表面处理对铝合金粘接修理性能的影响

GFRP粘接修复损伤铝板,粘接前对损伤铝合金表面采用不同浓度的硅烷偶联剂KH550、KH560进行处理,以未经偶联剂处理的铝板为对照组,通过拉伸试验与湿热试验研究偶联剂处理对修复效果的影响。试验结果表明:两种偶联剂KH550、KH560处理铝合金效果相当,铝板表面经1%~2%浓度的偶联剂溶液处理不仅有较高的初始强度,而且耐湿热性能也得到提高;湿热处理使不同表面处理的修理试样力学性能发生明显下降,同时,湿热环境对铝板-胶层之间粘接界面的渗透破坏要强于其对胶层-GFRP之间的界面破坏,铝板-胶层界面粘接强度的下降是引起试样性能下降的主要原因。     

铺层形状对复合材料粘接修复铝合金结构性能的影响

通过湿铺方式制备了复合材料补片,并利用该补片开展了受损铝合金试样的粘接修复,研究了补片铺层形状对试件疲劳性能和拉伸性能的影响。研究结果表明:补片铺层形状对试件疲劳性能和拉伸性能均具有一定的影响。在同等条件下,正三角形铺层对破孔和铣槽两类损伤修复试件的疲劳性能和拉伸性能的提升效果最佳,其中疲劳寿命分别提高5.86倍和2.82倍,临界裂纹长度分别增加6.12和8.31 mm,性能恢复系数H分别为87.3%和87.0%,性能提高系数T分别为27.1%和9.6%。     

固化工艺参数对复合材料帽形加筋壁板固化变形的影响研究

帽形加筋壁板具有高比强度、高比刚度、良好的可设计性等优点,在航空航天、能源交通、海洋工程、医疗、建筑、机械等工程领域得到了广泛应用.本文分析了固化工艺参数(固化温度、固化压力、降温速率)对帽形加筋壁板固化变形的基本规律,在深入研究预浸料固化动力学的基础上建立了帽形加筋壁板固化变形的理论模型.通过实验对该模型进行了验证和修正,修正后的理论模型与实际变形量具有较好的一致性.     

辐射固化复合材料进展

与传统的热固化成型技术相比,复合材料辐射固化具有快速,高效,低成本等优点,因而成为复合材料成型技术的“热点”之一。重点介绍了紫外光和电子束这两种方式对复合材料的固化,讨论了复合材料辐射固化技术的优点,发展与应用状况,以及存在的一些问题。     

复合材料胶接修补参数优化研究

针对复合材料层合板穿透性损伤,采用圆形复合材料补片胶接修补方式,对影响胶接修补效率的多个因素进行分析计算。修补结构采用“双板-胶元”模型,有限元分析运用NASTRAN软件。所得结论对工程设计有一定的实用价值。     

UV固化复合材料快速修复金属损伤结构

UV固化不仅可以使复合材料快速固化,而且不需要高温,能避免残余热应力的产生,在应急抢修中比通常的热固化复合材料更具优势。本文采用UV固化的方法实现了损伤金属结构的快速修复,分析了复合材料补片的铺设层数、长度以及损伤结构表面处理对修复效果的影响。     

粘结固化工艺对复合磁体性能的影响

1前官粘结剂在永磁材料中也得到广泛应用。永磁材料是当外磁场撤去后仍然保留磁感应强度的磁性材料，几乎可以永久储存能量。因此，永磁材料通常用作磁场源，在国民经济各方面应用得很广泛，例如伺服电机、磁选矿机、冰箱门封条、磁水器、磁性传感器和计算机硬盘驱动器马达等，是信息时代重要的功能材料。表征永磁材料性能的三个参量是：剩余磁感应强度或称剩磁Br（单位kGs），矫顽力tHe（单位hoe），最大磁能积BHmax（单位MGOe）它们可由永磁测量仪自动测定。一般地说，在矫顽力足够高的情况下，应当使剩磁和最大磁能积越高越好，从而…     

