A parametric study was performed to explore the effect of runner thickness,filtration,and hydrogen content on the mechanical properties and defect formation in Al-7%Si-0.3%Mg(2L99)sand castings.A two-level full factor...A parametric study was performed to explore the effect of runner thickness,filtration,and hydrogen content on the mechanical properties and defect formation in Al-7%Si-0.3%Mg(2L99)sand castings.A two-level full factorial design of experiments was used to statistically evaluate these parameters and the tensile properties were characterized via Weibull distribution analysis.The findings reveal that decreasing the runner thickness from25 mm to 10 mm and using 10 PPI ceramic filters improve mechanical properties by minimizing double oxide film entrainment as confirmed by electron microscopy examination.In addition,lowering hydrogen concentrations within the Al alloy from 0.24 cm^(3)/100 g Al to 0.12 cm^(3)/100 g Al is also shown to enhance casting integrity by suppressing bifilm inflation and subsequent pore formation.ANOVA results indicate that the hydrogen content is the most important factor,contributing 53%to the variability in mechanical properties,followed by filtration(25%)and runner thickness(17%).The optimized casting conditions including thin runners(10 mm thick),melt filtration,and a low hydrogen level(0.12 cm^(3)/100 g Al),result in an approximately 474%increase in the shape factor and a 107%increase in the characteristic life of UTS,as well as an approximately 413%increase in the shape factor and a 149%increase in characteristic life of elongation.The outcomes suggest that controlled filling systems and melt treatment are critical for producing consistent,high integrity aluminum castings in industrial applications.展开更多
Functionally graded cellular structures(FGCSs)have a multitude of applications to a wide range of industries.Utilising the ever-progressing technology of additive manufacturing(AM),FGCSs can be applied to control mate...Functionally graded cellular structures(FGCSs)have a multitude of applications to a wide range of industries.Utilising the ever-progressing technology of additive manufacturing(AM),FGCSs can be applied to control material grading and achieve the desired mechanical properties.The current study explores the design and optimisation of FGCSs for AM,with a focus on improving the compression and impact performance of below knee(BK)prosthetic limbs made of thermoplastic polyurethane(TPU).A multiscale research methodology integrating topology optimization(TO),finite element analysis(FEA),and design of experiments(Do E)was adopted to optimise lattice structures in terms of stiffness and lightweight properties.Two-unit cell designs were considered in the study:Schwarz P gyroid and body-centered cubic(BCC).Response surface methodology(RSM)was implemented to analyse the effect of minimum and maximum cell wall thickness,cell size,and unit cell type on the mechanical performance of TPU FGCS structures.The results indicated that a Schwarz P FGCS structure with cell size,minimum and maximum cell wall thickness of 6,0.9 and 2.8 mm,respectively,could be optimal for a compromise between performance and weight.In this optimized case,stiffness and volume fraction values of 684 N/mm and 0.64 were obtained,respectively.The study also presents a proof-of-concept design for a BK prosthetic damper,highlighting the potential of FGCSs to enhance patient comfort,reduce manufacturing costs,and enable personalised designs through 3D scanning and AM.The obtained results could be a step forward towards the incorporation of AM technologies in prosthetics,offering a pathway to lightweight,cost-effective,and functionally tailored solutions.展开更多
基金supported and funded by the Deanship of Scientific Research at Imam Mohammad Ibn Saud Islamic University(IMSIU)(Grant number IMSIU-DDRSP2603)。
文摘A parametric study was performed to explore the effect of runner thickness,filtration,and hydrogen content on the mechanical properties and defect formation in Al-7%Si-0.3%Mg(2L99)sand castings.A two-level full factorial design of experiments was used to statistically evaluate these parameters and the tensile properties were characterized via Weibull distribution analysis.The findings reveal that decreasing the runner thickness from25 mm to 10 mm and using 10 PPI ceramic filters improve mechanical properties by minimizing double oxide film entrainment as confirmed by electron microscopy examination.In addition,lowering hydrogen concentrations within the Al alloy from 0.24 cm^(3)/100 g Al to 0.12 cm^(3)/100 g Al is also shown to enhance casting integrity by suppressing bifilm inflation and subsequent pore formation.ANOVA results indicate that the hydrogen content is the most important factor,contributing 53%to the variability in mechanical properties,followed by filtration(25%)and runner thickness(17%).The optimized casting conditions including thin runners(10 mm thick),melt filtration,and a low hydrogen level(0.12 cm^(3)/100 g Al),result in an approximately 474%increase in the shape factor and a 107%increase in the characteristic life of UTS,as well as an approximately 413%increase in the shape factor and a 149%increase in characteristic life of elongation.The outcomes suggest that controlled filling systems and melt treatment are critical for producing consistent,high integrity aluminum castings in industrial applications.
基金financially supported and funded by the Deanship of Scientific Research at Imam Mohammad Ibn Saud Islamic University(IMSIU)(No.IMSIU-DDRSP2503)。
文摘Functionally graded cellular structures(FGCSs)have a multitude of applications to a wide range of industries.Utilising the ever-progressing technology of additive manufacturing(AM),FGCSs can be applied to control material grading and achieve the desired mechanical properties.The current study explores the design and optimisation of FGCSs for AM,with a focus on improving the compression and impact performance of below knee(BK)prosthetic limbs made of thermoplastic polyurethane(TPU).A multiscale research methodology integrating topology optimization(TO),finite element analysis(FEA),and design of experiments(Do E)was adopted to optimise lattice structures in terms of stiffness and lightweight properties.Two-unit cell designs were considered in the study:Schwarz P gyroid and body-centered cubic(BCC).Response surface methodology(RSM)was implemented to analyse the effect of minimum and maximum cell wall thickness,cell size,and unit cell type on the mechanical performance of TPU FGCS structures.The results indicated that a Schwarz P FGCS structure with cell size,minimum and maximum cell wall thickness of 6,0.9 and 2.8 mm,respectively,could be optimal for a compromise between performance and weight.In this optimized case,stiffness and volume fraction values of 684 N/mm and 0.64 were obtained,respectively.The study also presents a proof-of-concept design for a BK prosthetic damper,highlighting the potential of FGCSs to enhance patient comfort,reduce manufacturing costs,and enable personalised designs through 3D scanning and AM.The obtained results could be a step forward towards the incorporation of AM technologies in prosthetics,offering a pathway to lightweight,cost-effective,and functionally tailored solutions.
