In the realm of engineering practice,various factors such as limited availability of measurement data and complex working conditions pose significant challenges to obtaining accurate load spectra.Thus,accurately predi...In the realm of engineering practice,various factors such as limited availability of measurement data and complex working conditions pose significant challenges to obtaining accurate load spectra.Thus,accurately predicting the fatigue life of structures becomes notably arduous.This paper proposed an approach to predict the fatigue life of structure based on the optimized load spectra,which is accurately estimated by an efficient hinging hyperplane neural network(EHH-NN)model.The construction of the EHH-NN model includes initial network generation and parameter optimization.Through the combination of working conditions design,multi-body dynamics analysis and structural static mechanics analysis,the simulated load spectra of the structure are obtained.The simulated load spectra are taken as the input variables for the optimized EHH-NN model,while the measurement load spectra are used as the output variables.The prediction results of case structure indicate that the optimized EHH-NN model can achieve the high-accuracy load spectra,in comparison with support vector machine(SVM),random forest(RF)model and back propagation(BP)neural network.The error rate between the prediction values and the measurement values of the optimized EHH-NN model is 4.61%.In the Cauchy-Lorentz distribution,the absolute error data of 92%with EHH-NN model appear in the intermediate range of±1.65%.Also,the fatigue life analysis is performed for the case structure,based on the accurately predicted load spectra.The fatigue life of the case structure is calculated based on the comparison between the measured and predicted load spectra,with an accuracy of 93.56%.This research proposes the optimized EHH-NN model can more accurately reflect the measurement load spectra,enabling precise calculation of fatigue life.Additionally,the optimized EHH-NN model provides reliability assessment for industrial engineering equipment.展开更多
With increasing water depth,marine drilling conductors exhibit higher slenderness ratios,significantly reducing their resistance to environmental loads in Arctic waters.These conductors,when subjected to combined wind...With increasing water depth,marine drilling conductors exhibit higher slenderness ratios,significantly reducing their resistance to environmental loads in Arctic waters.These conductors,when subjected to combined wind,current,and ice loads,may experience substantial horizontal displacements and bending moments,potentially compromising off-shore operational safety and wellhead stability.Additionally,soil disturbance near the mudline diminishes the conductor’s bearing capacity,potentially rendering it inadequate for wellhead support and increasing operational risks.This study introduces a static analysis model based on plastic hinge theory to evaluate conductor survivability.The conductor analysis divides the structure into three segments:above waterline,submerged,and embedded below mudline.An idealized elastic-plastic p-y curve model characterizes soil behavior beneath the mudline,while the finite difference method(FDM)analyzes the conductor’s mechanical response under complex pile-head boundary conditions.Numerical simulations using ABAQUS validate the plastic hinge approach against conventional methods,confirming its accuracy in predicting structural performance.These results provide valuable insights for optimizing installation depths and bearing capacity designs of marine drilling conductors in ice-prone regions.展开更多
The interaction between regular waves and an oscillating wave energy converter(WEC)in front of a vertical seawall is investigated using a 2D analytical model.A three-degree of freedom(DOF)WEC and a WEC hinged to the s...The interaction between regular waves and an oscillating wave energy converter(WEC)in front of a vertical seawall is investigated using a 2D analytical model.A three-degree of freedom(DOF)WEC and a WEC hinged to the seawall(constrained to pitch mode)are considered to examine the influence of the DOF of the WEC on the wave energy extraction performance.Results show that the piston-mode water resonance in the gap and the coupled WEC and water column resonant motion significantly influence the wave energy extraction efficiency.At low frequency,the case with a 3-DOF WEC has a broader high-efficiency bandwidth than that with a heaving WEC.However,3-DOF WEC exhibits worse performance at high frequencies.The frequency response of the wave energy capture width ratio(CWR)for the pitching WEC case shows a trimodal trend under the specified conditions.It showcases the best overall wave energy extraction performance in terms of the high-efficiency bandwidth.Furthermore,a parametric study indicates that the gap distance between the WEC and the seawall has tremendous effects on the CWR of both cases.As the position of the hinge point of the pitching WEC changes,the CWR at the low and high frequencies shows opposite trends.展开更多
