| Theoretical formulas that relate peel and burst test results were developed using force diagram analysis. The formula, P = 2S/D (P = Burst Pressure, S = Seal Strength, and D = Plate separation) has been studied before (Feliu-Baez, 1998), and it was found to overestimate the actual burst values even when the bursting and peeling times were controlled to be the same. A new theoretical formula, which accounts for package size, was developed but it did not improve the accuracy of the results. The fact that the new formula did not improve accuracy, even when accounting for package size, indicates that random behavior of the package deformation during the burst test makes the actual values differ from the predicted ones. Wrinkles in the seal area, the amount of stretch around the package's perimeter, and its shape when pressurized are difficult to model and therefore cannot be included in the theoretical formulas. For that reason, empirical models were developed by using a linear multiple regression technique to fit experimental data to a power law relationship.; The empirical models developed include the formulas for theoretical development as independent variables. Three models were validated in three different types of Tyvek/plastic pouches. The results were good. The correlation coefficients (R) were all higher than 0.96 and the average percent errors between actual and predicted values ranged from 1% to 7% for predictions of burst test value from seal strength and vice versa. |
