Effect of temperature on formability of glass mat reinforced thermoplastic sheets with ductile dummy sheets

Given the increasing use of glass mat-reinforced thermoplastic(GMT)composites,the formability of GMT sheets is currently a topic of research.A new sheet forming process for solidified GMT was developed.In this process,a GMT sheet was sandwiched by dummy metallic sheets during deep drawing.The dummy metallic sheets acted as protective materials and media for heating the GMT sheet.In this study,tensile tests of GMT specimens were carried out under different temperature conditions.The effect of temperature on the tensile deformation was analyzed.The effect of temperature on the deep drawing process of GMT sheets with dummy sheets was further investigated.Finite element method(FEM)was conducted to simulate the deep drawing process.In the drawing force rising stage,the law of drawing force with the depth of the drawing was analyzed using FEM and experiments.

One-Dimensional-Unsteady Thermal Stress in Heat-Ray Absorbing Sheet Glass:Influence of a Sudden Weather Change

Heat-ray absorbing sheet glass can decrease electric energy used for air-conditioning by controling the incoming heat-ray through windows into the rooms.On the other hand,the glasses increase the temperature and sometimes yield heat cracks by thermal stresses.It is important to know the state of thermal stress accurately in order to develop heat-ray absorbing sheet glasses with higher performance and without heat cracks.A conventional design manual at field site treats the steady state and the thermal boundary condition that all heat-rays are absorbed at glass surface.In this paper,it is assumed that the heat-ray is absorbed over all the plate thickness.The idea of the local absorptibity per unit length is introduced.The modeling of internal heat absorbing process is proposed.It can explain well that the total absorptivity depends on the plate thickness.The temperature and the thermal stresses are calculated and discussed.Sudden weather changes such as rain and/or wind after the glass is heated to be steady state are also discussed.Those weather changes are treated with the change of amount of absorbed heat-ray and/or the change of heat transfer coefficient between the glass surface and the outside atmosphere.

Integration of measurement and simulation of film pressure for estimating deformation of a glass sheet on a noncontact air conveyor

Recently,large and thin glass substrates are transported by air film conveyors to reduce surface damage.On the production line,the glass substrates are desired to be transported flatly on the conveyor to ensure the quality inspection.A method by feedbacking film pressure to the theoretical model is proposed for estimation of the deformation of the glass sheet,and the validity of the method is theoretically and experimentally verified.First,a theoretical model including the flow behavior through a porous-walled gap is established,and the film pressure distribution can be predicted by solving the model.Then,an experimental setup that can simultaneously measure the film pressure and the flatness of the glass sheet is established,and,the validity of the model is verified experimentally.Next,with the pressure points at the grooves as the boundary and the pressure points at the flange area as the feedback,an algorithm is applied to shape the one-dimensional deformation at the centerlines in accordance with a quadratic curve.Furthermore,two-dimensional deformation of the glass sheet can then be estimated by an interpolation operation.Comparisons of the calculated results with the experimental data verify the effectiveness of the estimating method.

Influence of Patch Side of Heat-Ray Absorbing Film on One-Dimensional Unsteady Thermal Stresses in Window Glass

Heat-ray absorbing film is used to be bonded on the existing sheet glasses of the windows.It is effective for air-conditioning energy saving against the global warming,because it absorbs heat-ray in the thin film and decreases the incoming heat-ray into the room.On the other hand,the sheet glasses increase the temperature at the surface which the sheet is bonded and sometimes yield heat cracks by thermal stresses.It is important to know the state of thermal stresses accurately in order to develop the heat-ray absorbing film with higher performance and without heat cracks.In this paper,the analysis model is treated as the two-layer plate of the conventional soda sheet glass and the heat-ray absorbing film with different absorptivities.The unsteady temperature and thermal stresses are analyzed and calculated numerically.The influence of the patch side,which the heat-ray absorbing film is bonded at the exterior side or the interior side,on the heat-ray absorbing performance and the thermal stresses is discussed.It is found that the alternative patch side has no effect on the heat-ray absorbing performance and that the patch side is recommended to be interior side from a view point of decreasing thermal stresses against the heat crack of glasses.

