Single point incremental forming (SPIF) and fuseddeposition modeling 3D printing (FDM) are two methods of rapid prototyping. Each method has its own pros and cons. using SPIF method can provide an accurate forming process to shape sheets fabricated by 3D printing with their special characteristics. In this study, single-point incremental forming of Poly Lactic Acid (PLA) sheets fabricated by FDM 3D printer was investigated by experiments. The formability process was evaluated by two different experiments. In the first experiment, a lubricant was used at ambient temperature and SPIF was investigated and for the second experiment hot air and lubrication were employed to achieve better formability. In addition, the effects of sheet thickness and strategy of layering of printed sheets by FDM were also studied on SPIF formability. The results showed that the incremental forming of printed PLA sheets in hot air is a more successful state to produce dome shapes parts and ruptures are less and this forming method can be used for some applications such as making partial curve of skull as a medicine solution in surgeries. Also, it was shown that the best layering strategy to print the PLA sheets used for better forming of SPIF is triangular pattern strategy against with rectangular strategy. It was found that thickness of 2mm printed sheet has better formability and less rupture versus 3mm of thickness. پرونده مقاله

In Osteoporosis, bone mechanical strength decreases and as a result, the risk of bone fracture increases. Osteoporosis is also referred as a "silent illness" since it usually develops asymptomatic until it breaks a long bone, like the femur. In recent years, porous scaffolds have been utilized to repair damaged bone tissue. For bone tissue engineering, synthetic scaffolds should have acceptable mechanical properties, in addition to the required biological properties. In this regard, the finite element simulation is used to predict the mechanical properties of porous bone scaffolds as one of the most common methods for reducing the experimental tests, because the acquisition of mechanical properties of such scaffolds is very time-consuming and expensive. Due to the widespread use of hydroxyapatite (HA) in the manufacture of bone scaffold composites, the mechanical properties of HA-wollastonite scaffold composites are obtained by laboratory tests and finite element methods. Comparison of the simulation of finite element analysis (FEA) and the experimental results indicate the success of the FEA simulation. In conclusion, new finding satisfied expectations as being suitable for mechanical and biomaterial aspect of a porous scaffold which is proven by laboratory tests and FEA simulations. Due to that fact, the result of this study can be employed to obtain scaffolds well-suited for bone implementations. پرونده مقاله

The porous scaffold provides a temporary environment for bone growth and facilitates cell adhesion, cell growth and differentiation. In the present study, polymeric scaffolds were designed and fabricated via fused deposition modelling (FDM) method for orthopedic defect approaches using polycaprolactone (PCL) and polylactic acid (PLA) polymer. The prepared scaffold was coated with Chitosan-Hydroxyapatite (HA) as a reinforcement. The application of PLA, PCL and HA received attention of orthopedic surgeons to accelerate the bone healing. However, the comparison between the compression strength value of these scaffolds required more investigation and advance mechanical testing. In this study, we coat the novel PCL and PLA scaffold with chitosan-HA composite to mimic with humans' body. In the next stage, the mechanical strength and the biological response of the specimen were examined. Then, the morphology and phase characterization of the materials were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) technique. The apatite formation and weight change test were performed on the porous scaffold which showed proper hydrophilicity. The microstructure of the porous scaffold was simulated using the Abaqus simulation with the extracted data from the experimental work. At the end, it was concluded that the most suitable scaffold was fabricated made of PLA filament and coated with chitosan-hydroxyapatite nanocomposite which can be useful choice for bone tissue engineering. پرونده مقاله

The application of porous bio-nanocomposites polymer has greatly increased in the treatment of bone abnormalities and bone fracture. Therefore, predicting the mechanical properties of these bio-nanocomposites is very important prior to their fabrication. Investigation of mechanical properties like (elastic modulus and hardness) is very costly and time-consuming in experimental tests. Therefore, researchers have focused on mathematical methods and new theories to predict the artificial synthetic bone for orthopedic application. In this paper, porous bio-nanocomposites synthetic bone including nanocrystalline Hydroxyapatite (HA) nanoparticles and Titanium oxide (TiO2) containing (0 wt%, 5 wt%, 10 wt%, and 15 wt% of TiO2) as reinforcements and the biocompatible polycaprolactone (PCL) polymer as the matrix has been used for the fabrication of PCL-HA-TiO2. Then, the mechanical test was conducted on the samples and the extracted value from the experimental test was compared with the analytical model using molecular dynamics (MD) method. Finally, these properties were compared with the Dewey micromechanics theory, and the error rate between the experimental method and the Dewey theory was reported. It was found that as the porosity percentage increased in the sample three-phase in composites, the model has a higher error in this theory. Then, due to the importance of hydroxyapatite in the fabrication of bone scaffolds, the obtained results of mechanical properties (Elastic modulus and Poisson’s ratio) have been analyzed statistically. The application of these equations in the rapid prediction of Elastic Modulus and Poisson's ratio of the synthetic bone scaffolds made of hydroxyapatite is highly recommended. پرونده مقاله

The application of porous bio-nanocomposites polymer has greatly increased in the treatment of boneabnormalities and bone fracture. Therefore, predicting the mechanical properties of these bio-nanocompositesare very important prior to their fabrication. Investigation of mechanical properties like (elasticmodulus and hardness) is very costly and time-consuming in experimental tests. Therefore, researchershave focused on mathematical methods and new theories to predict the artificial synthetic bone for orthopedicapplication. In this paper, porous bio-nanocomposites synthetic bone including nanocrystallineHydroxyapatite (HA) nanoparticles and Titanium oxide (TiO2) containing (0 wt%, 5 wt%, 10 wt%, and 15wt% of TiO2) as reinforcements and the biocompatible polycaprolactone (PCL) polymer as the matrix hasbeen used for the fabrication of PCL-HA-TiO2. Then, the mechanical test was conducted on the samplesand the extracted value of the experimental test was compared with the analytical model using moleculardynamics (MD) method. Finally, these properties were compared with the Dewey micromechanicstheory, and the error rate between the experimental method and the Dewey theory was reported. It wasfound that as the porosity percentage increased in the sample three-phase in composites, the model hasa higher error in this theory. Then, due to the importance of hydroxyapatite in the fabrication of bonescaffolds, the obtained results of mechanical properties (Elastic modulus and Poisson’s ratio) have beenanalyzed statistically. The application of these equations in the rapid prediction of Elastic Modulus andPoisson’s ratio of the synthetic bone scaffolds made of hydroxyapatite is highly recommended. پرونده مقاله