This paper presents a bio-inspired geomagnetic navigation method for autonomous underwater vehicle(AUV) without using any a priori geomagnetic information. Firstly, the multi-objective search problem is raised. Second...This paper presents a bio-inspired geomagnetic navigation method for autonomous underwater vehicle(AUV) without using any a priori geomagnetic information. Firstly, the multi-objective search problem is raised. Secondly, the geomagnetic navigation model is established by constructing a cost function. Then, by taking into consideration the biological magneto-taxis movement behavior for the geomagnetic environment stimulus, the multiobjective evolutionary search algorithm is derived to describe the search process. Finally, compared to the state-of-the-art, the proposed method presents better robustness. The simulation results demonstrate the reliability and feasibility of the proposed method.展开更多
In order to pursue good crushing load uniformity and enchance energy absorption efficiency of conventional honeycombs, a kind of bio-inspired hierarchical honeycomb model is proposed by mimicking the arched crab shell...In order to pursue good crushing load uniformity and enchance energy absorption efficiency of conventional honeycombs, a kind of bio-inspired hierarchical honeycomb model is proposed by mimicking the arched crab shell structures. Three bio-inspired hierarchical honeycombs(BHHs) with different topologies are designed by replacing each vertex of square honeycombs with smaller arc-shaped structures. The effects of hierarchical topologies and multi-material layout on in-plane dynamic crushings and absorbed-energy capacities of the BHHs are explored based on the explicit finite element(FE) analysis.Different deformation modes can be observed from the BHHs, which mainly depend upon hierarchical topologies and impact velocities. According to energy efficiency method and one-dimensional(1D) shock theory, calculation formulas of densification strains and plateau stresses for the BHHs are derived to characterize the dynamic bearing capacity, which is consistent well with FE results. Compared with conventional honeycombs, the crushing load efficiency and energy absorption capacity of the BHHs can be improved by changing the proper hierarchical topology and multi-material layout. These researches will provide theoretical guidance for innovative design and dynamic response performance controllability of honeycombs.展开更多
Inspired by the microstructure of gecko’s toe,two kinds of polyvinyl chloride(PVC)gels with different modulus were poured on a silicon mold with micropillars,and then a bio-inspired adhesive with variable modulus was...Inspired by the microstructure of gecko’s toe,two kinds of polyvinyl chloride(PVC)gels with different modulus were poured on a silicon mold with micropillars,and then a bio-inspired adhesive with variable modulus was manufactured in this study.The adhesions of variable modulus and fixed modulus bio-inspired adhesives were tested,respectively,on a smooth glass and a printed circuit board(PCB)with different surface structures.The results show that PVC gel bio-inspired adhesives with variable modulus have many advantages compared with the fixed modulus bioinspired adhesives.The adhesion of variable modulus bio-inspired adhesives on the rough PCB surface increased by 2−5 times,and due to the use of variable modulus of PVC gel,the surface micropillars can maintain high aspect ratio and flexible tips at the same time.Moreover,the use of PVC gel makes it easier to demold during the bio-inspired adhesives preparation.An adhesion-desorption device was made according to the movement of the gecko toes,and the PCB was successfully grasped.展开更多
Metal superhydrophobic surfaces with anisotropic wettability and adhesion have become more and more important due to their promising applications. Herein, we report a new fabrication strategy through a combination of ...Metal superhydrophobic surfaces with anisotropic wettability and adhesion have become more and more important due to their promising applications. Herein, we report a new fabrication strategy through a combination of pulsed laser ablation and low-temperature annealing post-processing. An inclined cone structure array is made on stainless steel surfaces, and then 120 °C low-temperature annealing is applied. Such surface displays excellent mechanical durability and anisotropic superhydrophobicity. It is demonstrated experimentally that the contact angle of water droplets on the surface is different along the parallel(167° ±2°) and perpendicular directions(157° ±2°) of the inclined cone structure. The sliding behaviors of water droplets and mechanical durability of the inclined cone structures are studied. These surfaces obtained in a short time with environmentally friendly fabrication can be applied in industries for water harvesting, droplet manipulation, and pipeline transportation.展开更多
基金supported by the National Natural Science Foundation of China(5137917651179156)
文摘This paper presents a bio-inspired geomagnetic navigation method for autonomous underwater vehicle(AUV) without using any a priori geomagnetic information. Firstly, the multi-objective search problem is raised. Secondly, the geomagnetic navigation model is established by constructing a cost function. Then, by taking into consideration the biological magneto-taxis movement behavior for the geomagnetic environment stimulus, the multiobjective evolutionary search algorithm is derived to describe the search process. Finally, compared to the state-of-the-art, the proposed method presents better robustness. The simulation results demonstrate the reliability and feasibility of the proposed method.
