36号飞机座舱盖空中爆破故障分析

本文用断口分析和材料性能检测等方法，对座舱盖残留玻璃进行了分析，在观察的断口中３个断口有疲劳特征。     

30CrMnSiNi2A钢原始疲劳质量的评估

采用断口定量分析方法在，在断口宏、微观特征研究的基础上用断口微观细节特征实测出了疲劳裂纹扩展曲线，并用符合裂纹扩展特性的力学模型对实测曲线进行了拟合计算，反推出飞机用结构材料３０ＣｒＭｎＳｉＮｉ２Ａ的原始疲劳质量（ＩＦＱ）。     

机翼构件不同载荷谱下的寿命反推

对飞机机翼构件在不同截荷谱下的宏、微观断裂特征进行了观察与分析，并结合载荷谱中的应力变化特点，对A飞机和B飞机翼构件在不同载荷谱下的裂纹扩展寿命进行反推。结果表明，载荷谱中不同的应力变化在失效构件断口上反映出不同的宏、微观断裂特征，采用断口定量分析技术可反推构件的疲劳寿命，并依此反推构件疲劳裂纹形核的先后顺序。     

激光热应力切割玻璃实验与分析

CO２激光器平均输出功率为１００W时,通过聚焦光路在玻璃表面形成圆型的聚焦点。玻璃强烈地吸 收１０畅６μm的激光,激光能量被玻璃表面１５μm厚的吸收层吸收,形成局部的应力纹样分布（设定的切割线）。 介绍了淬火气嘴将冷空气吹到玻璃表面对受热区域进行快速淬火;１００W的激光能量照射玻璃表面,产生高于玻 璃软化的温度;吹气冷却形成应力集中的热应力层,使玻璃从切开的断口沿切割线断开,断口光洁。实验证明, 激光热应力切割玻璃的最佳速度是４００mm桙s。     

低熔可切削生物活性微晶玻璃的研究

选择一种出SiO₂-MgO-Al₂O₃-K₂O-CaO-P₂O₅-F基础玻璃体系,并添加不同量的ZnO,制备出性能良好的可切削生物微晶玻璃.结果表明,由于ZnO的添加,可使母玻璃的熔化温度由1450℃降至1300℃,可切削生物活性微晶玻璃的母玻璃能够在较低的温度熔化制备.母玻璃晶化后析出相主要为云母相和氟磷灰石相;各种晶相的组合形貌为花瓣形态,其断口呈现穿晶断裂的特征,并有晶体拔出,使材料具备了较高的强度;由于析出了较多的云母相,该微晶玻璃兼具良好的可切削性能.     

30CrMnSiNi2A钢构件焊缝边缘裂纹研究

研究了飞机主起落架半轮叉在使用过程中出现于３０ＣｒＳｉＮｉ２Ａ焊缝边缘的裂纹的形态，断口特征，形成及扩展原因。发现焊缝加强高凸部分和内侧板弧形表面的交角过小，引起应力集中；焊趾表层疏松及打磨的痕迹，蚀坑等促使裂纹萌生，主起落架在滑行，刹车，转弯的力矩使裂纹扩展。     

粘结剂种类对模压成形制备呋喃树脂类玻璃炭的影响

研究了粘结剂类型对模压成形法制备呋喃树脂基类玻璃炭性能影响.3种粘结剂分别是沥青、酚醛树脂和硼酚醛树脂作为粘结剂,含量均为30%(质量分数).采用DSC/TG研究类玻璃炭的炭化工艺,并用SEM观察其断口形貌,用排水法计算材料的密度,用检流计测定类玻璃炭的电阻率.研究结果表明:粘结剂种类对类玻璃炭的综合性能有较大影响.以酚醛树脂作为粘结剂时类玻璃炭综合性能最好,断口光滑平整,只有极少量直径＜0.2μm的孔洞,无裂纹,其密度为1.47g/cm3,电阻率为224.3μΩ·m.     

