查看更多>>摘要：Additive manufacturing(AM),also known as 3D printing,is a process of creating three-dimensional objects with complex geometries that is utilized in various engineering applications.Continuous carbon fiber(CCF)is a high-performance material that offers a range of benefits in terms of strength,weight,and durability.Fused filament fabrication(FFF)is a type of AM that uses a thermoplastic filament as a material with which to create a three-dimensional object,and it has been widely used in various applications,as it enables the faster,cheaper,and more customizable production of parts and products.Lightweight cellular composite structures consists of small,repeating unit cells that are interconnected to form a larger structure,and they are employed in high engineering applications.In this study,cellular composite structures were fabricated using FFF technology,considering two types of infill paths design(grid and triangular)manufactured at three infill density levels(20％,40％,and 60％).After the fabrication process,tensile and flexural properties were experimentally investigated,and the influence of the infill pattern and density on the cellular composite parts were studied.The achieved results demonstrated that the infill design pattern and its density had great influence on the mechanical properties of the cellular structure.The obtained results also showed that the lightweight cellular composite parts had great potential for use in structural applications.
查看更多>>摘要：A comprehensive three-dimensional transient computational fluid dynamics(CFD)model was developed to ana-lyze the thermophysical phenomena in the arc wire additive manufacturing(WAAM)process.The model includes droplet impact,gravity,heat and mass transfer,molten metal flow,and solid-liquid phase changes.By integrating the mass,energy,momentum,and volume of fluid(VOF)equations,a layer-by-layer additive process was suc-cessfully simulated.The accuracy of the model was validated by comparing the simulation results of single-pass single-layer weld beads at three welding positions with experimental data.The established model was utilized to quantitatively investigate the effects of three crucial welding process parameters-welding direction,droplet transfer frequency,and initial temperature-on the multi-layer cladding process.These findings suggest that the use of opposite welding directions in two adjacent layers can result in a well-distributed overall morphology of the weld bead.Moreover,the high initial droplet temperature enhanced the inclination of the weld bead mor-phology while decreasing the height of each layer.However,the high droplet transfer frequency caused both the height and width of the weld to increase.This research contributes to explaining the formation mechanism of the multi-layer cladding process and offers insights for improving weld bead morphology.This provides valuable theoretical guidance for the process optimization and control of arc additive manufacturing technology.
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