共查询到20条相似文献,搜索用时 218 毫秒
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拉削工艺在机械制造业中被广泛地用于零件的内孔精加工,但是很少用干机械装配(包括飞机装配)的最后精加工。我厂为了提高飞机总装的结合工作效率和精加工质量,采用了拉削工艺。首先在部件装配中进行偿试,进而用于飞机总装大部件结合交点孔的精加工。这项工艺改革的成功,取得了显著的技术经济效果。飞机部件交点孔的精加工,有两种类型:一种是飞机的几何参数,靠部件处于水平测量的状态下,在精加工台中用铰孔来保证;另一种是飞机的几何参数靠总装时全机处于水平测量的状态下,采用手工铰孔的办法来保证。我 相似文献
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一种适用于飞机装配的新型随动定位器 总被引:1,自引:0,他引:1
在飞机机身等大部件位姿调整、对接及精加工等装配过程中,如何保持调整后的飞机部件位姿不变并对其进行可靠固持一直是个技术难题。为此,提出一种基于气浮和万向球座的机身部件随动固持方法。采用该方法进行随动固持的具体步骤:首先将与机身部件刚性连接的芯轴插入处于浮动状态的万向球座中,芯轴在进入浮动球体的过程中,球体可在上、下半球座之间进行任意转动;然后根据受力状态使球体和上、下半球座一起平动;芯轴完全进入浮动跟随装置之后,液压锁紧上、下半球座和球体,同时锁紧芯轴,在保证不改变飞机大部件位姿前提下实现对其可靠固持;将油压卸载就可以释放与机身部件连接的芯轴,使机身部件恢复到自由调姿状态。试验和应用分析表明,这种新的随动固持方法可以满足机身对接装配、精加工要求。 相似文献
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飞机电源系统中的冗余设计提升了飞机系统的可靠性,但同时也增加了共因失效发生的概率。为了准确分析飞机电源系统的可靠性,首先,采取α因子模型对共因失效部件的失效率进行分解计算,并利用贝叶斯网络(BN)建立考虑共因失效的飞机电源系统可靠性模型。然后,对比分析考虑与不考虑冗余部件之间的共因失效因素时飞机电源系统及其子系统的可靠性。结果表明,考虑冗余部件之间的共因失效因素时,得到的飞机电源系统及其子系统可靠度相对于不考虑冗余部件之间的共因失效因素时较低,更加吻合实际情况。 相似文献
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一种新的飞机等效单一易损面积计算方法 总被引:1,自引:0,他引:1
基于Monte-Carlo技术,提出了一种新的飞机等效单一易损面积计算方法.将飞机单一易损部件及多重易损部件(余度部件)的杀伤事件模拟成'放球入盒模型',每个盒子面积大小对应于每个部件的易损面积.通过对威胁的打击点进行随机均匀抽样来获得导致飞机杀伤的期望打击数目,从而可以计算飞机等效单一易损面积.算例验证了所提出方法的正确性与可行性.分析表明,该方法弥补了目前计算方法存在的两个主要缺陷:①它可以进行含有多组多重易损部件的飞机等效单一易损面积计算; ②当每组多重易损部件组中的部件具有不同易损面积时,该方法仍然适用. 相似文献
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在外场停放的飞机,其起落架、进气道和尾喷等部件极易受到风沙、粉尘、湿气的侵蚀,因而在外场和机库停放时加强对飞机部件的防腐蚀保护具有非常重要的意义。本文介绍的已获专利认证的Rabon~(TM) VCI防腐蚀罩衣便可对飞机部件进行有效防腐蚀保护。 相似文献
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《中国航空学报》2020,33(9):2434-2444
Owing to reliability and high strength-to-weight ratio, large thin-walled components are widely used in the aviation and aerospace industry. Due to the complex features and sequence involved in the machining process of large thin-walled components, machining deformation of component is easy to exceed the specification. In order to address the problem, it is important to retain the appropriate finishing allowance. To find the overall machining deformation, finishing allowance-induced deformation (web finishing allowance, sidewall finishing allowance) and initial residual stress-induced deformation were considered as major factors. Meanwhile, machined surface residual stress-induced deformation, clamping stress-induced deformation, thermal deformation, gravity-induced deformation and inertial force-induced deformation were neglected in the optimization model. Six-peak Gaussian function was introduced to fit the initial residual stress. Based upon the obtained function of initial residual stress, a deformation prediction model between initial residual stress and finishing allowance was established to attain the finishing allowance-induced deformation. In addition, linear programming optimization model based on the simplex algorithm was developed to optimize the overall machining deformation. Results have concluded that the overall machining deformation reached the minimum value when sidewall finishing allowance and web finishing allowance varied between 1 and 2 mm. Additionally, web finishing allowance-induced deformation and sidewall finishing allowance-induced deformation were 1.05 mm and 0.7 mm. Furthermore, the machining deformation decreased to 0.3–0.38 mm with the application of optimized finishing allowance allocation strategy, which made 39–56% reduction of the overall machining deformation compared to that in conventional method. 相似文献