表面处理工艺对复合材料粘接修理的影响

为了满足应急抢修的需求,实现结构承载能力的快速恢复,研究了各种简化的表面处理工艺对于复合材料粘接修理的影响。研究结果表明,采用简单的喷砂或打磨处理工艺可以获得较为满意的粘接修理强度。如果增加喷砂或打磨前后的溶剂清洗,则可以获得更好的粘接强度。不进行表面处理或只是溶剂清洗难以满足修理的要求。不同表面处理工艺获得的修理试样,其拉伸破坏形式不同。     

电子束固化复合材料技术

简述了电子束（EB）固化复合材料的特点,介绍电子束固化机理,电子束固化树脂基体性能,复合材料试件及发动机壳体性能及电子束固化技术在航空航天复合材料其他领域的应用前景。     

飞机复合材料粘接修理技术及应用

介绍了飞机复合材料的粘接维修方法,重点介绍了胶粘剂的热固化、微波固化、电子束固化及光固化的工艺及设备。     

Restoration of the mechanical performance of damaged Al panels using bonded composite repair patches

The paper presents a study upon the behaviour of repaired Al panels under lateral pressure loads, in which various geometries and materials are used for the bonded composite repair patches. The repaired part of the panel is considered in central and side positions. The numerical simulations were validated by experiments in a number of cases, and then used to evaluate the whole proposed range of repair patching configurations. In all key studies, the stress distribution in the adhesive layer and restoration of the mechanical performance at the level of the pristine panel were assessed, in order to make possible the establishment of margins of safety for a wider range of repair patching parameters or configurations.     

Design guidelines for composite patches bonded to cracked aluminum substrates

Design guidelines are proposed for boron fiber-reinforced epoxy composite patches bonded to cracked aluminum substrates. Stress analysis was performed on the composite patch bonded to an uncracked aluminum substrate. The load transfer via the adhesive and the stress levels in the aluminum substrate and the patch were determined. The local stress and stress distribution in the repaired V-shape side cracked substrates were obtained. The effects of crack length and patch geometries including the length and number of plies on the failure behavior of the repair were identified. The results were validated by static tensile tests. It was found that the theoretical calculations were in agreement with the experimental results. This indicates that the proposed analysis can be used as design guidelines for composite repairs of cracked structures. These guidelines coupled with a simple surface preparation technique developed in this work might aid composite patch installation in service.     

Effect of carriers on the performance of aluminum alloy joints bonded with a structural film adhesive

The effect of polyester and nylon carriers on the durability of metal joints bonded with the modified epoxide adhesive BSL 312 has been examined. Joints have been exposed to air at 50°C and 100 percent RH for periods of up to 10,000 h. Some joints were under tensile stress and this seems to have no effect on durability. Carriers cause a slight lowering of the strength of dry joints, but they appear to have negligible effect on joint durability. An analysis of water distribution in exposed joints implies that the rate of strength loss is dependent upon the rate at which water enters joints by diffusion.     

碳纤维复合材料结构修理用胶黏剂应用研究

介绍了复合材料结构胶接修理常用胶黏剂的基本类型和应用情况,对比分析了不同胶黏剂的力学特性,并从胶接件表面处理、固化工艺、无损检测等方面介绍了胶结修理中胶黏剂应用的关键工艺。着重从胶黏剂的自身性能出发,对比贴补和挖补两种胶接修理方式,详细讨论了胶黏剂对胶接修理参数选择的影响。最后,对胶接修理后结构的抗冲击和耐湿热性能方面的研究作了总结,旨在为胶黏剂的破坏机理研究和工艺改进提供参考。     

Effect of residual stresses on fatigue crack growth behavior of aluminum substrate repaired with a bonded composite patch