We theoretically explore higher-order topological magnons in collinear altermagnets,encompassing a dimensional hierarchy ranging from localized corner modes to propagating hinge excitations.By employing antiferromagne...We theoretically explore higher-order topological magnons in collinear altermagnets,encompassing a dimensional hierarchy ranging from localized corner modes to propagating hinge excitations.By employing antiferromagnetic interlayer coupling in bosonic Bogoliubov–de Gennes Hamiltonian,our work reveals anisotropic surface states and spatially distributed hinge modes propagating along facet intersections.We track the adiabatic evolution of Wannier centers to identify the bulk polarization with second-order topological magnon insulator,where various magnon spectra demonstrate symmetry-protected band structure beyond conventional topology.Leveraging the stability and propagative properties of hinge modes,these unconventional magnons demonstrate manipulability in atomic-scale modifications of termination.Our study integrates altermagnetism with higher-order topology,which advances magnon-based quantum computing processing energy-efficient integrated architectures and information transfer.展开更多
Piezoelectric actuator has high stiffness, high frequency and infinite control precision, but a short output displacement which is often 1/1 000 of its length. In order to meet the requirements that tools feeding shou...Piezoelectric actuator has high stiffness, high frequency and infinite control precision, but a short output displacement which is often 1/1 000 of its length. In order to meet the requirements that tools feeding should be long-travel, high-frequency and high-precision in non-circular precision turning, a new one-freedom flexure hinge structure is put forward to amplify the output displacement of piezoelectric actuator. Theoretical analysis is done on the static and dynamic characteristics of the structure, differential equations are presented, and it is also verified by the finite element method. It's proved by experiments that the output displacement of the structure is 293 μm and its resonant frequency is 312 Hz.展开更多
快速扩展的互联网形成了具有高维、稀疏和冗余特性的复杂网络.因此需要有效的技术从这些复杂网络数据中提取出最为重要的信息进行链接预测,以便为用户服务.本文提出一种基于AUC(Area under Curve)优化的链接预测算法.在该算法中,将AUC...快速扩展的互联网形成了具有高维、稀疏和冗余特性的复杂网络.因此需要有效的技术从这些复杂网络数据中提取出最为重要的信息进行链接预测,以便为用户服务.本文提出一种基于AUC(Area under Curve)优化的链接预测算法.在该算法中,将AUC作为优化的目标函数,将链接预测问题转化为二分分类问题.将顶点之间是否存在链接作为它所在的类的标号.通过优化AUC来进行二分分类,使用铰链函数按随机次梯度下降算法迭代更新权重矩阵.最后在一些来自不同领域的真实网络上对本算法进行了测试.实验结果表明,本算法与其他算法的结果相比可以实现更高质量的预测.展开更多
Opening horizontal slit in the middle web of the beam end formed a new type of artificial plastic hinge. The calculation formulas about the hinge’s interior force and bearing capacity are set up. Based on these, the ...Opening horizontal slit in the middle web of the beam end formed a new type of artificial plastic hinge. The calculation formulas about the hinge’s interior force and bearing capacity are set up. Based on these, the condition of transfer, the location of crack and the cracking length of the artificial plastic hinge were studied further. The calculation method for the ductility factor was also presented. The calculation results and the test ones were compatible.展开更多
