许的加速度,满足防护要求。结论 基于上述运输包装设计五步法,所提出的包装方案满足跌落防护要求,也证实了基于该五步法进行包装防护设计的可行性。     

高脚杯缓冲包装力学性能有限元分析

目的研究设计的包装结构对高脚杯的缓冲效果。方法建立高脚杯缓冲包装件实体模型,导入Ansys/LS-DYNA中,确定材料的性能参数及边界条件,进行跌落仿真,分析仿真结果。结果根据跌落仿真得到的应力云图,分析在跌落和回弹过程中包装件及内装物的应力变化,通过对最大加速度进行分析表明,设计的缓冲包装结构能够使高脚杯的最大加速度在80g以下。结论设计的缓冲包装满足产品脆值要求,达到了缓冲包装的效果。     

基于Ansys Workbench的投影仪运输包装仿真分析

目的为某型号投影仪设计运输包装,并检验该方案的防护性能和安全性能。方法运用有限元软件并进行相关试验,对投影仪包装件进行模态分析、随机振动分析和跌落分析。结果在随机振动仿真分析中,包装件前6阶固有频率均大于25 Hz,避开了公路和铁路运输的共振频率范围,不会发生共振;最大等效应力为4.628 MPa,最大变形量为1.526 mm,各部件应力和变形量均在安全范围内,符合抗振强度要求。在跌落仿真分析中,投影仪裸机跌落时的镜片等效应力最大值为123.49 MPa,超过了玻璃的许用应力(28 MPa),镜头发生破裂;投影仪运输包装跌落时,镜片上等效应力最大值降低为2.1728 MPa,其余部件应力值均未超过对应材料的屈服强度,符合抗冲击强度要求。结论根据分析结果,采用EPE发泡塑料和E型瓦楞纸板的运输包装方案结构设计合理,能够在运输过程中对投影仪起到保护作用,具有一定的可行性。     

利乐砖棱跌落试验仿真研究

对装有液体的利乐砖型包装进行跌落试验,检测包装设计的效果。对于动态加载情况,ABAQUS/Explicit提供先进方法用于连续体非线性结构的动态仿真。通过有限元仿真代替真实的跌落试验,以降低试验成本,提高实验效率。仿真试验得到的结果与真实包装试验结果进行了比对,结果相似。在包装材料出现破损时,剪切应力集中通常出现在发生包装破损同样的地方。随着跌落高度的增大,应力增大,这与实际吻合很好。     

苹果–EPS泡沫系统冲击响应分析

目的 分析苹果在运输包装环境中的抗冲击性能，并优化苹果–EPS泡沫缓冲包装设计。方法 以80 mm果径洛川富士苹果为研究对象，通过万能压缩试验机对苹果进行压缩试验，得到应力–应变曲线。通过ABAQUS/Explicit建立苹果运输包装系统有限元模型，并进行有限元仿真分析，其中发泡聚苯乙烯有限元模型采用Crushable Foam模型，苹果采用线弹性力学模型。模拟苹果在沿轴竖直摆放和沿轴水平摆放2种摆放方式下跌落时的冲击响应，并分析不同厚度、密度为28kg/m³的EPS泡沫的缓冲效果。结果 得出苹果的弹性模量为2.44 MPa、屈服极限为0.38 MPa。通过模拟仿真分析可得出，EPS泡沫能有效减缓运输过程中冲击对苹果的损伤，并以此为基础得到了针对该包装系统的缓冲设计。结论 通过与龙格–库塔数值分析法的对比可以得出，本研究以试验为基础，结合仿真分析能为相关果蔬运输提供数据支持和参考。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.