Noisy Interiors: Creating & Evaluating August 7th 2017 (http://aleron - contractors.co.uk/images/nosy - office.png) Group 1: David Fredericks, Kenneth Mullinix, and Chris Novotny BMY 504 Arizona State University 1 THE CHALLENGE Designers that focus on the interior of cars, airplanes, and buildings are constantly challenged by noise — how to address the never - ending onslaught of (usually mechanical) noise in our spaces. In fact, there is a direct correlation between our health and t he amount of noise pollution in our lives. Noise is defined as "unwanted sound”, and while some circumstances require that we amplify sound, most of our interiors require the opposite. While solutions exist (and books have been written), none are fully successful. This report focuses on a biomimetic strategy for minimizing the impact of noise in interior spaces. For this challenge we were instructed to research and design a solution for existing commercial spaces in general, while using the Biomimicry Center at ASU as an example. The Biomimicry Center is housed in a large, mixed - use building with offices, classrooms, and gallery sp aces. The building is said to have moderate daytime foot traffic with increased foot traffic during gallery events and little - to - no foot traffic at night. The sources of noise have been categorized in order of importance, with mechanical sound being the pr imary issue. Human - generated sounds and exterior sounds from traffic and other buildings are the secondary and tertiary source issues. We have also been instructed to focus our solution on managing sound that has already been generated, rather than trying to dampen the noise at the source as this is seldom an option. SCOPING Primary Function : Manage ambient, unwanted sound (noise) Secondary Function : Reduce noise - related stress. Based on the challenge and the details about interior noise pollution, our group originally decided on a primary function of manage unwanted sound (noise) in isolated environments, however, after review we realized that the “isolated environments” part lim ited our search for biological champions. We also originally had a secondary function of improve sound (sonic and acoustic) quality in isolated environments, but realized that this is a completely separate issue altogether. After defining the function of our ultimate design, we put together a list of must - have (threshold) and nice - to - have (objective) requirements. We utilized these requirements (table 1) as guidelines throughout all phases of this project. DISCOVERY & BRAINS TORMING In order to identify biological organisms that manage noise in isolated environments we define noise as unwanted acoustic and sonic energy. At its core, sonic energy is modulated pressure moving in waves through the air. Sound interacts with animal s in generalist (being felt by the organism) and specialist (being heard by the organism) ways. This provided us with a wider lens to look at different natural strategies: those that dealt with sound and noise specifically and those that dealt with the mec hanical aspects of energy. It is difficult to find a variety of direct natural analogs for managing unwanted noise. In general, organisms want to hear and interact with the sounds around them for good reason: hear the 2 swoop of an approaching hawk; the call of a potential mate; or the vocal sounds between animals for general communication. However, nature does isolate certain forms, processes, and systems of noise and sound to particular environments on different scales. During the brainstorming process we initially used our own experience to think of natural models we were already familiar with such as birds of prey silencing their flight; sand dunes that reduce the sounds of the ocean; or trees that mask some sounds in the forest. Beyond those easy - to - find examples, we started using keyword searches like “reduce noise”, “sound absorption”, and “noise mitigation” against bio - related sources. This yielded a few more examples. Further brainstorming led us to inverse examples that might amplify sound and physic s examples that deal with mechanical wave energy. We found that some of the strategies just didn’t apply in the way we thought they would, and others were still too mysterious for researchers to pinpoint the actual mechanism that enabled the organism’s str ategy. THE SOLUTION CONTEXT Based on this criteria, our group generated a list of non - negotiables (threshold) and nice - to - haves (objective) requirements. REQUIREMENT VERIFICATION TABLE FOR FINAL DESIGN (Color coded by design compliance) Threshold Requirements Objective Requirements The solution must mitigate noise from interior mechanical noise, human noise, and exterior noise. The solution should be a passive system that does not require a power source. The solution must work address noise pollution beyond the source The solution should be built into the structure itself The solution must be function for multiple levels of sound The solution should be maintenance - free The solution must not create any additional noise The solution should increase the ambiance of the building The solution must not be intrusive in design or function to the normal operation of the building The solution should be multifunctional The so lution must follow Life’s Principles The solution should be scalable Table 1 BIOLOGICAL CHAMPION After careful consideration and investigation of more than a dozen potential biological champions, we came to the conclusion that the Nocturnal Moth ( Bombycoidea: Saturniidae) was the most viable biological champion for this challenge. In order to avoid predation from bats, moths have wings that capture sonic energy