Boreal peatlands represent a large global carbon pool. The relationships between carbon mineralization, soil temperature and moisture in the permafrost peatlands of the Great Hing＇an Mountains, China, were examined. ...Boreal peatlands represent a large global carbon pool. The relationships between carbon mineralization, soil temperature and moisture in the permafrost peatlands of the Great Hing＇an Mountains, China, were examined. The CO2 emissions were measured during laboratory incubations of samples from four sites under different temperatures （5, 10, 15, and 20℃） and moisture contents （0%, 30%, 60%, 100% water holding capacity （WHC） and completely water saturated）. Total carbon mineralization ranged from 15.51 to 112.92 mg C under the treatments for all sites. Carbon mineralization rates decreased with soil depth, increased with temperature, and reached the highest at 60% WHC at the same temperature. The calculated temperature coefficient （Q10） values ranged from 1.84 to 2.51 with the soil depths and moisture. However, the values were not significantly affected by soil moisture and depth for all sites due to the different peat properties （P 〉 0.05）. We found that the carbon mineralization could be successfully predicted as a two-compartment function with temperature and moisture （R^2 〉 0.96） and total carbon mineralization was significantly affected by temperature and moisture （P 〈 0.05）. Thus, temperature and moisture would play important roles in carbon mineralization of permafrost peatlands in the Great Hing＇an Mountains, indicating that the permafrost peatlands would be sensitive to the environment change, and the permafrost peatlands would be potentially mineralized under future climate change.展开更多
The vacuum plume effects experimental system （PES） is the first experimental system designed to study the effects of vacuum plume in China. The main equipment, a vacuum chamber of 5.5 m in diameter and 12.8 m in len...The vacuum plume effects experimental system （PES） is the first experimental system designed to study the effects of vacuum plume in China. The main equipment, a vacuum chamber of 5.5 m in diameter and 12.8 m in length, and structure design of hinged door are described. The finite element method （FEM） is adopted to analyze the static strength and stability of the PES vacuum chamber. It is demonstrated that the static strength and stability are qualified. For the 5.5 m diameter vacuum chamber door, three design schemes are put forward. After comparisons are made, the single-axis-double-pin hinged door is selected. The FEM is applied to checking its static strength as well as distortions. The results show that the door’s distortion and displacement change mainly due to the gravity of the door which leads to its sinking. The calculated displacement is less than 7.8 mm, while the actual measurement is 5 mm. The single-axis-double-pin hinged door mechanism completely satisfies the design requirements. This innovative structure can be introduced as a reference for the design of large-scale hinged doors.展开更多
The morphing wing has a significant positive effect on the aerodynamic performance of the aircraft.This paper describes a leading-edge of variable camber wing with concentrated flexibility based on the geared five-bar...The morphing wing has a significant positive effect on the aerodynamic performance of the aircraft.This paper describes a leading-edge of variable camber wing with concentrated flexibility based on the geared five-bar mechanism.The driving points of morphing skin formed by the glass fibre composite sheet were optimized to make the skin deformation smooth.A geared fivebar kinematic mechanism rigidly connected to the skin was proposed to drive the leading-edge deformation.Besides,a new kind of concentrated flexure hinge was designed using the pseudorigid-body method and applied to the joint between the rigid mechanism and the skin.Finally,the leading-edge prototypes with traditional hinges and flexure hinges were produced,respectively.The feasibility of the concentrated flexibility leading-edge was verified through the comparative experiments of ground deformation.Simultaneously,aerodynamic analysis was carried out to compare the concentrated flexure leading-edge wing with the original airfoil.展开更多
A flexure hinge is a major component in designing compliant mechanisms that o ers unique possibilities in a wide range of application fields in which high positioning accuracy is required. Although various flexure hin...A flexure hinge is a major component in designing compliant mechanisms that o ers unique possibilities in a wide range of application fields in which high positioning accuracy is required. Although various flexure hinges with di erent configurations have been successively proposed, they are often designed based on designers' experiences and inspirations. This study presents a systematic method for topological optimization of flexure hinges by using the level set method. Optimization formulations are developed by considering the functional requirements and geometrical constraints of flexure hinges. The functional requirements are first constructed by maximizing the compliance in the desired direction while minimizing the compliances in the other directions. The weighting sum method is used to construct an objective function in which a self-adjust method is used to set the weighting factors. A constraint on the symmetry of the obtained configuration is developed. Several numerical examples are presented to demonstrate the validity of the proposed method. The obtained results reveal that the design of a flexure hinge starting from the topology level can yield more choices for compliant mechanism design and obtain better designs that achieve higher performance.