One of our research engineers, Susan Nace, recently successfully defended her Ph.D. in Materials Engineering at University College Dublin! Her thesis is titled “Process design and fabrication of 3D printed custom-contoured wheelchair cushions.”

3D Printed cushion made from TPU. Contour designed for standardized testing.

Partially funded by a grant from the Irish Research Council, the non-profit Enable Ireland, and University College Dublin, her research involved the design and testing of a 3D printable custom-contoured wheelchair cushion. Custom-contoured wheelchair cushions refer to seating systems consisting of either a seat cushion, a back support, or both types of cushions that match the user’s body shape while supporting the best possible posture specific to the user. They are prescribed to facilitate a wheelchair user’s maximum function with minimum pathology while using their wheelchair.

Standard cushions that underwent testing. Foam (left) and 3D Printed (right).

The 3D printed cushion design developed through her work uses a low-density gyroid infill printed in flexible TPU to create a supportive cushion that allows for passive cooling of the wheelchair user at the seating surface. Susan developed a digital workflow for converting tessellation models to CAD surfaces; designed and conducted table-top tests to characterize materials as well as cushion performance characteristics; conducted trials with volunteers to gather and analyze user experience data; and developed a rapid-optimization method that uses finite element analysis to inform printing parameters in future iterations of 3D printed cushions. She has three first-author papers published in peer-reviewed journals related to this body of work with another manuscript in the works at this time.

Standardized test set up for hysteresis loss, for wheelchair cushions.

Through her Ph.D. work, Susan honed the research and problem-solving skills she now uses at bb7 to inform user and product requirements for client projects, as well as to design and conduct efficient and effective test methods to prove bb7 designs perform according to client needs and industry standards. She especially enjoys applying her expertise in flexible polymers and 3D printing of metamaterials, so consider your next product with complex lattice structures covered!