平板叶片斜撞击瞬态响应的计算分析

采用有限元法,对平板叶片在不同鸟撞击角度下的非线性瞬态响应进行了数值分析研究.结果表明,平板叶片在不同撞击角度下的弯曲变形、到达最大变形的时间及残余变形随着撞击角度的增加而增大;平板叶片的扭转变形随着撞击角度的增加先增大后减少,撞击角度在小于30°及90°附近对平板叶片的扭转变形影响很小.     

复合材料缠绕接头几种受力状态的解析分析

针对复合材料缠绕接头,利用Airy 应力函数,推导出与其相关的缠绕圆筒受内外压力的应力解析表达式,进而对缠绕圆拱形梁受弯矩以及受均匀拉伸载荷、不同材质复合材料多层缠绕圆筒承受内外压力的应力分析方法进行了研究。文中讨论了接头内圆弧处应力集中系数随外/内径比值和环向/径向弹性模量比值的增加情况,并对复合材料缠绕接头的两种增强方法,即施加预应力或混杂材质缠绕进行了探讨     

机械连接件中螺栓孔角裂纹应力强度因子数值计算(英文)

The three-dimensional finite element method is used to solve the problem of the quarter-elliptical comer crack of the bolt-hole in mechanical joints being subjected to remote tension. The square-root stress singularity around the corner crack front is simulated using the collapsed 20-node quarter point singular elements. The contact interaction between the bolt and the hole boundary is considered in the finite element analysis. The stress intensity factors （SIFs） along the crack front are evaluated by using the displacement correlation technique. The effects of the amount of clearance between the hole and the bolt on the SIFs are investigated. The numerical results indicate that the SIF for mode I decrease with the decreases in clearance, and in the cases of clearance being present, the corner crack is in a mix-mode, even if mode I loading is dominant.     

Nanofillers modification of Epocast 50-A1/946 epoxy for bonded joints

Epocast 50-A1/946 epoxy was primarily developed for joining and repairing of composite aircraft structural components. The objective of the present work is to modify the Epocast epoxy resin by different nanofillers infusion. The used nanofillers include multi-walled carbon nanotubes（MWCNTs）, SiC and Al2O3 nanoparticles. The nanofillers with different weight percentages are ultrasonically dispersed in the epoxy resin. The sonication time and amplitude for MWCNTs are reduced compared to Al2O3 and SiC nanoparticles to avoid the damage of MWCNTs during sonication processes. The fabricated neat epoxy and twelve nanocomposite panels were characterized via standard tension and in-plane shear tests. The experimental results show that the nanocomposites materials with 0.5wt% MWCNTs, 1.5wt% SiC and 1.5wt% Al2O3 nanoparticles have the highest improvement in the tensile properties compared to the other nanofiller loading percentages.The improvements in the shear properties of these nanocomposite materials were respectively equal to 5.5%, 4.9%, and 6.3% for shear strengths, and 10.3%, 16.0%, and 8.1% for shear moduli. The optimum nanofiller loading percentages will be used in the following papers concerning their effect on the bonded joints/repairs of carbon fiber reinforced composites.     

自制一种高效便利的静压接头

大气数据系统泄漏测试中静压连接困难,目前在用的两种静压接头都各有缺陷,因此自制了一种适用于各种机型的静压接头,其结构简单、高效易用、可靠性高,提高了工作效率。     

微型单叶轮涡扇发动机若干总体问题

对低增压比微型涡扇的总体气动热力学有效性进行了基础性的研究.结果表明, 该类发动机仍可有效地降低耗油率, 因而有发展的必要.进一步, 为解决微型涡扇发动机的结构复杂性困难, 提出了一种微型高矮叶片单叶轮风扇压气机的压缩系统气动布局和结构设计方案.借助一个具体例子的设计研究和流场检验的结果, 陈述了该方案的转子、静子的气动设计和结构设计特点.最后拟出了相应的发动机主体结构.      

胶粘剂弹性模量对间隙接头应力和强度的影响

 运用弹塑性有限元法,研究了胶粘剂弹性模量对含间隙的铝合金单搭接接头的影响。通过分析胶层和被粘物的应力分布,结果表明：间隙连接对接头端部的应力分布无明显影响,但对间隙附近的应力峰值影响较大;随着胶粘剂弹性模量的增大,间隙附近的应力峰值反而减小;对于高弹性模量胶粘剂接头,间隙对接头的应力峰值无明显影响,在不降低接头名义强度的基础上极大地提高了接头的实际强度;而对于低弹性模量胶粘剂接头,间隙使得接头的应力峰值明显上升,显著地降低了接头的名义强度和实际强度。数值模拟结果与已发表的试验数据大致吻合。     

基于Solid-Works的齿轮参数化设计

由于Solid-Works2003及以前版本的软件,其标准件图库中没有绘制各种齿轮的功能,本文介绍了在Solid-Works中实现参数化齿轮三维造型的一种方法,应用此方法可以在Solid-Works环境下完成齿轮的参数化三维绘制。     

应力比对不锈钢焊接接头疲劳寿命的影响研究

针对0Cr18Ni9不锈钢薄板焊接接头,开展了高周疲劳性能测试,研究了应力比对其疲劳极限和疲劳寿命S-N曲线的影响。结果表明应力比对疲劳寿命有较大的影响,在最大应力一定的情况下,应力比越大其疲劳寿命越大。基于试验结果,得到了反映应力比影响的0Cr18Ni9不锈钢薄板焊接接头Goodman修正和Walker修正的高周疲劳寿命预测模型。模型的预估寿命和试验数据对比表明,Walker修正模型对疲劳寿命的预测结果全部处于1.0倍分散带以内,其更能反映应力比对0Cr18Ni9不锈钢薄板焊接接头疲劳寿命的影响。     

法国SNECMA涡轮盘榫槽拉削波纹工艺分析

公司外贸产品法国SNECMA涡轮盘试制过程中出现榫槽表面拉削波纹，通过工艺分析找出了产生波纹的原因，并有针对性地改进了工艺及夹具，消除了榫槽表面拉削波纹，使涡轮盘表面质量达到了技术要求。