These Bricks Can Absorb Traffic Noise - Thesis Presentation on Helmholtz Resonators

I just finished a masters in architecture and the thesis was resonating soundscapes altering soundscapes in exterior environments using hemholtz resonators in ceramic bricks I'm a Portland native I'm Joe kirma my last name means a pub or a Tavern in Czech I went to University of Portland in business graduated in 2008 the thing that we're focusing on is London and sound in London so I was living there for the last eight years and I worked at a smaller startup we were selling 3D printers CNC machines laser cutters uh from 2015 on and then worked for a larger company marklay Bank larger Corporation and we also were having a lab similar to this kind of space and Incorporated the hardware side as well as the prototyping and education side as well as started my own business but within that space we took over the Olympic Village now this was was a media center during the 2012 Olympics in London and we converted it to a 700 person co-working space and had all sorts of companies ranging from uh well in in my field it was the hardware um side of VR AR companies electronic bike e battery companies and architecture firms and then the other side of the building was University College London and I was looking at this facility and it's amazing it's really state-of-the-art stuff uh they have a main campus um in downtown but we are East London and they really expanded well into this area and that's a sound booth there and light booth and they had a hardware lab to dream of HW CNC machines uh large robotic arms and I thought maybe I should work here and a professor said no you shouldn't work here you should get your postgrad from here it's like what can can I do there well a business major with some you know the hardware experience but I don't have the academics he said well we've got this program there's three of them there and it's under architecture there's design for performance interaction and you a lot of arduinos and and body and and scanning bioid dealing with melium and fungi and and how nature plays a role in architecture and designed for manufacture and I found like this is it this is what I wanted to do we had the ultimate play pen and I'm sure all of you guys would love to you know come over there and we could really uh make whatever you wanted and so after being rejected one time I tried it again and they accepted me so I said I'll stay for a little while longer here and I was looking into noise in London and it's a noisy city has it's interesting that parks around London have all of this traffic and they're sandwiched by all this noise and it's kind of ironic that we go to these natural areas to escape this Urban noise and yet we are bombarded with it the area that we're in uh our school is in Stratford in East London here so in the in our program we were looking into the lack of solutions for exterior sound barriers dealing specifically with low frequency noise in traffic and our boundaries that we had to work with the material that we had to use was Ceramics our director said we're going to focus on this as the medium to work with and different groups broke up into researching different areas on this so some were doing Ram to Earth and looking at structures and there were five of us that were looking into sound and we thought for a problem statement how how might we improve our health through the quality of our exterior environment soundscape and on further research we looked into even stroke and found that cardiovascular disease Rose by 8% for every 10 Deb of noise exposure this is from the World Health Organization and you know we spend money and resources trying to prevent noise from going into our living spaces but there's still an imbalance for solutions for exterior so we have a lot of indoor um Solutions but how can we use this for exterior especially when it comes to traffic noise the low frequency uh spreads far beyond like the road and can disrupt many surrounding areas so our Focus obviously was on Transportation this is a another sound map here and we were looking in the range of 20 to 300 Herz so in the low frequency range here and that's again where a lot of the the traffic noise is going to be heard and London was actually the noisiest city in Europe with over 1.6 million people being subjected to hearing hazards over 55 DB uh this was from the United Nations so we found that interesting and how London there's there's no limit on how loud something can be in London there's um times where they have to be quiet but the volume doesn't matter looking at the acoustic Services though so this was all new to me but there's three different types kind of that you can use for sound to to move it's either reflective it's either absorbed or it's diffused in the material and it was interesting that we have indoor options where we try to shelter ourselves we use double pane glass we try to make as much padding from the outside world to keep that out then in and then there's a couple options that you've seen they're not the most beautiful elegant options for freeway no one's really uh winning awards for that so we were looking into soundscapes and soundscape is the acoustic environment as perceived by humans in context uh the acoustic environment is a combination of all the acoustic resources natural and artificial within a given area as Modified by the environment however soundscape design in architecture not only focus focuses on the audio aspect which is objective values but also can considers how to improve the combined sensory experience