Research On Preparation And Mechanical Properties Of O-core Metal Sandwich Pipes

Due to the characteristics of light weight,high specific strength,high specific stiffness and multifunction,sandwich structure is widely used in automotive industry,aerospace,offshore platform,construction,wind power generation and other fields.In recent years,the preparation and properties of new high-performance sandwich structures are the frontier research topics in the field of materials engineering.The metal sandwich structure pipes is a new type of sandwich structure which can replace the traditional mezzanine pipes.The research on the preparation method and mechanical properties of the sandwich pipes is favored by researchers at home and abroad.In this paper,the O-core metal sandwich pipes is taken as the research object.The material is 304 stainless steel.By designing the orthogonal experiment,the sandwich pipes with 3 core pipes and 4 core pipes is prepared by laser welding.The tensile,three-point bending and bar compression tests of the sandwich pipes were carried out by Z250SNS electronic universal testing machine.At the same time,the finite element model of the sandwich pipes was established by using AN SYS finite element analysis software,and the numerical model was modified and optimized by combining the results of mechanical tests,and the strength,stiffness and stability of the sandwich pipes were further numerically simulated.The results show that:(1)within the allowable error range of the simulation,the curves of the simulation and the actual test are in good agreement;(2)Compared with the empty pipe,the carrying capacity of the sandwich pipe during stretching,three-point bending and compression is significantly improved;(3)No matter the strength,stiffness or stability of sandwich pipe,the number of core pipes has a significant effect on it.The elastic limit during stretching,the stiffness in the macro elastic range during bending and the critical pressure during compression are approximately proportional to the number of core pipes.(4)According to different number of core pipes,the load-displacement curves of sandwich pipes are analyzed.Origin software is used to fit the load-displacement curves of sandwich pipes,and the fitting equations and corresponding parameter values of tensile,three-point bending and compression are obtained respectively.It provides a reference and direction for the design and research of the sandwich pipes in the future.