Reconfigurable Origami Traffic Noise Barrier

Reconfigurable Origami Traffic Noise Barrier


NARRATOR: The sound from traffic is significant. It’s a large contributor to noise pollution
in urban environments and because of that, it presents a public health concern. This concern led researchers at the University
of Michigan to develop a reconfigurable origami sound barrier to block specific sound frequencies
based on how fast traffic is moving. THOTA: “There are existing structures which
can block the traffic noise. These kind of barriers are tuned to block
all frequencies at all times, which doesn’t happen very often.” These structures tend to be very opaque, dense,
and as a result, they create a lot of load on the foundation upon which it is built. Because of this, you cannot use it in applications
where there is a sensitivity of load. For example, you cannot build them on bridges,
or in your balcony in your apartment.” NARRATOR: The researchers created a prototype
of a new noise barrier that is lighter, more wind-permeable and better at diffusing sound
waves than traditional barriers. The first component is an array of cylindrical
rods to block and scatter sound waves of a specific frequency range. WANG: “The frequency range of these stopbands,
it really depends on a couple things. For example, the lattice density, that means
the distance between these inclusions. And also, the pattern, or the configuration,
the lattice configuration. And there are so-called full bandgaps. That means, inside that bandgap, no matter
where the noise is coming from in terms of noise direction, it will block all the noise. And that has a lot to do with the lattice
configuration.” NARRATOR: This method of arranging cylindrical
rods to block specific sound frequencies is similar to a concept already installed in
the Netherlands. The second component is the reconfigurable
origami base. Because the noise frequency of traffic changes
based on how fast traffic is moving, the researchers wanted to find a way to easily adjust the
arrangement of the rods. THOTA: “Rush hour traffic is dominated by
frequency around 500 Hertz, and the non-rush hour traffic noise is dominated by 1,000 frequency
Hertz. So in this research we tried to design this
origami structure so that, in a certain configuration it can block 500 frequency Hertz, and when
you change the configuration by folding the base of the origami structure, now it can
block 1,000 frequency Hertz.” NARRATOR: But one of the challenges of this
research was how to develop of a mechanism that could easily change the configuration
of the rods. THOTA: “You cannot easily convert from a
square to a hexagonal lattice using any linkage mechanisms. When you fold an origami sheet, it not only
contracts in the x-y direction, but it also lifts in the z direction, so that would allow
us to transform from a hexagon to a square. And obviously when you want to fold a structure,
you have to apply some time of actuation on the boundaries.” WANG: “The beauty of origami structure is
it is a one degree of freedom action. It’s very easy to change shape. You can use one single actuator, in theory,
and you can change the shape effectively. The other thing is it’s scale independent. That means you can use it for very large systems,
as well as very small devices.” NARRATOR: The researchers believe these origami
traffic sound barriers could be designed to change configuration at set times throughout
the day, but additional research and testing will be needed for these barriers to be implemented
alongside real roads.

4 thoughts on “Reconfigurable Origami Traffic Noise Barrier

  1. Brilliant! Just a couple of tubes in a certain configuration to block sound. But in the long run, I think it would be cheaper to put two barriers side by side, one for 500hz and another for 1000hz. No moving parts, less probability of breaking down, cheaper ongoing maintenance. Nevertheless, the origami base is ingenious and would be useful such as where space is a constraint.

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