Thin-walled lattice materials can be applied as energy absorbers in protective structures of civil defense. In this paper, quasi-static in-plane crushing tests were carried out to investigate the crushing behavior and...Thin-walled lattice materials can be applied as energy absorbers in protective structures of civil defense. In this paper, quasi-static in-plane crushing tests were carried out to investigate the crushing behavior and energy absorption of buckling induced meta-lattice structures (BIMSs) with different central angles made of plastic iron material DT3 and formed by wire cutting technique. Three crushing patterns were revealed and analyzed. The test results clearly show that the initial peak force (IPF), the crushing force efficiency (CFE), the specific energy absorption (SEA) and the mean crushing force (MCF) can be substantially improved by introducing buckling pattern into the straight-walled lattice structure. The MCF of the BIMS was consistently predicted based on the simplified super folding element (SSFE) and the flattening element.展开更多
Introducing buckling pattern into straight-walled lattice structure,anovel buckling inspired lattice meta-structure(BILM)was designed and fabricated using polylactic acid(PLA)by three-dimensional(3D)printing technolog...Introducing buckling pattern into straight-walled lattice structure,anovel buckling inspired lattice meta-structure(BILM)was designed and fabricated using polylactic acid(PLA)by three-dimensional(3D)printing technology.The square lattice structure with positive Poisson’s ratio(PPR)is transformed into negative Poisson’s ratio(NPR)structure by buckling induction.Curved struts decrease the maximum strain,prohibit strut fracture,increase strut contact and induce ductile bending deformation.The meta-topology changes the crushing pattern from brittle layer-by-layer fracture,hybrid crushing pattern to stable plastic crushing when increasing the central angle from 0°to 120°.Buckling inspired meta-lattice structures can obviously improve the energy absorption(EA)performance through reducing the initial peak force(IPF)while increasing the EA,specific energy absorption(SEA)and crushing force efficiency(CFE).Ductile crushing endows BILM excellent EA.展开更多
The connections between the building units of meta-stable lattice were generally considered to be easily disturbed during the doping process, causing serious hindrances blocking the development of functional doped mat...The connections between the building units of meta-stable lattice were generally considered to be easily disturbed during the doping process, causing serious hindrances blocking the development of functional doped materials. In this work, the synthesis of doped brookite, a typical meta-stable phase of TiO2, has been explored novelly by in-situ adding of cations of VIIIB and IB,IIB elements in the 3rd period（Fe, Co, Ni, Cu, Zn） during the urea-lactate aided low-basicity hydrothermal process. The results showed that only Cu-doped brookite could be successfully synthesized with trace amount of copper intensively internalized into the brookite lattice, while the other dopants lead to the formation of anatase TiO2. Extensive characterizations indicated a two-step doping process, where copper ions were firstly dispersed in an amorphous layer on the lattice surface and then they were internalized into brookite lattice. Cu-doped brookite exhibited significantly enhanced photocatalytic activity in the phenol degradation under visible light compared to bare brookite. The enhancement of catalytic performance was assigned to the impurity band gap and the reduction of charge carriers＇ recombination introduced by the internalization of Cu ions. The investigation reported herein contributes to the understanding of complex ion-doping effects on the structures of meta-stable materials, and provides hints for obtaining other functional doped materials.展开更多
基金Supports from National Natural Science Foundation of China(11972184 and U20A20286)China National Key Laboratory Foundation of Science and Technology on Materials under Shock and Impact(6142902200203)+1 种基金Natural Science Foundation of Jiangsu Province of China(BK20201286)Science and Technology Project of Jiangsu Province of China(BE2020716)are gratefully acknowledged.
文摘Thin-walled lattice materials can be applied as energy absorbers in protective structures of civil defense. In this paper, quasi-static in-plane crushing tests were carried out to investigate the crushing behavior and energy absorption of buckling induced meta-lattice structures (BIMSs) with different central angles made of plastic iron material DT3 and formed by wire cutting technique. Three crushing patterns were revealed and analyzed. The test results clearly show that the initial peak force (IPF), the crushing force efficiency (CFE), the specific energy absorption (SEA) and the mean crushing force (MCF) can be substantially improved by introducing buckling pattern into the straight-walled lattice structure. The MCF of the BIMS was consistently predicted based on the simplified super folding element (SSFE) and the flattening element.
基金This work was supported by the NSFC[11972184 and U20A20286].
文摘Introducing buckling pattern into straight-walled lattice structure,anovel buckling inspired lattice meta-structure(BILM)was designed and fabricated using polylactic acid(PLA)by three-dimensional(3D)printing technology.The square lattice structure with positive Poisson’s ratio(PPR)is transformed into negative Poisson’s ratio(NPR)structure by buckling induction.Curved struts decrease the maximum strain,prohibit strut fracture,increase strut contact and induce ductile bending deformation.The meta-topology changes the crushing pattern from brittle layer-by-layer fracture,hybrid crushing pattern to stable plastic crushing when increasing the central angle from 0°to 120°.Buckling inspired meta-lattice structures can obviously improve the energy absorption(EA)performance through reducing the initial peak force(IPF)while increasing the EA,specific energy absorption(SEA)and crushing force efficiency(CFE).Ductile crushing endows BILM excellent EA.
基金Financially supported by the Science and Technology Programs from Fujian Province(No.2013H0057)
文摘The connections between the building units of meta-stable lattice were generally considered to be easily disturbed during the doping process, causing serious hindrances blocking the development of functional doped materials. In this work, the synthesis of doped brookite, a typical meta-stable phase of TiO2, has been explored novelly by in-situ adding of cations of VIIIB and IB,IIB elements in the 3rd period（Fe, Co, Ni, Cu, Zn） during the urea-lactate aided low-basicity hydrothermal process. The results showed that only Cu-doped brookite could be successfully synthesized with trace amount of copper intensively internalized into the brookite lattice, while the other dopants lead to the formation of anatase TiO2. Extensive characterizations indicated a two-step doping process, where copper ions were firstly dispersed in an amorphous layer on the lattice surface and then they were internalized into brookite lattice. Cu-doped brookite exhibited significantly enhanced photocatalytic activity in the phenol degradation under visible light compared to bare brookite. The enhancement of catalytic performance was assigned to the impurity band gap and the reduction of charge carriers＇ recombination introduced by the internalization of Cu ions. The investigation reported herein contributes to the understanding of complex ion-doping effects on the structures of meta-stable materials, and provides hints for obtaining other functional doped materials.
