Dynamic Buckling Of Bar System-structural Mechanics Model For Buckling Of Graphene

Bar system is one of the most commonly used structural forms and the overall buckling is the main form of structural failure,so it is very important to analyze the buckling of the structure.At present,the research on the static buckling of the structure of bar system is mature,however,there are few studies on the overall dynamic buckling of the straight bar.Graphene is modeled as the macro structure of bar system using structural mechanics method,and the buckling behavior of the structure is analyzed.In this paper,the straight bar and the two-dimensional truss structure of the graphene is used as the research object,and an axial impact load with time is applied to increase the load.as a result,the buckling load is obtained by changing the loading speed.For the dynamic buckling of a straight bar using the derived governing equations,respectively based on the Runge-Kutta theory method and implicit transient analysis method,the relationship of loading speed and the buckling load is obtained with difference calculation and numerical simulation.The results show that with the increase of loading velocity,the buckling mode of straight bar will transform from the first-order buckling to second order buckling under certain loading rate.After that,the finite element analysis software is used to analyze the first order dynamic buckling model.The accuracy and feasibility of the two methods are verified by comparison with the Euler critical buckling load.For graphene structure,Two dimensional framework model is established by using beam element and mass element,by changing the size of the loading speed,the boundary conditions of the form,the cell structure of the chiral configuration and the overall structure of the length and width ratio a / b,the buckling load values are confirmed using numerical simulation and comparative analysis.The critical loading speed of graphene structure with different parameters is calculated in the aspect of confirmed length width ratio.The results show that Armchair graphene can bear greater buckling load and be more stable than Zigzag one,and the simply-supported boundary condition has greater bearing ability in buckling than clamped-free.The dynamic buckling of the structure is larger than that of the boundary condition,and the critical buckling load decreases with the increase of the aspect ratio which the change trend is obviously different in the aspect ratio a/b=1.