McRandal and McNulty (1980) carried out shearing
tests on forage grass stems, and, from the forcedisplacement
curve, obtained its mechanical properties,
which included shear strength, penetration resistance, and
shearing energy. They also used linear regression and
statistical methods to discuss the relevance of the crop
properties (maturity, solids content) and shear conditions
(bevel angle, shear velocity) of forage grass to the
abovementioned mechanical properties. Visvanathan et al.
(1996) used an impulse-cutting device to test the shearing
energy of cassava tubers, and found the optimum bevel
angle, shear velocity and the shear angle of cassava tubers.
The experimental results showed that the shearing energy
increased with the bevel angle and shear velocity.
Chattopadhyay and Pandey (1999) used a physical property
analyzer to test the shear properties of sorghum stalk. The
results showed that if the bevel angle was 30° to 70° and
the loading rate was 10 to 100 mm/min, the peak shear
strength and the specific cutting energy increased with the
bevel angle, and the peak shear strength and the specific
cutting energy decreased gradually as the loading rate
increased.