The Research On Virtual Prototype Of Large Three-dimensional Braiding Machine

For fiber reinforced composites,three-dimensional fabric is the most superior structure developed in the past thirty years.The composites using 3D textile preforms as reinforced fiber,have excellent mechanical properties,high damage tolerance and excellent anti ablation properties.These excellent properties provide a wide prospect for the application of composite materials in the main load-bearing structure and functional structure.Three dimensional textile technology includes three dimensional braiding technology,three dimensional weaving technology and three dimensional knitting technology,among which three dimensional braiding technology is a new technology developed in 1970 s for weaving three-dimensional fabrics.Compared with other three-dimensional fabric manufacturing technology,the three-dimensional braiding technology in this paper is a process of skewing and intersecting multiple yarns,which are aligned along the direction of fabric forming,according to certain rules.A three dimensional braiding machine,with three-dimensional braiding technology as its core,can weave a variety of different shapes,including circular,square,rules and special-shaped three-dimensional fabrics.The 3D braided fabric has the characteristics of non-stratified overall structure,continuous change along the cross section of the braiding direction,and the first forming of complex structural members,and has the advantages of shock resistance,resistance to delamination and creep resistance,and has been widely used in the field of biological tissue material,automobile,wind power blades,aeronautics technology,etc.In this paper,the virtual prototype model of a 3D braiding machine with "8" shaped track driven by synchronous toothed belt is designed,and the structural innovation design of the whole machine is completed,including parts design and virtual prototype assembly.By braiding in the core axis,the yarn is arranged in three directions to form a three-dimensional braiding fabric.The main contents are as follows:1)the braiding technology and braiding fabric of braiding machine is introduced.These include vertical and horizontal braiding,rotary braiding,maypole_type braider and so on,and the braiding principle of 3D braiding machine is elaborated.On this basis,the transmission principle and structure design scheme of large 3D braiding machine is putforward.The large-scale 3D braided fabric designed by this scheme is fast braided for the structural shape,braiding angle,yarn coverage factor and yarn volume fraction requirements of braided preform.2)Using the 3D modeling software UG,we design the synchronous belt drive system,the "8" shaped track,the yarn carrier and the whole structure system of the 3D braiding machine.The synchronous belt transmission wheel is used to drive horn wheel.The horn wheel push the bottom claws(horndog)of the yarn carrier to moves along the fixed shape of "8" track on the track plate.The horn wheel of 3D braiding machine is the same as maypole_type braiding machine,and the horn wheel is arranged in a circle,and each horn wheel has a symmetrical four equal circular notch.As the upper part of the yarn carriers claws contact with the circular notch of horn wheel,the yarn carrying device is pushed for a sinusoidal motion.The rotation direction of the adjacent horn wheel is opposite.When the motor is working,the horn wheel will drive the half of the yarn carriers to move clockwise,while the rest will move counterclockwise.3)In order to verify the motion and dynamic characteristics of the braiding process of the braiding machine designed in this paper,we carried out the motion simulation analysis of the virtual prototype model of the 3D braiding machine by means of ADAMS software.The rotation of the horn wheel is realized by toothed pulley transmission,and the simulation of the yarn carrier is carried out with the method of the space trajectory tracking simulation.Finally,a series of related simulation data curves are obtained.These data provide important reference value and guiding significance for further improvement and optimization of the 3D braiding machine.4)The key device of 3D braiding is the core shaft structure and its manipulator control system.The industrial robot technology and braiding machine structure are combined together,by using virtual prototyping technology,and the virtual prototype model with 6 degrees of freedom manipulator is designed in the SolidWorks,and the motion simulation of the manipulator is done in ADAMS,and the movement curve of the junction of the mechanical arm end and the core shaft is obtained.5)Based on pultrusion technology and RTM molding technology,a 3D braiding composite molding process is designed by combining braiding technology and RTM molding process,and these provide a new idea for 3D fiber reinforced composite production.