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在介绍磁流变抛光原理的基础上,分析了磁流变液所应具备的特性.通过配方试验配置了磁流变液,并对其稳定性进行了研究.配置出了沉降率达到8%且具有良好抗团聚稳定性的磁流变液,满足了光学元件抛光的要求.最后提出了进一步提高磁流变液稳定性应采取的几种可行性方法. 相似文献
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航空发动机整体叶盘磁力研磨光整实验 总被引:1,自引:0,他引:1
磁力研磨工艺抛光整体叶盘时,工件与磁极干涉严重,用径向磁极代替轴向磁极加工可有效避免干涉,但研磨压力小、研磨效率低.通过对磁力研磨径向磁极加工机理和单个研磨粒子的微观受力情况详细分析得到:提高磁场强度变化率可有效增大磁力研磨效率.经有限元模拟分析发现磁极表面沿轴线方向开矩形槽可使磁场强度变化率提高.对镍基高温合金材质整体叶盘进行磁力研磨实验,并对实验数据分析研究得出:以径向磁极为工具的磁力研磨法可实现对整体叶盘的无干涉加工,磁极开矩形槽后磁力研磨效率可提高31%,叶盘表面粗糙度值由研磨前的1.2μm降至0.18μm,验证了磁力研磨工艺对高效、高质量实现整体叶盘表面光整加工的可行性. 相似文献
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设计光学元件抛光亚表面损伤检测实验,使用原子力显微镜(AFM)检测传统抛光亚表面塑性划痕与磁流变抛光亚表面塑性划痕的最大深度,通过比较验证磁流变抛光对亚表面塑性划痕的抑制能力;同时利用二次离子质谱仪的深度剖析功能检测磁流变抛光石英样件后表面水解层的深度,指出磁流变抛光属于低损伤性抛光技术。 相似文献
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大飞机垂尾装配界面是由钛合金制成的大型结构件,由于结构刚度低,在精加工时易产生振动、回弹变形和让刀等现象,对其精加工质量造成严重影响。为此,基于电磁感应原理设计了一款新型电涡流阻尼器用于抑制装配界面精加工中的多模态振动。首先,介绍了阻尼器的结构,并建立了其阻尼特性的理论模型。然后,基于该模型分别研究了不同磁极厚度、导体厚度和磁极数等对阻尼器阻尼特性的影响,并确定了阻尼器关键零组件的材料及几何参数。基于此,建立了装配界面抑制系统的动力学模型,并通过数值分析和有限元仿真方法得到了装配界面振动速度与阻尼器阻尼特性的变化规律。最后,通过动力学测试和切削实验对阻尼器的抑振性能进行了验证。锤击测试结果表明该阻尼器能明显提高装配界面抑振系统的阻尼比和等效刚度,阻尼比最大能提高2.17倍,等效刚度最大能提高1.65倍,能大幅衰减装配界面在冲击激励下产生的自由振动。切削实验结果表明该阻尼器能显著提升装配界面精加工过程的稳定性,装配界面时域信号的振动幅值最大能降低64.4%。通过对比实验结果得知双阻尼器配置对装配界面的抑振效果更好,能明显提高其动态可加工性,工艺参数轴向切深能提高至2.0 mm,主轴转速可提升至500 r/min,这为保证和提高装配界面的精加工质量提供了一种简单可行的解决方案。 相似文献
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首先分析了该类零件的几何特点以及加工难点,然后提出了粗加工以及精加工当中的关键技术。阐述了插铣粗加工中,有关叶片直纹包络面的构建,刀轴矢量的选择;精加工中叶片整体加工中使用参数法规划均匀的刀具切削轨迹等关键技术。最后利用VERICUT软件,进行了加工仿真的验证,并且加工完成了开式整体叶轮的加工实例。 相似文献
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In the current practice of multi-axis machining of freeform surfaces, the interface surface between the roughing and finishing process is simply an offset surface of the nominal surface. While there have already been attempts at minimizing the machining time by considering the kinematic capacities of the machine tool and/or the physical constraints such as the cutting force, they all target independently at either the finishing or the roughing process alone and are based on the simple premise of an offset interface surface. Conceivably, since the total machining time should count that of both roughing and finishing process and both of them crucially depend on the interface surface, it is natural to ask if, under the same kinematic capacities and the same physical constraints, there is a nontrivial interface surface whose corresponding total machining time will be the minimum among all the possible (infinite) choices of interface surfaces, and this is the motivation behind the work of this paper. Specifically, with respect to the specific type of iso-planar milling for both roughing and finishing, we present a practical algorithm for determining such an optimal interface surface for an arbitrary freeform surface. While the algorithm is proposed for iso-planar milling, it can be easily adapted to other types of milling strategy such as contour milling. Both computer simulation and physical cutting experiments of the proposed method have convincingly demonstrated its advantages over the traditional simple offset method. 相似文献
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