The objective of this research was to evaluate and model the mechanical damage to corn seeds under impact loading. The experiments were conducted at moisture contents of 7.60 to 25% (wet basis) and at the impact energies of 0.1, 0.2 and 0.3 J, using an impact damage assessment device. The results showed that impact energy, moisture content, and the interaction effects of these two variables significantly influenced the percentage of physical damage in corn seeds (p<0.01). Increasing the impact of the energy from 0.1 to 0.3 J caused a significant increase in the mean values of damage from 23.73 to 83.49%. The mean values of physical damage decreased significantly by a factor of 1.92 (from 83.75 to 43.56%), with an increase in the moisture content from 7.6 to 20%. However, by a higher increase in the moisture from 20 to 25%, the mean value of damage showed a non-significant increasing trend. There was an optimum moisture level of about 17 to 20%, at which seed damage was minimized. An empirical model composed of seed moisture content and energy impact was developed for accurately describing the percentage of physical damage to corn seeds. It was found that the model has provided satisfactory results over the whole set of values for the dependent variable.

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Background Corn seeds have a high susceptibility to mechanical damage due to their large size and mass. The main purpose of this study was to evaluate the effects of the cushion box and closed let-down ladder usage in minimizing the negative influence of the free fall on the storage potential of corn seeds. Corn seeds were evaluated for the extent of physiological damage by measuring the seed deterioration by the accelerated aging test (percentage loss in germination in the accelerated aging test), using three drop methods (free fall, with cushion box, and with closed let-down ladder) at three drop heights (5, 10, and 15 m) and five different moisture contents (10, 15, 20 and 25%). Results The drop methods had a significant effect on the storage potential of corn seeds. Sample seeds dropped without a ladder (free fall) had a significantly higher average physiological quality loss of 13.87% (loss in accelerated aging germination). In the use of the cushion box, the average percentage loss in germination was calculated to be 11.38%, which was decreased by about 18% more than the free fall. Sample seeds dropped with the closed let-down ladder had a lower average percentage loss in the germination of 8.78%, which showed that the closed let-down ladder significantly helped to reduce mechanical damage to corn seeds by about 37% comparing free fall and by about 23% to the use of the cushion box. The amounts of loss in physiological quality of corn seeds increased significantly with increasing drop height and moisture content, but the use of the cushion box and closed let-down ladder systems somewhat reduced the adverse effect of the above factors. Empirical models were developed for the dependency of physiological damage to corn seeds due to the impact caused by free fall, on the drop height and moisture content at different drop methods. Conclusions To minimize mechanical damage to seeds as they fall into the bin, a let-down ladder should be installed in the bin so that it can receive seeds from the filling spout with minimum damage.

Corn is a staple food crop grown in over 100 countries worldwide. To meet the growing demand for corn, losses in its quality and quantity should be minimized. One of the potential threats to the quality and viability of corn is mechanical damage during harvesting and handling. Despite extensive research on corn, there is a lack of reliable data on the damage its seeds undergo when they are subjected to mechanical impact against different surfaces during handling and transportation. This study is designed to investigate the effects of (a) drop height (5, 10, and 15 m) during free fall, (b) impact surface (concrete, metal, and seed to seed), seed moisture content (10, 15, 20, and 25% w.b), and ambient temperature (−10 and 20 °C) on the percentage of physical damage (PPD) and physiological damage to corn seeds. The PPD and the extent of physiological damage were determined as the percentage of seed breakage and the percentage of loss in germination (PLG), respectively. The latter parameter was specifically chosen to evaluate seeds that showed no visible external damage, thus enabling the assessment of purely internal damage that PPD did not capture. This approach enabled a comprehensive analysis of free fall’s influence on the seeds’ quality and viability, providing a complete picture of the overall impact. Total damage was then calculated as the sum of PPD and PLG. An evaluation and modeling process was undertaken to assess how corn seed damage depends on variables such as drop height, moisture content, impact surfaces, and temperatures. The results revealed that seeds dropped onto metal surfaces incurred a higher total damage (15.52%) compared to concrete (12.86%) and seed-to-seed abrasion (6.29%). Greater total damage to seeds was observed at an ambient temperature of −10 °C (13.66%) than at 20 °C (9.46%). Increased drop height increased seeds’ mass flow velocity and correspondingly caused increases in both physical and physiological damage to seeds. On the other hand, increased moisture levels caused a decreasing trend in the physical damage but increased physiological damage to the seeds. The limitations of the developed models were thoroughly discussed, providing important insights for future studies. The results of this study promise to deliver substantial benefits to the seed/grain handling industry, especially in minimizing impact-induced damage.

The main purpose of this study was to evaluate the effects of the cushion box and closed let‐down ladder usage in minimizing mechanical damage to corn kernels during free fall. Kernels from a single lot of cultivar KSC 705 were evaluated for percentage of breakage using three drop methods (free fall, with cushion box, and with closed let‐down ladder) at five different moisture contents (10%, 15%, 20%, 25%, and 30%), and three drop heights (5, 10, and 15 m). The results showed that the drop methods had a significant effect on the breakage sensibility of kernels. Sample kernels dropped without a ladder (free fall) had a significantly higher average percentage breakage of 13.80%. In the use of the cushion box, the average kernel breakage was calculated to be 11.41%, which was decreased by about 17% more than the free fall. Sample kernels dropped with the closed let‐down ladder had a lower average breakage of 7.26%, which showed that the closed let‐down ladder significantly helped to reduce mechanical damage to corn kernels by about 47% comparing free fall and by about 37% than the use of the cushion box. The amounts of kernel damage increased significantly with increasing drop height and decreasing moisture content, but the use of the cushion box and closed let‐down ladder systems somewhat reduced the adverse effect of the above factors. To minimize mechanical damage to kernels as they fall into the bin, a grain let‐down ladder should be installed in the bin so that it can receive kernels from the filling spout with minimum damage. Empirical models were developed for the dependency of damage to corn kernels due to the impact caused by free fall on the drop height and moisture content at different drop methods.