In contrast to well-studied rift basins in NE China,the Hailar Basin has received relatively less attention regarding the combined patterns of different types of grabens and half-grabens.This study aims to explore whe...In contrast to well-studied rift basins in NE China,the Hailar Basin has received relatively less attention regarding the combined patterns of different types of grabens and half-grabens.This study aims to explore whether the combined patterns of grabens in the Hailar Basin exhibit similar characteristics to those in other NE China rift basins and to identify the underlying causes.To achieve this,a comprehensive analysis of the major fault systems and the combined patterns of faulted sub-depressions,as well as their controlling mechanisms,was conducted.This analysis utilized the latest 3D seismic data that cover nearly the entire Beier Depression.Three groups of pre-existing fault systems were observed in the basement of the Beier Depression,and they are the NEE-EW-trending fault systems,the NE-trending fault systems,and the NW-trending fault systems.The NEE-EW-trending fault systems were distributed in the central part of the Beier Depression and primarily controlled the sedimentary filling of the Tongbomiao and the Lower Nantun Formations.The NE-trending fault systems were distributed in the southwestern part of the Beier Depression and primarily controlled the sedimentary filling of the Upper Nantun Formations.The NW-trending fault systems were distributed rarely in the Beier Depression.Five kinds of combined patterns of the sub-depressions were developed in the Beier Depression,and they are the parallel,en echelon,face-to-face,back-to-back,and S-shaped combined patterns.They were controlled by the NEE-EW-trending and the NE-trending fault systems with different orientations,arrangements,and activation sequences.展开更多
对于小电流接地系统的单相接地故障选线,传统方法普遍采用基于一维信号的选线模型,存在选线准确率低、抗噪性弱等问题。为此提出一种改进的变分模态分解及Conv Ne Xt的小电流接地系统单相接地故障选线方法。首先引入蚁狮算法优化变分模...对于小电流接地系统的单相接地故障选线,传统方法普遍采用基于一维信号的选线模型,存在选线准确率低、抗噪性弱等问题。为此提出一种改进的变分模态分解及Conv Ne Xt的小电流接地系统单相接地故障选线方法。首先引入蚁狮算法优化变分模态分解算法,通过蚁狮算法自动寻优选取合适的分解次数和惩罚因子,计算分解得到的各分量的分布熵,将其中的噪声分量筛选去除,将其余有效分量进行线性重构得到降噪后的零序电流信号;其次,将经过降噪处理后的一维零序电流信号经格拉姆角场转换为二维图像,制备故障选线数据集;然后,引入预训练的ConvNeXt模型,根据该研究数据模型特征,在其已有权重基础上对模型参数进行对应微调,从而提高模型精度并形成最终的选线模型;最后引入绝对平均误差、均方根误差作为评价指标验证所提降噪算法有效性。分别在加入噪声与否的前提下,将所提模型与3种选线模型相比较。实验结果表明该模型的准确率最高、抗噪性方面更好,其中该研究算法准确率达到了99.82%并且在不同噪声条件下都能维持91%以上的准确率,高于其他选线模型,克服了传统故障选线方法准确率低、抗噪性差的问题。展开更多
A mechanical-piezoelectric system is explored to reduce vibration and to harvest energy. The system consists of a piezoelectric device and a nonlinear energy sink （NES）, which is a nonlinear oscillator without linea...A mechanical-piezoelectric system is explored to reduce vibration and to harvest energy. The system consists of a piezoelectric device and a nonlinear energy sink （NES）, which is a nonlinear oscillator without linear stiffness. The NES-piezoelectric sys- tem is attached to a 2-degree-of-freedom primary system subjected to a shock load. This mechanical-piezoelectric system is investigated based on the concepts of the percentages of energy transition and energy transition measure. The strong target energy transfer occurs for some certain transient excitation amplitude and NES nonlinear stiffness. The plots of wavelet transforms are used to indicate that the nonlinear beats initiate energy transitions between the NES-piezoelectric system and the primary system in the tran- sient vibration, and a 1：1 transient resonance capture occurs between two subsystems. The investigation demonstrates that the integrated NES-piezoelectric mechanism can re- duce vibration and harvest some vibration energy.展开更多
针对随机激励下振动系统的减振问题,提出了考虑摩擦与非线性阻尼的混联Ⅱ型惯容非线性能量阱(nonlinear energy sink,简称NES),建立了含新型NES主系统的动力学控制方程。首先,采用蒙特卡洛数值方法,研究了非线性刚度对减振性能的影响,...针对随机激励下振动系统的减振问题,提出了考虑摩擦与非线性阻尼的混联Ⅱ型惯容非线性能量阱(nonlinear energy sink,简称NES),建立了含新型NES主系统的动力学控制方程。首先,采用蒙特卡洛数值方法,研究了非线性刚度对减振性能的影响,当非线性刚度比κ_(21)逐渐增大时,主结构和混联Ⅱ型惯容NES的位移概率密度函数出现了双峰变为单峰,以及速度概率密度函数由单峰变为双峰的随机跳跃现象。主结构的位移概率密度函数对非线性刚度κ_(22)的敏感性比κ_(21)更高,κ_(22)最佳取值区间为200~1 000。其次,研究了噪声强度、阻尼比和惯质比对减振性能的影响,当噪声强度小于0.1或惯质比μ在0.1左右时,惯容NES的减振效果较好。虽然线性阻尼比λ_(1)和非线性阻尼比λ_(21)、λ_(22)增大会导致主结构和混联Ⅱ型惯容NES的概率密度函数出现分岔不稳定现象,但增大非线性阻尼比有助于改善惯容NES的减振性能。最后,采用差分进化法对惯容NES的参数进行了优化。本研究可为受随机激励的振动系统减振研究提供技术参考。展开更多
