PSI - Issue 82

Tsanka Dikova et al. / Procedia Structural Integrity 82 (2026) 58–64 Dikova et al. / Structural Integrity Procedia 00 (2026) 000–000

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2. Materials and Methods 2.1. Virtual models preparation

A virtual model was generated using a high-resolution peripheral QCT scan of distal tibia of a premenopausal woman (available at https://3d.nih.gov/entries/3DPX-021147), representing the morphological structure of the bone trabeculae. The Autodesk Fusion 360 software (Autodesk, Inc., San Francisco, California, USA) was used to prepare cubic samples with sizes of 10 mm x 10 mm x 10 mm from the virtual 3D bone model. The software allowed, in addition to a virtual model of the bone, to make a model of the empty spaces (pores) of the bone. In this so called “negative model”, the pores are dense areas, and the bone tissue is empty space. Two groups of samples were generated: Group 1, representing the bone tissue (positive model), designated as “Bone samples” and Group 2, comprising the interconnecting empty spaces (negative model), designated as “Bone pores samples” (Fig. 1). In each group, three sub-groups were created with different magnification of the bone structure: 1) first sub-group with original sizes; 2) second sub-group with 20% magnification and 3) third sub-group with 40 % magnification.

Fig. 1. (a) Virtual models of sample; (b) Printed samples; (c) 3D printing process.

2.2. 3D printing A laser stereolithographic 3D printer Form 3/3+ (Formlabs, Berlin, Germany) was used for manufacturing the samples. Five specimens of each sub-group were printed of Castable Wax 40 Resin (Formlabs, Berlin, Germany) with 0.025 mm layer thickness (Fig. 1). The printed cubes were subjected to post processing by lamp irradiation for polymerization of the residual monomer. After that, the samples were ultrasonically washed in isopropanol and the supports were removed. 2.3. Samples characterization The porosity of five samples of each sub-group was investigated by solid density analyzer Ultrapyc 5000 Foam (Anton Paar, Austria). The average of three measurements of each sample was used in evaluation.