## 1 Introduction  
Honeycomb-core material is a kind of high-stiffness, light-quality, heat-resistant, impact-resistant, fatigue-resistant, good-insulating soundproof stays-engineering composite material. [PERSON], [PERSON] and [PERSON] analyzed the mechanical properties and excellent qualities of honeycomb-core materials through theoretical modeling and experimental verification [1; 2; 3]. [PERSON] and [PERSON] introduced honeycomb parts used in the aerospace field such as helicopter power plant fairings, large aircraft wings, liquid fuel barriers in rockets, etc. [4; 5]. In order to meet the requirements of assembly and connection, the honeycomb-core material must be cut after it is formed. However, the honeycomb-core material is a typical difficult to machine material, it brings great challenges to the CNC machining of honeycomb-core material due to the particularity of honeycomb core structure and cutting mechanism. [PERSON], [PERSON] and [PERSON] proposed related process optimization methods for processing defects such as honeycomb core fracture and collapse, increased surface burrs and dust pollution during the CNC high-speed milling process of honeycomb core, which greatly reduces the performance of the honeycomb core structure and improves the product Safety and service life [6; 7; 8]. Oriented to the manufacturing requirements of honeycomb-core material parts, in view of the problems existing in CNC high-speed milling processing, scholars are constantly exploring new processing methods and improving the existing processing technology. Ultrasonic vibration-assisted cutting technology as a new advanced processing technology has been applied in the field of CNC machining of honeycomb core workpiece [9]. Compared with high speed milling, this machining method has significant advantages in machining accuracy, quality, efficiency and environmental friendliness [10; 11]. In the ultrasonic vibration-assisted machining of honeycomb-core material, there still have surface damage problems such as core tearing and machining surface burr. There is little research on the ultrasonic vibration-assisted cutting force of the disc-cutter. [PERSON] and [PERSON] studied the failure behavior of the honeycomb core through experimental means and concluded that the cutting force is an important physical parameter that causes defects in the honeycomb core workpiece [12; 13]. The research of rotating vibration cutting of honey comb core components with disc-cutter is only focusing on the test verification; mechanism study must be carried out to reveal the influence of the cutting parameters on machining quality. [PERSON] measured the elastic properties of the hexagonal honeycomb-core material through experiments [14]. Based on brittle fracture mechanics, [PERSON] studied the cutting mechanism of the ultrasonic cutting of the honeycomb core with a sharp knife and derived a theoretical model of cutting force [15]. However, the entire process of ultrasonic vibration-assisted cutting of disk cutters is time-consuming, the processing quality is unstable, the surface burrs on the processing, and the core damage are still outstanding. In order to solve the problem of cutting damage of the honeycomb core workpiece in ultrasonic vibration-assisted cutting, this study used finite element analysis software to establish a 3D honeycomb-core material model and a disc-cutter model according to the actual working conditions. A method of ultrasonically cutting the honeycomb-core material with a disk milling cutter is proposed. At the same time, the correctness of the finite element model is verified through experiments. The influence of process parameters on cutting quality was studied. At the same time, based on the response surface method, a simulation model was used to construct a cutting force prediction model for the honeycomb core of the disc-cutter ultrasonic machining, which provided a theoretical basis for the optimization of the cutting technology of the honeycomb-core material and the reasonable selection of processing parameters.