Specific Modulus Grade Of Dimension Bamboo Strips And Manufacture And Evaluation Of Bamboo Lamination

High strength and light weight of the bamboo engineering material has been gained a considerable attention and widely application in bridge,building,ships,wind generator blade,etc.In this work,moso bamboo(Phyllostachys edulis)as raw material was firstly measured the modulus of elasticity(MOE)and air-dry density,then the specific modulus was obtained.According to the distribution of specific modulus,the method of specific modulus grade based on modulus grade was established.Grade glued laminated bamboo was manufactured with grade dimension bamboo strips,then the physical mechanical properties of glued laminated bamboo and grade dimension bamboo strips were tested and evaluated.Analysising the influence of physical and mechanical properties between grading dimension bamboo strips and glued laminated bamboo in the same preparing process,so that explore a fast and efficient classification method for preparation of high strength and light weight engineering materials.The main research results were as follows:(1)The elastic modulus of dimension bamboo strips distributed from 4.86 to 15.06 Gpa with a normal distribution.The air-dry density distributed from 0.51 to 0.81 g/cm3.Established the method of MOE grade with with 1 GPa interval.Measuring and analysing date of specific modulus,and to built the method of specific modulus grade.(2)Dimension bamboo strips specific modulus distribution range was from 6 to 20 Gpa,and establised the method of specific modulus grade with 1 GPa interval.Using SPSS software,the specific modulus can be divided into three sections: low specific modulus(≤9 GPa),middle specific modulus(9-11 GPa)and high specific modulus(11-20 GPa).The number of dimension bamboo strips in specific modulus grade and MOE grade coincided with normal distribution.(3)With the increasing of specific modulus grade,the ari-dry density,MOE and MOR,compressive strength,tensile strength of strips presented an increased tendency,the tensile shear strength raised firstly and then fell down.In a same MOE grade,physical and mechanical properties decreased significantly as the rise of specific modulus grade except for the tensile shear strength.(4)Air-density of glued laminated bamboo kept unchanged when grading bamboo strips suffered a series of process.With the rising specific modulus grade,the proportional coefficient and increasing rate of MOE and specific modulus between dimension bamboo strips and glued laminated bamboo decreased.(5)The trend of physical and mechanical properties of grading glued laminated bamboo kept pace with dimension bamboo strips.(6)Longitudinal shrinkage rate was minimal of glued laminated bamboo,while radial shrinkage rate was the largest,and the range of radial shrinkage rate was 2.0-3.6%.With the increase of specific modulus grade,radial and tangnitial shrinkage rate showed the tendency of increasing.(7)Longitudinal expansion rate was minimal of glued laminated bamboo,while radial expansion rate was the largest,and the range of radial expansion rate was 3.0-4.0%.With the increase of specific modulus grade,radial expansion rate showed the tendency of increasing.In the same MOE grade,the radial expansion rate of specific modulus grade was gradually reduced.In the specific modulus grade,the radial expansion rate of MOE grade increaseed with the increase of MOE grade.