Usually my job is to observe and report about what’s next, with suggestions on how to prepare and implement. Yet there are so many cool things being done in the here-and-now, it would be a shame to only look ahead. Having said that, let me tell you about a cool thing being done with the Lattice Boltzmann (LB) method for computational fluid analysis (CFD).
Did you just say, “The what?!” OK then, we’ll start with a basic overview, then get to the cool thing.
LB is a highly praised method for describing the interaction of particles. Even better, it touches all the bases when taking particle size into consideration (macro/meso/micro). It starts by constructing a microscopic particle model, then uses it to derive the particle distribution of flow fields at a macroscopic level. LB then goes on to describe how the particles will react at mesoscopic scale. The end result is a very good model of flow fields in complex structures, and multicomponent multiphase flows.
One researcher notes it is coming into vogue because it is “so practical” for predicting hydrodynamic behaviors at all scales, and does so at a lower computational cost than other, more complicated and less rigorous methods.
If you are familiar with CFD tech, Lattice Boltzmann takes a linear approach to the math, while another popular CFD tech, Navier-Stokes, uses a non-linear approach. This means LB can use massively parallel compute resources, like from a HPC cluster or a high-end GPU, to grind through a complicated analysis faster than other methods.
One more attribute of the Lattice Boltzmann method, which leads up to the cool thing I hinted at earlier. LB is also good for calculating bounce-back phenomenon. Like what happens when a runner’s shoe bangs the pavement. Each step pushes the foot against the sole. Until now, shoe manufacturers would try to make their midsoles cushy, to save wear and tear on the runner. Now Adidas is getting rave reviews for figuring out how to have the midsole not only cushion the blow, but subtly move the foot forward.
The Adidas 4DFWD is a cutting edge running shoe created using
the latest design simulation technologies and 3D printing.
(Photo Source: Adidas; original at https://www.adidas.com/us/blog/680801/what-is-4dfwd)
Adidas Senior Vice President Alberto Uncini Manganelli says the new shoe (called the 4DFWD) is the company’s “most advanced digitally printed running midsole yet.” (We will get to the digitally printed part in a minute.) Adidas says 4DFWD generates three times the forward motion under vertical loading, while gaining a 15% improvement in peak braking force. Every step a runner takes involves an element of braking force, so this means a 15% better running experience on every step.
Previous generations of midsoles have brought increased comfort and performance. Adidas Design VP Sam Hardy says the combination of tech behind 4DFWD “provides us with the opportunity to design in a way that conventional foam midsoles do not allow.”
Adidas researchers used the BL method as the starting point for the new midsole. The target was not mass manufacturing, but additive manufacturing of a complex internal structure which could only be designed from the microscopic level up.
To make this all happen, Adidas uses XFLOW, an LB solver in Dassault Systemès SIMULIA’s Fluids Simulations portfolio. The target technology for manufacturing the midsole is Digital Light Synthesis (DLS), an additive manufacturing (3D printing) technology from Carbon. The process uses DLS along with oxygen permeable optics, and programmable liquid resins to produce parts with great mechanical properties, resolution, and surface finish. As Carbon proclaims on their website, the result is the ability to “iterate faster, deliver projects with less risk, and radically reimagine” products by “introducing consolidated parts, impossible geometries, and programmable lattices.”
The end result is a runner’s shoe “designed to move you forward.” Literally.