碳纤维是公认的下一代高性能材料，短切是其重要的加工技术。针对目前碳纤维短切生产效率低、刀具磨损快、理论缺乏等现状，项目开展大丝束碳纤维短切机理及断口形貌控制研究。以大丝束聚丙烯腈（PAN）基碳纤维为研究对象，研究多场（流场、力场、温度场）综合作用下碳纤维的切断机理，建立碳纤维切断模型；分析丝束堆叠密度和截面形状在短切时的演变规律，建立碳纤维丝束切断模型；研究短切碳纤维质量对复合材料性能的遗传作用，探讨缺陷和表面质量对短切质量的作用规律，发现基于缺陷的断口形貌控制方法；基于切断机理与模型，完成短切刀具及系统的优化设计，建立短切刀具的几何模型与刀具寿命评价方法，建立短切刀具系统的力学模型和振动模型；探索刀具系统与短切纤维质量之间的映射关系；通过对短切碳纤维质量的在线监测，实现刀具系统的寿命预测与主动控制。项目的实施，将形成一套完善的碳纤维短切理论及技术，促进碳纤维产业向国民经济各个领域的应用。

Carbon fiber is a new kind of material with high performance, and its chopping technology plays an important role in its industry. To deal with the low production efficiency,rapid tool wear and theory deficiency of chopped carbon fiber, the chopping mechanism and shape control method of large tow carbon fiber are studied.In this project, the study object is large tow polyacrylonitrile ( PAN ) based carbon fiber. The chopping mechanism of carbon fiber under multiple field action(fluid field, stress field, temperature field) is discussed. The cutting model of carbon fiber is established. Besides, the section shape changes and stacking density changes during chopping procedure are analyzed. Then the cutting model of large tow carbon fiber is set up. Moreover,the genetic effect of short carbon fiber quality on composite properties is studied. The influences of structure defects and surface quality on the quality of chopping carbon fiber are investigated. The control method of fracture morphology basing on defects is studied. Furthmore, basing on the cutting mechanism and models, the chopping tool and its system are designed. The geometric model and life estimation method of chopping tool are investigated. The mechanical model and vibration model of chopping tool system are built up. The mapping relationship between tool system and chopped fiber is explored. Through the on-line monitoring of chopped carbon fiber quality, the active control and life prediction of tool system are done. Therefore, the chopped theory and technology of carbon fiber will be found after the implementation of this project, and the application of carbon fiber to civilian areas will be promoted.