Experimental Research on Geometrics and Mechanics of Chinese Leek in Mature Harvesting Period

In order to obtain design basis of leek harvester，geometric and physical mechanical characteristics of leek in mature harvesting period were experimental studied by taking Chinese typical leek as the research object.Results showed that the plant height and stem diameter of three varieties of leek in mature harvesting stage of“Dugenghong”“791”and“Dajingou”were 389，358 and 341 mm，and 3.8，3.5 and 3.1 mm，respectively.The plant height was more than 85% in 250-400 mm，and 65% in 300-400 mm.The stem thickness between 2.5 and 4.0 mm was accounting for 85%.The maximum radial shear stress of leek stem was 0.79，0.67 and 0.57 MPa at three different loading speeds of 20，50 and 100 mm/min，respectively.With increase of loading speed，maximum shear stress decreased.The average radial compressive strength of leek stalk was 0.13 MPa.In process of compression，compression stress of the stalk of leek kept increasing，and the rate of increase was also increasing.When compression stress reached critical value of stalk pressure lost，there would be a decline fluctuation inflection point，and then compression stress would continue to increase with loading time.