Functionally graded porous materials have been widely studied for use in applications with inhomogeneous constraints such as energy absorption and filtration of impurity. Researchers have, however, faced numerous challenges owing to limited available fabrication methods. This include, inefficient representations for geometrical computation and manufacturing, poor aesthetics, poor mechanical performance, and the inability to describe the relationship between the materials’ properties and structure which is highly beneficial in their characterization and tailoring. This has further led to low design efficiency due to high computational memory consumption.
To this note, Huaqiao University scientists: Bin Liu, Huihui Chen and Wei Cao proposed a new method for the design and fabrication of functionally graded porous materials with tailored elastic distributions. Focused on overcoming the challenges associated with the traditional fabrication methods, the main objectives included lowering the computational memory consumption, improving material appearance and enhancing the mechanical performance. Their work is currently published in International Journal of Mechanical Sciences.
The goal-driven method entailed the integration of additive manufacturing and geometric modeling methods to prevent high memory consumption. To enhance the natural appearance and mechanical performance, the porous structures were constructed from a combination of the implicit surface representations and 3D Voronoi tessellation. This was attributed to the fact that these structures are highly stochastic and thus continuously graded. Furthermore, a mapping model was formulated from the elasticity distribution to the density field. This model was used to easily map the graded porous structures to achieve tailored elasticity distributions.
The integrated design approach combining both foam modeling and additive manufacturing processes was observed to address numerous challenges associated with the traditional fabrication methods. For example, it was easy to simultaneous control the pore distribution and retail the continuous variations in the geometry and properties of the functionally graded porous materials. Additionally, the mapping model correlating the density and elasticity required a relatively shorter time to rapidly map the tailored elasticity distribution to the density field. In addition to improving the appearance, the skeleton implicit surfaces eliminated the effects of stress at the nodal points.
The authors also presented a procedural and parallel approach for foam production to further improve computational efficiency and save memory consumption. It was necessary to validate this method and compare it to other types of foam production methods. The approach significantly reduced memory consumption. From the foam modeling results, smoothly graded and naturally realistic porous structures were observed. Based on the compression tests, it was worth noting that the Youngs modulus of the tailored foams could be predicted using the mapping model. On the other hand, the proposed foam exhibited superior mechanical performance as compare to foams based on straight beams. This could be improved by adding elasticity distribution for a specified loading condition.
In summary, Bin Liu and colleagues study presents a novel method for tailoring elasticity distributions of functionally graded porous materials with great versatility in other disciplines including ergonomics, engineering design and optimization. Therefore, it paves the way for exploring various challenges in the design and fabrication of other new porous structures.
Liu, B., Chen, H., & Cao, W. (2019). A novel method for tailoring elasticity distributions of functionally graded porous materials. International Journal of Mechanical Sciences, 157-158, 457-470.Go To International Journal of Mechanical Sciences