Due to the urgent demand for lightweight and high-strength materials in rail transportation,this study proposed foamed polylactic acid(PLA)composites reinforced with continuous basalt fibres using a 3D printing techni...Due to the urgent demand for lightweight and high-strength materials in rail transportation,this study proposed foamed polylactic acid(PLA)composites reinforced with continuous basalt fibres using a 3D printing technique to address the limitations posed by foaming-induced strength reduction in foam.Through a combination of parametric calculations,microscopic observations and compression experiments,the effects of printing parameters on the expansion ratio and print accuracy of foamed composite were investigated.It was found that adding fibres to foamed PLA reduced the expansion ratio of PLA by up to 9.52%at lower printing temperatures and layer heights but increased it at higher settings.The expansion ratio of the composite significantly increased with high printing temperatures and layer heights.When the composites were fabricated at low print temperatures and high layer heights,noticeable interlayer gaps and exposed fibres leading to poor impregnation were observed at cross-section.This phenomenon was improved as the expansion ratio increased.In addition,specimens with optimal print accuracy were prepared at specific combinations of printing temperature and layer height.In light of this discovery,a predictive function based on combined printing parameters was established to design composites with excellent print accuracy and specific densities.Finally,compression test results showed that with the same density of 0.5 g/cm^(3),the foamed composite exhibited substantial improvements in compressive strength,modulus and strain energy density compared to the foamed PLA,with increases of 44.44%,57.02%and 24.19%,respectively.展开更多
A study was conducted to evaluate the current production capabilities of the Mark One? 3D printer in printing carbon fibre reinforced thermoplastic (CFRTP) tensile test specimens according to the JIS K 7073 by making ...A study was conducted to evaluate the current production capabilities of the Mark One? 3D printer in printing carbon fibre reinforced thermoplastic (CFRTP) tensile test specimens according to the JIS K 7073 by making use of fused deposition modelling. Several different types of CFRTP tensile test specimens are printed and are tensile tested in the longitudinal direction to obtain an overview of the mechanical properties of 3D printed CFRTP material. These properties are compared with the literature values known for composite materials to see if these agree. The main goal of this research is to increase the knowledge of the 3D printing process of CFRTP and to later use this knowledge to further improve the 3D printing process to obtain stronger 3D printed CFRTP materials.展开更多
In order to predict the damage behaviours of 3D-printed continuous carbon fibre(CCF)reinforced composites,when additional short carbon fibre(SCF)composite components are employed for continuous printing or special fun...In order to predict the damage behaviours of 3D-printed continuous carbon fibre(CCF)reinforced composites,when additional short carbon fibre(SCF)composite components are employed for continuous printing or special functionality,a novel path-dependent progressive failure(PDPF)numerical approach is developed.First,a progressive failure model using Hashin failure criteria with continuum damage mechanics to account for the damage initiation and evaluation of 3D-printed CCF reinforced polyamide(PA)composites is developed,based on actual fibre placement trajectories with physical measurements of 3D-printed CCF/PA constituents.Meanwhile,an elastic-plastic model is employed to predict the plastic damage behaviours of SCF/PA parts.Then,the accuracy of the PDPF model was validated so as to study 3D-printed CCF/PA composites with either negative Poisson's ratio or high stiffness.The results demonstrate that the proposed PDPF model can achieve higher prediction accuracies in mechanical properties of these 3D-printed CCF/PA composites.Mechanism analyses show that the stress distribution is generally aggregated in the CCF areas along the fibre placement paths,and the shear damage and matrix tensile/compressive damage are the key damage modes.This study provides a new approach with valuable information for characterising complex 3D-printed continuous fibre-matrix composites with variable mechanical properties and multiple constituents.展开更多
基金financial support of the Natural Science Foundation of Hunan(Grant No.2024JJ5434)the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20240646).
文摘Due to the urgent demand for lightweight and high-strength materials in rail transportation,this study proposed foamed polylactic acid(PLA)composites reinforced with continuous basalt fibres using a 3D printing technique to address the limitations posed by foaming-induced strength reduction in foam.Through a combination of parametric calculations,microscopic observations and compression experiments,the effects of printing parameters on the expansion ratio and print accuracy of foamed composite were investigated.It was found that adding fibres to foamed PLA reduced the expansion ratio of PLA by up to 9.52%at lower printing temperatures and layer heights but increased it at higher settings.The expansion ratio of the composite significantly increased with high printing temperatures and layer heights.When the composites were fabricated at low print temperatures and high layer heights,noticeable interlayer gaps and exposed fibres leading to poor impregnation were observed at cross-section.This phenomenon was improved as the expansion ratio increased.In addition,specimens with optimal print accuracy were prepared at specific combinations of printing temperature and layer height.In light of this discovery,a predictive function based on combined printing parameters was established to design composites with excellent print accuracy and specific densities.Finally,compression test results showed that with the same density of 0.5 g/cm^(3),the foamed composite exhibited substantial improvements in compressive strength,modulus and strain energy density compared to the foamed PLA,with increases of 44.44%,57.02%and 24.19%,respectively.
文摘A study was conducted to evaluate the current production capabilities of the Mark One? 3D printer in printing carbon fibre reinforced thermoplastic (CFRTP) tensile test specimens according to the JIS K 7073 by making use of fused deposition modelling. Several different types of CFRTP tensile test specimens are printed and are tensile tested in the longitudinal direction to obtain an overview of the mechanical properties of 3D printed CFRTP material. These properties are compared with the literature values known for composite materials to see if these agree. The main goal of this research is to increase the knowledge of the 3D printing process of CFRTP and to later use this knowledge to further improve the 3D printing process to obtain stronger 3D printed CFRTP materials.
基金Supported by National Natural Science Foundation of China (Grant No.12302177)Guangdong Provincial Basic and Applied Basic Research Foundation of China (Grant No.2024A1515010203)+1 种基金Shenzhen Science and Technology Program of China (Grant No.JCYJ20230807093602005)Shenzhen Key Laboratory of Intelligent Manufacturing for Continuous Carbon Fibre Reinforced Composites of China (Grant No.ZDSYS20220527171404011)。
文摘In order to predict the damage behaviours of 3D-printed continuous carbon fibre(CCF)reinforced composites,when additional short carbon fibre(SCF)composite components are employed for continuous printing or special functionality,a novel path-dependent progressive failure(PDPF)numerical approach is developed.First,a progressive failure model using Hashin failure criteria with continuum damage mechanics to account for the damage initiation and evaluation of 3D-printed CCF reinforced polyamide(PA)composites is developed,based on actual fibre placement trajectories with physical measurements of 3D-printed CCF/PA constituents.Meanwhile,an elastic-plastic model is employed to predict the plastic damage behaviours of SCF/PA parts.Then,the accuracy of the PDPF model was validated so as to study 3D-printed CCF/PA composites with either negative Poisson's ratio or high stiffness.The results demonstrate that the proposed PDPF model can achieve higher prediction accuracies in mechanical properties of these 3D-printed CCF/PA composites.Mechanism analyses show that the stress distribution is generally aggregated in the CCF areas along the fibre placement paths,and the shear damage and matrix tensile/compressive damage are the key damage modes.This study provides a new approach with valuable information for characterising complex 3D-printed continuous fibre-matrix composites with variable mechanical properties and multiple constituents.
