Hybrid lattice structures consisting of multiple microstructures have drawn much attention due to their excellent performance and extraordinary designability.This work puts forward a novel design scheme of lightweight...Hybrid lattice structures consisting of multiple microstructures have drawn much attention due to their excellent performance and extraordinary designability.This work puts forward a novel design scheme of lightweight hybrid lattice structures based on independent continuous mapping(ICM)method.First,the effective elastic properties of various microstructure configurations serve as a bridge between the macrostructure and the multiple microstructures by the homogenization theory.Second,a concurrent topology optimization model for seeking optimized macroscale topology and the specified microstructures is established and solved by a generalized multi-material interpolation formulation and sensitivity analysis.Third,several numerical examples show that hybrid lattice structures with different anisotropic configurations accomplish a better lightweight effect than those with various orthogonal configurations,which verifies the feasibility of the presented method.Hence,anisotropic configurations are more conducive to the sufficient utilization of constitutive material.The proposed scheme supplies a reference for the design of hybrid lattice structures and extends the application field of the ICM method.展开更多
The aim of this study is to explore the heterogeneous ice nucleation behavior based on controllable micro-cubic array structure surfaces from the statistic perspective.To this end,we firstly constructed a group of mic...The aim of this study is to explore the heterogeneous ice nucleation behavior based on controllable micro-cubic array structure surfaces from the statistic perspective.To this end,we firstly constructed a group of micro-cubic array structures on silicon substrates by a selective plasma etching technique.After grafting low-free-energy substance,the as-constructed micro-cubic array structure surfaces exhibited higher non-wettability with the water contact angle being up to 150°.On this basis,500 cycles of freezing and melting processes were accurately recorded to analyze the instantaneous ice nucleation behavior according to the statistical results of freezing temperature.As a consequence,the statistical freezing temperature of the sample with micro-spacing distance of 40μm is as low as−17.13°C.This microstructure configuration(conforming to Cassie-Baxter wetting regime)not only could entrap more air pockets,but also achieved lower solid-liquid contact area,resulting in lower ice nucleation rate(~2–3 orders of magnitude less than that on the flat substrate).Furthermore,the gradually increasing micro-spacing distance to 60μm would induce the transition from CassieBaxter to Wenzel wetting state,leading to higher freezing probability and ice nucleation rate.The complete understanding on microstructure configuration improving the ice nucleation will lay the foundation stone for the microstructure design of ice-repellent materials.展开更多
基金This work was supported by the Beijing Natural Science Foundation(No.3192005)National Natural Science Foundation of China(No.11872080)Taishan University Youth Teacher Science Foundation(No.QN-01-201901).
文摘Hybrid lattice structures consisting of multiple microstructures have drawn much attention due to their excellent performance and extraordinary designability.This work puts forward a novel design scheme of lightweight hybrid lattice structures based on independent continuous mapping(ICM)method.First,the effective elastic properties of various microstructure configurations serve as a bridge between the macrostructure and the multiple microstructures by the homogenization theory.Second,a concurrent topology optimization model for seeking optimized macroscale topology and the specified microstructures is established and solved by a generalized multi-material interpolation formulation and sensitivity analysis.Third,several numerical examples show that hybrid lattice structures with different anisotropic configurations accomplish a better lightweight effect than those with various orthogonal configurations,which verifies the feasibility of the presented method.Hence,anisotropic configurations are more conducive to the sufficient utilization of constitutive material.The proposed scheme supplies a reference for the design of hybrid lattice structures and extends the application field of the ICM method.
基金This work was supported by the National Natural Science Foundation of China(No.51671105,51705244)Natural Science Foundation of Jiangsu Province(No.BK20170790)+2 种基金the Project Funded by China Postdoctoral Science Foundation(No.2019M661826)Fund of State Key Laboratory of Aerodynamics(SKLA2019020401)Open Fund of Key Laboratory of Icing and Anti/De-icing(No.IADL20190202).
文摘The aim of this study is to explore the heterogeneous ice nucleation behavior based on controllable micro-cubic array structure surfaces from the statistic perspective.To this end,we firstly constructed a group of micro-cubic array structures on silicon substrates by a selective plasma etching technique.After grafting low-free-energy substance,the as-constructed micro-cubic array structure surfaces exhibited higher non-wettability with the water contact angle being up to 150°.On this basis,500 cycles of freezing and melting processes were accurately recorded to analyze the instantaneous ice nucleation behavior according to the statistical results of freezing temperature.As a consequence,the statistical freezing temperature of the sample with micro-spacing distance of 40μm is as low as−17.13°C.This microstructure configuration(conforming to Cassie-Baxter wetting regime)not only could entrap more air pockets,but also achieved lower solid-liquid contact area,resulting in lower ice nucleation rate(~2–3 orders of magnitude less than that on the flat substrate).Furthermore,the gradually increasing micro-spacing distance to 60μm would induce the transition from CassieBaxter to Wenzel wetting state,leading to higher freezing probability and ice nucleation rate.The complete understanding on microstructure configuration improving the ice nucleation will lay the foundation stone for the microstructure design of ice-repellent materials.
