Concrete 3D printing has revolutionized the construction industry by reducing both time and cost through the elimination of traditional formwork. However, most current systems rely on extrusion-based methods, limiting design flexibility and structural integrity. This is because the material is deposited layer by layer very close to a nozzle, making it difficult to print around reinforcement bars without risking collisions.
To address this limitation, Kenji Shimada and his team at Carnegie Mellon University’s Computational Engineering and Robotics Laboratory (CERLAB) have developed a new simulation tool for spray-based concrete 3D printing. This innovative method involves spraying a modified shotcrete mixture from a nozzle to build up on a surface, even around reinforcement bars.
The ability to print freely around reinforcement is crucial in earthquake-prone regions like Japan and California, where structural strength is of utmost importance. Shimada explains, “To make this technology viable, we must be able to predict exactly how the concrete will spray and dry into the final shape. That’s why we developed a simulator for concrete spray 3D printing.”
This new simulator can model the viscoelastic behaviors of shotcrete mixtures, including drip, particle rebound, spread, and solidification time. Contractors can now assess multiple printing paths based on a CAD design to determine the feasibility of using spray 3D printing for their structures.
In a validation test in Tokyo, Japan, the team worked with Shimizu Corporation, which already operates spray 3D printing robots. The simulator accurately predicted the height of the sprayed concrete with 90.75% accuracy based on the speed of the nozzle’s movement. This breakthrough technology opens up new possibilities for construction projects, offering enhanced design flexibility and structural strength. The results of the second test conducted on the simulator developed by researchers showed promising accuracy in predicting printing over rebar. The simulator achieved 92.3% accuracy for predicting the width of the printing, and an even higher accuracy of 97.9% for predicting the thickness. This demonstration of precision highlights the potential of the simulator in enhancing the efficiency and accuracy of 3D concrete printing processes.
Soji Yamakawa, a research scientist in Shimada’s lab and the lead author of the research paper published in IEEE Robotics and Automation Letters, emphasized the significance of the simulation. Typically, simulations of this nature would require hours, if not days, to run. However, by simplifying the complex physics simulation into a combination of efficient algorithms and data structures, the team was able to achieve highly realistic output in a more streamlined manner.
The research team’s future work will focus on further improving the accuracy of the simulator. This includes identifying and incorporating environmental parameters such as humidity, optimizing performance, and integrating plastering simulation to enhance the smoothness of finished products. Kyshalee Vazquez-Santiago, a co-author of the paper and a Ph.D. candidate in mechanical engineering leading the Mobile Manipulators research group within CERLAB, expressed enthusiasm for the possibilities offered by robotics in the field of concrete 3D printing.
The development of innovative applications and technologies in robotics, particularly in concrete 3D printing, presents numerous advantages and opportunities for advancement. The research team’s dedication to exploring new approaches and applications in this domain underscores the vast potential for growth and innovation in the field. This ongoing research and development efforts aim to harness the capabilities of robotics to revolutionize concrete construction processes and pave the way for future advancements in the industry.
For more information on the Concrete Spray 3D Printing Simulator and its trajectory planning capabilities, the research paper by Soji Yamakawa and his colleagues in IEEE Robotics and Automation Letters provides valuable insights into the advancements in this cutting-edge technology.
