CRH3高速动车组空调通风口胶接结构设计

通过理论分析和计算确定了动车组空调通风口部件与铝合金车体胶接用胶粘剂的强度指标。介绍了胶粘剂的选择及胶接结构的设计原则,考查了搭接长度、搭接宽度、胶层厚度和被粘接材料厚度等对胶接件粘接强度的影响。结果表明:车体与空调通风口部件的胶接接头选择受剪切应力作用的搭接接头较适宜,并且搭接接头的承载能力随搭接长度或宽度增加呈先快速上升后趋于稳定态势;当搭接长度为10 mm、胶层厚度为6 mm、铝合金板厚度为5 mm且常温湿固化型单组分PU(聚氨酯)胶粘剂的剪切强度超过0.23 MPa时,搭接接头的承载能力相对最大。     

结构胶粘接厚度对建筑幕墙抗形变能力影响分析

隐框式建筑幕墙是当前建筑幕墙设计的主要形式,其结构胶粘接厚度对于幕墙安全性尤为关键,因此分析了结构胶粘接厚度对建筑幕墙抗形变能力影响。根据胶粘剂力学性能中的拉伸弹性模量与剪切模量进行结构胶粘接厚度计算,确定建筑幕墙最佳结构胶粘接厚度,并分析建筑幕墙结构胶变形性能,获取了结构胶拉伸变形同剪切变形的相关性。根据结构胶相关拉伸剪切强度测试标准,利用电子万能测试机进行结构胶粘接厚度对结构胶变形能力的影响测试和结构胶变形对建筑幕墙抗变形能力的影响测试。测试结果显示当结构胶粘接厚度达到最优值后,随着粘接厚度逐渐增加结构胶粘剂拉伸与剪切强度整体表现为逐渐降低状态,而粘接厚度下降则易导致胶粘剂粘接强度下降;结构胶受外力加载条件下产生的变形是建筑幕墙结构变形位移量的20%左右。     

动车组座椅弹性支撑粘接接头设计

对动车组座椅弹性支撑的粘接接头进行了设计,采用Bigwood法测算出胶层在接头边缘部位承受的极限载荷,通过试验对两种备选胶粘剂老化前后的强度进行了测试并计算其特征参数。研究结果表明:粘接面长度、宽度值至少应大于96 mm时,可以避免应力集中;极限载荷约为5.6 MPa;胶粘剂A特征参数为-3.25 MPa,胶粘剂B为7.75 MPa,胶粘剂B可满足接头要求。     

高速动车组车窗粘接强度校核方法研究

提出了基于胶粘剂粘接平面法向正应力(σ)和切向剪应力(τ)的粘接强度校核方法,针对高速动车组车窗粘接结构在实际使用过程中往往承受拉伸力和剪切力的共同作用,引入了嵌接接头,并分别设计了粘接角度为0°、15°、30°、45°、60°、75°、90°的7组试样进行试验。研究结果表明:通过7组不同正剪比时的胶粘剂破坏应力,可拟合出一条胶粘剂破坏应力的包络线,然后根据该包络线总结出一种高速动车组车窗粘接强度的校核方法;该校核方法在预测粘接结构所能承受的最大安全载荷方面具有较好的可靠性、可行性和指导作用,能有效保证安全、可靠地使用车窗粘接结构。     

SMC基材粘接用双组分聚氨酯胶粘剂的研制

研究了用于粘接SMC(纤维增强塑料)基材的双组分PU(聚氨酯)胶粘剂的配方,考察了PU预聚体、硅烷偶联剂、EP(环氧树脂)和表面处理方式等对胶粘剂在SMC基材上的粘接强度和硬度的影响。研究结果表明:加入PU预聚体、硅烷偶联剂和EP后,PU胶粘剂对SMC基材的粘接效果明显改善,剪切强度增大,基材破坏率达到100%。     

不同温度湿度下鞋靴用聚氨酯胶粘剂强度变化数值模拟分析

以赫兹接触理论为基础,设计鞋靴用聚氨酯胶粘剂数值模拟基本模型,数值模拟分析搭接接头、对接接头与嵌接接头鞋靴用聚氨酯胶粘剂在不同温度、湿度下的强度变化.研究结果表明:三种接头胶粘剂的剪切强度与粘接强度会随着温度的增加逐渐下降,对接接头的剪切强度与粘接强度受温度影响最小;三种接头胶粘剂的平压强度随着温度的增加均呈现"W"型...     

