Inderjit Chopra – författare

The twenty-first century could be called the 'Multifunctional Materials Age'. The inspiration for multifunctional materials comes from nature, and therefore these are often referred to as bio-inspired materials. Bio-inspired materials encompass smart materials and structures, multifunctional materials and nano-structured materials. This is a dawn of revolutionary materials that may provide a 'quantum jump' in performance and multi-capability. This book focuses on smart materials, structures and systems, which are also referred to as intelligent, adaptive, active, sensory and metamorphic. The purpose of these materials from the perspective of smart systems is their ability to minimize life-cycle cost and/or expand the performance envelope. The ultimate goal is to develop biologically inspired multifunctional materials with the capability to adapt their structural characteristics (such as stiffness, damping and viscosity) as required, monitor their health condition, perform self-diagnosis and self-repair, morph their shape and undergo significant controlled motion over a wide range of operating conditions.

This paper reviews some of the important technical barriers that must be overcome to achieve truly efficient flying adaptive micro air vehicles (MAVs). As defined by the Defense Advanced Research Agency (DARPA), MAVs are vehicles with no length dimension greater than 6 inches. These vehicles typically weigh less than 100 grams and some can fly for approximately 30 minutes. Over the past decade significant progress has been made in developing these small-scale mechanical flying machines. However, there is still much work to be done if these vehicles are to approach the efficiency and performance of biological fliers. This paper reviews the status of current miniature mechanical flying machines and compares their performance with common biological flyers such as birds, and small insects. This comparison reveals that advances in aerodynamic efficiency, lightweight and adaptive wing structures, energy conversion/propulsion systems and flight control are required to match or exceed the performance of nature’s great flyers.