through a non - uniform lattice structure comprised of ridges and crossribs with layered s cales. When sonic energy hits the scales of a moth’s wing, it is passed to the internal structure 3 of the scales through micropores. The inside of each scale is a mesh - like structure that creates a network of air gaps in the moth’s wing where the sonic ener gy can be dissipated as heat rather than reflected ba ck. Figure 1 Nocturnal Moth Figure 2 Macro Structure of Moth Wing Figure 3 Micro Structure of Moth Scale 4 ABSTRACTED DESIGN PRINCIPLE Layered, semi - hollow porous plate structures with non - uniform construction and networked air gaps trap sonic energy. Figure 4 Micro Side View of ADP Figure 5 Micro Top View of ADP CREATING The creating phase took place over a series of group discussions. The mind map below is a graphical representation of the thought process. Four areas of interest dominated this section: the physics of the abstracted design principle; the function of our fi nal product; manufacturing constraints and ideas; and keeping the system aligned with life’s principles. 5 Figure 6 B rainstorming / Process B reaking down the physics regarding sound interaction required the most research. We initially assumed that a portion of the mechanism was due to th e moth scales being tuned to the acoustic wavelength and frequency of bat sonar (50 mHz). Calculations showed us that to scale this principle for the acoustic frequencies we are concerned with (85 - 250 hz) only requires a size increase of less than one orde r of magnitude. Looking into further research regarding the composition of moth scales and evaluating our source material again led us to find three major considerations which were also reflected in our Abstracted Design Principle: 1. The non - uniform distribu tion and size of the scales was important to sound absorption and scattering (rather than reflection). 2. The micro - porous structure of the scales allowed sound to be captured and funneled to the interior of the scales and wing structure itself where it is th en dissipated as heat. 3. The air gaps coupled with the Impedance Matching Structure (IMS) within the scales allowed the right amount of energy absorption and scattering and thus should be providing the maximum benefit to the design. 6 Figure 7 Design Overview Form & Function Once we understood the scale of the build and required components, we moved onto form and function. Brainstorming form and function led us to developing a modular structure which could be hung or built into a wall, or used as a stand - alone structure. The s tand - alone structure could function to divide the room, provide a path for guiding guests in a desired manner, or simply placed in areas of increased noise. The benefit to both structures is that it could be used as an art piece as well. There are no const raints to size and shape and may be chosen by the customer to satisfy their particular needs. Manufacturing Manufacturing was closely tied to Life’s Principles during the discussion and consideration of options. Overall, the solution should be iteratively developed to determine the best mix of materials for performance and manufacturability. The matrix on which the other components hang could be made from renewable resources like bamboo or a starch - based polymer. If using an additive manufacturing process, then the matrix could be formed into just about any macro shape desired by the client. Additive manufacturing was decided upon because of its low waste, high precision, and ability to use biodegradable plant - based materials. Researching materials used in 3D Figure 8 Potential Interior Placement 7 printing led us to Polylactic Acid (PLA), and other starch - based polymers. Impedance matching our specific noise challenge to one of these starch - based polymers is necessary for achieving the highest level of noise reduction. One of the challenges relat ed impedance is finding the correct material that absorbs enough of the acoustic energy, but does not transfer it to other materials. The Impedance Matching Struc ture (IMS) on the interior of the matrix a nd between the scales could be 3D printed as ins erts, specific closed - cell foams cut to shape, or as part of the matrix itself. This is a key component of the overall solution that provides refraction of the sound waves once they are captured to increase attenuation and di ssipation of the energy. Other required qualities of the material include resilience to humidity and temperature, as well as the ability to be impregnated with colorfast dye since color options will be given to the customer. Figure 10 Design Breakdown E VALUATING Our solution is evaluated using Life’s Princi ples as listed below. Highlighted sub principles are those that weren’t addressed and show areas for improvement. Green text responses are those that were met and how. ● Evolve to Survive ○ The design’s success is based on whether or not in contributes to the continuity of life Figure 9 Potential Exterior Placement 8 ● The design builds on what works. Our design is based upon a biological strategy championed by the nocturnal moth. ● There are opportunities for cross - pollination of info rmation and ideas. The design can be integrated into other acoustic dampening designs. ● The design receives and incorporates an influx of new information ● Mistakes are used to encourage continual idea generation. We have specified that the design should be iterated to incorporate feedback on what works and what doesn’t to ensure optimization. ● Integrate Development with Growth ○ Both development and growth are optimized ● Components are modular and nested. The fi nal design is modular that will