Experiment And Numerical Simulation On Axial Mechanical Properties Of Bamboo Tubes

Bamboo has great axial mechanical properties and bending properties.However,it depends on the conection forms that the development of bamboo structure bacause of the characteristic of thin-walled and hollow about bamboo tube.Nowadays,there is lack of accepted design code of bamboo structure.Focused on the screw connection and hooping measure,which are widely used in bamboo structure,the mechanical properties and the failure modes of bamboo tube in axial direction are studied by tests and methods of numerical simulation,in order to provide some advises to engineering design.Considering the damage to the cross section of bamboo caused by screw connection,axial compression tests of specimens with different conditions are carried out.It shows that the ultimate strength of specimens decreases about 10-20%with holes and the hooping measure is not useful.A multi-layer tube model is set based on the anisotropic and elasto-plastic constitutive relation.Then the model is analyzed by two steps of eigenvalue buckling and nonlinear buckling.It is found that the result of calculation can match the failure modes well.There is little difference among specimens with different hole-end distance on ultimate load of pin bearing according to the pin bearing tests.While,hooping measure improves the pin bearing capacity obviously.Design formula on axial pin bearing yield load can be established based on tests and the simulation.We attempt to explore the relationship on compressive strength between single bamboo and multiple bamboo bundle by compression tests.According to the capacity and failure modes of single bamboo with different slenderness ratio,the length of single leg in multiple bamboo bundle is proposed.And it is also analyzed about the effects of horizontal spacing,slenderness ratio and other factors on the axial compression properties of multiple bamboo bundle.compared with the performance of single bamboo.