Fig. 1.
Cruciform mechanical response to off-axis hold and equibiaxial stretch. (A) Inset shows a representative cruciform in mold with horizontal and vertical arm widths of 8 and 4 mm, respectively. Parameters A and B, which define the mechanical response of a network fiber, were selected so that the model predictions (red lines) matched the off-axis hold experiment (circular markers) and were used to predict the model response to equibiaxial stretch. In the off-axis hold test (A), the vertical arms of the cruciform were each displaced 2 mm (λy = 1.29) in 15 sec while the horizontal arms remained stationary. The average loading response of both axes is plotted as a function of vertical axis extension. (B) For equibiaxial stretch, both arms were extended 1.5 mm (λy = 1.21) in 15 sec. The model reasonably predicted the cruciform response but underpredicted nonlinearity in the vertical arm.