The Effects of Loading Conditions on Strength and Energy Requirement for Onion Leaf Removing

Abstract

Development of onion harvesting machine is the important goals in the mechanization of this product. One of the major onion harvesting
machines is topper. To design a topper system, knowing of some physical and mechanical properties such as cutting strength and energy requirement
are important. In this study the strength of onion leaf and specific rupture energy for onion leaf removing from its bulb in three loading rates (50,100
and 200 mm/min), three loading types (leaf cutting at the attached point to the bulb, leaf cutting at 5cm above the bulb and leaf tensile at 5cm above
the bulb) and two moisture contents of leaf (65 and 85 percentage) were measured. Results showed that by increasing the loading rate, strength
of the onion leaves was changed from 1.06 to 0.48 MPa and specific rupture energy was varied from 11.59 to 5.25 mJ/ mm 2. By reducing of leaf
moisture, strength of onion leaf and specific rupture energy were changed from 0.86 to 0.62 MPa and from 11.91 to 5.4 mm J/ mm 2respectively.
Cutting the leaves attached to the bulb had the maximum strength and specific rupture energy with values of 1.54 MPa and 11.52 mJ/ mm 2.