3 0CrMnSi 2A钢飞机主梁疲劳断裂分析

用扫描电镜观察了某型飞机机翼主梁的疲劳断口，和疲劳条带估算了裂纹扩展寿命，并用Zheng-Hirt公式估算出裂纹尖端应力强度因子范围，估算结果与实验测定值十分接近，从而为研究老龄飞机的使用寿命，进行了有益的探索。     

失效分析技术及其应用—第六讲 韧性与脆性断裂的显微形貌特征

韧性与脆性断裂失效的显微形貌特征,即断口的高倍观察,基本上是应用电子显微镜来实现的。在失效分析中经常使用的电子显微镜,主要有两种类型:(1)透射电子显微镜;(2)扫描电子显微镜。利用透射电子显微镜研究断口形貌特征时,必须掌握断口试样的复型技术;经常使用的倍率为2000～30000X,使用扫描电子显微镜观察断口形貌特征时,不必使用复型技术可直接观察断口试样;经常使用的倍率为20～5000X。通常将用电子显微镜来分析研究断口的显微形貌特征技术称之为电子显微断口学,简称为电子断口学。     

自发梯度炭／炭复合材料弯曲性能研究

对包埋－粉末涂刷高温烧结工艺制备的自发梯度二维炭/炭（2D C／C）生物活性玻璃涂层复合材料进行了弯曲力学性能测试和断口形貌观察,结果表明：生物玻璃涂层的2D C／C试样的断口形貌显示,涂层与C／C结合紧密;部分纤维插入生物玻璃内;同时,生物玻璃涂层内的裂纹能沿纤维与其界面扩展,表明位于涂层内的纤维与涂层的结合为弱结合;统计分析表明,涂层处理后的试样弯曲模量、抗弯强度都有所提高,而挠度无显著差异。     

On statistical moments of fatigue crack propagation

A new statistical theory is proposed for the analysis of fatigue crack propagation, based on the concepts of fracture mechanics and random processes. Focus is centered on conceivably more useful information of the random time at which the crack size grows to any specific value. Given an initial crack size, recursive relationship is obtained for the statistical moments of this random time for a rather general class of material behaviors, and examples are given for the case where the crack propagation rate is governed by a power law. A procedure to estimate the parameters in the power-law model is also illustrated, using the experimental data of some 7475-T7351 aluminum fastener hole specimens subjected to the excitation of a certain bomber load spectrum.     

An Experimental-Theoretical Method of Measuring the Surface Energy of Polar Dielectrics

A physical model of the initial reversible stage of electrical breakdown is formulated, which provides a basis for a method of measuring the surface fracture energy of a thin dielectric layer of a metal-dielectric-metal structure at the instant of fracture.__________Translated from Izmeritel’naya Tekhnika, No. 4, pp. 57–60, April, 2005.     

Observations of the dislocation substructure produced by elevated temperature fatigue crack propagation in the type 316 stainless steel

The dislocation substructure produced by elevated temperature fatigue crack propagation in annealed Type 316 stainless steel was surveyed by post-test transmission electron microscopy. Both un-irradiated and neutron irradiated specimens were examined. The results for the unirradiated specimens show that dislocation cell formation was limited to within approx. 1 mm of the fracture surface. The dislocation cell size within this region was found to reflect the test temperature and effective stress level. No evidence of dislocation cell formation was observed m the neutron irradiated fatigue specimens. It was concluded that dislocation cell formation, if it occurs in neutron irradiated specimens, is confined to within approx. 0.75 mm of the fracture surface.     

Effect of the asymmetry factor on the nature of failure and deformation of the surface of fatigue fractures

Electron and x-ray fractography were used to examine fracture surfaces of 38KhN3MA structural steel produced in tests of cyclic cracking resistance with different asymmetry factors of the load cycle. The variation of the failure mechanism in crack propagation was determined: from striated to ductile in the fatigue zone of fractures, brittle, quasicleavage in the zone of uncontrolled failure, and back to ductile in the final fracture zone. The experiments show that the strain, on the fracture surface rapidly increases in the zone of uncontrolled failure. The minimum deformation on the surface, of all fractures corresponds to the same values of the range of the stress intensity factor and the crack growth rate. These values are similar to the coordinate of the points of intersection of the kinetic diagrams of fatigue failure of specimens tested at different asymmetry factors of the load cycle.Translated from Problemy Prochnosti, No. 5, pp. 56–61, May, 1990.The authors are grateful to V. G. Kudryavsho for discussing the experimental results.     

