Theoretical Study And Experimental Verification Of Vibration And Sound Transmission Characsterstics In Sandwich Structure With Pyramidal Lattice Truss Core

Sandwich structures are commonly consisted of two thin but stiff face sheets separated by the lightweight core material,which have broad application prospects in the fields of aviation,shipping and transportation,as its superior properties of low density,high strength,high modulus and potential application in heat transfer,impact resistance,energy absorbing.The pyramid lattice sandwich structure is characterized by its unique porous characteristics and periodic configuration.The structure itself has excellent comprehensive performance,including mechanical,acoustic and other characteristics.The mainly research of lattice structure focuses on the areas of manufacture,statics properties,and dynamic performances.The dynamic studies are concentrated in the vibration and shock loading but seldom about the sound propagation which is worthy to be discussed.But in the actual work environment,there will be a lot of problems about vibration and noise.In this context,it is an necessary and meaningful task to study the vibration and sound insulation characteristics of structures,to analyze the influence law of geometric and physical parameter pairs,and finally to achieve the optimal design of lattice sandwich structures.By establishing a theoretical model of structural acoustic vibration coupling,the theoretical solutions for the natural frequencies and sound insulation quantities of the theoretical model are derived.By the Acoustics module in the finite element software LMS Virtural.Lab the numerical model is established,and numerical solutions of the natural frequency and sound insulation are obtained.Then,the numerical results are used to verify the theoretical results.The influence on vibration and sound transimission properties of different sandwich height,length and width of sandwich edge,thickness and length width of the panel,the material of the structura,the layers of the sandwich panels are anslysized.Then,the influence rules of the parameters are analyzed,and the vibration and sound insulation characteristics of sandwich panel structure are optimized,and the sandwich panel structure with good comprehensive performance is obtained.The vibration transmission characteristics of the attice truss core sandwich panel are also studied.It shows that the vibration transmission properties of pyramid lattice sandwich structures are better than those of square honeycomb structures,and the excellent transmission characteristics of structures are verified by the same material and geometry parameters.At last,a sandwich structure with the same theoretical model and finite element structure parameters is fabricated by the method of punching and folding brazing.Three dimensional laser vibrometer is used to verify the vibrat ion characteristics of the structure,and the rationality and feasibility of the theoretical model and the numerical simulation model are verified.In this paper,the vibration and sound insulation characteristics of Pyramid lattice sandwich structures are studied and analyzed by means of theoretical,numerical and experimental methods,which is of great importance to structural optimization design and further research.