of other senses such as light touch um and maybe even smell these would be subjective factors So within our group we were looking at how can soundscape be focused on more than one sense this is not the first uh to think of sound in in architecture uh the guy up there who's basically the father of architectural Acoustics is Marcus vrus Da Vinci made it a famous illustration of him he was born in Italy around 75 BC and died sometime after 15 BC and his only document that survived was de architectura which is the um 10 books on architecture and he dedicated this to Emperor Augustus and in this he outlined some basic um uses of improving sound in architecture through using bronze ears called eia now these would be placed in a theater and it would open up to face the stage and the stage actor's voice would cause the vessel to resonate and produce an increased harmonized note now these ear Arrangements could be tuned depending if the venue was small or large now acousticians have debated whether they were effective in either amplifying the sound or if they reduced reverberations leading to a better listening environment as well as in the 1400s especially 1430s they were found um over 100 churches in France had these pots that were found in the Nave of this church and all of these uh areas in um Al France and of these there's 29 pots 27 are present but they would they would look like this and they'd be up kind of in the ceilings and and walls so I was very curious of what what's going on here and what it is is Mr heml is coming into play Herman Ludwig Ferdinand Von hemholtz he was basically a German Renaissance Man lived from 1821 to 1894 he had improved fields in physiology the age of the Earth psychology the origins of the solar system physics and philosophy but in 1862 he wrote this book called on the sensations of tone where he explained how how a device could focus on a small frequency tone in a multiplex of sounds and what this is is a hem Holts absorber or resonator and what you have is a area a neck and then a cavity and this acts as a spring so Acoustic sound is turned into heat when it's absorbed into this because this neck is um basically absorbing a specific bandwidth of frequencies using uh this equation so you can tune that to absorb um certain sounds that you want this is used in car exhaust Mufflers as well as airplane engines um they Ed it as an acoustic liner surrounding the motor I had never heard of pem Holtz resonators and then now once you see it you can't unsee it and you're going to be looking for these everywhere you go now so just a quick example a couple examples um there's in this theater in Queen Elizabeth Hall there are these holes in the walls it's it's like what's going on here well this was actually U one of my professors uh had made this and what they're doing is they're changing to four different sizes to absorb um specific frequencies that you want because you have a neck and then behind that you have your cavity also the Elizabeth line the newest line that they put in London had all these um these beautiful facades but what they're actually they're not just for aesthetic reasons the more important function was absorbing noise and people were saying wow you hear how quiet it is here uh same with Paddon station uh they're not saving bricks there they're actually removing every other so that you have a neck and then a cavity so once you see it you're not going to be able to unsee it a company that we had seen use these for traffic um it's based out in Northern Italy and they're using clay and cement and inorganic oxides to make a whole bunch of range of colors uh but it's basically a cinder block with slits in it and this one has also some highdensity rock wall to AB extra absorb as well as some other frequencies and same with another Colwell um company out of the UK and these are actually pretty good in absorbing the specific range now you're going to be able to absor every range but the certain ranges that you want to focus on so we started looking into testing for ourselves is ceramic really going to work in this uh you know being burdened with a material is um is very limiting so we looked at some microt testing of materials and we had some wood that we carved into this wavy pattern this foam the Sheffield foam is our standard and we used an impedance tube here and within that wood pattern we also grew mycelium and we're testing that uh this wouldn't work well for exterior environments but then we had to move to ceramic and we noticed that actually slipcasting this terra cotta was well it was okay but how are we going to make this work for us well you can uh do this thing called burnouts where you take slip which is a liquid clay and you take a sponge or something that's going to be sacrificed you dip that in the clay let that dry and then when you fire it in the Kiln the sponge is burnt out and the clay is kept so you've had this very interesting uh complex structure that can be used and could this possibly work to absorb sound so we built our own test box to uh be able to test our future bricks that we were going to build and this was just concrete box with a speaker on it and it ran through a frequency so it would make an you know an entire frequency uh sound wave it would go like and within that certain wave you could see oh yeah at this one uh output uh the bricks or mini bricks actually worked so we had our box we had our Test Facilities now it was onto the site and again we're focusing on East London here it's sandwiched between some some roads underneath and some train lines up above so