Scientists from Cornell University, Purdue University, and Case Western Reserve University have taken inspiration from bone to create more durable 3D printed structures. These structures could prove beneficial to the construction industry to support heavy loads, the same way our bones resist constant stress during a lifetime without breaking. 3D printing in this sector is actually in its early developments, early adopters are only just beginning to investigate the capabilities of the technology. While there are a lot of R&D initiatives and pilot projects, actual real-life case studies are few and far between – nevertheless, 3D applications in the construction industry are promising!
The researchers from the three universities focused on studying how a ‘beam’ in human bone material handles a lifetime’s worth of wear and tear. Pablo Zavattieri, a professor in Purdue’s Lyles School of Civil Engineering explains: “Bone is a building. It has these columns that carry most of the load and beams connecting the columns. We can learn from these materials to create more robust 3D printed materials for buildings and other structures.” By running tests, the researchers discovered that when they mimicked this beam and made it about 30% thicker, the artificial material could last up to 100 times longer.
The researchers discovered that when they mimicked this beam and made it about 30% thicker, the artificial material could last up to 100 times longer | Credits: Purdue University photo/Pablo Zavattieri
The structure of bone could make stronger 3D printed buildings
The scientists explain that bones get their durability from a spongy structure called the trabeculae. This structure can be compared to a network of interconnected vertical plate-like struts and horizontal rod-like struts acting as columns and beams. In fact, the denser the trabeculae, the more resistant the bone will be, something which changes as humans get older. What the scientists call the horizontal rod-like struts are what significantly increase the bone’s resistance. Hernandez, professor of mechanical, aerospace and biomedical engineering at Cornell comments: “When people age, they lose these horizontal struts first, increasing the likelihood that the bone will break from multiple cyclic loads.”
This is where it would be interesting to apply this knowledge to architecture, making buildings stronger in the case of natural disasters for example. Pablo Zavattieri’s lab tested their research findings by 3D printing polymers with architectures similar to trabeculae. The simulations revealed that the thicker the horizontal struts, the longer the polymer would last as it took on load. “When we ran simulations of the bone microstructure under cyclic loading, we were able to see that the strains would get concentrated in these horizontal struts, and by increasing the thickness of these horizontal struts, we were able to mitigate some of the observed strains,” said Adwait Trikanad, a co-author on this work and civil engineering Ph.D. student at Purdue University.
Moreover, since thickening these horizontal struts did not have a significant impact on the weight of the polymer, the researchers are led to believe that they could well design resistant yet lightweight materials. Pablo Zavattieri concludes: “To create a stronger material without making it heavier would mean 3D printed structures could be built in place and then transported. These insights on human bone could be an enabler for bringing more architected materials into the construction industry.” You can find more information HERE.
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