Study On Impact Behavior Of Tubular Truss Structures With Precompression Chord

Tubular truss structures combines the beautiful architectural effects of tubular structures,excellent mechanical properties,and easy construction of steel structures.It is widely used in offshore platform,airport,train station,breakwater and highway toll stations.Due to the existence of gravity,equipment load and other loads in the actual project,the structure will bear axial force during its service period.Therefore,considering the actual situation,the specimens are preloaded in the process of experiment.During its service period,due to the collision and impact caused by accidental events,structures in different parameters and impacting site are easy to suffer severe damage with different failure modes under these events,and progressive collapse of the whole structure may eventually occurs.Therefore,it is of great theoretical and engineering significance to study the impact bahaviour of tubular truss with precompression chord.The main aspects are listed as follows:(1)Axially preloaded tubular trusses under impact load are tested.Compared with the failure mode,impact force,displacement,strain of different parameters and impacting site,the results show that the plasticity of the truss include the local indentation and bending deflection of the impacted chord between two joints,some global flexural deformation of the tubular truss as well as the deformation of brace.While,there is no bending deflection of impacted chord in the specimen impacted on mid-span of the top chord within the middle K-joint.Furthermore,due to the existence of the axial force,the axial force exacerbates the bending second-order effect,resulting in the fluctuation of the impact.(2)The finite element(FE)models of the tubular trusses subjected to impact loadings are then developed by commercial software of ABAQUS,where nonlinear material behaviour and pre-compressive loads are all considered.The numerical findings exhibit close agreement with experimental results in terms of failure pattern as well as the development of impact force.(3)The mechanical mechanism of tubular truss with precompression chord is studied by analyzing the brace deformation,capacity,dissipated energy and so on.(4)The ratio of axial stress to strength and geometric parameters were compared and analyzed using FE software to reveal the impact bahaviour of tubular truss with precomprssion chord.