粘接界面泡沫铝夹芯板的三点弯曲失效数值模拟

对粘接界面泡沫铝夹芯板三点弯曲载荷下的变形特性进行了实验和数值模拟方面的研究。基于有限元软件ABAQUS建立了泡沫铝夹芯板的三维有限元模型,应用内聚力模型对三点弯曲过程中典型的破坏模式——面板与芯层的界面脱粘给予了合理的模拟,模拟所得的结果与实验结果比较吻合。并在此基础上分析了面板和芯层厚度对夹芯板承载能力和吸收能量能力的影响。结果表明,增加芯层的厚度能够更大程度上提高泡沫铝夹芯板的承载能力和吸收能量的能力。     

层叠式纸浆模塑平托盘结构设计与性能分析

在分析原有纸浆模塑托盘结构的不足的基础上,设计出层叠式纸浆模塑托盘。利用有限元法对静载和叉车作业进行了仿真,得到了托盘的变形和应力分布云图。仿真结果表明:与单层式托盘相比,新型托盘较好地解决了应力集中的问题,使载荷分布更加均匀,提高了承载能力,减小了变形量,降低了各向力学性能的差异。另外,层叠式托盘降低了单层厚度,易于干燥。     

基于FEM的单层E型瓦楞纸箱托盘稳态数值分析

目的对单层E型瓦楞纸箱托盘进行稳态分析,以便能对其结构进行优化设计。方法首先借助弹性力学理论,通过微分方程法对单层E型瓦楞纸箱托盘的临界载荷进行推导;然后通过UG(Unigraphics NX)对单层E型瓦楞纸箱托盘进行建模,利用试验测定的单层E型瓦楞纸箱托盘的工程常数,通过有限元法(FEM),在Ansys平台上对单层E型瓦楞纸箱托盘进行静态分析和屈曲分析,求解单层E型瓦楞纸箱托盘的屈曲模态和临界载荷。对理论方法推导和FEM试验验证的结果进行定性分析。结果对比分析结果,仿真结果和理论推导的结果具有一致性,两种方法对比验证,为E型瓦楞纸箱的结构设计提供了理论参考。结论理论方法推导和FEM对单层E型瓦楞纸箱托盘进行稳态分析,能够缩短产品设计周期,提升产品市场竞争力。     

等腰梯形蜂窝芯玻璃钢夹芯板的热性能

为研究等腰梯形蜂窝芯玻璃钢夹芯板传热机制,利用导热仪对夹芯板的传热性能进行了实验测试与模拟研究。结果表明:夹芯板稳态导热系数模拟结果与Swann and Pittman经验公式的计算结果相吻合,验证了数值计算胞体平面模型的合理性;Part2为夹芯板稳态传热的主要构件,Part2胞壁厚度与边长对夹芯板导热系数有显著影响,Part2高度、Part1与Part3厚度及面板厚度对夹芯板导热系数的影响偏弱;同时,若仅需降低夹芯板的导热系数,而忽略对夹芯板静力学性能要求,应该更换蜂窝芯层材料;若需夹芯板同时满足隔热性能与静力学性能,多层蜂窝芯夹芯板是很好的选择。      

泡沫金属子弹撞击载荷下多孔金属夹芯板的动态响应

应用泡沫金属子弹撞击加载的方式研究了固支多孔金属夹芯板的塑性动力响应。讨论了多孔金属夹芯板在冲击载荷作用下的破坏模式。结果表明夹芯板的破坏主要表现在前面板的压痕与侵彻失效,芯层压缩和芯层剪切破坏。基于实验研究,应用LS-DYNA 3D非线性动力学有限元分析软件对夹芯板动力响应进行了有限元分析。数值研究结果与实验结果吻合较好。考察了加载冲量、面板厚度、芯层厚度及相对密度对多孔金属夹芯板抗撞击性能的影响。夹芯板的结构响应对其结构配置比较敏感,增加面板厚度或芯层厚度能够明显地减小后面板的挠度,提高夹芯板的抗撞击能力。研究结果对多孔金属夹芯板的优化设计具有一定得参考价值。     