we had a wonderful uh noise machine on both the North and the South and the overground here passes right through a lovely area that that was home for studios and restaurants and bars and Community Gardens and event spaces that they wanted to grow so we said well maybe if we could make some sort of Pavilion that would alter the soundscape would this have the potential to improve natural sounds like birds chirping and water and conversations and also minimize traffic noise so minimize a low frequency but keep mid and high frequencies so the problem statement again how might we improve our health through the quality of our exterior environment soundscape the research question was to investigate alternative strategies for the design and manufacture of fired clay hemholtz resonators to alter the soundscape of external spaces and then I had four objectives that I was looking into one was a proof of concept to make sure that these shells would work um absorbing a certain frequency two it would be in low frequency also to develop a design to workflow um fabrication so that this could be somewhat repeated and to incorporate other senses would this also possibly be a visual reminder um could we use touch and or smell in this final Pavilion so our group split up into four different um methods one guy in our group looked into Extrusion and it was really interesting of how he was going to make some sort of Pavilion this was the fuzzy front end where we all didn't know we had a year to work on this we didn't know what this was going to be two other people in our group looked at bricks in a facade using hem Holtz resonators but they're inverting the neck so hemholtz resonator can work with either I'm giving it away early but a neck extruded out or inside as long as you have a neck in cavity it'll be able to absorb another I'll skip me and then another guy was looking into robotic arms into reflection uh but he's also using a brick and to be truthfully honest I wasn't sure what I was doing at this moment probably pretty clear I did know that I wanted to look at all of the opportunities that we had so there's clay 3D printing which is what's going on here with these mini bricks so I started 3D printing with Clay now it's different than regular fdm machines your are extruding something and it's without the temperature and so you're basically working with vacuums and um air uh compression so you want to have this chamber it's it's huge and it kind of pushes this clay through this screw using sheer factors and everything um to move the clay around now it works well with certain shapes that I tested to like extrude out and see what the overhang but your your draft angles and your overhangs are going to be very limited to say the least and it takes a long time so I wasn't going to go down that route so yeah this was what we were doing here with these samples that you can come see afterwards uh taking it through grasshopper and being able to change um whatever we wanted for our G-Code and adapt um the tool head in any um any ways that we saw fit and they were interesting and I thought maybe These Bricks could interlock somehow but 3D printing just wasn't going to work so then I looked into slip casting where you have your mold you take a plaster mold around that that is going to be able to uh dry out and you pour your liquid clay in your slip and it will suck up all that moisture and then you'll have a basically a hollow um form after you pour it out and hooray you you have your your piece and then you let that dry after 24 hours from going from leather hard to bone dry and then fire it in the Kil and so we're looking at the first three prototypes I was I was going with a regular standard brick size the important thing was because we're going from 20 to 300 Herz it must have a large enough cavity and neck for a UK brick so there's three different types of bricks I didn't know this there's the US brick there's a UK brick and there's an Australian brick Australia is the largest they're nine inches then the UK is like 8.45 inches then the US is at eight like can we fix this this is where the smallest brick so yeah to make these cavities um in the brick it would need to be Hollow and this would maybe also worked as being lighter and easier for um The Brick Layers to to handle and be able to use so the first brick I made in fusion and I thought okay I'll make a kind of place that can be removed here which would be plaster and then the outside would be plaster as well with a front of being a different neck so I 3D printed it and prototyped it and I wanted the neck to kind of be different widths to allow for different frequencies to absorb and the first prototype was this kind of blaster block that I had different levels here so that the brick could be raised and lowered um depending on the size of the cavity that I would like this was then slipcast and you can see that I've got um two little holes here for the front of this and those were to be able to take in different widths um for different frequencies for an interchangeable neck and yes it looks wonderful how this is the fabrication workflow where you design cast it dry and then fire however there were M major issues coming on here first was that uh the cavity internal cavity um that piece keep floating up um it wasn't weighing down the plaster once it had been cast was very difficult to remove and there weren't any clean edges around this whole brick and the biggest part it was warping on me you could see why there's a big piece out the front missing so maybe could I change this inner cavity into