http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Liu Jikai (검색결과 10 건)
- 무료
- 기관 내 무료
- 유료
-
A Topology Optimization Method for Hybrid Subtractive–Additive Remanufacturing
Jikai Liu,Yufan Zheng,Yongsheng Ma,Ahmed Qureshi,Rafiq Ahmad 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.7 No.5
This paper presents a hybrid subtractive–additive remanufacturing oriented topology optimization method. This method provides a design-for-remanufacturing approach, which offer solutions for product upgrade or repair. To be specific, a used part is first machined to remove material, and then additively deposited of materials on top. In this way, either the function of the part is upgraded or the broken part is repaired. Beneficially, the used part is economically and environment-friendly recycled. This method is developed under the level set framework and innovatively, the layer-wise level set representation of the additive manufacturing part is adopted for self-support and material anisotropy control. Especially for the latter point, the hybrid deposition path, a combination of contour-off set and zig–zag path patterns, is adopted for deposition path planning, which will be concurrently optimized for the best material anisotropy distribution. Therefore, what will be presented in this paper is a novel combination of structural topological design and process planning to derive the optimal hybrid remanufacturing strategy. This is a very novel trial and we have performed experiments to verify its effectiveness.
-
Stress-constrained topology optimization for material extrusion polymer additive manufacturing
Liu Jikai,Yan Jingjing,Yu Huangchao 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.3
This paper presents a comprehensive numerical and experimental study on stress-constrained topology optimization for Fused Deposition Modeling (FDM) additive manufacturing. The qp method is employed to avoid the singularity issue of stress-constrained problems. The P-norm function with stability transformation is adopted to build the global stress constraint with iterative corrections to eliminate the gap between the maximum local stress and the P-norm stress. The Heaviside projection is employed to generate clear-cut 0–1 designs. Two benchmark examples have been studied with the numerical algorithm. Experiments are performed on the topologically optimized MBB beam to investigate the impact of the FDM process parameters, including deposition path direction, building direction, and slicing layer height, on the resulted structural strength. The stress-constrained designs without and with Heaviside projection are comparatively tested with experiments. The stress-minimization designs subject to different P-norm parameters are compared both numerically and experimentally. Experiments show that the deposition path direction and the building direction evidently affect the derived structural strength. Moreover, overthin structural members may severely degrade the structural strength due to manufacturing and loading uncertainties.
-
-
A novel lattice structure topology optimization method with extreme anisotropic lattice properties
Zhang Chenghu,Liu Jikai,Yuan Zhiling,Xu Shuzhi,Zou Bin,Li Lei,Ma Yongsheng 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.5
This research presents a lattice structure topology optimization (LSTO) method that significantly expands the design space by creating a novel candidate lattice that assesses an extremely large range of effective material properties. About the details, topology optimization is employed to design lattices with extreme directional tensile or shear properties subject to different volume fraction limits and the optimized lattices are categorized into groups according to their dominating properties. The novel candidate lattice is developed by combining the optimized elementary lattices, by picking up one from each group, and then parametrized with the elementary lattice relative densities. In this way, the LSTO design space is greatly expanded for the ever increased accessible material property range. Moreover, the effective material constitutive model of the candidate lattice subject to different elementary lattice combinations is pre-established so as to eliminate the tedious in-process repetitive homogenization. Finally, a few numerical examples and experiments are explored to validate the effectiveness of the proposed method. The superiority of the proposed method is proved through comparing with a few existing LSTO methods. The options of concurrent structural topology and lattice optimization are also explored for further enhancement of the mechanical performance.
-
Lu, Jiadong,Liu, Jinglin,Hu, Yihua,Zhang, Xiaokang,Ni, Kai,Si, Jikai The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.5
High frequency signal injection (HFI) is an alternative method for estimating rotor position of interior permanent magnet synchronous motor (IPMSM). The general method of frequency and amplitude selection is based on error tolerance and experiments, and is usually set with only one group of HF parameters, which is not efficient for different working modes. This paper proposes a novel rotor position estimation scheme by HFI with optimized frequency and amplitude, based on the mathematic model of IPMSM. The requirements for standstill and low-speed operational modes are met by applying this novel scheme. Additionally, the effects of the frequency and amplitude of the injected HF signal on the position estimation results under different operating conditions are analyzed. Furthermore, an optimization method for HF parameter selection is proposed to make the estimation process more efficient under different working conditions according to error tolerance. The effectiveness of the propose scheme is verified by the experiments on an IPMSM motor prototype.
