This study investigates the mechanical properties and biocompatibility of eight commercially available filaments tailored for Fused Deposition Modeling (FDM) additive manufacturing. Test specimens were fabricated using original PRUSA MK4 printers, with ten samples from each selected polymer. Mechanical evaluations through static tensile and three-point bending tests revealed that PETG Carbon and PA+15CF exhibited superior tensile and flexural strengths, making them highly suitable for applications requiring high mechanical resilience. Biocompatibility assessments in line with the ISO 10993-5:2009 and ISO 10993-12:2021 standards indicated that all materials except FiberFlex 40D Fiberlogy were non-cytotoxic, supporting their potential in biomedical applications. The experimental data established material constants within the Johnson–Cook strength model, which effectively predicted the mechanical behaviors of monotonic materials like FiberFlex 40D, PETG, HIPS, TPU, and PA+15CF Rosa 3D, with maximum fitting errors not exceeding 2.6%. However, the model was inadequate for non-monotonic materials like PLA and PETG, resulting in higher errors and less accurate simulations. Scanning electron microscope (SEM) analyses provided insights into fracture mechanisms, correlating fracture surface characteristics with mechanical performance. This comprehensive study advances the understanding of mechanical properties in thermoplastic materials for 3D printing, validates numerical models for certain materials, and confirms material suitability for biomedical use.

In this study, the authors performed a strength analysis of seven groups of commercially available materials based on SLS incremental technology. Test samples were made with Original PRUSA SL1S printers, with 10 samples of each type from 7 resins selected for testing. The tests were carried out on an MTS Bionix machine in a static tensile test, during which the basic mechanical properties were determined. This is also a preliminary study to determine material constants in the Johnson-Cook strength model. The authors then performed numerical simulations to mirror the experimental tests in order to tune the rheological model. In addition, a fracture criterion was determined based on a hybrid FEM/SPH numerical method. This allowed for the expansion of material libraries currently used in numerical simulations, as well as the sensitivity of the materials’ models. In subsequent studies, in order to determine the nature of material destruction, analysis of fracture surfaces was performed using a scanning electron microscope (SEM). The final study was a biocompatibility test to assess the biological properties of the material. The conducted research made it possible to determine the strength properties of resins currently used in 3D printers, expand the libraries of material models in the computational environment (with an error rate of less than 5%), as well as observe the nature of the cracks formed and biocompatibility in the context of predicting the use of these materials for biomedical applications.

Fused deposition modelling (FDM) technology provides a flexible and cost-effective solution for the manufacture of polymer components, enabling the precise design of structures and the incorporation of a variety of composite materials. Its development is confirmed by numerous studies on fibre reinforcements (e.g., GFRP and CF) and thermosetting resin modifications, resulting in improved impact strength and fracture toughness and increased thermal stability of products. The final mechanical properties are significantly influenced by processing parameters (e.g., fill density, layer height, and printing speed) and internal geometry (e.g., lattice structures), which can be further optimised by numerical analyses using constitutive models such as the Johnson–Cook model. The focus of the study presented here is on the fabrication of composites from FDM dies filled with F8 polyurethane resin. Filaments, including PETG carbon and PETG, were tested for potential applications with the resin. A static compression test, supported by numerical analysis using the Johnson–Cook model, was carried out to identify key mechanical characteristics and to predict the material’s behaviour under different loading conditions. The results indicate that these structures exhibit numerous potential delamination planes and voids between filament paths, leading to relatively low maximum stress values (σ_m ≈ 2.5–3 MPa). However, the impregnation with polyurethane resin significantly enhances these properties by bonding the layers and filling the pores, resulting in a more homogeneous and stronger composite. Additionally, numerical simulations effectively captured key aspects of structural behaviour, identifying critical stress concentration areas, particularly along the side walls and in regions forming triangular stress zones. These findings provide valuable insights into the potential of resin-filled FDM structures in engineering applications, demonstrating their improved performance over purely printed samples.

