1994 Volume 56 Issue 4 Pages 75-82
The purpose of this research is to propose a method of weight reduction design procedure for agricultural frost control fan in which the surplus design was considered in structural strength. In this paper, a commercial frost control fan was tested for analysis and the structural strength characteristics of the blade of frost control fan was clarified by use of experimental stress analysis method. The brittle lacquer coating method was applied for investigating the stress distribution of the blade, and the direction of principal stress was investigated. Two element rectangular rosette gauges were attached on seven points along its direction. Stress at each measuring point under various rotating speed (740, 840, 940, 1060, 1150rpm) conditions was analyzed and the driving torque of fan was measured. Frequency analysis was applied for the strain wave of blade at the point where the maximum stress could be observed. It was clarified from the results that in the designing stage the blade of frost control fan had surplus strength enough to be operated, and proposed one of the methods for calculating the thickness of blade from the viewpoint of weight reduction.