Electrochemical Study and Application on Shikonin at Poly（diallyldimethylammonium chloride） Functionalized Graphene Sheets Modified Glass Carbon Electrode

The electrochemical behaviors of shikonin at a poly（diallyldimethylammonium chloride） functionalized graphene sheets modified glass carbon electrode（PDDA-GS/GCE） have been investigated. Shikonin could exhibit a pair of well-defined redox peaks at the PDDA-GS/GCE located at 0.681 V（Epa） and 0.662 V（Epc）[vs. saturated calo- mel electrode（SCE）] in 0.1 mol/L phosphate buffer solution（pH=2.0） with a peak-to-peak separation of about 20 mV, revealing a fast electron-transfer process. Moreover, the current response was remarkably increased at PDDA- GS/GCE compared with that at the bare GCE. The electrochemical behaviors of shikonin at the modified electrode were investigated. And the results indicate that the reaction involves the transfer of two electrons, accompanied by two protons and the electrochemical process is a diffusional-controlled electrode process. The electrochemical para- meters of shikonin at the modified electrode, the electron-transfer coefficient（a）, the electron-transfer number（n） and the electrode reaction rate constant（ks） were calculated to be as 0.53, 2.18 and 3.6 s^-1, respectively. Under the optimal conditions, the peak current of differential pulse voltammetry（DPV） increased linearly with the shikonin concentra- tion in a range from 9A72×10^-8 mol/L to 3,789×10^-6 mol/L with a detection limit of 3,157× 10^-8 mol/L. The linear regression equation was Ip=O.7366c＋0.7855（R=0.9978; lp： 10-7 A, c： 10-8 mol/L）. In addition, the modified glass carbon electrode also exhibited good stability, selectivity and acceptable reproducibility that could be used for the sensitive, simple and rapid determination of shikonin in real samples. Therefore, the present work offers a new way to broaden the analytical application of graphene in pharmaceutical analysis.

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。

玻璃纤维增强聚丙烯/尼龙混杂板材的制备与性能研究

玻璃纤维增强热塑性复合材料具有重复成型、高韧性、高耐久性、可设计、环境友好及可回收利用等优势。为解决由聚丙烯树脂粘度高与尼龙树脂吸水率高引起的复合材料成型工艺与耐久性问题,本项目采用模压工艺研发并制备了玻璃纤维增强聚丙烯/尼龙混杂复合材料板材,研究了混杂模式对于板材力学性能与热性能的影响规律与机理,比较分析了水分子在混杂复合材料内的扩散行为。研究发现,单层层间交替混杂模式板材具有最高的力学性能,拉伸、弯曲和剪切强度最大提升率为132.8%、127.4%和110.4%,归因于混杂板材中两种预浸带在层间粘结-挤压作用下协同受力,材料性能充分发挥;相比之下,五层预浸带层间交替混杂模式板材存在明显薄弱界面层,削弱了板材整体协同受力作用。此外,混杂板材由于聚丙烯树脂憎水性以及逐层交替混杂模式,延缓或阻止了水分子在尼龙树脂内部的吸收和扩散行为,导致混杂板材吸水率大幅下降,这对于提升尼龙树脂基复合材料的耐久性具有重要意义。

乌鲁木齐机场T4航站楼双曲面金属屋面工程设计

乌鲁木齐机场T4航站楼为双曲造型的金属屋面,在实现建筑美学追求的同时,也给工程在设计与安装施工上带来诸多挑战。本文重点介绍了该项目的金属屋面系统、天沟系统、采光天窗系统、檐口蜂窝铝板系统和室外吊顶系统的设计要点、安装施工难点及采用的创新性解决方案。

