Quasi-Static Folding and Deployment of Ultrathin Composite Tape-Spring Hinges

Deployable structures made from ultrathin composite materials can be folded elastically and are able to selfdeploy by releasing the stored strain energy. This paper presents a detailed study of the folding and deployment of a tape-spring hinge made from a two-ply plain-weave laminate of carbon-fiber reinforced plastic. Aparticular version of this hinge was constructed, and its moment-rotation profile during quasi-static deployment was measured. The present study is the first to incorporate in the simulation an experimentally validated elastic micromechanical model and to provide quantitative comparisons between the simulations and the measured behavior of an actual hinge. Folding and deployment simulations of the tape-spring hinge were carried out with the commercial finite element package Abaqus/Explicit, starting from the as-built unstrained structure. The folding simulation includes the effects of pinching the hinge in the middle to reduce the peak moment required to fold it. The deployment simulation fully captures both the steady-state moment part of the deployment and the final snap back to the deployed configuration. An alternative simulation without pinching the hinge provides an estimate of the maximum moment that could be carried by the hinge during operation. This is about double the snapback moment

Ballistic transport properties across nonuniform strain barriers in graphene

We study the effect of uniaxial strain on the transmission and the conductivity across a strain-induced barrier in graphene. At variance with conventional studies, which consider sharp barriers, we consider a more realistic, smooth barrier, characterized by a nonuniform, continuous strain profile. Our results are instrumental towards a better understanding of the transport properties in corrugated graphene.Comment: High Press. Res., to appea