Physics – Stretching with out Buckling
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• Physics 16, s62
Supplies that stretch on demand typically bend in undesired instructions, however a brand new theoretical mannequin can produce stress-free designs that change form with out buckling.
Liquid-crystal elastomers (LCEs) are shape-shifting supplies that stretch or squeeze when stimulated by an exterior enter comparable to warmth, gentle, or a voltage. Designing these supplies to supply desired shapes is a difficult math downside, however Daniel Castro and Hillel Aharoni from the Weizmann Institute of Science, Israel, have now offered an analytical answer for flat supplies that shape-shift inside a single airplane—like font-changing letters on a web page [1]. Such “planar” designs may assist in producing rods that change their cross part (from, say, spherical to sq.) with out buckling.
LCEs encompass networks of polymer fibers containing liquid-crystal molecules. When uncovered to a stimulus, the molecules align in a means that causes the fabric to shrink or lengthen in a predefined route—known as the director. Researchers can design an LCE by selecting the director orientation at every level within the materials. Nevertheless, calculating the “director subject” for an arbitrary form change is troublesome, so approximate strategies are usually used.
Castro and Aharoni targeted on a selected design downside: tips on how to create an LCE that stretches solely in two dimensions. These planar LCEs typically endure from residual stress that causes the fabric to wrinkle or buckle out of the airplane. The researchers confirmed that discovering a buckle-free design is much like a widely known mathematical downside that has been studied in different contexts, comparable to minimizing the mass of load-carrying constructions. Taking inspiration from these earlier research, Castro and Aharoni offered a technique for precisely deriving the director subject for any desired planar LCE. “Our outcomes might be readily applied by a variety of experimentalists, in addition to by engineers and designers,” Aharoni says.
–Michael Schirber
Michael Schirber is a Corresponding Editor for Physics Journal based mostly in Lyon, France.
References
- D. Castro and H. Aharoni, “Form morphing of planar liquid crystal elastomers,” Phys. Rev. Lett. 130, 178101 (2023).
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