一种新型可伸缩调节托盘的设计与实现

目的研究并解决托盘尺寸与铁路运输常用运载工具规格不匹配的问题。方法设计了一种新型的托盘,在常规托盘的基础上增加可移动部分,以实现托盘尺寸规格的可调节。结果对比计算表明,在绝大多数情况下,尺寸调节后的托盘在铁路运输常用运载工具上装载后,载盘效率会随着托盘拉伸长度的增加而增加。为了进一步说明托盘拉伸后的允许载荷量,运用Solid Works软件针对3种常用材质的托盘进行了有限元分析,在托盘拉伸100 mm后其载荷仍可达1.5 t左右。结论尺寸规格可调节的新型托盘较之常规托盘,在与运载工具匹配性和载荷量两方面都具有优越性。     

铝合金托盘有限元分析及优化设计

目的通过对不同托盘结构进行分析,选出满足托盘承载性能要求的轻量化的铝合金托盘结构。方法利用Solid Works软件对不同类型托盘进行三维建模,并用Ansys Workbench对其进行静力分析,对比不同类型托盘应力、变形及安全系数,选出结构最优的铝合金托盘,并对其尺寸进行优化。结果方案C的托盘质量、纵梁应力、纵梁变形和纵梁安全系数分别为19.68 kg,247.39 MPa,3.41 mm和1.13,优于其他类型托盘,对其铺板厚度及纵梁相关尺寸进行优化后,其质量减少22%,纵梁安全系数提高20.4%。结论铺板厚度为1 mm,垫块厚度为1.5 mm,以及其他相关尺寸分别为5,5,30 mm的方案C铝合金托盘为载荷一定条件下的最优结构。     

加筋平托盘面板复杂载荷下最大挠度算法研究

根据板的小变形理论,结合加筋平托盘的简化模型以及变厚度板的挠度方程,推导出在地面承载、叉举和上架等3种不同工况下加筋平托盘受到复杂载荷时的最大挠度方程。由于载荷函数和弯曲刚度函数都是关于x,y的函数,其求解相当复杂,因此对其作离散化处理,离散化的最大挠度方程易于编程,且为研究平托盘面板结构对最大变形的影响提供了便利的途径。研究表明,离散化的最大近似挠度方程能够保证精度要求,其相对误差小于0.4%。最后展示了该算法的软件应用实例。     

不同铺层方式下连续玻璃纤维/聚丙烯复合材料波纹夹芯板的力学性能

制备了多种铺层方式的连续玻璃纤维/聚丙烯（GF/PP）复合材料波纹夹芯板,并研究了GF/PP复合材料波纹夹芯板的平压性能和弯曲性能。结果显示:面板相同时,增加芯板厚度可大大增加夹芯板整体的平压性能;芯板相同时,面板的铺层方式对夹芯板的平压性能有一定影响,且面板含有0°和90°铺层的波纹夹芯板具有最高的平压模量,为59.55 MPa,而单纯增加面板厚度对提升波纹夹芯板的平压性能影响不大;面板铺层方式对弯曲性能具有较大影响,面板为0°铺层的波纹夹芯板具有最高的横向弯曲模量,为783.66 MPa,面板为90°铺层的波纹夹芯板具有最高的纵向弯曲模量,为732.09 MPa;面板为单向铺层（0°或90°铺层）时,会使夹芯板另一方向（纵向或横向）的弯曲性能形成短板。      

轻型环保泡沫复合托盘力学性能研究

目的对一种轻型环保泡沫托盘进行力学性能测试,以确定其额定载荷,评估其各项工作性能,为研究新型托盘性能提供方法和思路。方法根据ISO 8611—2011托盘检测标准对轻型环保泡沫复合托盘进行力学性能检测,结合不同试验项目的试验数据,对不同用途的情况下这种复合托盘所体现的力学性能进行评估。结果新型泡沫复合托盘在各项试验中均表现出了良好的力学性能,托盘在不同用途下所表现的额定载荷不同。结论为合理地设计托盘结构、科学地选择托盘以适于不同物流环境提供可靠的数据支持。     

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.