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.51805447)Natural Science Foundation of Jiangsu Higher Education of China(Grant No.22KJB460010)+2 种基金Jiangsu Provincial Innovation and Promotion Project of Forestry Science and Technology of China(Grant No.LYKJ[2023]06)Yangzhou Science and Technology Plan(City School Cooperation Project)of China(Grant No.YZ2022193)Cyan Blue Project of Yangzhou University of China。
文摘In the realm of engineering practice,various factors such as limited availability of measurement data and complex working conditions pose significant challenges to obtaining accurate load spectra.Thus,accurately predicting the fatigue life of structures becomes notably arduous.This paper proposed an approach to predict the fatigue life of structure based on the optimized load spectra,which is accurately estimated by an efficient hinging hyperplane neural network(EHH-NN)model.The construction of the EHH-NN model includes initial network generation and parameter optimization.Through the combination of working conditions design,multi-body dynamics analysis and structural static mechanics analysis,the simulated load spectra of the structure are obtained.The simulated load spectra are taken as the input variables for the optimized EHH-NN model,while the measurement load spectra are used as the output variables.The prediction results of case structure indicate that the optimized EHH-NN model can achieve the high-accuracy load spectra,in comparison with support vector machine(SVM),random forest(RF)model and back propagation(BP)neural network.The error rate between the prediction values and the measurement values of the optimized EHH-NN model is 4.61%.In the Cauchy-Lorentz distribution,the absolute error data of 92%with EHH-NN model appear in the intermediate range of±1.65%.Also,the fatigue life analysis is performed for the case structure,based on the accurately predicted load spectra.The fatigue life of the case structure is calculated based on the comparison between the measured and predicted load spectra,with an accuracy of 93.56%.This research proposes the optimized EHH-NN model can more accurately reflect the measurement load spectra,enabling precise calculation of fatigue life.Additionally,the optimized EHH-NN model provides reliability assessment for industrial engineering equipment.
基金financially supported by the National Natural Science Foundation of China(Grant No.U22B20126)the National Key Research and Development Program of China(Grant No.2022YFC2806100).
文摘With increasing water depth,marine drilling conductors exhibit higher slenderness ratios,significantly reducing their resistance to environmental loads in Arctic waters.These conductors,when subjected to combined wind,current,and ice loads,may experience substantial horizontal displacements and bending moments,potentially compromising off-shore operational safety and wellhead stability.Additionally,soil disturbance near the mudline diminishes the conductor’s bearing capacity,potentially rendering it inadequate for wellhead support and increasing operational risks.This study introduces a static analysis model based on plastic hinge theory to evaluate conductor survivability.The conductor analysis divides the structure into three segments:above waterline,submerged,and embedded below mudline.An idealized elastic-plastic p-y curve model characterizes soil behavior beneath the mudline,while the finite difference method(FDM)analyzes the conductor’s mechanical response under complex pile-head boundary conditions.Numerical simulations using ABAQUS validate the plastic hinge approach against conventional methods,confirming its accuracy in predicting structural performance.These results provide valuable insights for optimizing installation depths and bearing capacity designs of marine drilling conductors in ice-prone regions.
