Experimental Study On Poplar Seedling Property Detection Based On Ultrasonic

Poplar is widely used in artificial forest planting and has became an important raw material of plywood,fiberboard,paper matches and packaging industry.Wood properties is a key factor to determine the quality of wood.There is a correlation between the seedlings and the mature trees,so it is important to choose the good quality specimens in a batch of seedlings.At present,in our country,the classification of seedling quality is mainly made use of the morphological indexes,which dose not take into account the material condition of the seedlings.This paper used the poplar seedlings as the study object,studied on the ultrasonic velocity distribution,and its relationship with seedling diameter,the growth days,the density,the elastic modulus,the moisture content and the microfibril angle.This paper want to do some basic work for the establishment of nondestructive detection and the classification method based on the ultrasonic wave.The test results showed that the ultrasonic wave velocity was similar to normal distribution for poplar seedlings,there was no obvious correlation between the velocity and diameter,but the velocity would increase with the increasing seedling age;with the increasing of the density,the ultrasonic wave velocity would decrease,and the wave velocity has a positive linear correlation with the elastic modulus of the seedling;The higher the moisture content,the lower the wave speed;The greater the microfibril angle,the smaller the wave velocity.There was a negative correlation between the ultrasonic velocity and the growth day in the diploid poplar seedlings,but for the triploid poplar seedlings,with the material density increasing,ultrasonic velocity would also decrease.It could be concluded that the ultrasonic velocity is expected to be the means and index of nondestructive testing and evaluation of poplar wood.