Advancements in machine learning for material design and process optimization in the field of additive manufacturing

Additive manufacturing technology is highly regarded due to its advantages,such as high precision and the ability to address complex geometric challenges.However,the development of additive manufacturing process is constrained by issues like unclear fundamental principles,complex experimental cycles,and high costs.Machine learning,as a novel artificial intelligence technology,has the potential to deeply engage in the development of additive manufacturing process,assisting engineers in learning and developing new techniques.This paper provides a comprehensive overview of the research and applications of machine learning in the field of additive manufacturing,particularly in model design and process development.Firstly,it introduces the background and significance of machine learning-assisted design in additive manufacturing process.It then further delves into the application of machine learning in additive manufacturing,focusing on model design and process guidance.Finally,it concludes by summarizing and forecasting the development trends of machine learning technology in the field of additive manufacturing.

Mechanical and damping performances of TPMS lattice metamaterials fabricated by laser powder bed fusion

Lattice metamaterials based on three-period minimum surface(TPMS)are an effective means to achieve lightweight and high-strength materials which are widely used in various fields such as aerospace and ships.However,its vibration and noise reduction,and damping properties have not been fully studied.Therefore,in this study,the TPMS structures with parameterization were designed by the method of surface migration,and the TPMS structures with high forming quality was manufactured by laser powder bed fusion(LPBF).The mechanical properties and energy absorption characteristics of the beam and TPMS structures were studied and compared by quasi-static compression.The modal shapes of the beam lattice structures and TPMS structures were obtained by the free modal analysis,and the damping properties of two structures were obtained by modal tests.For the two structures after heat treatment with the same porosity of 70%,the yield strength of the beam lattice structure reaches 40.76 MPa,elastic modulus is 20.38 GPa,the energy absorption value is 32.23 MJ·m^(-3),the damping ratio is 0.52%.The yield strength,elastic modulus,energy absorption value,and damping ratio of the TPMS structure are 50.74 MPa,25.37 GPa,47.34 MJ·m^(-3),and 0.99%,respectively.The results show that TPMS structures exhibit more excellent mechanical properties and energy absorption,better damping performance,and obvious advantages in structural load and vibration and noise reduction compared with the beam lattice structures under the same porosity.

Four undescribed pyrethrins from seeds of Pyrethrum cinerariifolium and their aphidicidal activity

Four undescribed pyrethrins C-F(1-4)as well as four known pyrethrins(5-8)were isolated from seeds of Pyrethrum cinerariifolium Trev.The structures of compounds 1-4 were elucidated by UV,HRESIMS,and NMR(^(1)H and ^(13)C NMR,^(1)H-^(1)H COSY,HSQC,HMBC and ROESY),among which the stereostructure of compound 4 was determined by calcu-lated ECD.Furthermore,compounds 1-4 were evaluated for their aphidicidal activities.The insecticidal assay results showed that 1-4 exhibited moderate aphidicidal activities at the concentration of 0.1 mg/mL with the 24 h mortality rates ranging from 10.58 to 52.98%.Among them,pyrethrin D(2)showed the highest aphidicidal activity,with the 24 h mortality rate of 52.98%,which was slightly lower than the positive control(pyrethrin II,83.52%).