Abstract:
It must be exactly known the critical stress of the crop just not causing biological damage at the development of the mechanized cultivation technologies and the planning of horticulture machines.
This critical stress can be calculated from the dropping height of the crop, applying the energy equation for collision, the basic equations of the contact stress of Hertz and the rule of gravitation.
On the basis of our experiments the fallingheight is 160 cm at the 7 cm long cucumber, and it is 105 cm at the 12 cm ones and the critical stresses are 61 = 41.4 daN/cm2, and 62 = 37.2 daN/cm2.
Accordingly, the motion of machine parts touching the cucumbers should be designed in a way not to cause heavier stress at collision than the critical value calculated.
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