浮空器囊体用聚氨酯胶粘剂性能测试分析研究

介绍了胶粘剂在浮空器上的应用,分析了浮空器囊体粘接用胶粘剂基本要求,然后对浮空器国产专用胶粘剂和某进口胶粘剂进行初粘性、胶接强度、耐高温性能及老化性能对比试验研究,最后根据试验结果阐述了国产胶粘剂的综合性能相对进口胶粘剂存在的不足,为提升国产浮空器囊体粘接用胶粘剂综合性能提供一定的参考。     

改性环氧树脂光固化速粘胶的粘接应用研究

采用玻璃纤维布/光固化胶粘剂复合材料补片,实现对铝合金片的快速粘接与固化。考察了国产UV胶粘剂预聚物和进口UV胶的粘接性能、耐温性能以及粘接强度随胶粘剂相对分子质量及其分布的变化规律。结果表明:进口光固化胶/玻璃纤维布复合材料补片与铝合金片的剪切强度在14.5～23.1MPa之间,国产光固化胶体系剪切强度在11.3～16.6MPa之间,两者均高于铆接强度(10.3MPa);作为胶粘剂基体树脂,相对分子质量分布越宽越有利于粘接强度的提高;此外,-40℃低温与100℃高温对体系粘接强度的影响很小(不超过10%)。     

陶氏化学推出风电叶片用新型EP胶粘剂

<正>陶氏化学近日推出专为风电叶片制造行业研制的EP(环氧树脂)胶粘剂产品系列。其中AIRSTONE77-T3胶粘剂可直接将风机叶片的两片外壳粘接在一起,形成完整的叶片结构。与传     

复合硅烷化预处理对铝合金/环氧胶粘剂粘接强度的影响

研究了铝合金表面复合硅烷化预处理对铝合金与环氧胶粘剂粘接强度和粘接耐久性的影响,并与铬酸盐预处理进行了比较。用反射吸收红外光谱和透射电镜分析观察铝合金表面复合硅烷化膜层的结构,分别用扫描电镜、X-射线光电子能谱和俄歇能谱分析了不同粘接件断裂表面。结果表明,铝合金经复合硅烷化预处理能明显提高铝合金基体与环氧胶粘剂的粘接强度和粘接耐久性。搭接件断面呈现一层层撕开的破坏现象,而铬酸盐处理的搭接断裂件的断面较平齐。硅烷化处理的楔子试样断裂件的断裂面也呈现明显的韧性断裂,表明在铝合金与胶粘剂界面区域形成的Al-O-Si和硅氧烷共价键网络和复合硅烷化膜层表面的环氧基团起着明显的界面和表面改性作用。     

风电叶片用国产碳纤维预浸料工艺性能和力学性能研究

应用碳纤维制备风电叶片结构件是大型风电叶片制作技术的一个发展方向。为推动国产碳纤维的发展应用,给出了风电叶片对碳纤维预浸料的技术要求,研究了国产碳纤维预浸料和进口碳纤维预浸料的力学性能和工艺性能,通过对比分析发现,面密度低的国产碳纤维预浸料力学性能高于进口碳纤维预浸料,但面密度≥600g/m2的国内碳纤维预浸料的工艺性能较差,需要进一步改进。     

腈纶设备大型箱体保温材料粘接

采用国产胶粘剂代替美国进口胶粘剂,进行了腈纶设备大型箱体保温材料的粘接,效果良好。本文讨论了胶粘剂的选择试验情况,并详细介绍了保温材料粘接工艺及粘接注意事项。     

风电叶片用结构胶粘剂粘度及触变性试验分析

风力发电是结构胶粘剂的新兴应用领域,在风电叶片的生产、组装、部件制造中有着广泛的应用,是风电叶片整体结构中的关键组成。有效地分析评价风电叶片用结构胶粘剂对于保证叶片的质量极为重要。胶粘剂的流变性是评价其质量和工艺性能的关键因素,其中粘度和触变性是两个极为重要的表征量。通过对风电叶片用结构胶粘剂在不同测试条件下的粘度和触变性试验,总结不同测试条件对胶粘剂粘度及触变性评价的影响,并提出使用触变环法评价结构胶粘剂的触变性的方法。经过分析表明,触变环法能够定性定量地表征胶体的触变性。     

风电叶片涂料的评价方法及实例

根据风电叶片涂料所处使用环境,制定了一套科学的评价体系并用实例进行了说明.该评价体系分为常规性能评价部分和关键性能评价部分,且均可通过常规检测仪器和检测方法得以实现.通过对2家进口和3家国产风电叶片涂料分别进行评价,结果发现:国产涂料和进口涂料均能达到常规性能指标；进口涂料在耐酸、耐碱方面不如一些国产涂料；有2家国产涂...     

