Morphology and Mechanical Response of a Compressed Cylindrical Shells

Hung-Chieh Fan Chiang^1*, Hsin-Huei Li¹, Tzay-Ming Hong¹

¹Department of Physics, National Tsing Hua University, Hsinchu, Taiwan

* Presenter:Hung-Chieh Fan Chiang, email:mnb11338@gmail.com

Uniaxially compressed cylindrical shells are common in our daily life, such as rolled-up sleeves and retreated package of drinking straws. The deformations are complex and unpredictable, but often contain arrays of diamond. Is there any other modes of pattern? How does the cylinder respond mechanically when these modes transit? To clarify these problems, we perform both experiments and Molecularly Dynamics simulation. A rod is inserted inside and coaxial to the cylindrical shell in both approaches to avoid folding. It turns out that there are five more different patterns, besides the famous Yoshimura diamonds. These six modes of deformation are respectively spiral, ladder, diamond, wrinkle, ridge, and sagging. Phase diagram is drawn in a 3D plot with the spacing between shell and rod, compression strain and compression rate as axes. Material properties are incorporated to render these three parameters dimensionless. Two main features that worth noting are that different modes are allowed to mix and mode transitions are always accompanied by the absorption or release of latent heat. Simulation reveals that plasticity may disrupt and cause nonuniformity of the pattern.

Keywords: phase diagram, compression, cylindrical shell