three different pieces here and those would be filled with plaster with threaded inserts and that way I could flip the whole thing upside down pour my clay in and this one I had a um piece of plaster on top with a tube in it with a hole in it so I would pour it I'd cut that off or else I would just pour in my plaster and then take out the three plaster blocks you can obviously see that there's going to be some problems here uh same fabrication workflow style and we've got some issues that the clay would tear when these Corners um would shrink uh from the outside and inside also the three plaster blocks were not as easily to remove as expected the clay would also shrink and grip the blocks and even if I removed it successfully the walls still warping and ripping we could see that there so I was fighting this plaster clay relationship I wasn't letting the form be Hollow so I said well okay maybe I can make an entire 90 degre because I still want to keep with that brick shape that classic brick shape so I put a bunch of more threaded inserts into plaster and took some bolts with water washes and held the whole thing together and then poured in my clay let that sit for 40 minutes then pour it out the perpendicular angles keep being this classic brick shape and I also experimented with some other materials this was dark clay with vulcanized Grog particles um Stone wear just different Clays uh but mainly you can again see what we're coming with here the drawing these were the best photos by the way these cracking and fired and the fabrication workflows of the first three prototypes are okay okay we're learning things but we've still got major issues of the POR hole is really small it's warping it's cracking it's exploding in the Kiln uh we've got uneven drying and um I'm now like fighting the entire process I'm not working with what plaster does I'm saying no you're going to be a 90 Dee angle here you're going to be this perfect rectangle in with slip casting and I'm forcing this clay to do something that it's not wanting to do either it's it's drooping in certain places it's not sticking on certain areas and and falling in on itself so these weren't natural for um both of these materials to be uh used in this way yeah different clay same results the materials may change the outcomes didn't and a big glaring aspect here was the hemholtz resonator was becoming very difficult to absorb low frequency we have a small teeny neck and the cavity size is actually getting smaller as well so how could having like a two-part simple plaster mold built with complexity in it be used to possibly produce a more successful outcome so the rectangular brick wasn't working but to understand other loads and and future iterations on this brick I tried generative design and although that it wasn't used in further CAD models it led to a new understanding that the bricks could fit together possibly in a way that could be made up with larger more interlocking patterns than traditional rectangular brick design but I was still nervous that this wasn't going to work because we had about six months left of the course and I didn't want to be one of those students that's like yeah you know conclusions uh not really conclusive and it's like well that's that's kind of lame I want to have something to like say yes like I put my my name to this this was great it worked then the other guy Binga um who was doing the robotic arm manipulation here he's looking at that reflective and diffusive surfaces with robotic arms and he was cutting and carving um with personalized attachments on this arm and playing around with different materials and he had this shape um that he was using and I said that's an interesting brick that you have there I like this shape like what's going on and what's happening is it's a four-part brick making up one hemh resonator find resonator with our neck and our large cavity but also on the flip side of that we have a neck and a small cavity and each of these would Now work on both sides of a wall so you would reverse it this four-part cavity would have that neck to start with and then on the flip side of that wall you're going to have another cavity being made of those bricks so I thought by adapting this it was interesting on using like these external geometry shapes to make this brick so I said let's CN see it out of foam first so made my SE my mold of one half then took a plaster cast of that you put four different little little divots in here and then you put like marbles or wall bearings in there so that you you have a location so that they can be lined up perfectly and then I took a big drill bit and drilled two holes for my por holes that I'd be able to use to pour in the the slip poured in the slip poured it out after 40 minutes and I had a brick now this was solid so same fabrication work flow but we've got some more issues it's cracking so this whole brick is now drying completely at uneven rates demolding was difficult pouring out the clay was difficult it's it's obviously warping and cracking and and I'm in a worse spot and the worst thing is I can't even fire this in the Kil so it's going to explode I'm going into desperation mode Let's poke a bunch of holes in it and that'll help it dry I wasn't even going to bother putting that in the Kiln uh so but I'm I'm not done with this yet it's it's saying okay what do I have I have this this brick I have this shape let's make the neck of this rather than trying to make it small let's make it big and put it up in the front it's kind of let's celebrate that fact so put this neck in the major