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Research Project
Bio-inspired gyroid foams by machine learning optimization and meshless methods
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A bio-inspired remodelling algorithm combined with a natural neighbour meshless method to obtain optimized functionally graded materials
Publication . Pais, A.I.; Alves, J.L.; Belinha, Jorge
Recent developments suggest the use of triply periodic minimal surfaces (such as the gyroid) as a possibility for
bone tissue scaffold. Moreover, through functional gradients of cellular structures, the mechanical properties
can be edited and enhanced to achieve the most efficient results. One of the main concerns when designing
bone scaffold is avoiding stress shielding, which occurs when the Young’s modulus of the implant is higher than
the Young’s modulus of the bone it is replacing. If so, bone decay occurs in the surrounding tissue. While the
literature possesses some approaches exploring functional gradients of material density, there are no solutions
based on bone tissue phenomenological laws. Thus, the gyroid infill obtained with PLA (𝐸 = 3145 MPa) was
characterized with mechanical tests, namely tensile and compression, and the obtained model was implemented
in a bone remodelling algorithm. Using the natural neighbour radial point interpolation method (NNRPIM)
it was found that similar bone density distributions were obtained for the gyroid infill and for bone tissue
when subject to the same boundary conditions. Finally, the gyroid mechanical behaviour was extrapolated to
other materials and it was concluded that similar properties can be obtained for bone tissue and titanium alloy
(𝐸 = 110 GPa) scaffold.
3D printed devices to avoid hand contact with commonly shared surfaces
Publication . Pais, A.; Ferreira, C.; Pires, V.; Silva, V.; Alves, J. Lino; Bastos, João; Belinha, Jorge
In the context of the COVID-19 pandemic, public spaces had to be quickly adapted to the new circumstances especially under the uncertainty of the pandemic development. Door handles are some of the most touched surfaces and so, this point of contagion was chosen to be tackled and two solutions were developed that would prevent direct touch with the handle: a portable and a fixed device. The portable device (HYHOOK + HYTIP) is a hook-like device holding a finger cover, which permits to open doors and push buttons safely. The fixed device (HANDGENIC) is meant to be assembled in door handles to equip buildings, such as universities or schools. With the fixed device, the user can open the door using their forearm which makes them less likely to transfer any particles to eyes, nose or mouth. The 3D printing Fused Filament Fabrication (FFF) process was selected as manufacturing technique, which allows the fast production of prototypes. This work portrays the development process and design iterations taking into consideration the concerns about the functioning of the devices and possible failures or alternative uses. To assure structural integrity of the parts, finite element (FE) analysis was used to verify its mechanical response. As conclusion, it was found that FE analysis indicate that the devices are structurally sound to be used in public spaces and that 3D printing is a useful way to rapidly develop devices while testing several design possibilities.
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Funding agency
Fundação para a Ciência e a Tecnologia
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Funding Award Number
SFRH/BD/151362/2021