Composite patches bonded to cracked metallic aircraft structures have been shown to be a highly cost-effective method for extending the service life of the structures. The fatigue crack growth behavior of pre-cracked 7075-T6 aluminum substrate with the 12.7-mm V-notch crack repaired with boron/epoxy composite patches was investigated. 1-ply, 2-ply, 3-ply and 4-ply composite patches were studied. The residual stresses due to mismatch of the coefficients of thermal expansion between the aluminum plate and boron/epoxy composite patch were calculated based on the classical equation. The effects of the residual stresses and patch layers on fatigue lifetime, fatigue crack growth rate, and fatigue failure mode of the repaired plates were examined experimentally. A modified analytical model, based on Rose's analytical solution and Paris power law, was developed for this research. This model considered the residual stress effect and successfully predicted the fatigue lifetime of the patched plates. Results showed that the composite patch had two competing impacts on the structure. The composite patch could cause residual tensile stress in the aluminum substrate, which could consequently increase the crack growth rate. Moreover, reinforcement with the composite patch could also retard the crack propagation in the aluminum plate. If a 4-ply composite patch was used, it resulted in high residual stresses and effectively would not extend the fatigue lifetime of cracked aluminum plates.     

固化工艺对胶接接头冲击性能的影响

研究了固化温度、时间等固化工艺参数对结构钢／环氧胶接接头冲击韧度的影响。结果表明,固化温度从60℃增加到120℃时,冲击韧度值变化显著：当固化时间为1h时,结构钢胶接接头的冲击韧度先随固化温度的提高而有所上升,在90℃时达到最大值,其后随温升而降低;当固化时间为2h时,随固化温度提高冲击韧度出现两个峰值。研究还发现,在研究所采取的工艺条件下,被粘物的待胶接表面经粗细不同的砂纸打磨处理后,冲击性能有一定差异,粗砂纸打磨引起接头冲击韧度实验结果的离散度增大。     

单面和双面复合材料粘接修理胶层中的应力分析

胶层在复合材料粘接修理结构中起着载荷传递作用,采用有限元分析方法,研究了单面和双面粘接修理胶层中的应力分布特点,比较了2种不同修理形式胶层的VonMises应力、剥离应力和剪切应力的分布。结果表明,相同载荷下,单面修理的胶层VonMises、端部的剥离应力都较大,受剪切也比较严重。还研究了补片尺寸对胶层应力的影响。     

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。     

Thermal curing study of bisphenol A benzoxazine for barrier coating applications on 1050 aluminum alloy

Polybenzoxazine coatings were elaborated by dip coating of a solution, prepared from a commercial bisphenol A benzoxazine (BA-a), on a 1050 aluminum alloy. The monomer was dissolved in acetone and the influence of the different application parameters (withdrawal speed and viscosity of the solution) on the wet coating thickness was evaluated. A heat treatment was then performed on the coating to polymerize the benzoxazine monomer by a ring opening mechanism attested for by Fourier Transform Infrared spectroscopy (FT-IR) and followed by Differential Scanning Calorimetry (DSC). Dielectric Analysis (DEA) and Thermogravimetric Analysis (TGA) showed a particular behavior related to a partial decomposition taking place at 180 °C and associated with the creation of intermediary ionic and volatile species. Finally, the barrier protection was evaluated by Electrochemical Impedance Spectroscopy (EIS) for 30 days in sodium chloride solution (0.1 M). The results showed an improvement of the impedance modulus from 10⁴ Ω cm² for an uncoated aluminum to a value as high as 10⁹ Ω cm² with a 10-μm thick polybenzoxazine coating.     

几种机械表面处理方法对6013铝合金接头胶接性能的影响

采用砂纸打磨、湿喷砂、纳米化等3种机械处理方法对6013铝合金表面进行处理,测试其粘接剪切强度,并与P2化学表面处理方法的结果进行对比。利用SEM、AFM、接触角测量仪等技术对铝合金表面处理前后的表面微观结构、微观粗糙度、润湿性等特性进行了研究。结果表明,不同的表面处理方法对铝合金接头的胶接性能影响不同。湿喷砂和砂纸打磨方法处理后铝合金接头的胶接性能与P2化学法表处的效果接近。纳米化方法不利于铝合金胶接性能的提高。微观粗糙度对铝合金的粘接性能具有重要影响,粗糙度越大,铝板胶接性能越好。润湿性不是影响胶接性能的关键因素。