## 3 Results and Discussion
### Brusing Susceptibility
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**S. I**} & \multirow{2}{*}{**Surface Type**} & **Packaging Thickness** & \multirow{2}{*}{**Impact Height (m)**} & **Time at Maximum** & **Time at Pear** & \multirow{2}{*}{**\(\Delta\)t (ms)**} \\ \cline{1-1} \cline{5-6}  & & & 0.25 m & 3.20 & 6.40 & 3.20 \\ \hline
1 & & & 0.25 m & 3.20 & 6.40 & 3.20 \\ \cline{1-1} \cline{5-6}
2 & & Rigid Floor & 0.5 m & 3.00 & 5.80 & 2.80 \\ \cline{1-1} \cline{5-6}
3 & & & 1.0 m & 2.60 & 5.40 & 2.80 \\ \cline{1-1} \cline{5-6}
4 & & & 0.25 m & 3.20 & 6.40 & 3.20 \\ \cline{1-1} \cline{5-6}
5 & & & 0.5 m & 3.00 & 6.00 & 3.00 \\ \cline{1-1} \cline{5-6}
6 & & Rubber & & 1.0 m & 2.40 & 5.40 & 3.00 \\ \cline{1-1} \cline{5-6}
7 & & & 0.25 m & 5.80 & e\({}^{*}\) & e\({}^{*}\) \\ \cline{1-1} \cline{5-6}
8 & & & 0.5 m & 5.60 & e\({}^{*}\) & e\({}^{*}\) \\ \cline{1-1} \cline{5-6}
9 & & & 1.0 m & 5.60 & e\({}^{*}\) & e\({}^{*}\) \\ \hline
10 & & & 0.25 m & 3.80 & 7.40 & 3.60 \\ \cline{1-1} \cline{5-6}
11 & & & 0.22\({}^{\prime\prime}\) & 0.5 m & 3.40 & 7.00 & 3.60 \\ \cline{1-1} \cline{5-6}
12 & & Corrugated & & 1.0 m & 3.20 & 6.20 & 3.00 \\ \cline{1-1} \cline{5-6}
13 & & & 0.25 m & 4.20 & 8.00 & 3.80 \\ \cline{1-1} \cline{5-6}
14 & & & 2.1\({}^{\prime\prime}\) & 0.5 m & 3.80 & 7.60 & 3.80 \\ \cline{1-1} \cline{5-6}
15 & & & 1.0 m & 3.60 & 7.00 & 3.40 \\ \cline{1-1} \cline{5-6}
16 & & & 0.25 m & 3.20 & 6.20 & 3.00 \\ \cline{1-1} \cline{5-6}
17 & & & 0.5 m & 3.00 & 6.00 & 3.00 \\ \cline{1-1} \cline{5-6}
18 & & Honeycomb & & 1.0 m & 2.60 & 5.40 & 2.80 \\ \cline{1-1} \cline{5-6}
19 & & & 0.25 m & 3.80 & 7.60 & 3.80 \\ \cline{1-1} \cline{5-6}
20 & & & 2.1\({}^{\prime\prime}\) & 0.5 m & 3.40 & 7.00 & 3.60 \\ \cline{1-1} \cline{5-6}
21 & & & 1.0 m & 3.20 & 6.60 & 3.40 \\ \hline \hline \end{tabular}  
* e\({}^{*}\): rebound time exceeded simulation time.  
\end{table} 
Table 2: Drop Impact Simulation Time to Maximum Stress and Rebound. rubber. At some heights, such as 0.25 m and 0.5 m, the honeycomb does not perform any better than just dropping the fruit on a wooden floor. This was mainly due to the tip edges of the honeycomb causing sharp points of contact upon which the pear would be more easily damaged; this highlights the fact that the geometrical optimization for lattice structures would be an important consideration for future simulations. Figure 11C shows that the pear experiences almost identical peak stress for all surfaces. However, despite the lower energy transfer to the fruit in the corrugated shape, Figure 11D demonstrates why bruising can still occur for corrugated cardboard packages over long-distance transits. In fact, corrugated cardboard boxes have been shown in the literature to undergo large plastic deformations, which lead to damage [35]. More study would be required to investigate the effect of impact on damaged corrugated cardboard but would require an exponentially more computationally expensive simulation. The second impact of a fruit during a rebound will lead to subsequent damage and bruising [36]. A comprehensive simulation comparison was carried out using the explicit solver across the different surfaces (rigid floor, rubber, corrugated cardboard, and ABS honeycomb) to model the pear's fall at three different heights of 0.25 m, 0.5 m, and 1 m, as shown in Table 3. The bruising volume was calculated by extracting the average nodal values over the computational time that exceeded the bio-yield value of 0.3 MPa. This is the maximum stress the pear can sustain before it becomes susceptible to bruising. The maximum and minimum values for the internal energy, contact force, and von Mises stress are summarized for all the drop impact tests with red and green highlighted tables, respectively. The bruising susceptibility was reported by the ratio of bruising volume to the internal energy absorbed by the pear fruit.