Characterization of synthetic foam structures used to manufacture artificial vertebral trabecular bone

Some Practical Considerations for Compression Failure Characterization of Open-Cell Polyurethane Foams Using Digital Image Correlation

“…Open-cell rigid polyurethane (PUR) foam is considered a reliable cancellous bone surrogate because of its similarities with regards to morphometry and mechanical behavior [1][2][3][4][5]. Its increasing relevance in the biomechanical field has motivated several investigations aiming at characterizing this foamed structures, either commercial [1][2][3][4]6,7] or self-produced [5,6]. This material presents some advantages with respect to real bone specimens, such as it does not suffer from dehydration or biodegradation and has a lower cost [1].…”

“…This material presents some advantages with respect to real bone specimens, such as it does not suffer from dehydration or biodegradation and has a lower cost [1]. Hence, several works in the literature have used open-cell PUR foams to mimic healthy or osteoporotic cancellous bone, for the evaluation of orthopedic implants or cement augmentation [3,5,7].…”

“…Under quasi-static compression conditions, open-cell polyurethane foams response presents the following stages: linear elastic, softening after yield, plastic plateau and densification (at a high nominal strain) [8,9]. The mechanical behavior characterization of this kind of structures has been addressed from simplified [8,10,11] and realistic morphologies [3][4][5][6]12]. The simplified models developed by Gibson et al considered the deformation modes involved (bending, elastic buckling and plastic collapse of the struts) as function geometrical features such as strut length and thickness and the apparent density [8,10,11].…”

“…Advanced imaging systems such as SEM or micro-CT permit analysis of the microarchitectural characteristics of foam specimens [1,[3][4][5][6]. Other works apply micro-CT during specimen testing to evaluate the deformation mechanisms of failure at different length scales [3,6].…”

“…The images resulting from this procedure may be analyzed using digital volume correlation (DVC) technique to estimate 3D displacement fields [13]. Moreover, image-based numerical models can be developed from the scans to simulate foam mechanical behavior with a high degree of discretization and assess the influence of morphometry [3][4][5][6]12]. However, the application of these techniques requires high economic and time costs.…”