RESEARCH OF THE AGGREGATE COEFFICIENT OF RIGIDITY OF THE WALNUT FRUIT BRANCHES

Abstract

The article deals with the scientific problem of determining the physical and mechanical properties of walnut trees and particularly the aggregate coefficient of rigidity of the fruit branches. This allows to ground the parameters of manual shakers of vibration and vibration and impacts action, as well as to describe the physical and mathematical models of the fruit branch in the system «man - manual shaker - fruit branch».

A tensioning device (strainer) was developed for measurements of the perpendicular force applied to a branch with a change of the point of application. This unit consists of a post with a support and pins or dowels for mounting and fixing of the post near the branch. On the post, a movable bracket with a roller is mounted, which allows one end of the line (cable) to be fixed perpendicular to the branch, depending on the point of force application. The second end of the line through the dynamometer is attached to the support. The deviation of the branch from the equilibrium position after the application of force was determined using a laser range finder, and force by the dynamometer.

It is defined that the aggregate coefficient of rigidity of the branches depends on the tree species, the diameter of the branch at the base and at the distance from the base of the branch to the place of application of the force. In the resulted studies the skeletal branches of a walnut with a diameter in the basis from 50 to 90 mm, which are divided into two dimensional groups are considered. The first group had a diameter of 50…70 mm for which the distance of the force application was 1,25…1,75 m, the second group – the branches with a diameter of 70…90 mm, and the distance of the force application was 1,75…2,25 m. The aggregate coefficient of rigidity was increased with the growth of the diameter of the branch at the base and with the reduction of distance from the base of the branch to the place of force application.

For branches of the first dimensional group with a diameter in the basis of 50 to 70 mm at a holding distance of 1,25…1,75 m, the aggregate coefficient of rigidity varies in the range of 429,0…3210,7 N/m. The smallest value of 429.0 N/m at this interval corresponds to Dг = 50 mm and ℓг = 1,75 m, and most of all – 3210,7 N/m is achieved if Dг = 70 mm,

ℓг = 1,25 m. For the branches of the second dimension group of (Dг = 70…90 mm, ℓг = 1,75…2,25 m), the rigidity of the branches varies from 474,6 N/m, if Dг = 70 mm and ℓг = 2,25 m, to 2260,6 N/m in the case of Dг = 90 mm and ℓг = 1,75 m.