用国产胶粘剂修理大型及进口设备

用国产胶粘剂修理大型及进口设备刘光成（南京市内燃机配件厂，南京市２１０００８）１前言使用国产（包括自配）胶粘剂，成功地修复了一些国内大型及进口大型设备，使生产得以正常进行，取得了可观的经济效益和社会效益。２粘接修复实例２．１南京火柴厂火柴连续生产自动...     

浅议PFMEA在海上风电叶片粘接工艺中的应用

在海上风电叶片产品设计开发早期,充分识别潜在失效原因并制定验证相应防范措施,是开发风电叶片产品的重要措施。本文介绍了PFMEA应用与海上风电叶片设计开发的实例,通过分析潜在失效原因,发现粘接胶涂胶尺寸设计与界面处理方式是风电叶片后缘粘接是否出现空腔、气泡等缺陷的关键影响因素,并通过NDT无损探伤检测,验证粘接胶涂胶工艺设计的可行性,有效控制产品开发的风险。     

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。     

一种高性能刹车片胶黏剂的研究

本文制备了一种不含橡胶的刹车片胶黏剂,既可以作为盘式刹车片胶黏剂,也可以作为鼓式刹车片胶黏剂。这种胶黏剂柔韧性好,耐热性能优异,而且对几乎所有非金属材料都具有良好的粘接性能。     

国内主要厂家金刚石锯片的胎体成分和性能研究(下)

采用扫描电子显微镜和能谱分析对国内主要厂家的金刚石锯片的胎体成分、微观形貌和烧结情况进行分析研究,并对实际切割效率进行对比.结果表明,目前国内金刚石锯片胎体主要以Cu、Fe为主,其含量约占胎体总量的70％左右;金刚石锯片刀头中的金刚石晶形完整,胎体烧结致密,且胎体与金刚石界面结合较紧密;不同的金刚石锯片根据胎体中主要金属含量的不同,适用于切割不同的岩石,且实际使用性能良好,寿命均在150～170m2之间.     

Experimental investigation on the enhancement of Mode I fracture toughness of adhesive bonded joints by electrospun nanofibers

ABSTRACT

The use of an electrospun nylon nanofibrous mat at the interface between adjacent plies of a composite laminate is a promising mean to improve the delamination strength, as the nanomat acts a reinforcing web enabling a ply-to-ply bridging. This kind of reinforcement can be potentially used in other applications, such as adhesive bonding, where it may also work as adhesive carrier. The present work is therefore aimed at analysing the potential of an electrospun polymeric nanomat as adhesive carrier and reinforcing web in adhesive bonding. The adhesive is used to pre-impregnate a nylon nanofibrous mat that is then placed at the interface between two metal pieces and cured. The effectiveness of this procedure is evaluated by comparing of the mode-I fracture toughness measured 2024-T3 aluminum alloy DCB (Double Cantilever Beam) specimen bonded using a two-part epoxy resin with and without the nanomat.     

Quasi-Static Adhesive Fracture

The concept of quasi-static crack propagation is used in the present paper to study quantitatively the effects of environmental fluids on fracture in adhesive joints. The mechanisms and mechanics of environmental adhesive fracture under rising loads are discussed. Two types of cracking behaviour were observed. (1) When the dissolution or the “surface energy reduction” mechanism prevailed, the fracture toughness of the adhesive joint in the environment was reduced. (2) However, when environment-enhanced crazes were formed in the adherend at the crack tip region, the local fracture toughness of the adhesive joint would be increased. But cracking was usually unstable so that crack velocities were not readily measurable.

Except in so far as the adhesive surfaces may have considerable effects, the fracture toughness of an adhesive joint is independent of the specimen geometries used in the present work. Also, the variation of fracture toughness with crack velocity for an Aluminum/ Araldite joint in a carbon tetrachloride solution is reported.     