基金the financial support provided by the Natural Science Foundation of Hebei Province of China [No. A2020502005]the Fundamental Research Funds for the Central Universities [No. 2020MS113]Science & Technology Program of Baoding [No. 1911ZG019]。
文摘In order to pursue good crushing load uniformity and enchance energy absorption efficiency of conventional honeycombs, a kind of bio-inspired hierarchical honeycomb model is proposed by mimicking the arched crab shell structures. Three bio-inspired hierarchical honeycombs(BHHs) with different topologies are designed by replacing each vertex of square honeycombs with smaller arc-shaped structures. The effects of hierarchical topologies and multi-material layout on in-plane dynamic crushings and absorbed-energy capacities of the BHHs are explored based on the explicit finite element(FE) analysis.Different deformation modes can be observed from the BHHs, which mainly depend upon hierarchical topologies and impact velocities. According to energy efficiency method and one-dimensional(1D) shock theory, calculation formulas of densification strains and plateau stresses for the BHHs are derived to characterize the dynamic bearing capacity, which is consistent well with FE results. Compared with conventional honeycombs, the crushing load efficiency and energy absorption capacity of the BHHs can be improved by changing the proper hierarchical topology and multi-material layout. These researches will provide theoretical guidance for innovative design and dynamic response performance controllability of honeycombs.
基金Projects(51605220,U1637101)supported by the National Natural Science Foundation of ChinaProject(BK20160793)supported by the Natural Science Foundation of Jiangsu Province,ChinaProject(NS2020029)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Inspired by the microstructure of gecko’s toe,two kinds of polyvinyl chloride(PVC)gels with different modulus were poured on a silicon mold with micropillars,and then a bio-inspired adhesive with variable modulus was manufactured in this study.The adhesions of variable modulus and fixed modulus bio-inspired adhesives were tested,respectively,on a smooth glass and a printed circuit board(PCB)with different surface structures.The results show that PVC gel bio-inspired adhesives with variable modulus have many advantages compared with the fixed modulus bioinspired adhesives.The adhesion of variable modulus bio-inspired adhesives on the rough PCB surface increased by 2−5 times,and due to the use of variable modulus of PVC gel,the surface micropillars can maintain high aspect ratio and flexible tips at the same time.Moreover,the use of PVC gel makes it easier to demold during the bio-inspired adhesives preparation.An adhesion-desorption device was made according to the movement of the gecko toes,and the PCB was successfully grasped.
基金Project(A19C2a0019) supported by the Advanced Remanufacturing and Technology Centre (ARTC) under its RIE2020 Advanced Manufacturing and Engineering (AME) IAF PP,Singapore。
文摘Metal superhydrophobic surfaces with anisotropic wettability and adhesion have become more and more important due to their promising applications. Herein, we report a new fabrication strategy through a combination of pulsed laser ablation and low-temperature annealing post-processing. An inclined cone structure array is made on stainless steel surfaces, and then 120 °C low-temperature annealing is applied. Such surface displays excellent mechanical durability and anisotropic superhydrophobicity. It is demonstrated experimentally that the contact angle of water droplets on the surface is different along the parallel(167° ±2°) and perpendicular directions(157° ±2°) of the inclined cone structure. The sliding behaviors of water droplets and mechanical durability of the inclined cone structures are studied. These surfaces obtained in a short time with environmentally friendly fabrication can be applied in industries for water harvesting, droplet manipulation, and pipeline transportation.
