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261.
Automated fibre placement(AFP) systems have successfully intensified the demand for high-quality composite component manufacturing in both the military and civilian fields. One of the main elements of these systems is the AFP mechanism for accomplishing individual fibre delivery,clamp/cut/restart(CCR) and the consolidation process, and it consists of several functional submechanisms presenting strong coupling relationships and motion sequences. This review aims to summarize the development of AF... 相似文献
262.
Optimization of flow field in electrochemical trepanning of integral cascades (Ti6Al4V) 总被引:1,自引:0,他引:1
《中国航空学报》2022,35(10):354-364
Ti6Al4V is widely applied in the integral cascades of aero engines. As an effective machining method, electrochemical trepanning (ECTr) has unique advantages in processing surface parts made of hard-to-cut materials. In ECTr, the state of the flow field has a significant effect on processing stability and machining quality. To improve the uniformity of the flow field when ECTr is applied to Ti6Al4V, two different flow modes are designed, namely full-profile electrolyte supply (FPES) and edges electrolyte supply (EES). Different from the traditional forward flow mode, the flow directions of the electrolyte in the proposed modes are controlled by inlet channels. Simulations show that the flow field under EES is more uniform than that under FPES. To further enhance the uniformity of the flow field, the structure of EES is optimized by modifying the insulating sleeve. In the optimized configuration, the longitudinal distance between the center of the inlet hole and the center of the blade is 6.0 mm, the lateral distance between the centers of the inlet holes on both sides is 16.5 mm, the length to which the electrolyte enters the machining area is 1.5 mm, and the height of the insulating sleeve is 13.5 mm. A series of ECTr experiments are performed under the two flow modes. Compared with EES, the blade machined by FPES is less accurate and has poorer surface quality, with a surface roughness (Ra) of 3.346 μm. Under the optimized EES, the machining quality is effectively enhanced, with the surface quality improved from Ra = 2.621 μm to Ra = 1.815 μm, thus confirming the efficacy of the proposed methods. 相似文献
263.
为开发具有良好防隔热和力学性能的高性能石英纤维毡,基于传热数学方程,预测了石英纤维毡的厚度对其隔热性能的影响规律;为提高纤维毡的力学性能,探究了在纤维毡中添加不同层数的石英纤维布对其力学性能的影响规律;此外还探讨了针刺密度对石英纤维毡隔热性能和力学性能的影响。结果表明:石英纤维毡传热模型与实验吻合度可达94.8%;石英纤维毡厚度提升2 mm,其隔热性能提高20 ℃左右;添加石英纤维布可以显著提高纤维毡断裂强力和撕破强力;针刺密度可以提升纤维毡力学性能,但针刺密度过大会破坏纤维毡结构,使其力学性能下降。 相似文献
264.