Rezaei AbdolMajid, Izadi Razie, Fantuzzi Nicholas
Department of Structural and Geotechnical Engineering, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Viale del Risorgimento 2, 40136 Bologna, Italy.
Nanomaterials (Basel). 2024 Jun 28;14(13):1113. doi: 10.3390/nano14131113.
Fused deposition modelling (FDM) is an additive manufacturing technique widely used for rapid prototyping. This method facilitates the creation of parts with intricate geometries, making it suitable for advanced applications in fields such as tissue engineering, aerospace, and electronics. Despite its advantages, FDM often results in the formation of voids between the deposited filaments, which can compromise mechanical properties. However, in some cases, such as the design of scaffolds for bone regeneration, increased porosity can be advantageous as it allows for better permeability. On the other hand, the introduction of nano-additives into the FDM material enhances design flexibility and can significantly improve the mechanical properties. Therefore, modelling FDM-produced components involves complexities at two different scales: nanoscales and microscales. Material deformation is primarily influenced by atomic-scale phenomena, especially with nanoscopic constituents, whereas the distribution of nano-reinforcements and FDM-induced heterogeneities lies at the microscale. This work presents multiscale modelling that bridges the nano and microscales to predict the mechanical properties of FDM-manufactured components. At the nanoscale, molecular dynamic simulations unravel the atomistic intricacies that dictate the behaviour of the base material containing nanoscopic reinforcements. Simulations are conducted on polylactic acid (PLA) and PLA reinforced with silver nanoparticles, with the properties derived from MD simulations transferred to the microscale model. At the microscale, non-classical micropolar theory is utilised, which can account for materials' heterogeneity through internal scale parameters while avoiding direct discretization. The developed mechanical model offers a comprehensive framework for designing 3D-printed PLA nanocomposites with tailored mechanical properties.
熔融沉积建模（FDM）是一种广泛用于快速成型的增材制造技术。这种方法有助于制造具有复杂几何形状的零件，使其适用于组织工程、航空航天和电子等领域的先进应用。尽管具有这些优点，但FDM通常会在沉积的细丝之间形成空隙，这可能会损害机械性能。然而，在某些情况下，例如用于骨再生的支架设计中，增加孔隙率可能是有利的，因为它允许更好的渗透性。另一方面，将纳米添加剂引入FDM材料可提高设计灵活性，并可显著改善机械性能。因此，对FDM生产的部件进行建模涉及两个不同尺度的复杂性：纳米尺度和微观尺度。材料变形主要受原子尺度现象的影响，特别是对于纳米级成分，而纳米增强材料的分布和FDM引起的不均匀性则处于微观尺度。这项工作提出了一种多尺度建模方法，该方法连接了纳米尺度和微观尺度，以预测FDM制造部件的机械性能。在纳米尺度上，分子动力学模拟揭示了决定含有纳米增强材料的基体材料行为的原子细节。对聚乳酸（PLA）和用银纳米颗粒增强的PLA进行了模拟，并将从MD模拟中获得的性能转移到微观尺度模型中。在微观尺度上，使用了非经典微极理论，该理论可以通过内部尺度参数考虑材料的不均匀性，同时避免直接离散化。所开发的力学模型为设计具有定制机械性能的3D打印PLA纳米复合材料提供了一个全面的框架。
