特征长度理论与含缺口ARALL层板分层损伤相关性的研究

本文研究了胶粘剂、胶粘剂含量及不同残余应力状态对含缺口ＡＲＡＬＬ层板的分层损的影响，并试图采用特征长度理论来描述不同缺口层板的分层状态。结果表明：运用源于密集能量区概念的特征长度理论可以定性地分析或半定量地描述ＡＲＡＬＬ缺口层板的分层损伤。     

ARALL层板剥离特性的研究（一）：胶粘剂对层板层间性能的影响

本文采用了Ｂｅｌｌ－剥离法研究了胶粘剂性质及其含量对ＡＲＡＬＬ层间剥离特性的影响。结果表明，层板的剥离过程为多重混合型破坏。由于芳纶／胶粘剂界面结合较前，其剥离强度值较低。使该界面脱粘而破坏，胶粘剂发生内聚破坏以及胶粘剂的韧性增大或含胶量提高均使剥离强度值提高。改善胶粘剂与芳纶的界面粘合状况，提高胶粘剂的韧性是提高层板层间性能的有效途径。     

ARALL层板剥离特性的研究（二）：——残余应力对层板怪间性能的影响

本文通过预应力法调整ＡＲＡＬＬ层板残余应力，研究了自由层板与两种预应力层板的Ｂｅｌｌ－剥离特性。结果表明，结层板施加预应力有效地降低了其中的残余应力，无论自由层板还是预应力层板，剥离所造成的断裂均为多重混合型破坏，其实质是劳纶／胶粘剂界面破坏和纤维自身的破坏，给芳纶施加预应力有利于Ｂｅｌｌ－剥离强度的提高，同时预应力的施加使剥离面上的纤维破坏状态发生改变。     

残余应力与胶粘剂对ARALL层板疲劳裂纹扩展特性的影响

研究了粘剂性质、含量及残余应力状态对纤维－铝合金胶接层板（ＡＲＡＬＬ）疲劳裂纹扩展特性的影响，分析了裂纹扩展过程中的分层状态的变化，结果表明，ＡＲＡＬＬ层板内富胶层的剪切形变和伴随裂纹扩展的分层区越大，即这两方面耗散能量越多，则疲劳裂纺扩展速率越低；胶粘剂含量的影响不明显，给层板施加预应力极大降低了层板的疲劳裂纹扩展速率，其本质在于裂尖在同样的疲劳载荷下实际所受到的有效应力降低。     

ARALL层板剥离特性的研究（一）──胶粘剂对层板层间性能的影响

本文采用了Ｂｅｌｌ─剥离法研究了胶粘剂性质及其含量对ＡＲＡＬＬ层间剥离特性的影响。结果表明，层板的剥离过程为多重混合型破坏。由于芳纶／胶粘剂界面结合较差，其剥离强度值较低。使该界面脱粘而破坏，胶粘剂发生内聚破坏以及胶粘剂的韧性增大或含胶量提高均使剥离强度值提高。改善胶粘剂与芳纶的界面粘合状况、提高胶粘剂的韧性是提高层板层间性能的有效途径。     

维尼纶增强铝合金叠层板（VIRALL）——一种新型超混杂复合材料

本文采用胶接技术，制成维尼纶增强铝合金叠层板（ＶＩＲＡＬＬ）复合村料。结果表明，同相应的Ａ１合金相比，ＶＩＲＡＬＬ层板密度小，强度有一定程度的提高，还具有良好的变形性，并且价格低于Ａ１合金。ＶＩＲＡＬＬ层板可以作为民用Ａ１合金的部分替代品。     

ARALL层板剥离特性的研究（二）──残余应力对层板层间性能的影响

本文通过预应力法调整ＡＲＡＬＬ层板残余应力，研究了自由层板与两种预应力层板的Ｂｅｌｌ－剥离特性。结果表明，给层板施加预应力有效地降低了其中的残余应力，无论自由层板还是预应力层板，剥离所造成的断裂均为多重混合型破坏，其实质是芳纶／胶粘剂界面破坏和纤维自身的破坏，给芳纶施加预应力有利于Ｂｅｌｌ－剥离强度的提高，同时预应力的施加使剥离面上的纤维破坏状态发生改变。     

