Distribution characteristics of potato contact stress during the drop impact

Objective  To explore the damage principle of potato under drop impact.

Method  Prescale sensitive film and high speed photogrammetry were used to characterize the contact stress distribution of potato when it collided with five types of materials and dropped from different heights. The relationship between potato damage and contact stress distribution was determined by studying the distribution law of contact stress in potato.

Result  The response surface analysis of combination orthogonal test for potato showed that collision material, dropping height and potato mass had significant influences on the impact compression deformation amount of potato collision. The influence degree in order was collision material>dropping height>potato mass. When colliding with 65Mn steel, the potato had damage at the dropping height of 300 mm. When colliding with plastic ABS, clods, potatoes and nitrile rubber, the potato had damage at the dropping height of 400 mm. At the dropping height of 200−800 mm, the major contact area was under the contact stress of 0.01−0.50 MPa, which played a major role in potato damage. At the dropping height of <300 mm for 65Mn steel and <400 mm for other collision materials, the major contact area was under the contact stress of ≤0.20 MPa. At the dropping height of ≥300 mm for 65Mn steel and ≥400 mm for other collision materials, the major contact area was under the contact stress of (0.20, 0.60 MPa. The critical stress causing damage of potato was 0.20 MPa under drop impact. Dropping height and contact area showed a highly linear positive correlation, with the determination coefficient (R²) above 0.95. Impact force was the product of contact stress and contact area, which had highly linear correlation with impact compression deformation, and R² was above 0.96.

Conclusion  The constructed linear regression model can accurately predict and evaluate damage of potato under drop impact.