Closed thoracic drainage can be performed using a steel-needle-guided chest tube to treat pleural effusion or pneumothorax in clinics.However,the puncture procedure during surgery is invisible,increasing the risk of s...Closed thoracic drainage can be performed using a steel-needle-guided chest tube to treat pleural effusion or pneumothorax in clinics.However,the puncture procedure during surgery is invisible,increasing the risk of surgical failure.Therefore,it is necessary to design a visualization system for closed thoracic drainage.Augmented reality(AR)technology can assist in visualizing the internal anatomical structure and determining the insertion point on the body surface.The structure of the currently used steel-needle-guided chest tube was modified by integrating it with an ultrafine diameter camera to provide real-time visualization of the puncture process.After simulation experiments,the overall registration error of the AR method was measured to be within(3.59±0.53)mm,indicating its potential for clinical application.The ultrafine diameter camera module and improved steel-needle-guided chest tube can timely reflect the position of the needle tip in the human body.A comparative experiment showed that video guidance could improve the safety of the puncture process compared to the traditional method.Finally,a qualitative evaluation of the usability of the system was conducted through a questionnaire.This system facilitates the visualization of closed thoracic drainage puncture procedure and pro-vides an implementation scheme to enhance the accuracy and safety of the operative step,which is conducive to reducing the learning curve and improving the proficiency of the doctors.展开更多
Designing,modeling,and analyzing novel nonlinear elastic elements for the nonlinear energy sink(NES)have long been an attractive research topic.Since gravity is difficult to overcome,previous NES research mainly focus...Designing,modeling,and analyzing novel nonlinear elastic elements for the nonlinear energy sink(NES)have long been an attractive research topic.Since gravity is difficult to overcome,previous NES research mainly focused on horizontal vibration suppression.This study proposes an origami-inspired NES.A stacked Miura-origami(SMO)structure,consisting of two Miura-ori sheets,is adopted to construct a nonlinear elastic element.By adjusting the initial angle and the connecting crease torsional stiffness,the quasi-zero stiffness(QZS)and load-bearing capacity can be customized to match the corresponding mass,establishing the vertical SMO-NES.The dynamic model of the SMO-NES coupled with a linear oscillator(LO)is derived for vibrations in the vertical direction.The approximate analytical solutions of the dynamic equation are obtained by the harmonic balance method(HBM),and the solutions are verified numerically.The parameter design principle of the SMO-NES is provided.Finally,the vibration reduction performance of the SMO-NES is studied.The results show that the proposed SMONES can overcome gravity and achieve quasi-zero nonlinear restoring force.Therefore,the SMO-NES has the ability of wide-frequency vibration reduction,and can effectively suppress vertical vibrations.By adjusting the initial angle and connecting the crease torsional stiffness of the SMO,the SMO-NES can be achieved with different loading weights,effectively suppressing the vibrations with different primary system masses and excitation amplitudes.In conclusion,with the help of popular origami structures,this study proposes a novel NES,and starts the research of combining origami and NES.展开更多
