Investigation On The Design Of 3D-Printed Local Resonance Phononic Crystal And Its Cutting Vibration Suppression Characteristics

Vibration and noise can seriously affect the safe and stable operation of equipment and cause irreversible damage to the physical and mental health of operators,so it is especially important to find suitable methods of vibration and noise suppression.As an artificial periodic structure with a special control function for elastic waves,phononic crystals can produce a vibration suppression bandgap in a special frequency range.Local resonance phononic crystals have the characteristic of "small size control large wavelength",which plays a great role in vibration and noise control.However,there are a series of problems in the field of phononic crystals in vibration suppression aspects.Firstly,the bandgap of phononic crystals is unchangeable when the structure is designed and manufactured,which severely restricts the flexibility of its application.Thus,the tunable bandgap can fully utilize the potential of phononic crystals for vibration suppression.Furthermore,most of the phononic crystal are manufactured by non-metallic materials such as ABS,PLA,resin or multi-part assembly methods,while the metal phononic crystal with high load-bearing capacity and wide range of vibration suppression will have a wider application prospect.Finally,the phononic crystal often has a large number of thin-walled and hollow complex structures,which is a great challenge for the traditional manufacturing technology.Furthermore,the flourishing development of 3Dprinted technology provides an effective solution for the fabrication of complex structures,and metal 3D-printed methods offer new possibilities for the future engineering applications of phononic crystals.To address this situation,this thesis designs three different types of phononic crystals and completes the engineering application of cutting chatter suppression as a typical scenario.The main research contents include.1.Three different structures are designed based on the local resonance mechanism.In order to obtain the ultra-low frequency bandgap and tunable bandgap characteristics,an Archimedean spiral beam structure is designed with an ultra-low frequency bandgap below 20Hz,and a magnetic field-driven strategy of bandgap tunable is proposed to construct a tunable phononic crystal,and the change of structural stiffness is realized by altering the currency in the electromagnet to obtain the tunable bandgap.In order to obtain a high load-bearing capacity and a wide bandgap,a phononic crystal with a body-centered cubic lattice structure and embedded high-density resonators are designed for 3D-printed magnesium alloy to obtain a wide bandgap.A 3D-printed beam-type phononic crystal with a double-bending beam structure is designed for bending wave control in a typical engineering scenario of milling chatter suppression.The band structure and modes of bandgap boundary are studied by finite element simulation to reveal the local resonance bandgap generation mechanism and establish three theoretical models,and the dispersion curves and transmission characteristics of different structures are obtained by calculating the theoretical models.2.The influence of the main structural parameters of the three phononic crystals on the bandgap is studied by using COMSOL finite element simulation,and the relationship between geometric parameters and bandgap boundary is established.The influence of geometric parameters,such as spiral beam cross-section width,rotation angle,lattice radius,and bending beam cross-section width,on the bandgap boundary and bandwidth are investigated.The samples of three phononic crystals are prepared using the SLM technique,and the accuracy of the bandgap is verified by obtaining the transmission characteristics of the structures through the hammering test and excitation test.3.For the typical scenario of cutting chatter suppression,the method of thin-walled part milling chatter suppression based on local resonant phonon crystals is proposed.The stability model of the thin-walled part milling process is established and the stability limition of thinwalled part milling chattering is obtained.By comparing the stability of the milling process with and without phononic crystals,the effectiveness of the local resonance phononic crystal for thin-walled part milling chatter suppression is demonstrated.