大型机身复合材料加筋壁板制造技术及应用

复合材料机身是我国新研制的大型民用客机的重要结构之一,其制造工艺直接影响产品的质量一致性、产能、成本等,传统手工为主的制造技术已远远不能满足当前要求。为了验证大型机身复合材料帽型加筋壁板的自动化成型工艺进行了多方位的研究探索和验证,通过串联自动铺带、自动铺丝、长桁毛坯的叠层滑移成形、填充芯材自动成形、长桁定位等工艺,完成了大型壁板的制造。研究表明,选择的壁板制造工艺技术风险低,质量一致性高,为大型复合材料机身帽型加筋壁板的自动化制造提供了基础。

叠层滑移工艺制造大型机身帽型长桁

叠层滑移工艺是自动化制造大型帽型长桁的一种新工艺,为验证该工艺进行了多方位的研究探索和验证,通过串联自动铺带、超声切割、长桁毛坯的叠层滑移成形、热压罐固化等工艺,完成了大型机身帽形长桁的制造。采用多种手段对长桁的质量进行了检查。研究结果表明,该套工艺技术风险低,质量一致性高,为大型复合材料长桁的自动化制造提供了技术基础。

Model Investigation on Composite Failure Prediction of π-Joint Structures

This paper was concerned with the tensile mechanics behavior of the composite π-joint under static tensile loading. The numerical strength analysis methodology was presented containing the basis assumption for the analysis, the material modeling, and the selected element type. It was assumed that the composite ply had transverse isotropic material properties and the adhesive had linear elastic properties. With the goal of the strength analysis to determine the onset of the damage initiation and the ultimate failure load, two stiffness degradation models were discussed and a modified maximum stress failure criteria was presented. To verify the numerical model, a pull-off test scheme was performed and the experimental data of five specimens were given. The experimental results indicate that the damage initiation location and the failure load were consistent with numerical predictions and verified the feasibility of the numerical model.

黔南少数民族正常成人脑动脉多层螺旋CT数据三维重建与相关解剖学分布

目的:了解黔南州少数民族正常人脑动脉多层螺旋CT血管成像(MSCTA)上主要脑动脉的起始部走行、形态及其分支的显示情况,测量起始部内径的正常值范围,观察脑底动脉环解剖结构及变异,为脑血管疾病的诊断及治疗提供参考资料。方法:选择500名健康体检者行全脑血管64层MSCTA检查,采用西门子signo工作站,经三维重建后测量各主要动脉起始部内径,观察其走行、形态和变异,并统计各级分支的显示率。结果:黔南少数民族正常人脑动脉的常见的变异发生在组成脑底动脉环的大脑前动脉A1段、前后交通动脉及大脑后动脉起始段,以后交通动脉变异最大。正常脑动脉Willis环分型,Ⅰ型为3%;Ⅱ型为1%;Ⅲ型为54%;Ⅳ型为42%。结论:黔南少数民族正常人脑血管变异主要发生于脑底动脉环,主要变异为Ⅲ型和Ⅳ型。

实验分析帽型加筋壁板填充芯材下方蒙皮褶皱成因

研究了碳纤维/环氧树脂复合材料帽型加筋壁板在长桁先固化、蒙皮未固化的共胶接工艺下,填充芯材下方蒙皮褶皱的形成过程及产生原因。测试了预浸料的树脂流变特性,由压力监测设备对填充芯材下方蒙皮内部压力进行监测获得了其内部压力的分布,采用金相显微镜对褶皱进行了表征。结果表明:在树脂流动的窗口期,当填充芯材下方蒙皮内部出现压力差时,树脂向低压区流动并聚集,导致褶皱产生。