未来轰炸机热管理系统方案及关键技术浅析

通过对国外飞机先进热管理系统的分析,提出了我国未来轰炸机机的综合热管理系统,并对系统的初步方案及关键技术进行了初步分析,为国内研制未来轰炸机热管理系统系统提供了参考。     

Fractography and structure of the subsurface cleavage zone in molybdenum

Transmission electron microscopy of thin foils was used to examine the structure of fracture surfaces of single crystals of molybdenum failed by cleavage along different crystallographic planes, and the dislocation structure of the zone adjacent to the fracture surface was also studied. The results show that cleavage steps are the main characteristic element in failure along any plane in the group of the examined planes ({100}, {110}, {211}, {123}). The number, dimensions, and crystal geometry of the cleavage steps depend on the cleavage plane. The primary cleavage elements are steps of the minimum size (height 8–17 nm). The results also show that with an increase of the work used in failure in transition from one cleavage of macroplane to another the thickness of the zone with high (in comparison with the initial value) dislocation density increases together with the dislocation density directly on the fracture surface.Translated from Problemy Prochnosti, No. 1, pp. 58–63, January, 1991.     

Modeling the kinetics of crack development in bearing plates of adhesive-bonded laminated members

The use of the finite-element method for calculating adhesive joints of plates during their work under shear and bending conditions was substantiated within the scope of a combined theoretical and experimental investigation. The possibility of extending the models developed to the area of linear fracture mechanics for laminated metal-polymer composites is shown and experimentally confirmed. The effect of a number of mechanical characteristics of a polymer binder on the character of fracture in the region of through and surface cracks in metal-fiber-reinforced plastics is evaluated.Translated from Problemy Prochnosti, No. 7, pp. 47–52, July, 1994.     

武器模拟训练系统软件功能模块间通信设计

某型轰炸机武器模拟训练系统软件的开发采用模块化设计方法,各功能模块负责部分训练功能,为实现模拟训练系统的整体功能,必须使各功能模块协调工作,而功能模块间的数据交换是实现整个系统协调工作的重要途径,结合模拟训练系统的开发,本文利用串行通信、进程通信和线程通信等技术设计了软件功能模块间的通信机制,实验结果表明,该通讯机制能满足功能模块间数据交换的要求.     

Failure of Zr<Subscript>50</Subscript>Ti<Subscript>16.5</Subscript>Cu<Subscript>15</Subscript>Ni<Subscript>18.5</Subscript> amorphous metallic ribbon

The deformation and fracture behavior of Zr₅₀Ti_16.5Cu₁₅Ni_18.5 bulk amorphous metal in the form of a thin ribbon have been determined in tensile test at room temperature. The fracture is localized in a major shear band and the fracture angle between the tensile stress axis and the fracture plane is close to 45°. Fractographic observations have revealed that the fracture surface of the amorphous metallic glass consists mainly of a vein-like pattern morphology. We present a scheme of three zones of fracture surface morphology: progressive smooth sliding region (A), dominating vein like pattern (B), and river-like ripples (C). __________ Translated from Problemy Prochnosti, No. 1, pp. 28–31, January–February, 2008.     

Criteria of the contact strength,ductility, and fracture of materials in shear with buckling

A model is presented of the origination and suppression of the fracture of a contact surface during shear of its layers. The process is examined as a function of the configuration of projections on the rigid body, the thickness of the layers undergoing deformation, and the distribution of the contact stresses. Two mechanisms of fracture suppression on the contact surface are found: an unstable mechanism dependent on the thickness of the layer undergoing shear and the properties, roughness, and condition of the surface of the material being deformed; a stable mechanism independent of these factors. Both mechanisms are found to be of practical value in the solution of problems which involve increasing the strength of contact layers and resistance welds in various structures and optimizing regimes of plastic deformation and resistance welding. Criteria of contact strength are also presented for ductile and low-ductility materials.Translated from Problemy Prochnosti, No. 6, pp. 26–32, June, 1992.