Visualization of planar stress distributions in cucumber cultivars using a multiple-point sheet sensor

Planar stress distribution of cucumber fruits was visualized for four cultivars. The planer stress distribution of a cross-sectional sample was measured using a multiple-point sheet sensor during uniaxial compression by an Instron universal testing machine. The concentric distribution pattern of stress gradients was the common characteristic for all cultivars. The correspondence between the tissue and its mechanical properties was estimated by comparing the stress distribution and a sample photograph. The stress property differed among different tissues within the cross-section. The center of the cross-sectional slice, where the seed cavity occupies formed the lower stress region, the surrounded area, where the flesh locates showed the middle-range stress, and the exterior skin exhibited the highest stress. The wider distribution of the lower stress was statistically significant for two cultivars. This visualization method provided qualitative information about the geometrical and mechanical distribution of the cucumber and allowed the breed specificity of the cucumber cultivar to be characterized.