板管式空气预热器在柴油加氢加热炉中的应用

论述某项目中采用的板管式金属-玻璃空气预热器技术原理、设计计算和运行分析,从理论和实践两方面论证该新型空气预热器工艺结构特点和设备性能表现。

X射线荧光光谱法对硅砂中主要成分的检测

建立了一种对硅砂中成分进行快速测定的方法。样品经过碳化钨的研磨,制成能通过200目(筛孔径0.075 mm)标准筛的粉末,经1000℃灼烧2 h,去除里面含有的碳以及有机物。按照特定的比例在1050℃的高频熔样炉中制成玻璃片。标准物质采用日本耐火材料技术协会系列标准物质,按照说明书800℃灼烧后,按照和样品同样的熔样方法制作玻璃标片,在XRF光谱仪中选定待测元素的2θ角以及PHD能级范围,进行测定。标准曲线制作完毕后,用国家标准物质进行检测,经检测,该方法检测精确度高,误差小,能够满足化学分析的要求,结果令人满意。该方法适用于硅质砂岩以及铸造用砂。

废玻璃粉对泡沫混凝土力学及热工性能影响分析

文中以泡沫混凝土为研究对象,通过开展物理力学实验及热工试验,分析废弃玻璃粉在0%~50%的河砂替代率下,泡沫混凝土物理特性、力学特性及热工性能。结果表明,玻璃粉掺量为30%时,泡沫混凝土的可加工性最好,泡沫混凝土的初凝和终凝时间也随着玻璃粉掺量的不断增加而提高,最高分别增加58%,29%;玻璃粉的加入能够显著改善泡沫混凝土的力学性能;玻璃粉最佳掺量为20%,泡沫混凝土的平均抗压强度提高17%,劈裂强度提高38%,抗弯强度提高30%;当掺量为20%时,超声波脉冲速度略有提高,而当掺量更高时超声波脉冲速度下降;玻璃粉的加入,能在一定程度上提高泡沫混凝土的热工性能。

大片水平堆垛机的应用

随着大吨位浮法玻璃的出现,传统的堆垛机已无法满足大板、厚板等玻璃的需要。通过系统阐述大片水平堆垛机的工作原理、结构特点、部件功能和优缺点等,指出大片水平堆垛机在大吨位浮法玻璃生产线应用中的重要性,可以满足生产要求,降低成本,提高利润水平。

车门钣金异响解决方法介绍与探究

汽车异响问题严重影响用户的驾乘体验,文章从一个车门钣金异响的实例入手,对其异响来源,产生原因,解决措施及验证进行了深入的介绍。主要探讨了钣金间隙中电泳涂层玻璃化转变温度(Tg)对异响形成的影响,建立了振动力学模型,并对其从材料机理上做出了解释。最终通过烘烤温度和时间的提升,提高了电泳涂层的玻璃化转变温度,彻底消除了此类异响。文章提出的异响分析方法为相关工作的开展提供了思路。

Super-plasticity of Zr_(64.80)Cu_(14.85)Ni_(10.35)Al_(10) bulk metallic glass at room temperature

Generally,bulk metallic glasses(BMGs)exhibit a very limited plastic deformation under a compression load at room temperature,often less than 2% before fracturing.In this letter,through an appropriate choice of BMGs' composition,an amorphous rod of Zr64.80Cu14.85Ni10.35Al10 with a diameter of 2 mm was prepared by using copper mold suction casting.X-ray diffraction and differential scanning calorimetry were utilized to determine its structure and thermal stability,and the uniaxial compression test was adopted to study its plastic deformation behavior at room temperature simultaneously.The results showed that the glass transition temperature and onset temperature of the exothermic reaction of the amorphous rod were 646 and 750 K,respectively,and its micro-hardness was 594.7 Hv.During com-pression,when the engineering strain and engineering stress arrived at 9.05% and 1732 MPa,respec-tively,i.e.,the true strain and true stress reached 9.42% and 1560 MPa,respectively,the amorphous rod started to yield.After yielding,with the increase of load,the strain increased and the glass rod ulti-mately were compressed into flake-like form.Although the maximum engineering strain was larger than 70%,i.e.,the maximum true strain exceeded by 120%,the amorphous specimen was not fractured,indicating that it has super-plasticity at room temperature.Through the appropriate choice of compo-sition and optimization of the technological process,flexible BMG with super-plasticity at room tem-perature could be produced.