玻璃纤维-铝合金层板(GLARE)的残余应力

对确定纤维金属层板残余应力的几种方法的基本原理进行了介绍，用Ｘ光衍射法，解析法和腐蚀去层法确定了玻璃纤维－铝合金层板（ＧＬＡＲＥ）的残余应力，对以上几种测试方法的优缺点进行了分析，提出了确定纤维金属层板残余应力的建议。     

大飞机用Glare层板的性能综合评价研究

主要介绍了一种先进玻璃纤维增强铝合金复合材料Glare层板的研究进展,并综合分析欧美Glare层板的研究文献,评述了Glare层板的拉伸性能、压缩性能、冲击性能、剪切性能、缺口残余强度、承载强度、疲劳性能等力学性能,分析了Glare层板环境耐久性和阻燃性等稳定性研究.通过与铝合金和Arall层板的性能比较、分析,论述了Glare层板作为替代铝合金应用于飞机制造方面所具有的优异性能及经济性,简单评述了Glare层板铺层结构与性能的关系,为其应用提供评价基础.     

ARALL层板蠕变特性的研究

本文研究了施加不同预应力及含不同胶粘剂的ARALL层板130℃时的蠕变特性,利用唯像分析的方法,采用陈化理论对实验得到的层板蠕变曲线进行了拟合,并且采用宏观与微观机理相结合的方法对其进行了分析.结果表明,ARALL层板的蠕变主要是由铝合金决定的,施加预应力使ARALL层板残余应力下降,从而降低了层板的蠕变程度.另一方面,采用高模量胶粘剂体系有利于降低层板的蠕应变量.     

Numerical analysis of the notch effect and the behaviour of notch crack in adhesively bonded composite laminates

In this study the finite element method is used to analyse the notch effect and the behaviour of notch cracks in adhesively composite laminate under tension by computing respectively the stress concentration factor at the notch tip which characterize the notch strength and the stress intensity factor at the crack tip which characterize the resistance to the crack propagation. The effects of the adhesive properties and fiber orientation on the variation of both stress concentration and stress intensity factors are highlighted. The obtained results show that the notch strength is reduced in the layer of the laminate of which the fiber orientation is in the applied load direction; the resistance to the crack propagation is also reduced in this type of layer. The stress intensity factor at the tip of notch crack exhibits an asymptotic behaviour as the crack length increases.     

碳纤维增强铝合金层压材料的研究

本文探索了碳纤维增强铝合金层压材料(CFALL)的制备工艺,并制得了具有优异力学性能、耐温、耐疲劳的层压材料.就纤维含量、纤维取向及温度等对层压材料力学性能的影响作了探讨,并对它的疲劳性能以及预应变对疲劳性能的影响进行了研究.试验表明,CFALL具有轻质、高强、耐温、耐疲劳等特点,它的拉伸、弯曲强度超过了ARALL和GLALL,它的疲劳性能与ARALL相近.     

Static and Dynamic Behavior of a Notch Filled by Either Welding or Adhesive Bonding

In the present work, gas metal arc welding (GMAW) and adhesive bonding have been considered as mild steel notch filling techniques. Static as well as dynamic characteristics of filled and unfilled specimens, at different notch angles are assessed and reported.

The present work showed that adhesive bonding is a far superior notch filling technique, when compared with gas metal arc welding due to the absence of distortions, minimum or no metallurgical damage, added to the good joint sealing and better appearance. The present work suggests that metals be cut before repair to a notch angle of 60^°, since maximum ultimate strength (546 MPa) was obtained at a 60^° notch angle.     

低碳钢表面硅烷化处理对聚乙烯涂层结合强度的影响

利用硅烷偶联剂(KH-550,KH-560,KBM-7103)对低碳钢表面进行预处理,制备了聚乙烯(PE)涂层,通过对涂层的结合强度、抗热震性能等实验,研究了硅烷化处理对涂层性能的影响.结果表明:KH-560处理法能显著提高PE涂层的结合强度,比砂纸打磨、喷砂处理分别提高了40.3%,13.2%,而KH-550,KBM-7103不能显著提高PE涂层的结合强度;对于PE涂层的硅烷化处理,适宜的KH-560的浓度为5%(体积分数),水解时间为48h;"喷砂 KH-560"处理法抗热震实验后涂层的结合强度仅降低了10.9%,远低于其他处理方法热震后的下降幅度.     

