Fig. 7: Experimental and theoretical results of petal amplitude ratios under strain states with different α.

The square points represent the experimental results of petal amplitude ratios under biaxial loadings. The ratio α between the two normal strain components are 1, 0.81, 0.51, 0.13, –0.31, indicated by the color of pink, green, blue, red and black, respectively. The solid lines represent the theoretical values corresponding to the experimental results, with the α of 1 (pink), 0.81 (green), 0.51 (blue), 0.13 (red), –0.31 (black). The dashed lines represent the theoretical values under other cases of α, including 0, –0.1, –0.5 and –1, indicated by the color of hippie blue, light green, dark yellow and orange, respectively. The error bars mean the standard deviations between the two sets of petals. The error bars are smaller than the symbol size if not shown.