格陵兰地区GLASS反照率产品质量评价及反照率变化趋势分析

冰雪反照率是影响和评估全球气候变化的重要因子。北极格陵兰岛拥有世界第二大冰盖,定量获取该地区反照率是研究北半球能量收支变化的关键。全球陆表卫星(global land surface satellite,GLASS)产品系统生产的反照率产品是目前国际上时间序列最长(1981—2017年)的全球反照率产品。利用格陵兰气候观测网络(Greenland climate network,GC-Net)与格陵兰冰架监测计划(programme for monitoring of the Greenland ice sheet,PROMICE)网络观测的反照率数据,评估了格陵兰地区GLASS地表反照率产品的精度;并基于2000—2017年的GLASS地表反照率产品,分析了格陵兰地区7月份反照率的年际变化趋势与空间分布特征。结果表明:GLASS与GC-Net反照率的均方根误差(root mean squared error,RMSE)为0.0778(决定系数R2=0.4907),与PROMICE反照率差异的RMSE为0.0786(R2=0.8999),GLASS产品的反照率数值呈现一定的低估现象,但已满足格陵兰地区冰雪反照率研究的需要。基于2000—2017年7月份格陵兰地区的GLASS反照率变化分析可以看出,格陵兰地区的反照率在此期间整体呈现变小的趋势,平均速率约为0.0006/a,变小的地区约占格陵兰总面积的64%;其中,位于格陵兰西部海拔750~1500 m之间的区域对气候变化最为敏感,反照率变小速率也最大,达到了0.026/a。

适用于玻璃幕墙的TA-CNTs/SiO_(2)黑色透明超亲水涂层及性能

将单宁酸改性碳纳米管(TA-CNTs)、树枝状纳米SiO_(2)溶胶、正硅酸乙酯(TEOS)水解液制成分散液,通过喷涂工艺将其喷涂到载玻片上,经室温固化后得到具有自清洁、防雾效果的TA-CNTs/SiO_(2)黑色透明涂层载玻片。采用FTIR、TEM、TG对改性前后的碳纳米管进行了表征,通过SEM、AFM、XPS对涂层形貌和元素组成进行了表征和测试,采用接触角测量仪和紫外-可见分光光度计探究了TA-CNTs和TEOS水解液质量对涂层接触角(CA)的影响以及单位面积涂层中TA-CNTs质量对涂层透光率的影响,并对涂层进行了防雾、自清洁和耐磨性评价。结果表明,当TEOS水解液为6.00 g、TA-CNTs为0.16 g时,制备的涂层具有超亲水性(CA=2.5°)、优异的自清洁和防雾效果,其承受120次摩擦实验后仍保持超亲水性,表现出一定的耐磨性。TA-CNTs的加入使涂层表面更为粗糙,有利于减少光反射,从而降低光污染。此外,当单位面积涂层中TA-CNTs质量为2.0×10^(–3) g/cm^(2)时,涂层的透光率降至60%,此时涂层在保持一定透明度的同时具有隐私性。