基金supported by the Key R&D Program of Shandong Province,China(No.2021ZLGX04)the National Natural Science Foundation of China(No.52171284)。
文摘The interaction between regular waves and an oscillating wave energy converter(WEC)in front of a vertical seawall is investigated using a 2D analytical model.A three-degree of freedom(DOF)WEC and a WEC hinged to the seawall(constrained to pitch mode)are considered to examine the influence of the DOF of the WEC on the wave energy extraction performance.Results show that the piston-mode water resonance in the gap and the coupled WEC and water column resonant motion significantly influence the wave energy extraction efficiency.At low frequency,the case with a 3-DOF WEC has a broader high-efficiency bandwidth than that with a heaving WEC.However,3-DOF WEC exhibits worse performance at high frequencies.The frequency response of the wave energy capture width ratio(CWR)for the pitching WEC case shows a trimodal trend under the specified conditions.It showcases the best overall wave energy extraction performance in terms of the high-efficiency bandwidth.Furthermore,a parametric study indicates that the gap distance between the WEC and the seawall has tremendous effects on the CWR of both cases.As the position of the hinge point of the pitching WEC changes,the CWR at the low and high frequencies shows opposite trends.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1402802)the National Natural Science Foundation of China(Grant Nos.92165204 and 12494591)+2 种基金Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices(Grant No.2022B1212010008)Research Center for Magnetoelectric Physics of Guangdong Province(Grant No.2024B0303390001)Guangdong Provincial Quantum Science Strategic Initiative(Grant No.GDZX2401010)。
文摘We theoretically explore higher-order topological magnons in collinear altermagnets,encompassing a dimensional hierarchy ranging from localized corner modes to propagating hinge excitations.By employing antiferromagnetic interlayer coupling in bosonic Bogoliubov–de Gennes Hamiltonian,our work reveals anisotropic surface states and spatially distributed hinge modes propagating along facet intersections.We track the adiabatic evolution of Wannier centers to identify the bulk polarization with second-order topological magnon insulator,where various magnon spectra demonstrate symmetry-protected band structure beyond conventional topology.Leveraging the stability and propagative properties of hinge modes,these unconventional magnons demonstrate manipulability in atomic-scale modifications of termination.Our study integrates altermagnetism with higher-order topology,which advances magnon-based quantum computing processing energy-efficient integrated architectures and information transfer.
文摘Piezoelectric actuator has high stiffness, high frequency and infinite control precision, but a short output displacement which is often 1/1 000 of its length. In order to meet the requirements that tools feeding should be long-travel, high-frequency and high-precision in non-circular precision turning, a new one-freedom flexure hinge structure is put forward to amplify the output displacement of piezoelectric actuator. Theoretical analysis is done on the static and dynamic characteristics of the structure, differential equations are presented, and it is also verified by the finite element method. It's proved by experiments that the output displacement of the structure is 293 μm and its resonant frequency is 312 Hz.
文摘快速扩展的互联网形成了具有高维、稀疏和冗余特性的复杂网络.因此需要有效的技术从这些复杂网络数据中提取出最为重要的信息进行链接预测,以便为用户服务.本文提出一种基于AUC(Area under Curve)优化的链接预测算法.在该算法中,将AUC作为优化的目标函数,将链接预测问题转化为二分分类问题.将顶点之间是否存在链接作为它所在的类的标号.通过优化AUC来进行二分分类,使用铰链函数按随机次梯度下降算法迭代更新权重矩阵.最后在一些来自不同领域的真实网络上对本算法进行了测试.实验结果表明,本算法与其他算法的结果相比可以实现更高质量的预测.
文摘Opening horizontal slit in the middle web of the beam end formed a new type of artificial plastic hinge. The calculation formulas about the hinge’s interior force and bearing capacity are set up. Based on these, the condition of transfer, the location of crack and the cracking length of the artificial plastic hinge were studied further. The calculation method for the ductility factor was also presented. The calculation results and the test ones were compatible.
