The Variation Pattern Of Bamboo Properties Of Phyllostachys Pubescens And Anatomy Structure

Since bamboo properties vary significantly,rapid detection of physical-mechanical properties of bamboo and classification is the inevitable trend of bamboo industry development.Phyllostachys pubescens is the main research object.Along height direction comparative and analysis the geometry size of bamboo and study it on segmentation.Though indentation technology rapid detection indentation-strength of bamboo.To explore the correlation between bamboo basic density and indentation-strength.We verify if the indentation method for rapid detection of bamboo density is actually correct.Analyze the microstructure characteristics of vascular bundle and the size of microfibril angle in different grade of indentation-strength.Discuss the microstructure characteristics of vascular bundle and the size of microfibril angle on the influence mechanism of physical and mechanical properties of bamboo.The main conclusion of this are shown as follows:(1)The 0.9 m and branch height as the split points divided bamboo into three sections,that is: root segment(fell point-0.9 m)、the trunk section(0.9 m-branch height)and top segment.The fresh weight and volume of the bamboo increases with increasing in the diameter grade of 0.9 m.We take the diameter grade of 0.9 m as the main indicators divided it into four levels :small diameter class: φ≤10 cm;middle diameter class: 10 cm<φ≤12 cm;high-middle diameter class: 12 cm<φ≤14 cm;high diameter class: φ≥14 cm.(2)Reference standards both at home and abroad and according to the results of preliminary experiments,the method for measuring indentation-strength is determined.In the case of convenience of processing,ensuring the effective test times,improving work efficiency and avoiding appear eccentricity and splitting phenomena in test process.Ultimately,the roller diameter is 15 mm,the pressure head shap is cross,the pressed depth is 3 mm and the length of the specimen is 20±0.5 mm.(3)It is obvious that a certain linear relationship exists between the tindentation-strength and basic density(R2=0.8794).And they have no significant difference within bamboo,but they have significant difference individual bamboo.Thus,it is feasible to quickly check the strength of fresh bamboo with indentation method.We can use the relational expression(y=0.0188x+0.1113)to calculate bamboo’s basic density.Referring to the AITC Grading Handbook for Laminating Lunber,the E-rated Grades methods were used to divided indentation-strength into four levels.According to each level of indentation strength,the scope of the base density is speculated.Provide data support for directional using of bamboo.(4)Basic density has a positive correlation with parallel-to-grain compression,bending strength and elasticity modulus in different indentation-strength grade.And they have significant statistically.Indentation-strength has a positive correlation with parallel-to-grain compression,bending strength and elasticity modulus and they have significant statistically.Thus,it is reasonable and feasible to quickly check the strength of fresh bamboo with indentation method and graded them.(5)Vascular bundle area and fiber sheath area increases with the bamboo’s basic density.The inside the fiber sheath area of the bamboo’s maximum density(0.71 g/cm~3)is 3 times higher than the bamboo’s minimum density(0.46 g/cm~3).The long and short axis of fiber sheath increased with the density.And when the density greater than 0.61 g/cm~3,with the increase of density the long axis of fibrous sheath increase slowly,more compact between the fibers,the single fiber appears small and dense,bamboo mechanical performance increases at the same time.The dense fibre in bamboo of bundle sheath determine the bamboo density and mechanical properties.In radial,microfibril angle variation is not obvious and the difference was not significant.Bamboo microfibril angle has significant correlation with indentation-strength,bending strength and elasticity modulus.