Mode II Fracture Toughness of a Brittle and a Ductile Adhesive as a Function of the Adhesive Thickness

The main goal of this study was to evaluate the effect of the thickness and type of adhesive on the Mode II toughness of an adhesive joint. Two different adhesives were used, Araldite ® AV138/HV998 which is brittle and Araldite 2015 which is ductile. The end notched flexure (ENF) test was used to determine the Mode II fracture toughness because it is commonly known to be the easiest and widely used to characterize Mode II fracture. The ENF test consists of a three-point bending test on a notched specimen which induces a shear crack propagation through the bondline. The main conclusion is that the energy release rate for AV138 does not vary with the adhesive thickness whereas for Araldite 2015, the fracture toughness in Mode II increases with the adhesive thickness. This can be explained by the adhesive plasticity at the end of the crack tip.     

An experimental study on the dependence of the strength of adhesively bonded joints with thickness and mechanical properties of the adhesives

Adhesive bonding joints are widely applied in many engineering fields. Their overall strength is much dependent on the thickness of adhesive layers. Many previous experimental studies have found that the ultimate failure strength of the bonding structure increases with the decrease of the adhesive thickness. However, few of them consider the effect of adhesive intrinsic material parameters on the relation between the overall strength and adhesive thickness. In the present investigation, the effect of the adhesive thickness on the overall strength of the lightweight metallic adhesive bonding joints was experimentally studied, considering the effect of the adhesive toughness. The results show that the variations of overall strength resulting from the adhesive thicknesses have remarkable discrepancy due to the toughness of the adhesive, which is in agreement with the previous model prediction.     

Effect of high loading rate and low temperature on mode I fracture toughness of ductile polyurethane adhesive

The mode I fracture toughness of an adhesive at low temperatures under high loading rates are studied experimentally. Typical R-curves of the polyurethane adhesive under different loading rates (0.5?mm/min, 50?mm/min, 500?mm/min) at different temperatures (room temperature, ?20?°C, ?40?°C) respectively are obtained. From the experimental results, the mode I fracture toughness of this adhesive is extremely sensitive to the high loading rates and low temperatures. With the increase of the loading rate and decrease of temperature, the mode I fracture toughness of this adhesive decreases significantly. Under the loading rate of 500?mm/min at ?40?°C, the mode I fracture toughness of adhesive is 15% of the value at room temperature (RT) under quasi-static conditions. Through the experiment, the relationship between mode I fracture toughness of this adhesive, nominal strain rate and temperature is obtained.     

Novel surface and interfacial analysis techniques as aids to the development of new, high fracture toughness film adhesives

An experimental film adhesive of high fracture toughness had given a promising range of adhesive properties on pickled 2024-T3 clad aluminum alloy, but a wide variation in peel performance resulted when this adhesive was used to bond anodized aluminum adherends. High resolution scanning electron microscopy/ energy dispersive X-ray analysis of the fracture interfaces coupled with transmission electron microscopy of ultramicrotomed sections through the same specimens has shown that the problem was non-wetting of the substrate on a microscopic scale. The rheological properties of the adhesive system have been altered to overcome the problem, yielding a high fracture toughness film adhesive of consistent performance.     

The Effect of Adhesive Thickness on the Mechanical Behavior of a Structural Polyurethane Adhesive

One parameter that influences the adhesively bonded joints performance is the adhesive layer thickness. Hence, its effect has to be investigated experimentally and should be taken into consideration in the design of adhesive joints. Most of the results from literature are for typical structural epoxy adhesives which are generally formulated to perform in thin sections. However, polyurethane adhesives are designed to perform in thicker sections and might have a different behavior as a function of adhesive thickness. In this study, the effect of adhesive thickness on the mechanical behavior of a structural polyurethane adhesive was investigated. The mode I fracture toughness of the adhesive was measured using double-cantilever beam (DCB) tests with various thicknesses of the adhesive layer ranging from 0.2 to 2 mm. In addition, single lap joints (SLJs) were fabricated and tested to assess the influence of adhesive thickness on the lap-shear strength of the adhesive. An increasing fracture toughness with increasing adhesive thickness was found. The lap-shear strength decreases as the adhesive layer gets thicker, but in contrast to joints with brittle adhesives the decrease trend was less pronounced.