The Tensile Stiffness and Strength of Trabecular Bone Structure along its Three Princpal Orientations: A 3D printed model
Poster Number
045
College
College of Arts and Sciences
Department
Biology
Faculty Mentor
Meir Barak, Ph.D., D.V.M.
Abstract
Trabecular bone is a complex 3D mesh of bony rods and plates, which is found internally to the cortex of many long and short bones. Since trabecular bone structure is unique (no two tissues are the same), and mechanically testing a trabecular sample involves loading until failure (each sample can be tested only once), the precision of trabecular bone tissue mechanical measurements tends to be low, and it is impossible to mechanically test the exact same trabecular structure in multiple orientations. This introduces a significant problem when trying to measure trabecular stiffness (the amount of deformation under load) and strength (the maximum load before structure failure). Here, we are using a novel technique, namely 3D printing, to reproduce a large number of identical trabecular bone structure replicas reconstructed from a sheep talus bone. In this study, we are testing in tension a cubical 3D-printed sample (4.5 mm on a side) along its three principal axes (n = 30 per orientation, for a total of 90 samples). In order to apply tension, two antipode planes of each cube were extended as solid 9-mm beams in opposite directions (final beam dimensions of 22.5 × 4.5 × 4.5 mm), to allow hold by the testing machine grips (Instron 5942). Each beam was loaded between the two grips such that only the center 4.5-mm trabecular replica was subjected to tension. Each test (n = 90) was run until failure, and cube stiffness and strength were recorded. The working hypothesis is that the axial direction (parallel to the long axis of the bone) will demonstrate the highest stiffness and strength values compared to the other two orthogonal directions. Currently, we have 3D printed and loaded 45 of the 90 replicas. Preliminary results reveal that, as predicted, the trabecular structure is significantly stronger in tension along the axial direction.
Previously Presented/Performed?
Fourth Annual Showcase of Undergraduate Research and Creative Endeavors (SOURCE), Winthrop University, April 2018
Start Date
20-4-2018 2:15 PM
End Date
20-4-2018 4:15 PM
The Tensile Stiffness and Strength of Trabecular Bone Structure along its Three Princpal Orientations: A 3D printed model
Richardson Ballroom (DIGS)
Trabecular bone is a complex 3D mesh of bony rods and plates, which is found internally to the cortex of many long and short bones. Since trabecular bone structure is unique (no two tissues are the same), and mechanically testing a trabecular sample involves loading until failure (each sample can be tested only once), the precision of trabecular bone tissue mechanical measurements tends to be low, and it is impossible to mechanically test the exact same trabecular structure in multiple orientations. This introduces a significant problem when trying to measure trabecular stiffness (the amount of deformation under load) and strength (the maximum load before structure failure). Here, we are using a novel technique, namely 3D printing, to reproduce a large number of identical trabecular bone structure replicas reconstructed from a sheep talus bone. In this study, we are testing in tension a cubical 3D-printed sample (4.5 mm on a side) along its three principal axes (n = 30 per orientation, for a total of 90 samples). In order to apply tension, two antipode planes of each cube were extended as solid 9-mm beams in opposite directions (final beam dimensions of 22.5 × 4.5 × 4.5 mm), to allow hold by the testing machine grips (Instron 5942). Each beam was loaded between the two grips such that only the center 4.5-mm trabecular replica was subjected to tension. Each test (n = 90) was run until failure, and cube stiffness and strength were recorded. The working hypothesis is that the axial direction (parallel to the long axis of the bone) will demonstrate the highest stiffness and strength values compared to the other two orthogonal directions. Currently, we have 3D printed and loaded 45 of the 90 replicas. Preliminary results reveal that, as predicted, the trabecular structure is significantly stronger in tension along the axial direction.