In this study, the authors analyzed modern resin materials typically used for temporary reconstructions on implants and manufactured via 3D printing. Three broadly used resins: NextDent Denture 3D, NextDent C&B MFH Bleach, and Graphy TC-80DP were selected for analysis and compared to currently used acrylic materials and ABS-like resin. In order to achieve this, mechanical tests were conducted, starting with the static tensile test PN-EN. After the mechanical tests, analysis of the chemical composition was performed and images of the SEM microstructure were taken. Moreover, numerical simulations were conducted to create numerical models of materials and compare the accuracy with the tensile test. The parameters obtained in the computational environment enabled more than 98% correspondence between numerical and experimental charts, which constitutes an important step towards the further development of numeric methods in dentistry and prosthodontics.

Multi-layer fabrics are commonly used in ballistics shields with a lower bulletproof class to protect against pistol and revolver bullets. In order to additionally limit the dynamic deflection of the samples, layers reinforced with additional materials, including non-Newtonian fluids compacted by shear, are additionally used. Performing a wide range of tests in each case can be very problematic; therefore, there are many calculation methods that allow, with better or worse results, mapping of the behavior of the material in the case of impact loads. The search for simplified methods is very important in order to simplify the complexity of numerical fabric models while maintaining the accuracy of the results obtained. In this article, multi-layer composites were tested. Two samples were included in the elements subjected to shelling. In the first sample, the outer layers consisted of aramid fabrics in a laminate with a thermoplastic polymer matrix. The middle layer contained a non-Newtonian shear-thickening fluid enclosed in hexagonal (honeycomb) cells. The fluid was produced using polypropylene glycol and colloidal silica powder with a diameter of 14 µm in the proportions of 60/40. The backing plate was made using a 12-layer composite made of Twaron^® para-aramid fabrics with a DCPD matrix—not yet used in a wide range of ballistics. Then, numerical simulations were carried out in the Abaqus/Explicit dynamic analysis. The Johnson–Cook constitutive strength model was used to describe the behavior of elastic–plastic materials constituting the elements of the projectiles. For the non-Newtonian fluid, a Up-Us EOS was used. The inner layers of the fabric were treated as an orthotropic material. Complete homogenization of the sample layers was carried out, thanks to which each layer was treated as a homogeneous continuum. As a parameter of fracture mechanics for shield components, the strain criterion was used with the smooth particles hydrodynamics method (SPH). Then, the results of simulations were compared with the results of the ballistic test for both samples placed next to each other, which resulted in the formation of a multi-layer composite in one ballistic test subjected to impact loads during firing with a 9 × 19 mm Parabellum FMJ projectile with an initial velocity of 370 ± 10 m/s. The results of numerical tests are very similar to the ballistic tests, which indicates the correct mapping of the process and the correct conduct of layer homogenization. The applied proportions of the components in the non-Newtonian fluid allowed a reduction in the deflection compared to previous studies. Additionally, the proposal to use a DCPD matrix allowed to obtain a much lower deflection value compared to other materials, which is a novelty in the field of production of ballistic shields.

This article analyzes the composition and distribution of chemical elements in friction films and their effect on the tribological properties of the self-lubricating, high-temperature antifriction composite based on EP975 powder nickel alloy with CaF₂ solid lubricant. Analysis of the chemical elements by energy-dispersive spectroscopy (EDS) showed their uniform distribution, on both the composite’s surface and the counterface’s surface. The alloying elements’ uniform distribution leads to a uniform distribution of the corresponding phases and structural elements in the antifriction film. This ensures high tribological properties at high temperatures. Analysis of the material’s tribological properties, by means of metallographic and micro-X-ray research confirmed the correctness of the technology for producing the composite. Solid lubricant CaF₂, alloying elements, and their corresponding phases form the continuous antiscoring film. The film influences the antifriction properties formation during the friction process and provides a self-lubricating mode under the action of high temperature and oxygen. Antiscoring, self-lubricating CaF₂ films minimize wear of the friction pairs and defend the contact surfaces against intensive wear. The dense antifriction films have smooth microtopography, which stabilizes the high-temperature friction unit operation. Thus, the self-lubrication mode is realized for a long exploitation time. Tribological properties analysis allowed us to determine the ranges of rational exploitation modes for the material being studied: a load up to 5.0 MPa, a slide speed from 0.3 to 1.0 m/s, a temperature up to 800°C, in the air. The results obtained opened the opportunity to control the antifriction film formation and the composite’s tribological properties by the choice of the initial ingredients while taking into account the operating conditions.