基金supported by the National Natural Science Foundation of China (No. 40671013,40871245)
文摘Boreal peatlands represent a large global carbon pool. The relationships between carbon mineralization, soil temperature and moisture in the permafrost peatlands of the Great Hing＇an Mountains, China, were examined. The CO2 emissions were measured during laboratory incubations of samples from four sites under different temperatures （5, 10, 15, and 20℃） and moisture contents （0%, 30%, 60%, 100% water holding capacity （WHC） and completely water saturated）. Total carbon mineralization ranged from 15.51 to 112.92 mg C under the treatments for all sites. Carbon mineralization rates decreased with soil depth, increased with temperature, and reached the highest at 60% WHC at the same temperature. The calculated temperature coefficient （Q10） values ranged from 1.84 to 2.51 with the soil depths and moisture. However, the values were not significantly affected by soil moisture and depth for all sites due to the different peat properties （P 〉 0.05）. We found that the carbon mineralization could be successfully predicted as a two-compartment function with temperature and moisture （R^2 〉 0.96） and total carbon mineralization was significantly affected by temperature and moisture （P 〈 0.05）. Thus, temperature and moisture would play important roles in carbon mineralization of permafrost peatlands in the Great Hing＇an Mountains, indicating that the permafrost peatlands would be sensitive to the environment change, and the permafrost peatlands would be potentially mineralized under future climate change.
文摘The vacuum plume effects experimental system （PES） is the first experimental system designed to study the effects of vacuum plume in China. The main equipment, a vacuum chamber of 5.5 m in diameter and 12.8 m in length, and structure design of hinged door are described. The finite element method （FEM） is adopted to analyze the static strength and stability of the PES vacuum chamber. It is demonstrated that the static strength and stability are qualified. For the 5.5 m diameter vacuum chamber door, three design schemes are put forward. After comparisons are made, the single-axis-double-pin hinged door is selected. The FEM is applied to checking its static strength as well as distortions. The results show that the door’s distortion and displacement change mainly due to the gravity of the door which leads to its sinking. The calculated displacement is less than 7.8 mm, while the actual measurement is 5 mm. The single-axis-double-pin hinged door mechanism completely satisfies the design requirements. This innovative structure can be introduced as a reference for the design of large-scale hinged doors.
基金supported by National Natural Science Foundation of China(No.50975230)Natural Science Basic Research Plan in Shaanxi Province of China(No.2017JM500)National Natural Science Foundation of China(No.51375383)。
文摘The morphing wing has a significant positive effect on the aerodynamic performance of the aircraft.This paper describes a leading-edge of variable camber wing with concentrated flexibility based on the geared five-bar mechanism.The driving points of morphing skin formed by the glass fibre composite sheet were optimized to make the skin deformation smooth.A geared fivebar kinematic mechanism rigidly connected to the skin was proposed to drive the leading-edge deformation.Besides,a new kind of concentrated flexure hinge was designed using the pseudorigid-body method and applied to the joint between the rigid mechanism and the skin.Finally,the leading-edge prototypes with traditional hinges and flexure hinges were produced,respectively.The feasibility of the concentrated flexibility leading-edge was verified through the comparative experiments of ground deformation.Simultaneously,aerodynamic analysis was carried out to compare the concentrated flexure leading-edge wing with the original airfoil.
基金Supported by National Natural Science Foundation of China(Grant Nos.51605166,51820105007)Fundamental Research Funds for the Central Universities of China
文摘A flexure hinge is a major component in designing compliant mechanisms that o ers unique possibilities in a wide range of application fields in which high positioning accuracy is required. Although various flexure hinges with di erent configurations have been successively proposed, they are often designed based on designers' experiences and inspirations. This study presents a systematic method for topological optimization of flexure hinges by using the level set method. Optimization formulations are developed by considering the functional requirements and geometrical constraints of flexure hinges. The functional requirements are first constructed by maximizing the compliance in the desired direction while minimizing the compliances in the other directions. The weighting sum method is used to construct an objective function in which a self-adjust method is used to set the weighting factors. A constraint on the symmetry of the obtained configuration is developed. Several numerical examples are presented to demonstrate the validity of the proposed method. The obtained results reveal that the design of a flexure hinge starting from the topology level can yield more choices for compliant mechanism design and obtain better designs that achieve higher performance.
