Design And Mechanical Performance Analysis Of A Large-span Structure Support Based On Pentamode Lattices

The large-span structure represents the development level of a country’s construction industry.In recent years,large-span bridges and large-span spatial structures emerge in endlessly.As an important part of large-span structure,bearing plays an important role.At present,steel bearing and rubber bearing are commonly used in large-span structure.The steel bearing has the problems of large steel consumption,easy corrosion and high maintenance cost.The mechanical properties of rubber bearings are greatly affected by environment and temperature,and the shear modulus is small,which leads to large shear deformation.Therefore,many scholars have been concerned about the design of new bearings.As the basic unit of pentamode materials,the bulk modulus of pentamode lattice is far greater than the shear modulus.Micro pentamode lattice is often used in the design of pentamode materials,which makes it have the mechanical properties of bulk modulus far greater than the shear modulus.In this paper,based on the pentamode lattice,the unique advantages of the pentamode lattice are brought into play.Through reasonable rod design,the micro lattice is transformed into the macro lattice,and the pentamode lattice support with appropriate configuration is obtained by copying the periodic matrix.The pentamode lattice support is applied to large-span structures such as bridges,so that it can be used as a new type of support to avoid the problems such as the rubber bearing is easy to be affected by the environment and small shear modulus.The specific research of this paper is as follows:Firstly,the lattice structure and materials used to form the pentamode lattice support are proposed;Then,the proper lattice constant,rod diameter and plate thickness are selected,and the pentamode lattice support is obtained by periodically copying the lattice.Secondly,the influence of the diameter of the member and the thickness of the plate on the vertical stiffness,horizontal stiffness and the ratio of the vertical stiffness to the horizontal stiffness of the pentamode lattice support are analyzed by ANSYS numerical simulation.The simulation results show that the diameter of the member has a significant influence on the stiffness of the support under the two replication modes;The ratio of vertical stiffness to horizontal stiffness of pentamode lattice supports in multi-layer replication mode is relatively large,and the mechanical properties are relatively good.Then,through ANSYS numerical simulation,the bearing capacity of pentamode lattice support under different lattice constants,corresponding rod diameter and plate thickness is analyzed.The results are compared with rubber plate support,which provides reference for the selection of five-mode lattice support.The change of bearing capacity of pentamode lattice supports is analyzed under different lattice constant,different rod diameter and different plate thickness.The results show that the lattice constant has the most obvious effect on bearing capacity,the diameter of the member is the second,and the thickness of the plate has little influence on the bearing capacity of the support.Finally,pentamode lattice support is designed and applied to engineering example;Compared with the plate rubber support,the unique advantages of pentamode lattice support are summarized.As structural support,pentamode lattice support has stiffness adjustment performance and can adapt to different structures without changing bearing capacity.