We compared the ability of three different posterior cruciate ligament (PCL) reconstructions to restore normal anteroposterior laxity to the knee from 0 to 130 degrees of knee flexion. Cadaver knees were tested intact, after PCL rupture or after bone-patellar tendon-bone grafting. Grafts were performed isometrically or with a single bundle representing the anatomical anterior PCL fibre bulk (aP...

This paper is concerned with the design of a new type of multi-purpose deployable membrane reflector. The reflector structure consists of a central expandable hub, a number of thin-walled foldable ribs connected radially to the hub, and a precision-shaped membrane supported and tensioned by the ribs. This concept is known as a collapsible rib-tensioned surface reflector. A methodology for the d...

When tensioned, ordinary materials expand along the direction of the applied force. Here, we explore network concepts to design metamaterials exhibiting negative compressibility transitions, during which a material undergoes contraction when tensioned (or expansion when pressured). Continuous contraction of a material in the same direction of an applied tension, and in response to this tension,...