Bio-inspiration: The Mantis Shrimp is a marine crustacean native to tropical regions of the Indian and Pacific Ocean. It earned this name because its body resembles a shrimp and its head resembles a praying mantis. It is actually neither shrimp nor mantis and is classified as a stomatopod. The mantis shrimp may reach 12 inches in length, with largest recorded measuring in at 15 inches.
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One feature that makes this creature very unique and interesting and provided inspiration for a new product is its extremely powerful punch. This punch is reputedly strong enough to break through the glass walls of aquariums.
The mantis shrimp’s punch is regarded as one of the strongest in the natural kingdom. The punch is deployed at blinding speed, with an acceleration of 10,400 g and speeds 50 mph (80 kph) and peak forces of 1,500 newtons from a standing start. The strike is so rapid that it generates bubbles which burst, producing extremely high temperatures. The mantis shrimp uses both of these weapons, its powerful punch and the resultant bubbles, to kill or maim its prey; mainly crabs by cracking their shells.
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Video of the mantis shrimp using its punch is available at the link below:
Considering that this feat is achieved under water makes the mantis shrimp’s ability even more impressive. Mantis shrimps are able to achieve such extreme forces by slowly storing muscular energy with a spring and latch mechanism. Once the arm is cocked, a ratchet locks it firmly into place. The large muscles present in the upper portion of the arm contract and build up energy gradually. When the latch is released, all this energy is released at once and the lower arm is launched forwards with tremendous force. An illustration of this phenomenon created by S. N. Patek, W. L. Korff & R. L. Caldwell in Nature is given below. The diagram illustrates the essential components in the mantis shrimp’s arm. In the simplified diagram the red is the strong muscular spring, the latch mechanism is shown in yellow, the blue shapes are the arm, and the four dots show the hinges of the four-bar linkage used to generate this motion.
Proposed Idea: Power Assist for Stunt Bicycles
The mechanism used by the organism to store energy and rapidly release it may have great applications in extreme sports especially bicycling. We believe this will be very useful in providing the extra boost of speed while performing stunt maneuvers such as jumps.
The challenge with these maneuvers is that they require the rider to build up a significant speed prior to taking off. Sometimes the margin of error is small and failure to achieve a high enough speed may result in crashes and injuries. During our research we found that almost 30% of accidents occur due to rider not building up enough speed.
Our proposed solution to this problem is to use an energy storage mechanism similar to the biological system the mantis shrimp uses to for its punch; only in this case it would be adapted as a power assist mechanism to generate extra wheel speed. The aim is to design a device which stores energy generated by normal movements of the cyclist in the form of elastic energy and can release it on demand to provide extra acceleration as desired.
The product would store energy using a strong torsion spring mounted on the rear wheel, and would use a ratchet to ensure that the spring does not unwind prior to desired deployment. The energy would be generated either by various forces applied to the bicycle during use, or may be manually wound to achieve full energy potential prior to riding. The rider would have a manual switch on the handlebars to release the ratchet, activating the power assist of the spring and accelerating the bicycle.
Creative Process: In order develop this idea the team started with individual ideation processes to identify biological sources of inspiration. The group came together, presented these ideas, and through an open discussion explored opportunities related to each. Examples were the mantis shrimp’s punch, plate tectonics, and pheromones. There was an initial set of product ideas, and the group worked to juxtapose some of these to try to find new creative options. This led to ideas such as pheromones to help track customer habits in malls, energy storage for above elbow prosthetics, and considering automobile emissions as a method for distributing deer repellent around roads. Group members then took these ideas and used individual ideation processes to branch off from the central ideas of the group. Several days later the group reconvened to compare their divergent ideas and use those to develop a final central idea for the project. The ideas of the mantis shrimp energy storage and roadway pheromone deer repellent were discussed in detail, considering alternatives within each technology. Through this discussion the group coalesced around the idea of an energy storage / power assist system for high performance stunt bicycles.
There were a series of provocation that spurred the idea of applying the energy storage system on a bicycle. The two most significant provocations are discussed here. The original idea had been to use the system for storing energy to actuate a prosthetic arm, and it was a short leap to consider wheelchairs as a similar handicap which may benefit from a power assist mechanism. This brought the discussion to the realm of wheeled vehicles, and the potential for rapid acceleration was raised. This next provocation led the group to consider high performance situations, which is how the idea of stunt bicycle riding was introduced into the discussion.
After developing the idea it was noted that this is similar to KERS technology used in Formula One racing. KERS stands for kinetic energy recovery system; kinetic energy of a moving vehicle is recovered under braking and stored in a reservoir (for example a flywheel or a battery) for later use under acceleration.This energy is usually used to provide the extra burst of acceleration which can be critical in overtaking opponents during the race.
This is not the same as spring assist technologies currently available for bicycles such as the E-Hub. That spring system is designed to smooth energy consumption by storing energy on the downhill automatically and automatically releasing it as the rider slows down on the uphill. The E-Hub is designed to decrease the average energy output of the rider by smoothing over time, whereas this proposed system aims to increase the maximum energy delivered to the wheels during a high performance situation via a controlled release of the stored energy.
http://t1.gstatic.com/images?q=tbn:ANd9GcRWAF8k_OsHQ15h3qGTyjGA01a1Su_jCap8nqCqyXcZr6CXPszYew
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRgUmqQ-maI7femKQET6yvYcrwC2nAhkSNYfpFtPOOI2Zt8ORr19IlJHfpiFWuRyUOfjzHw2r_FHjdX5jYSm8zuv93vfhweC5wHwFmpLSxZIaE8cqp9IaSROiJ77jIbA986c5p9UaUQQ9l/s1600/mantis.jpg
http://en.wikipedia.org/wiki/Mantis_shrimp#cite_note-Patek_et_al.-6
http://www.nature.com/nature/journal/v428/n6985/full/428819a.html
http://classic.the-scientist.com/news/display/57731/
http://naturalhistorymag.com/biomechanics/082071/knockout-punch
http://www.nature.com/nature/journal/v428/n6985/fig_tab/428819a_F1.html
C M Illingworth, BMX compared with ordinary bicycle accidents, 461-464
http://en.wikipedia.org/wiki/KERS
http://www.ehub.si/eng/default.asp?stran=opis