超级蒙烯材料:石墨烯家族的新成员

超级蒙烯材料是石墨烯材料家族的新成员。通过高温生长过程和巧妙的工艺设计,在传统材料表面沉积连续态石墨烯薄膜。借助高性能石墨烯“蒙皮”,赋予传统材料全新的功能,让原子级厚度的石墨烯薄膜搭乘传统材料载体走进市场。不同于石墨烯涂料在材料表面的物理涂敷,这种直接生长的连续态石墨烯“蒙皮”最大程度地保存了石墨烯的本征特性,有着广阔的应用前景。超级蒙烯材料体现了连续态石墨烯薄膜应用的新理念,借助传统材料衬底,解决了超薄石墨烯薄膜的无法自支撑问题,同时回避了金属衬底上薄膜生长的剥离转移难题。由于纳米级到亚微米厚度的石墨烯蒙皮基本上不改变支撑衬底材料的宏观形态,因此超级蒙烯材料具有工艺兼容性强的巨大优势,在不改变现役工程材料加工工艺的前提下发挥其独特的功能,可借力现役工程材料的广阔应用市场,将石墨烯薄膜推向实际应用。超级蒙烯材料可分为蒙烯非金属材料和蒙烯金属材料。按照支撑衬底材料的形态分类,又可细分为蒙烯箔材、蒙烯纤维、蒙烯粉体以及蒙烯泡沫等多种形态,构成琳琅满目的超级蒙烯材料家族。不同形态的超级蒙烯材料进行后加工处理或者与其他材料复合,将进一步丰富超级蒙烯材料家族的内涵。蒙烯玻璃纤维是超级蒙烯材料的典型代表,完美地融合了石墨烯与玻璃纤维的优异性能,已成功用在飞行器的防除冰领域。超级蒙烯材料新概念的提出将有力推动石墨烯与传统材料的融合,为连续态石墨烯薄膜材料的实用化开辟新路,为加快石墨烯材料的产业落地提供新的动力。

超高层公共建筑玻璃幕墙设计

梳理、汇总了相关规范要求,并结合超高层工程设计经验,对常见幕墙玻璃参数进行解析,对建筑节能、反射光控制、影像畸变、玻璃幕墙自爆、玻璃幕墙内防护等诸多因素进行分析,进而探索超高层公共建筑外幕墙玻璃选择方面的客观规律。超高层公共建筑玻璃幕墙宜采用两玻一腔的中空玻璃形式,且外片玻璃宜采用半钢化夹层玻璃,内片玻璃宜采用半钢化玻璃,玻璃原片宜采用超白玻,钢化玻璃应进行均质化处理,寒冷地区超高层玻璃幕墙Low-E膜宜位于空气腔室内侧一面,反射率严格控制在0.30以下。

越龙山人行玻璃悬索桥总体设计

越龙山人行玻璃悬索桥为主跨710 m的空间索面地锚式人行玻璃悬索桥。该桥主缆垂跨比为1/11.8,采用大张开量的空间索面,跨中设置3对柔性中央扣,桥下设置空间索面的抗风缆,以提高桥梁整体抗风稳定性,主索鞍采用竖向摩擦隔板技术以提高索鞍的抗滑移安全系数。桥塔采用门式结构,由混凝土塔柱和钢横梁组成。根据地形因素,西北侧及东南侧主缆设置隧道式锚碇,东北侧及西南侧主缆设置重力式锚碇,抗风缆设置岩锚桩结构。加劲梁采用纵横梁格构体系,纵梁采用4道工字钢,横梁采用箱梁形式,外侧2道纵梁间距由跨中8.5 m按抛物线变化至桥塔处17.5 m,中纵梁3 m宽度范围内设置玻璃桥面,外侧设置压型钢板超韧性混凝土桥面。

自承重式超大全玻幕墙施工质量管控关键要点研究

某中心图书馆采用276块超大玻璃打造外立面,最大高度将近16 m,总厚度为133 mm,单块玻璃重达10 t。这样大规模应用超大自承重式的全玻璃结构在国际上尚无先例,对于设计、施工及玻璃加工等都是重大挑战。本文从超限全玻幕墙的玻璃配置、结构胶选型入手,介绍了幕墙大玻璃的安装方法及超厚超限结构胶现场注胶的质量控制要点。