-
-
Wang Yifan,Wu Tao,Liu Jikai,Yu Huangchao 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.6
This paper presents a lightweight support design method for material extrusion-type three-dimensional printed panel structures that innovatively involves the deposition path curvature information for support point determination. Specifically, this support design method provides a robust segmentation algorithm to divide the filament deposition paths into segments based on the curvature sign alternating condition, and then searches for the fewest support points for the filaments counting on the experimentally calibrated relationship between the maximum allowable self-support distance and the local mean curvature. The proposed method features in generating thin-walled skeleton-ray styled support structures that are lightweight while providing firm support for the panels. More importantly, the support design method provides a new type of self-support criterion for structural topology optimization involving non-designable planar panels, i.e., only a sparse point set would be sufficient to support the panel. Consequently, more materials could be spent on enhancing the load-bearing capacity instead of being wasted on oversupporting. The achievable structural performances from self-support topology optimization with this new self-support criterion can improve significantly. Support design and printing tests were conducted on a few panel structures that validated the improved support effect compared with equal-volume supports generated by commercial software. Equidistant and gap-free deposited filaments, no filament collapse due to insufficient support, and no isolated voids reflect the improved support effect. The improved self-support topological design was also validated through a comparative numerical case study, and a compliance reduction of 7.76% was achieved.
-
Jiadong Lu,Jinglin Liu,Yihua Hu,Xiaokang Zhang,Kai Ni,Jikai Si 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.5
High frequency signal injection (HFI) is an alternative method for estimating rotor position of interior permanent magnet synchronous motor (IPMSM). The general method of frequency and amplitude selection is based on error tolerance and experiments, and is usually set with only one group of HF parameters, which is not efficient for different working modes. This paper proposes a novel rotor position estimation scheme by HFI with optimized frequency and amplitude, based on the mathematic model of IPMSM. The requirements for standstill and low-speed operational modes are met by applying this novel scheme. Additionally, the effects of the frequency and amplitude of the injected HF signal on the position estimation results under different operating conditions are analyzed. Furthermore, an optimization method for HF parameter selection is proposed to make the estimation process more efficient under different working conditions according to error tolerance. The effectiveness of the propose scheme is verified by the experiments on an IPMSM motor prototype.
-
Hu, Qun,Yang, Guangyu,Ma, Jing,Liu, Jikai Korean Chemical Society 2003 Bulletin of the Korean Chemical Society Vol.24 No.10
A new method for the simultaneous determination of heavy metal ions in cigarette material by microwave digestion and reversed-phase high-performance liquid chromatography (RP-HPLC) has been developed. The cigarette material was digested by microwave digestion. Lead, cadmium, mercury, nickel and tin ions in the digested samples were pre-column derivatized with tetra-(2-chlorophenyl)-porphyrin ($T_2$-CPP) to form color chelates, which were then enriched by solid phase extraction with a $C_{18}$ cartridge. The chelates were separated on a Waters Xterra$^{TM}RP_{18}$ column by gradient elution with methanol (containing 0.05 mol/L pyrrolidine-aceticacid buffer salt, pH = 10.0) and acetone (containin0.05 mol/L pyrrolidine-acetic acid buffer salt, pH = 10.0)as mobile phase at a flow rate of 0.5mL/min and analyzed with a photodiode array detector from 350-600 nm. The detection limits of lead, cadmium, mercury, nickel and tin were 4,3,3,8 and 5 ng/L, respectively, in the original samples. This method was afforded good results.
-
Yining Mu,Tuo Zhang,Tianqi Chen,Fanqi Tang,Jikai Yang,Chunyang Liu,Zhangxiaoxiong Chen,Yiming Zhao,Peng Du,Haibo Fan,Yan Zhu,Guozhen Liu,Ping Li 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2020 NANO Vol.15 No.03
In recent years, all inorganic bismuth lead-halide perovskite nanocrystals [CsPbX3 (X=Cl, Br, I)] have received extensive attention due to their high performance in fluorescence quantum yield, narrow emission spectrum, and adjustable emission range. However, the disadvantages of high cost and poor stability have greatly limited the development prospects of the material. Here, in order to develop a perovskite quantum dot lasing cavity with high chemical stability, high quality factor and low fabrication cost, we have successfully fabricated a 3D random cavity device based on porous silicon/TiO2 nanowires. A TiO2 nanowire is grown on the porous silicon to form a 3D resonant cavity, and a perovskite quantum dot is spin-coated on the surface of the 3D resonant cavity to form a novel 3D complex film. The novel structure enhances the chemical stability and lasing quality factor of the resonant cavity while the fluorescence generated by the large quantum dots in the spatial interference structure constitutes the feedback loop, which will provide favorable support for the development of information optics.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
