Fabrication And Properties Of Pyramidal Lattice Structures Based On FDM Process

The composite lattice truss core sandwich structure has high specific strength,high specific stiffness and light weight,and its internal open and continuous space has been reviewed much more in aerospace,ship,sports equipment,building facilities and medical materials.On the basis of the research work of pyramid lattice structure in the past,this paper adopts fuse forming method which based on the FDM process to fabricate pyramid lattice core,and study the soluble core manufacturing process,which is easy to demould,to integrate the pyramid lattice sandwich structure,and the mechanical properties of the integrally formed pyramid lattice sandwich structure are tested and analyzed.The main contents are as follows:Firstly,in the introduction,the current research status of the preparation and mechanical properties of lattice structures of composite materials at home and abroad is reviewed,from which the key problems to be solved in this subject are proposed,and its research significance is expounded.Secondly,the compression strength and dissolving rates of the water-soluble core-mould materials prepared under different process parameters were tested.The results showed that: When 30% PVP solution was used as the adhesive of water soluble core mold,quartz sand with a particle size of 200-300 mesh was used as the reinforcing material,the premix is prepared according to the mass ratio of the adhesive and quartz sand of 16:100,and then under the condition of the temperature of 130? to heat water soluble core mold drying to constant weight preparation of water-soluble core model can satisfy the late pyramid lattice sandwich structure production requirement for pressure,and the water-soluble core mold prepared under the process parameters has good dissolving rates at a water temperature of 60?.Next,on the basis of the research work of pyramid lattice structure in the past,this paper adopts fuse forming method which based on the FDM process to fabricate the pyramid lattice core on the water-soluble core materials.Analyze the forming path of the pyramid lattice core,write the G.code file,import it into the 3D printer to prepare the lattice core,and explore the molding quality under different process parameters.The conclusions are as follows: When the nozzle temperature is 210°C,the molding chamber temperature is 45°C,and the moving speed is 450mm/min,the pyramid lattice core prepared on the water-soluble core mold has a good molding quality.Finally,the mechanical properties of this structure are studied by out-of-plane compressive,three-point bending and in-plane compression tests.Observe the failure mode and compare the experimental results with the theoretical results.Under the action of compressive load,the main failure mode of the sandwich structure is the fracture of the core;Under bending load,the main failure mode is the shear failure between the panel and the core;Under the in-plane compression load,the main failure mode is the shear fracture of the core rod and the debonding between the panel and the core.