Ti/Al3Ti金属间化合物基层状复合材料抗侵彻性能数值模拟

采用LS-DYNA非线性有限元软件对Ti/Al₃Ti金属间化合物基层状（MIL）复合材料靶板的弹道侵彻过程进行了数值模拟。考察了等厚度下Ti体积分数、层数和材料梯度分布对复合材料抗侵彻性能的影响。结果表明,Ti体积分数约为20%时,靶板的抗侵彻性能最好。随着层数的增加,复合材料靶板的抗侵彻性能逐渐增强;但超过25层后,靶板的抗侵彻性能逐渐趋于稳定。不同铺层结构功能梯度板的抗侵彻性能相差较大,正向铺层梯度板的抗侵彻性能明显优于等厚均质复合材料靶板。     

冲击荷载作用下EPS混凝土动态性能研究

配置聚苯乙烯(Expanded Polystyrene,EPS)颗粒体积掺量分别为10%,20%,30%,40%,50%的EPS混凝土,采用Φ100 mm分离式霍普金森压杆(SHPB)试验装置,以动态抗压强度和临界应变为指标,研究EPS混凝土在冲击荷载作用下的动态性能,探索EPS颗粒对混凝土动态性能的改善机理。结果表明:由于应变率效应,相同体积掺量的EPS混凝土动态抗压强度与临界应变随应变率的增加而提高,具有显著的应变率相关性;以临界应变为变形性能指标,由于EPS颗粒的微结构效应,在EPS颗粒体积掺量0～40%范围内,其变形性能随EPS体积掺量的增加而提高,当EPS颗粒体积掺量达到50%时,其变形能力有所降低。EPS颗粒体积掺量为40%时对混凝土变形性能的改善效果最佳。     

钨合金材料动态拉伸性能与微观断裂机制关系的研究

测定了光滑和缺口钨合金材料在不同应变率下动态拉伸性能的变化规律，观察了材料断裂的微观机制。结果发现，光滑试样具有正应变率效应，缺口试样具有负应变率效应，在不同应变率下，两种试样的断裂方式没有明显的差别。     

Improvement of the fracture toughness of adhesively bonded stainless steel joints with aramid fibers at cryogenic temperatures

Adhesives should be reinforced with reinforcing fibers for the bonding of adherends at cryogenic temperatures because all the adhesives become quite brittle at cryogenic temperatures. In this work, the film-type epoxy adhesive was reinforced with randomly oriented aramid fiber mats to decrease the CTE (Coefficient of Thermal Expansion) of the adhesive and to improve the fracture toughness of adhesive joints composed of stainless steel adherends at the cryogenic temperature of −150 °C. The cleavage tests of the DCB (Double Cantilever Beam) adhesive joints were performed to evaluate the fracture toughness and crack resistance of the adhesive joints. Also, the thermal and mechanical properties of the fiber reinforced adhesive layer were measured to investigate the relationship between the fracture toughness of adhesive joints and fiber volume fraction of aramid fibers. From the experiments, it was found that the crack propagated in the adhesive with the stable mode of significantly increased fracture toughness when the film-type epoxy adhesive was reinforced with aramid fiber mats. The optimum volume fraction of aramid fibers was suggested for the film-type epoxy adhesive in the adhesive joint at the cryogenic temperature of −150 °C.     

The influence of manganese addition on mechanical properties of commercial Al‐4Mg casting alloys

The aim of this study was to investigate the mechanical properties of Al‐Mg‐Si alloys aged to peak hardness with different dispersoid volume fraction. It was found that the tensile strength increases with dispersoid content, for alloys having similar ductility. The effect of an increasingly triaxial stress state on a fracture strain above mentioned alloys were measured using a series of notched tensile specimens whose notch root radius of curvature was changed. The alloy ductility was found to increase with dispersoid content and root radius and to decrease with increased stress triaxiality. The fracture toughness of these alloys was determined as a function of dispersoid content and notch root radius of curvature. It was observed that the fracture toughness increased as the dispersoid content and the notch root radius increased. scanning electron microscope analysis of the fracture surfaces revealed that fracture mechanism was transgranular fracture with dimples formation. It is argued that optimum mechanical properties in these alloys can be achieved at about 0.5 % Mn content.