梳解前后小径杉木细胞的微观形态及力学性能

Mechanical properties and micro conformation of small Chinese fir cell before and after combing

研究了饱和水状态下小径杉木Cunninghamialanceolata在不同条件静压或梳解前后木材横截面上细胞的微观形态与木束条顺纹抗拉强度,并进行了对比试验,得出小径杉木较佳的静压梳解力学性能参数。结果表明:经静压实验得出不同径级的杉木在饱水状态下较佳的压缩率在50%左右;不同定压力或定压缩率2种静压试验后所得的木材细胞微观形态基本相同,横截面的开裂和破坏情况也基本相同。采用不同径向压力静压后的杉木管胞破坏程度不同,当压缩率大于30%,杉木部分管胞开始皱折,并随着压力的增大而增加;当压缩率超过50%后,随着压力增大,大部分管胞发生皱折,甚至压溃,但超过了该值管胞破坏程度减慢,并且在横切面上仍然能够看到管孔存在。在同一压缩率下,径级小的杉木所需的单位压力较大。拉伸试验可知经静压梳解后的木束条顺纹抗拉强度随静压压力加大而降低。

A comparative study of the micro conformation and tensile strength of wood parallel to grain of small Chinese fir cell in the water saturation condition under different static pressures or before and after combing test was conducted. The best mechanical properties parameters of small Chinese fir under static pressure or by combing were gained in the study. The results showed that the best compression set of small Chinese fir was about 50%. A few tracheids of small Chinese fir began to break when the compression set of small Chinese fir was greater than 30%. The condition will turn serious with the increase in static pressure. Most of tracheids of small Chinese fir began to break when the compression set was greater than 50%. However, the destruction rate slowed down and a few tracheid holes could be seen on the cross section of cell. The tensile test showed that tensile strength of wood along grain would be decrease with the increasing static pressure.