Mechanical properties of lettuce (Lactuca sativa L.) for horticultural machinery design

Xavier, Reuel ScherrerGalvão, Cezário BeneditoRodrigues, Ruan LessaGarcia, Angel PontinAlbiero, Daniel

ABSTRACT: Currently, there is a growing need to develop machines that replace human work efficiently and effectively in horticulture with the same sensibility of the human hand, since horticultural foods are notably very fragile to handle and process, especially considering machinery and systems. This work aimed to determine the mechanical properties of lettuce (Lactuca sativa L.) variety Crispa. For that, two methodologies were used in the field of material engineering: one specific for polymers and composites the standard ASTM D3039 Standard test method for tensile properties of polymer matrix composite materials (ASTM, 2002a) and the other specific for plastic films the ASTM 882 Standard test method for tensile properties of thin plastic sheeting (ASTM, 2002b). The tests were adapted for lettuce samples. The mechanical properties for the leaf and stem of head lettuce (var. Crispa) were obtained with appropriate statistical rigor, which can be considered valid initial estimates for dimensioning mechanisms and systems of machines for horticultural works specialized in lettuce. These properties provide fundamental engineering parameters to design machine elements that interact with biological materials, allowing to develop devices that generate minor damage to biological structures in lettuce.

1. tensile test
2. modulus of elasticity
3. biological material