A MULTIFUNCTIONAL AND RECONFIGURABLE MICROVASCULAR COMPOSITE

2021 ◽  
Author(s):  
URMI DEVI ◽  
REZA PEJMAN ◽  
ZACHARY J. PHILLIPS ◽  
KALYANA B. NAKSHATRALA ◽  
AHMAD R. NAJAFI ◽  
...  

Fiber-reinforced polymer (FRP) composites, consisting of stiff/strong fibers embedded within a continuous matrix, are a lightweight structural platform supporting an array of modern applications. Bioinspired vascularization of fiber-composites can augment existing performance with dynamic functionalities via liquid infiltration of the internal micro-fluidic network. Some vascular-enabled capabilities include self-healing to repair delamination damage and active-cooling to prevent thermal degradation. While such attributes have been demonstrated in separate platforms, research investigations that combine functionalities within a single composite have been limited. Here we provide a recent study that highlights a promising pathway for achieving both multifunctional, and reconfigurable behavior in microvascular FRP composites. Specifically, we detail the ability to regulate temperature and modulate electromagnetic signature via fluid substitution within the same serpentine vasculature. Varying microchannel density alters both active-cooling efficiency by water circulation and polarized radio-frequency wave reflection by liquid metal infiltration. We control these bulk property pluralities by widespread vascularization, while minimizing impact on structural performance, and decode the effects of micro-vascular topology on macromechanical behavior. Our in-depth experimental and computational investigation provides a new benchmark for future design optimization and real-world translation of multifunctional and adaptive microvascular composites.

2012 ◽  
Vol 33 (3) ◽  
pp. 397-403 ◽  
Author(s):  
Ahmad R. Shafieizadegan-Esfahani ◽  
Ali A. Katbab ◽  
Ali R. Pakdaman ◽  
P. Dehkhoda ◽  
Mohammad H. Shams ◽  
...  

2007 ◽  
Vol 78 (8) ◽  
pp. 083502 ◽  
Author(s):  
T. Yamada ◽  
A. Ejiri ◽  
Y. Shimada ◽  
T. Oosako ◽  
J. Tsujimura ◽  
...  

Author(s):  
Chris Norris ◽  
Ian Bond ◽  
Richard Trask

Self-healing in fibre reinforced polymer (FRP) composites is an active area of research, principally aimed at restoring the losses in mechanical strength associated with impact induced damage. This bioinspired function may be imparted upon a composite structure via the embedment of a vasculature that is capable of delivering functional agents from an external reservoir to regions of internal damage. A simple segregated vasculature design incorporated into a FRP via a ‘lost wax’ process was found to facilitate a self-healing function which resulted in an outstanding recovery (≥97%) in post-impact compression strength. The process involved infusion of a healing resin through the vascule channels. Resin egress from the backface damage, ultrasonic C-scan testing and microscopic evaluation all provide evidence that sufficient vascule-damage connectivity exists to confer a reliable and efficient self-healing function.


1965 ◽  
Vol 43 (11) ◽  
pp. 2021-2035 ◽  
Author(s):  
Robert J. Papa ◽  
Carl T. Case

A radio-frequency wave is normally incident upon an inhomogeneous plasma slab. The plasma slab is composed of partially ionized high-temperature air corresponding to the characteristics of the plasma sheath surrounding hypersonic reentry vehicles. The isotropic part of the electron velocity distribution function is Maxwellian because of electron–electron collisions. The electromagnetic wave is intense enough to heat selectively the electron gas, altering the various electron production and loss processes. The high-frequency limit is considered, and expressions are obtained for the electron number density and effective collision frequency as a function of electron temperature. The effective collision frequency takes into account the effects of electron–neutral and electron–ion collisions for momentum transfer. From an energy balance equation, the electron temperature is found to be a function of both the frequency and field strength of the wave. The electron temperature is found also to exhibit an instability that gives rise to a hysteresis effect.


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