CFRP/铝合金粘接接头在低温环境中的老化机理研究

采用胶粘剂哑铃试件,结合SEM(扫描电镜)分析,研究了胶粘剂、CFRP和CFRP/铝合金粘接接头在长期低温(-40℃)作用下的老化失效机理。研究结果表明:低温老化对胶粘剂的力学性能和CFRP表面粘接性能影响不大,但是热应力会降低胶粘剂和CFRP纤维/基体界面力学性能;CFRP/铝合金剪切接头失效强度的下降主要是由胶粘剂的性能下降引起,对接接头失效强度的下降主要是由胶粘剂和CFRP性能共同下降引起,随着老化时间的增加,CFRP的影响减小。因此,在复合材料粘接结构老化研究时需要考虑胶粘剂、复合材料的老化以及受力形式的影响。     

国产水性胶和聚氨酯胶粘剂对地板布的粘接性能测试

选择两种国产水性胶（Ⅰ型和Ⅱ型）以及一种双组分聚氨酯胶粘剂,将地板布粘接到不同材质的地板上,即铝合金和木质地板,测试粘接剥离强度,对比分析了在不同地板基材上的粘接破坏形式。研究结果表明：Ⅰ型胶粘剂在铝合金和木地板上的剥离强度分别为1.182和1.731 N/mm,不但具有一定的粘接强度,还能满足动车组地板布拆除的要求,且适用于动车组导槽处地板布的粘接。而水性Ⅱ型胶在铝合金和木地板基材上的剥离强度值分别为0.355和1.172 N/mm,不适合作为动车地板布粘接胶。国产双组分聚氨酯胶在铝合金、木地板基材上的剥离强度分别为3.089和2.698 N/mm,均有较高的粘接强度,适合用作城轨车地板布胶粘剂。     

不锈钢/天然橡胶的粘接性能研究

对比了不同处理工艺下的不锈钢/天然橡胶粘接强度和变形量,研究了胶粘剂类型及其厚度、喷涂方式对粘接强度的影响.结果表明,采用活化处理工艺可获得较小变形量和优良粘接表面;采用胶粘剂T811/胶粘剂T835组合有利于不锈钢/天然橡胶的粘接,胶粘剂厚度推荐值在5～20μm之间;采用自动喷涂工艺有利于控制胶粘剂厚度.     

旋翼调整片粘接强度分析与影响因素研究

详细分析了旋翼调整片粘接剥离破坏过程和应力分布变化,并研究了粘接宽度和胶层厚度对粘接强度的影响。使用共固化制备相应的粘接试样,通过剥离试验得到接头的破坏模式及载荷-位移曲线。研究结果表明:接头有限元数值分析结果与试验相契合,接头破坏形式为调整片粘接界面的破坏,破坏为从左向右和由边向中逐渐发生失效;粘接强度随胶接宽度的增加而提高,但增长速度逐步变缓,80 mm为较优搭接宽度值;粘接强度受胶层厚度影响较小,增加厚度时粘接强度先缓慢增加后下降。     

金属工件的表面处理及胶接工艺对胶接剪切强度的影响

采用环氧树脂-DDS固化体系作为胶接剂,探讨了各种金属表面处理方法、胶接时对胶接面施加的压力、胶层厚度等因素对胶接剪切强度的影响.结果表明,对不锈钢工件采用盐酸氧化法及草酸-硫酸氧化法进行表面处理,得到的胶接剪切强度最好;对铝合金工件采用硅酸磷酸钠法进行表面处理,得到的胶接剪切强度最高.胶接时对胶接面施加0.1～0.4Mpa的压力、胶层厚度在0.10～0.23 mm范围内时胶接效果最好.由于处理液对金属表面产生适度的化学腐蚀,改变了金属表面的物理化学性质,表现出更好的可浸润性和更强的表面吸附力,可以有效地提高胶接剪切强度.     

论以无机粘接取代过盈配合

YW - 1无机胶用于套接粘接 ,套接压剪强度可达 14 0 - 180MPa。从高射机枪枪管与枪管套和坦克平衡肘的粘接实例来看 ,无机粘接完全能取代机械结构中的过盈配合。     

船窗玻璃用弹性胶黏剂的安全裕度评价

采用端硅烷聚醚改性环氧树脂配制的弹性胶粘剂用于舰船窗玻璃的粘接,对窗玻璃的受力进行了理论分析,对胶粘剂粘接层的厚度与宽度进行了理论计算,并计算出使用该胶的安全裕度。结果表明:使用所研制的弹性胶粘接船舶前挡风玻璃时,即使在最恶劣工况条件下,粘接强度仍有较大的安全裕度(KA>6),为该胶的实际使用提供了理论依据。     

Experimental study of adhesively bonded CFRP joints subjected to tensile loads

The tensile performance of adhesively bonded CFRP joints has been investigated experimentally. In this study, overlap length, adherend thickness, adherend width and scarf angle were chosen as design parameters. All load–displacement curves are linear, except that the thicker single-lap joints behave slightly nonlinearity due to the bending effect caused by eccentric loading. The lap shear strength is not directly proportional to overlap length, adherend thickness, adherend width and scarf angle for the brittle adhesive studied in the paper. The major failure mode includes adhesive shear failure and adherend delamination failure, sometimes accompanying with some fiber pull-out. Finally, the lap shear strength of three different lap types with similar bonding area (W=25 mm, L=10 mm, θ=5.71°) and adherend thickness (0.96 mm) was analyzed. It is found that the double-lap joint has the highest ultimate failure load. However, when considering the lap region weight, the scarf-lap joint is the most efficient.     

