Saturday, 30 May 2015

Bio Inspiration

1. Clingfish Offer Inspiration for New Medical Devices

The northern clingfish has a suction cup-like discs on the belly which can stick to wet and uneven surfaces. If these fish were scaled up to human size, the suction cup-like discs on their undersides would easily be strong enough to lift several cars! Hence, their sticking power can be of particular interest for new technologies such as medical devices.

The location of the disc makes the clingfish so suction-able. Clingfish is well able to cling to the surfaces which have various levels of roughness due to the layers of hairlike structures found at the edge of the disc. Frictional force acts between the edge of the disc and the surface that it is stuck to when they are contacted to each other.

Similarly, surgical tool mimic the clingfish’s technique to increase the efficiency of laparoscopic operation which require to work through very small incisions elsewhere in the body using a lighted tube. The procedure can now go as fast and easy when the internal organs or other tissues grip tightly in a narrow clamped space with the help of these medical devices.

2. Flexible Bullet Proof Armor Inspired by Fish Scales

The conventional familiarity when mentioned bulletproof vest are usually attributed to large, bulky, inconvenient and also heavy. Especially on the last two attributions, the weight could range from as light as 7.4kg to as heavy as 11.4kg. Where the issue with weight could be easily overcome with strength conditioning, there seemed to be no direct solution towards movement restrictions. It is understandable that, this disadvantage leads to a burden and difficulty upon physical task performance.

Issues related to such that the current design of bulletproof vest prevents user from properly bending their torso and it tends to irritate the rotator cuffs/ shoulder movements causing in discomfort that could possibly disrupt their focus upon task at hand; resulting in endangering their safety.

With several major fields in the industry that heavily relies on bulletproof vests such as the security services, astronauts, military and any other services that revolves around high threat activity where mobility is important, it is imperative that these vests does not pose any form of liability in motion to the user as they are the only thing standing in between high impact/velocity projectile or external implication of edged force and their lives.

As effective and safe as the bullet proof vest can be, it could not be ignored that there are still rooms for improvement for this product; especially upon the flexibility issue. Current designed seemed to face an issue where if flexibility is desired, effectiveness of penetration prevention had to be sacrificed; vice versa. Thus, the researchers at MIT took an approach through biomimicry; to design a bulletproof vest that is flexible enough to accommodate user’s fluidity in motion without sacrificing the effectiveness of the initial purpose; which is to shield from external puncture force.

The biomimicry is inspired by the nature’s fish hard scales which synergized well with its flexibility. Fishes are known to be flexible as it is the core for primary propagation for its locomotion in the water; swimming, through the generation of flexion waves.

Taking the base concept upon the synergy of hard scales versus flexibility, the research which was led by Assistant Professor Stephen Rudykh, successfully achieved to design a bulletproof armor that is flexible. The key lies in within the different layers of the armor which consist of two components; a soft tissue-like layer upon the inner section and a hard, bullet proof substance to constitute as the ‘armor’ upon the outer layer. These two components combined to create a protecto-flexibility property that is highly desired for bulletproof vests.
Multiple layers depicting the concept design.

 Professor Rudykh demonstrating the flexibility of the material
(hard scales over soft material)
Tests done on varying angles from 10 degrees (top), to 20 degrees (middle) and to 30 degrees (bottom) to observe the penetration resistance pattern. The arrangement were hard scales on top of soft elastic material, providing great flexibility.

As far as the progress goes, currently Professor Rudykh  and his team are materializing this design through 3D printing to allow for physical testing. On top of that, it has been claimed that the team had discovered a way to increase the penetration resistance by a factor of 40, while only sacrificing the flexibility of the soft material by a factor of 5.

 It is observed that the next milestone is to incorporate this design to military uniforms, further improving strength, providing better overall protection and enhancing flexibility as well. For the space suits, it would greatly benefit from the flexibility as it would pose far less resistance during spacewalks and increases the impact resistance making it impervious to micro-metorites. It is also recorded that Rudykh’s work had been published in the journal of “Soft Matter”

3. VIVACE hydropower

University of Michigan (UM) recently had patented MHK device, the VIVACE converter (Vortex Induced Vibration for Aquatic Clean Energy). VIVACE harnessed river or ocean current flow over its cylinder body to generate vortexes that push the cylinder up and down and thus generate electricity. This transformational renewable technology has low environmental impact, low installation cost and high energy efficiency which only require 2 to 3 knots of water currents to start operate. The inspiration of VIVACE come from observing the fish swimming inside the aquarium tank according to Dr. Michael Bernitsas of the University of Michigan’s department of marine engineering. When fish swims forward, they curve their body to collect the vortexes, and then straighten their body and curve to other side and create another vortex to allow them to glide along the vortexes which propel them forward. This phenomenon is called Vortex Induced Vibration (VIV) where vortices are formed and shed on the downstream side of a bluff body and hence creating a pressure differences that generate oscillatory lift. Besides, Cylinder oscillations are rather slow at about a cycle/sec which do not create physical impact on marine life. The YouTube video below shows how the VIVACE works under different knots of water current. VIVACE is a simple device which can generate high actual power and more cost effective than wind turbine. Table 1 below shows the comparison between Oscylator 33 comparisons to 1.5MW GE wind Turbine. The Oscylator 33 has lower rated power than 1.5MW GE wind turbine, however Oscylator has higher capacity factor than wind turbine. Capacity factor is the rated power over the average actual generated power throughout a year. The higher the capacity factor, the greater the power efficiency for a device. Moreover, the total cost to buy and install Oscylator 33 is lower than the wind turbines. Hence, VIVACE can be concluded as a more sustainable renewable energy product than a wind turbine when a design is inspired from the nature (Field et al., 2013).

VIV cylinder motion movement

Fishes apply VIV to swim

Table 1. Oscylator 33 (VIVACE) comparison to 1.5 MW GE wind turbines (Field et al., 2013).

References,. 'Tough, Flexible Material Could Protect Soldiers & Astronauts : ATS'. N.p., 2015. Web. 15 May 2015.
Mail Online,. 'Body Armour Based On A FISH Could Lead To Bulletproof Uniforms'. N.p., 2015. Web. 15 May 2015.
Rudykh, Stephan, Christine Ortiz, and Mary C. Boyce. 'Flexibility And Protection By Design: Imbricated Hybrid Microstructures Of Bio-Inspired Armor'. Soft Matter 11.13 (2015): 2547-2554. Web. 15 May 2015.
Field, D. O. E., Officer, C., Brodie, P., Field, D. O. E., Management, G., Kerry, S., … Mauer, E. (2013). DE-EE0003644 Advanced Integration of Power Take-Off in VIVACE Vortex Hydro Energy Final Scientific/Technical Report, 1–28.

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