王草茎秆拉伸与剪切的强度特性

Tensile and Shearing Strength Properties of the Stems of King Grass(Pennisetum sinese Roxb)

为研发优质高效的王草收获机械和加工机械,采用响应面试验设计和统计分析,从根径、取样高度2个维度上研究了收获期王草茎秆拉伸与剪切的强度问题,同时考察了茎秆含水率与观测截面的长径、短径、圆度对强度的影响。结果表明,在根径20~30 mm、取样高度10~200 cm、含水率72.53%~90.65%、长径15.20~30.40 mm、短径13.90~27.65 mm、圆度1.0144~1.2428范围内时,王草植株的节间抗拉强度、节间抗剪强度和茎节抗剪强度处于3.2456~28.9373MPa范围内。茎秆含水率在72.53%~90.65%之间变化时,对上述3个强度指标的影响在0.005水平上显著。根径、取样高度、长径、圆度等对3个强度指标的影响0.05水平上均不显著。含水率与根径、取样高度、长径、短径、圆度等在0.05水平上均线性无关。综上,相近生长期的王草植株,虽然其根径、取样高度、长径及圆度不同,但对茎秆强度无显著影响,茎秆强度的差异主要取决于茎秆内部组织结构的不同,含水率是独立影响茎秆强度的重要因子。

A response surface test design and statistical analysis were used to study the tensile and shear strength properties of the stem of king grass at harvest time based on the root diameter and sampling height to develop high quality and efficient harvesting and processing machinery for king grass(Pennisetum sinese Roxb). The effect of stem water content, as well as the major diameter, minor diameter and roundness of stem observation cross section on the strength of the stem was investigated. When the root diameter, sampling height, water content, major diameter, minor diameter,roundness was 20-30 mm, 10-200 cm, 72.53%-90.65%, 15.20-30.40 mm, 13.90-27.65 mm, 1.0144-1.2428, the tensile and shear strength of the internode together with the shear strength of the stem node was from 3.2456 MPa to 28.9373 MPa. Stem water content at the range of 72.53%-90.65% had a significant effect on the above three strength indices(0.005). The effect of root diameter, sampling height, major diameter and roundness on the three strength indices was not significant(0.05). Stem water content was not linearly correlated with root diameter, sampling height, major diameter, minor diameter and roundness. The plants of similar growth period with different root diameter, sampling height, the major diameter and roundness had a almost the same stem strength. The difference of stem strength depended on plant tissue anatomical structure. Stem water content was an important factor that independently affected the stem strength of king grass.