Study On Compression Performance Of Glue-Pressed Engineered Honeycomb Bamboo

This study originated from the National Forestry Public Welfare Scientific Research Program(31470582),entitled "The key technology,equipment development and demonstration of large size bamboo-based engineering material".The objective of this study is to provide a reliable theoretical basis and data support for the application of bamboo-based engineering material in the construction field,by using the honeycomb bionics principle with characterizing the strength and rigidity of the bamboo column in the original state of bamboo.The research contents of this paper are as follows: the production and performance evaluation of large-sized bamboo engineering components are carried out by studying the compressive performance and destructive characteristics of the bamboo column with the multi-body material of bamboo.And it is designed and researched the pressure machine of Glue-Pressed Engineered Honeycomb Bamboo(GPEHB).It provides a effective program of the provide effective useof the program.The main research work and achievements of this paper are summarized as follows:(1)The preparation technology of bamboo composite unit of GPEHB and the forming process of bamboo column were completed.The two kinds of bamboo composite unit,length 1100 mm and 1500 mm,were studied,and the compressive performance was characterized.The results show that the two kinds of bamboo units are buckling damage.The maximum compressive strength of bamboo units with length of 1100 mm and 1500 mm is 34.4kN and 31.5kN respectively.And the maximum vertical deformation is 9.7mm and 13.4mm respectively.Both of the bamboo units show obvious elastic stage and plastic decline stage.It puts forward the calculation formula of the allowable stress of bamboo unit.Through the mechanical calculation formula,the bamboo unit can be screened in the engineering design,and the bamboo unit with the mechanical performance requirement can be provided for the preparation of the GPEHB.(2)The failure modes and compressive properties of five kinds of GPEHB with different slenderness ratio were studied.The results show that the destruction of the bamboo column is mostly in the external bamboo unit,and outside the drum,split as the main form.There is no obvious damage of the adhesion of the bamboo unit;the main feature of damage in short column(bamboo column length of 368 mm,736mm)is failure of the bamboo material.To the long column(bamboo column length of 1840mm),it is the occurrence of buckling damage.The bearing capacity of the five kinds of bamboo columns decreased slightly with the increase of the slender ratio of the bamboo column.The bearing capacity of the bamboo column obviously decreases from the slenderness ratio of 4 to 6(that is,the length of the bamboo column is 736 mm to 1104mm).It is the second quadratic equation between the maximum axial compression deformation and the slenderness ratio.(3)The failure modes and compressive properties of the GPEHB made of six different inner diameter bamboo units were studied.The results are as follows: the failure characteristics of the bamboo column are mainly due to the destruction of the outer drum,splitting and the end of the bamboo unit.With the increasing diameter of the bamboo unit,the maximum vertical deformation and limit load has a tendency to increase.And the elastic phase increases with the increase of the diameter of the bamboo unit.The compressive performance of the bamboo column with the inner diameter of 80~100mm is similar.The change rule of bamboo unit diameter and the ultimate load is consistent with the cubic function.With the increase of bamboo unit inner diameter,the maximum deflection becomes smaller.This shows that the larger the diameter of the bamboo unit,the more difficult to appear bending phenomenon.The deflection of the bamboo column tends to a fixed value.(4)The failure modes and compressive properties of the GPEHB were studied in four different finger joint positions.The conclusion is as follows: the first destruction of the GPEHB with the finger joint is the section of finger joint,the main phenomenon of damage is the bump bamboo of bamboo unit,split and the crush of finger joint,adhesive exfoliated;as the finger position moves toward the upper part of the GPEHB,the maximum load of the specimen tends to increase.The influence of the deflection of the bamboo column is not obvious when the bamboo shoot is located at 1/3,1/4,1/5 at the upper end of the bamboo material.Where in the bamboo post at the 1/5 of the upper end of the finger is least affected by the finger position.It puts forward the criterion of failure of GPEHB,which can be used for the failure of bamboo pillars.It is of great significance to the use of bamboo pillars.(5)The overall design scheme and the main mechanism of pressure machineof GPEHB are studied,and the pressure and transmission system are designed.It is mainly composed of the chain lift cylinder,flat pressure cylinder,vertical cylinder,gear motor and other components.This machine has the characteristics of green,environmental protection and energy saving,so that the equipment has the characteristics of simple and practical,high reliability,easy operation and maintenance,which not only reduces the labor intensity,but also improves the production efficiency and can reach the multi-of the large-scale production requirements.