Research On Fracture Mechanism Of Ultrasonic Cutting For Nomex Honeycomb Composites

Nomex honeycomb composite material has properties of excellent mechanical,good insulation and wave-transparent,so it is widely used in electronic machinery,radar,aerospace and other special requirements of the industry.Nomex honeycomb composite material is short fiber material which is difficult to manufacture and has porous lattice structure.What’s more,Traditional CNC milling with honeycomb composites has low milling efficiency,poor milling quality,severe working environment and other issues.To resolve such difficulties,ultrasonic cutting technique is applied to the actual processing of Nomex honeycomb composite materials,and increases the cutting quality and cutting efficiency.However,due to the special ultrasonic cutting has just started,and the research on the mechanical properties of Nomex honeycomb composite material and fracture mechanism of ultrasonic cutting for Nomex honeycomb composites established yet also have not expanded.Not establishing a sound material constitutive model and fracture Analysis of the mechanism also hampers the promotion and development of Nomex honeycomb composite material.In connection with this status,this paper carry out research on fracture mechanism of ultrasonic cutting for Nomex honeycomb composites,the main research work and achievements are as follow:(1)using the method of composite materials macro-mechanical analysis,study the Nomex fiber unidirectional plate,and establishing its constitutive model.Then on the basement of Nomex honeycomb structure characteristic,moving forward a single step on establishing a Nomex honeycomb composite material constitutive mechanical model.(2)Research on the ultrasonic cutting processing of honeycomb composites.Aimed at ultrasonic machining with straight blade cutter and ultrasonic machining with circular cutter,by analysis of the kinematics for straight blade cutter and circular cutter,establishing ultrasonic cutting mechanical model of straight blade cutter and circular cutter.(3)As an example of ultrasonic cutting of Nomex honeycomb composites by straight blade cutter,research on the fracture mechanism of ultrasonic cutting for Nomex honeycomb composites.By analysis of stress and fracture mode about ultrasonic cutting of honeycomb composites,establishing ultrasonic cutting fracture mechanics model,and using MATLAB to prove the correctness of mechanics model,providing the theoretical support for parameter selection and process setting of ultrasonic cutting.(4)Based on the cutting feed angle as single factor variable,through ultrasonic cutting of honeycomb composite material experiments by straight blade cutter,provingcorrectness of constitutive mechanical properties of Nomex honeycomb composite material.Based on the front angle of cutting tool as single factor variable,through ultrasonic cutting of honeycomb composite material experiments by straight blade cutter,proving rationality of fracture mechanism of ultrasonic cutting for Nomex honeycomb composites.