part of this cavity and that's when it kind of hits me it's a beautiful moment where you're you're on this path and you never thought you'd go down this certain Road and you realize not only am I making a brick that has a hemil resonator on one side and a hiltz resonator on the back side as well so you have two different tones that you can um adjust and tune for but you also have a major hem Holtz resonator here of the brick itself you have a neck and you have a cavity on the inside so you've got three hilts resonators out of one and that was all incorporated into the brick itself so with this excitement I'm pouring in the slip 40 minutes pour it back out and then let that dry overnight and we have our brick and these were then fired in the Kiln no problems in the Kiln there were same fabrication prototype there were some issues still demolding on the cast was an issue they'd stick to it sometimes they'd fall in they wouldn't stick but about 60% of them were successful some talcon powder was add to help with demolding and I'm sticking with just Terra Cotta on all of this as well as compressed air to help release uh the molds here and then was the testing part of this to see how much they shrunk now I originally designed that they would shrink by 12% and then after being scanned these were accurate as the initial design so yes from the cad to the fire brick these measurements in Terra Cotta stayed consistent with the increased size of the digital file and we had our successful outcome of four bricks making up a neck and cavity for a hemholtz resonator then it was time for major production mode and I built I think around like 50 of these and it was important on the construction site for the brick layer not to need to have the architect or the designer showing how to install each brick but instead by having the assembly pre-programmed in the block that's obvious and clear so the most important part was your first layer of bricks that they were all either the small cavity or the large cavity that would be facing this this the certain way incorporating these techniques may lead to other efficient and elegant designs in sound absorbing structures so you can see there that was the front side and then I flipped it back on the back side and then was the testing site um so we took our box and we were uh actually surprised to find out that the frequency that we had designed these for and around 310 Hertz that they were actually the hemil resonators were working as good as wood Andor foam when they were tested in this box next to the microphone so this was actually a surpris that ceramic can work with hilts properties and then the current sizing of these bricks would you'd still have to factor in scaling them up to absorb even lower frequencies of noise coming from the overground and train and traffic but yes this concept did work these were then glazed the top six of these were glazed this was the day of the show so don't judge my grout um brick L skills and um they this glaze would also help with weatherproofing the bricks from exterior elements of freeze thaw and other weathering and as well give it a really nice look so some future work was maybe lessening the noise from all these trains would actually uh be absorbed and other sounds of the soundscape of of nature like birds chirping or conversations would be brought more to the Forefront not only could we see this benefit the audio environment but also have a visual impact on the land uh by seeing this Pavilion people can be reminded of noise in urban environments which can have a negative impact on people's health and maybe city planners would take note of this in considering you know characteristics of sound um when it comes to planning and in nature as well as the integration with the structure with the environment Birds could use this as homes and fill this with nest and that would increase the absorption for more frequencies and Moss and algae and and fungi and stuff can grow on these bricks which would help with the visual but also um the absorption of of sound some alternative methods of making these would be to do High Press resin mold casting and that's a different kind of method where with regular plaster you're getting about 100 to 150 Cycles before it's um basically full it can't take any more um water from all the all the dirt and and and and things the pores get clogged but with this high pressure casting resin casting you can do 40,000 Cycles so this is faster and cheaper uh less water it's how toilets are made and this Pavilion would directly impact the soundscape from an audio level but also act as a visual reminder and this would remind that acoustics in architecture should be designed in parallel with building environments for example Architects May design a structure without considering acoustic issues and then put up sound dampening panels once the project was complete as an afterthought so in D architecture Marcus vus wrote that the idea building should have three elements utilitas fitas and venas and this translates into sturdy useful and beautiful and hopefully this Pavilion checks all three of those long established requirs thank [Applause] you

Channel: Joe Makes

Views: 1,210,194

Keywords: helmholtz, resonators, absorbers, sound, traffic, noise, soundscape, ceramic, bricks, low frequency, exterior enviornments, London, UCL, The Bartlett, architecture, 3D Printing, CNC, slip casting, terracotta, clay, Fusion 360, Autodesk, Rhino, Grasshopper, CAD, Design, thesis, bartlett, design

Id: y9-p4AkgVU8

Length: 34min 5sec (2045 seconds)

Published: Fri Dec 08 2023