Graded Cellular Materials with Improved Properties


The Problem:

Cellular materials possess unique combinations of strength, stiffness, and low density that traditional engineering materials cannot achieve. Graded cellular materials present superior combinations of static and dynamic properties when lightweight, stiff, and strong structures are needed. However, a simple method for designing and fabricating such complex materials that is also suitable for material extrusion additive manufacturing (AM) has been elusive until now. 

The Solution:

Researchers at the University of Tennessee have developed a method to fabricate graded cellular structures that is tailored for material extrusion AM processes. This method can create cellular structures having gradients in both density and cell shape, enabling an unprecedented range of properties using only one base material. The grading schemes allow the design of advanced materials with spatially varying stiffness and strength, incremental hardening or softening behavior to maximize energy absorption, and programmable collapse paths to protect designated regions in a structure. The novel method couples with existing material extrusion AM technology (i.e., fused deposition modeling and direct ink writing) to access a wider range of material properties and functionality than is currently available and is designed to be implemented within the process flow of existing commercial AM technology. 


  • Suited to existing material extrusion AM methods
  • Couples with existing grading schemes
  • Material properties can be tailored for a wide range of applications
  • Programmable failure behavior for maximized energy absorption
  • Creation of multifunctional parts with new combinations of static, dynamic, transport, and sensing properties
  • Potential to incorporate sub-cell functionality with macro-scale design


Dr. Brett Compton is an assistant professor in the mechanical engineering department at UTK.  He received his Ph.D. from the University of California Santa Barbara in 2012. His research interests include mechanical properties of advanced composite materials, developing high-performance materials for additive manufacturing, and understanding the fundamental processing-property-performance relationships in additive manufacturing materials. He has particular expertise in 3D-printable thermoset-based composite materials.


Patent Information: