Shear cutting theory for the peripheral edges of brush blades, and tests of its effectiveness

In this study, a shear cutting theory for wood or harsh brush is proposed, which can be applied to cases of usual supported cutting. Based on the proposed theory, a peripheral edge that takes full advantage of the proposed shear cutting theory is developed and tested for brush cutting. The new blade is composed of a conventional radial edge and the proposed peripheral edge. The peripheral edge cuts the brush in the first stage, and the radial edge cuts any remaining brush in the second stage. The decreases in cutting force and cutting energy due to the peripheral edge can be computed as a function of the shear angle for each given knife angle. A decrease in cutting energy signifies reduction in working time, gas consumption, and air pollution from a two-cycle engine, in which the lubrication oil is mixed directly with the fuel. The natural frequencies of the conventional and proposed blades are analyzed and the impact response of the peripheral edge, which is closely connected with the safety of the operator, is tested and compared with that of a conventional radial edge using the commercial software package.