含水率对重组竹静态和动态横纹冲击力学性能的影响OA北大核心CSTPCD

Bamboo scrimber is a new type of biomass composite material that exhibits superior mechanical properties compared to wood like larch and can be easily processed into structural components such as beams and columns.While extensive research has been conducted on the static mechanical properties of bamboo scrimber,studies focusing on its behavior under dynamic loading conditions remain limited.In extreme environments,such as hailstorms,typhoons with debris,or impacts from external objects,materials may experience significant dynamic loads that can cause intense dynamic responses,potentially leading to cracking or failure of the bamboo scrimber,thus affecting the safety and longevity of the entire structure.Therefore,it is essential to analyze the dynamic response of the material to understand its mechanical performance under dynamic loads.Given that the compressive direction of bamboo scrimber columns in buildings is typically parallel to the grain,they mainly endure impacts perpendicular to the grain when subjected to horizontal impact loads.This study investigated bamboo scrimber with an average density of 1.13 g/cm3,conducting static uniaxial compression tests at various moisture contents(4％,8％,10％,12％and 16％)as a baseline.Additionally,dynamic impact tests were performed on bamboo scrimber at the same moisture contents and different impact velocities(10,13 and 16 m/s),using a split Hopkinson pressure bar(SHPB)apparatus.The results indicated that the static compressive strength and elastic modulus of bamboo scrimber perpendicular to the grain decreased with increasing moisture content.Under dynamic loading conditions,the dynamic compressive strength of bamboo scrimber perpendicular to the grain significantly increased with the impact velocity(loading rate)while the moisture content remained constant.This increase ranged from 2.39 times of the static loading to 5.63 times,with the rate of increase gradually slowing.The impact velocity had a minimal effect on the elastic modulus.When the impact velocity remained constant,both the dynamic compressive strength and elastic modulus of bamboo scrimber perpendicular to the grain decreased gradually as the moisture content increased from 4％to 16％.By fitting the dynamic increase factor(DIF)and the ratio of static to dynamic elastic modulus,this study derived formulas that described the effects of moisture content and loading rate on the impact mechanical properties of bamboo scrimber perpendicular to the grain.These findings provide a theoretical basis for establishing a constitutive model of bamboo scrimber under impact loads.