Photoelastic Determination of Flaw Size and Distribution Effects on Adhesively Bonded Lap Joints

It is well known that the load carrying capacity of adhesively bonded lap joints can be influenced by the presence of flaw-like defects which are often created during its bonding process. To design an effective adhesive joint containing possible bonding defects, adequate knowledge and understanding of the shear stress distribution along the entire lap joint are necessary.

This paper describes an investigation into the effects of internal adhesive flaw size and distribution on the fracture behaviour of adhesively bonded lap joints. Photoelasticity is used to gain a quantitative understanding of the localized shear stress concentrations due to the presence of the internal flaws along the bonding layer. It is observed that a 20% increase in the maximum shear stress may be induced when an isolated central flaw of S. O mm was extended to 37.5 mm representing a flaw size of 75% of the lap length. For the presence of multiple flaws along the bonding line, there is no significant effect of the flaw separation distance on the maximum shear stresses. There is, however, a marked increase in the maximum shear stress up to about 45% when a flaw size is increased from 2.5 mm to 7.5 mm.     

螺旋桨用榉木层板胶粘剂性能测试及工艺研究

为了解决木质螺旋桨的稳定性与变形问题,选用自制的聚氨酯(PU)胶粘剂对榉木层板进行胶接后再加工成螺旋桨。分别对胶接件的力学性能、耐热性、耐寒性、耐水性和耐湿热老化性能等进行了测定,探索了自制PU胶粘剂的最佳工艺条件,并进行了常温、高低温处理后的发动机试车试验。结果表明:自制PU胶粘剂具有较高的综合力学强度及稳定性能(其平均常温拉伸剪切强度和压缩剪切强度分别为8.13 MPa和15.00 MPa,平均高低温拉伸剪切强度和压缩剪切强度分别超过6.50 MPa和7.10 MPa;在水中浸泡20 h或湿热环境中放置24 h后,其平均压缩剪切强度分别为5.85 MPa和11.75 MPa),完全满足木质螺旋桨的使用要求。     

风电叶片用双组分聚氨酯胶粘剂的研制

考查了自制缓凝剂用量对混合后胶粘剂黏度和适用期的影响,以及多元醇对胶粘剂强度的影响,添加填料及其他助剂制备了双纽分聚氨酯结构胶。该胶混合后适用期达65min,本体拉伸强度迭39．5MPa,拉伸剪切强度达17．5MPa．且胶片韧性好,应用于风力发电行业的叶片粘接效果好,应用前号广阔。     

超支化聚合物改性明胶胶粘剂的制备及性能

以二乙醇胺、丙烯酸甲酯、三羟甲基丙烷以及环氧氯丙烷为原料,合成不同代数的端环氧基超支化聚（胺-酯）(EHPAE)。其后,以从制革废弃物中提取的明胶为原料,不同代数的EHPAE分别作为交联单体进行改性,制得一种环保型鞋用或包袋用胶粘剂。采用FT-IR光谱,1H-NMR谱图和GPC对超支化聚合物和胶粘剂的结构及相对分子质量分布进行表征,之后对胶粘剂的粘接性能进行测定,结果表明：EHPAE-Ⅲ较其余两者的改性效果更为明显,当EHPAE-Ⅲ用量为明胶用量的30％时,改性后胶粘剂的固含量由11.42%提高到了30.33%,同时剪切强度为2.216 MPa,T-剥离强度为3.375 N/mm,水接触角为100.9o,相较于市售胶粘剂的剪切强度 (1.88 MPa),T-剥离强度 (2.864 N/mm),水接触角(84.8o),制备得到胶粘剂的粘接性能和疏水性均更优。     

Strength model of adhesive bonded composite pipe joints under tension

A theoretical model is developed to predict the strain of the pipe, coupling, and adhesive under tensile loading of an adhesive bonded joint. The model is found to be within 10 percent of the experimental pipe and coupling strain. Based on the model, several failure modes and their locations are defined and related to the measured data. In this investigation, delamination is the dominating mode of failure. The delamination stress for each test sample is within 7 percent of the average theoretical delamination stress. In addition, the effect of the coupling length, coupling Young's modulus, adhesive shear modulus, and adhesive thickness on the delamination failure are investigated. The model shows that decreasing the modulus of the coupling improves the delamination failure load; however, the coupling strain at the middle of the joint is increased by this variation. Increasing the shear modulus of the adhesive provides the most significant improvement of the joint delamination failure load. Two geometric factors, the joint length and the adhesive thickness also affect the joint failure load. The joint delamination failure load can only be significantly improved by increasing the bonding length up to a certain limit. Increasing the adhesive thickness increases the delamination failure load, however, a large gap between the pipe and coupling may contribute to misalignment during installation which may result in imposed moments under tensile loading. This study can supply the manufacturers with the appropriate design parameters to improve the joint performance significantly under tensile loading.