Mohammad Hosseinpour-Zarnaq - Biosystems Engineering Department, Tarbiat Modares University, Tehran, Iran
Saeid Minaei - Biosystems Engineering Department, Tarbiat Modares University, Tehran, Iran
Alireza Mahdavian - Biosystems Engineering Department, Tarbiat Modares University, Tehran, Iran
Mohammad Hadi Khoshtaghaza - Biosystems Engineering Department, Tarbiat Modares University, Tehran, Iran

To develop cutting, harvesting, crushing or grinding machines, knowledge of crop physical and mechanical properties is needed. In this study, shear strength, shear energy and maximum shear force in cutting parsley stems have been examined. Cutting of multiple stems (۸ stems) was performed by using blades with oblique angles of ۰, ۲۰, and ۴۰ degrees. In order to examine the effect of stem arrangement in cutting operation, stems were placed in row and bundle arrangements. Results of statistical analysis showed that shear strength and maximum shear force decrease with increasing oblique angle. The average values of shear strength, specific cutting energy and maximum shear force for cutting ۸ stems laid in row arrangement, using blade oblique angle of zero degrees, were ۰.۴۹ MPa, ۲.۲۵ mJ mm-۲ and ۵۶.۱۳ N, respectively, while at blade angle of ۴۰ degrees the values were ۰.۱۹ MPa, ۴.۱۲ mJ mm-۲ and ۱۸.۲ N, respectively. Blade angle of ۲۰ degrees is recommended as it does not require more cutting energy compared to zero degrees and the shear force is reduced, which lessens the effect of impacts on the cutting system.

Parsley stems, Mechanical properties, Blade angle, Postharvest