Nomex蜂窝复合材料的超声切割技术克服了传统高速铣削中存在的工件固持困难、加工粉尘大等问题。基于断裂力学研究Nomex蜂窝复合材料的超声切割机理，为超声切割工艺参数优化以及超声波声学主轴的优化设计提供理论依据。根据直刃刀超声切割Nomex蜂窝复合材料加工工艺，建立直刃刀的运动学方程，分析得到超声切割断续加工过程中直刃刀与材料相互作用时间关系；应用断裂力学理论，引入动态应力强度因子建立蜂窝复合材料的断裂韧性模型，研究超声切割作用下蜂窝复合材料的微观断裂过程，根据直刃刀位移和裂纹扩展的关系模型，分析切削力的影响因素，并进行仿真研究。研制了超声切割工艺试验台，对蜂窝复合材料进行了有超声和无超声切割加工的对比试验，试验结果显示超声切割显著地减小了切削力，也证实了冲击产生的微裂纹扩展是蜂窝复合材料在直刃刀超声切割作用下，切割力减小的主要原因。理论分析和试验研究表明基于断裂力学的Nomex蜂窝复合材料超声切割机理研究具有有效性和合理性。
黄秀秀
,
胡小平
,
于保华
,
吴胜游
. 基于断裂力学的Nomex蜂窝复合材料超声切割机理研究[J]. 机械工程学报, 2015
, 51(23)
: 205
-212
.
DOI: 10.3901/JME.2015.23.205
There are many problems, such as work-piece fixed difficultly and dusty chip, which exist in high speed milling Nomex honeycomb composites. They could be solved by using the technology of ultrasonic cutting. Mechanism of cutting Nomex honeycomb composites combining with ultrasonic are studied based on fracture mechanics, so that the rationale are supplied for optimizing those technological parameters and the design of ultrasonic cutting spindle. The ultrasonic cutting process with straight blade cutter is introduced and the dynamical function of cutter is presented. The interaction time relationship between cutter and material is analyzed in the condition of ultrasonic intermittent cutting. According to fracture mechanics, the model of fracture toughness is built with dynamic stress intensity factor to study the micro fracture process of Honeycomb composites. The factors affecting cutting force are analyzed according to the relation of feeding distance and crack propagation length, and it is demonstrated by means of simulation example. The experiment is carried out by means of ultrasonic cutting experimental platform self-made, to compare the cutting force with ultrasonic or not. The result reveals the cutting force with ultrasonic was much less. And it also demonstrates that crack propagation is the main to reduce the cutting force of machining honeycomb composites with ultrasonic. Theoretical analysis and experimental results prove that the research on the ultrasonic cutting mechanism for Nomex honeycomb composites based on fracture mechanics is reasonable and effective.
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