allow it to be repaired if damaged or expanded as necessary. ● It is built to shape (e.g., no cutting and therefore no waste cuttings). We are proposing additive manufacturing to reduce the amount of waste during manufacturing ● The components of the system are self - organizing ● The design fosters emergent relationships ● It creates more opportunities (niches) for life ● Adapt to Changing Conditions ○ The design adapts to temporal and spatial changes ● The design maintains integr ity by constantly adding energy, information, matter to improve the system. We have specified an iterative design process that incorporates feedback on the design as well as performance metrics to improve the product as time goes on. ● The design withstands disturbance while maintaining function ● It incorporates a variety of different forms. The form can be customized depending on the implementation and space requirements. ● It duplicates critical elements. Because we are using an overlapping scalar structure, i t is by nature duplicative. ● Its functions are distributed and decentralized. Because we are using an overlapping scalar structure, there is no “centralized” point of failure for the design. ● The design includes multiple forms, processes, and systems to meet functional needs over time and space. The design uses additive manufacturing and may be shaped per the customer’s request and specific needs. ● The design co - evolves with other parts of the s ystem to increase the rate of adaptation Feedback from customers can be incorporated into new designs quickly without having to redesign manufacturing jigs or molds. ● Be Locally Attuned and Responsive ○ The design fits into and integrates with the surrounding environment ● It is resourceful with opportunities and limitations ● Materials used in the design are local and abundant Starch - based polymers are abundant and readily available. 9 ● It harnesses freely available energy. The design itself doesn’t require energy to function, and we are proposing renewable sources of energy for production. ● It fosters symbiotic, cooperative, community - savvy relationships. The design is intended to be used as a part of a wh ole strategy for noise abatement. It is complementary to typical noise insulation techniques used in construction. ● The design avoids competition by finding a new niche. The design is novel. Additive manufacturing also allows for a new level of customizati on per customer specifications. ● The design cooperates with other parts of the system to make the most of what is available. The design doesn’t interfere with any other systems within the building, and is intended to be a passive system that interoperates w ith anything in its environment. ● It maintains community ties through reciprocal actions ● The design co - evolves with other parts of the system. The design can be refined for acoustic tuning based upon the acoustic function of each room or building. ● The desig n leverages existing cycles ● The design detects local feedback loops ● It responds quickly and appropriately to feedback Customer feedback can easily be incorporated into the next build. ● It learns by trial, error, and imitation ● The signal it sends, the “ antennae” it uses to detect the signal, and its response match. The design receives and collects energy in ideally impedance - matched interior structures and materials. ● Use Life - Friendly Chemistry ○ The design uses chemistry that supports life processes ● The design assembles a small subset of elements in elegant ways to achieve function. The design itself is modular (lattice, IMS, scales), and is intended to be scaled as needed to achieve a greater function. ● It uses a safe subset of the periodic table. T he design is intended to be produced with biodegradable polymers that require no unsafe chemicals for production. ● The breakdown of the design results only in by - products that cause no harm. Starch - based polymers breakdown to their respective constituents s uch as water, biomass, gasses, and salts. ● All chemistry is done using water as the solvent. ● Chemical reactions tap the power of self - assembly ● Be Resource Efficient (Material and Energy) ○ The design skillfully and conservatively takes advantage of resources and opportunities ● It is respectful of the limits of habitat (e.g., water, nutrients, or niches). The design is neutral in this regard. ○ The design meets its functional needs with mi nimal outlay of material and energy ● A single design meets more than one need. The design is functional as intended as well as an art piece that promotes biophilia. ● The design takes the energy path of least resistance. No energy is required for the produc t, and the only energy it gives off is an immeasurable amount of heat. 10 ● The design reduces required temperatures, pressures, and/or time for reactions. Design uses standard additive manufacturing techniques at room temperature. ● The design reuses materials or uses recycled materials. The design could be used from recycled materials and is intended to be biodegradable. ● It stays in either a technical or a biological cascade ● It is designed for disassembly, reuse, and reconfiguration. The design can be co mpletely disassembled when part of a larger, modular wall. It can be reused in different environments and in different shapes. ● The design uses shape and information to reduce the use of material and energy. The design uses additive manufacturing so there i s minimal waste material and so that its formation is exactly as needed. ● The form provides the function. The design meets this goal exactly. ● The design taps the power of limits. 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