地下粮仓具有充分利用地下空间和抵抗外部干扰能力强等优点。为研究地下粮仓结构与土场相互作用的动力学特征,以装配式地下粮仓结构中钢桩为研究对象,利用非线性能量阱(nonlinear energy sink,NES)理论,将地下粮仓周围简化为非线性Wink...地下粮仓具有充分利用地下空间和抵抗外部干扰能力强等优点。为研究地下粮仓结构与土场相互作用的动力学特征,以装配式地下粮仓结构中钢桩为研究对象,利用非线性能量阱(nonlinear energy sink,NES)理论,将地下粮仓周围简化为非线性Winkler地基,钢桩简化为简支的Euler-Bernoulli梁。利用Hamilton原理,建立梁-土系统的运动方程;引入地基反力系数,描述土体的非线性刚度;利用增量谐波平衡法,求得运动方程的半解析解,并与数值解对比验证。与不考虑NES效应的结果对比,分析阻尼、质量比和地基反力系数等参数对结构在简谐激励下动力响应的影响,分析不同参数条件下土场对结构振动响应的抑制效果。研究表明:选取合理的阻尼、质量比和地基反力系数等参数时,弹性土体能在宽频带范围内减小结构稳态振动能量,显著降低结构共振能量峰和响应幅值;在经分析所得到的最优参数条件下,振动能量衰减率达99.39%。研究成果进一步阐释了土-结构相互作用效应的减振吸能作用,并为基于NES理论的地下粮仓减振设计提供了理论依据。展开更多
为拓宽非线性能量阱(nonlinear energy sink,NES)的频率变化范围,基于负刚度原理,通过预压弹簧构造负刚度系统,设计水平向的负刚度NES减震器。利用ABAQUS有限元软件对负刚度NES减震器进行数值模拟,在导杆无摩擦且弹簧不发生侧向屈曲的...为拓宽非线性能量阱(nonlinear energy sink,NES)的频率变化范围,基于负刚度原理,通过预压弹簧构造负刚度系统,设计水平向的负刚度NES减震器。利用ABAQUS有限元软件对负刚度NES减震器进行数值模拟,在导杆无摩擦且弹簧不发生侧向屈曲的状态下,分析弹簧行程长宽比、预压缩量、刚度和阻尼比对负刚度NES减震器抗震性能的影响。研究结果表明:在固定弹簧行程长宽比的条件下,增加弹簧的预压缩量,可提高减震器的抗震性能;在固定弹簧预压缩量的条件下,随着弹簧行程长宽比的增大,减震器的承载力逐渐减小,抗震性能下降;弹簧刚度和阻尼比的增加可显著增大减震器的承载力,提高抗震性能。研究结果为负刚度NES减震器的工程应用提供参考。展开更多
Aiming to decrease the vibration of wing induced by dual-rotor civil turbofan engines,the dynamic models of a single-degree of freedom (DOF) linear main oscillator coupled with single-DOF and two-DOF nonlinear energy ...Aiming to decrease the vibration of wing induced by dual-rotor civil turbofan engines,the dynamic models of a single-degree of freedom (DOF) linear main oscillator coupled with single-DOF and two-DOF nonlinear energy sink (NES) are established.According to the related energy criteria for the optimization of the dynamic vibration absorber,focusing on the effects of external excitation on the kinetic energy of the primary mass and total system energy,the vibration suppression effects of single-DOF,two-DOF serial and parallel NES on the main oscillator system are studied.Under the condition that the characteristic parameters of the main oscillator system and additional total mass of the vibration absorber remain unchanged,results show that the two-DOF parallel NES has the best vibration energy suppression effects,which can provide data reference for the optimal design of NES vibration suppression under dual-frequency excitation.展开更多
基金supported by the Major National Science and Technology Programs of China(No.2016E-0202,No.QGYQZYPJ2022-1).
文摘In contrast to well-studied rift basins in NE China,the Hailar Basin has received relatively less attention regarding the combined patterns of different types of grabens and half-grabens.This study aims to explore whether the combined patterns of grabens in the Hailar Basin exhibit similar characteristics to those in other NE China rift basins and to identify the underlying causes.To achieve this,a comprehensive analysis of the major fault systems and the combined patterns of faulted sub-depressions,as well as their controlling mechanisms,was conducted.This analysis utilized the latest 3D seismic data that cover nearly the entire Beier Depression.Three groups of pre-existing fault systems were observed in the basement of the Beier Depression,and they are the NEE-EW-trending fault systems,the NE-trending fault systems,and the NW-trending fault systems.The NEE-EW-trending fault systems were distributed in the central part of the Beier Depression and primarily controlled the sedimentary filling of the Tongbomiao and the Lower Nantun Formations.The NE-trending fault systems were distributed in the southwestern part of the Beier Depression and primarily controlled the sedimentary filling of the Upper Nantun Formations.The NW-trending fault systems were distributed rarely in the Beier Depression.Five kinds of combined patterns of the sub-depressions were developed in the Beier Depression,and they are the parallel,en echelon,face-to-face,back-to-back,and S-shaped combined patterns.They were controlled by the NEE-EW-trending and the NE-trending fault systems with different orientations,arrangements,and activation sequences.
文摘对于小电流接地系统的单相接地故障选线,传统方法普遍采用基于一维信号的选线模型,存在选线准确率低、抗噪性弱等问题。为此提出一种改进的变分模态分解及Conv Ne Xt的小电流接地系统单相接地故障选线方法。首先引入蚁狮算法优化变分模态分解算法,通过蚁狮算法自动寻优选取合适的分解次数和惩罚因子,计算分解得到的各分量的分布熵,将其中的噪声分量筛选去除,将其余有效分量进行线性重构得到降噪后的零序电流信号;其次,将经过降噪处理后的一维零序电流信号经格拉姆角场转换为二维图像,制备故障选线数据集;然后,引入预训练的ConvNeXt模型,根据该研究数据模型特征,在其已有权重基础上对模型参数进行对应微调,从而提高模型精度并形成最终的选线模型;最后引入绝对平均误差、均方根误差作为评价指标验证所提降噪算法有效性。分别在加入噪声与否的前提下,将所提模型与3种选线模型相比较。实验结果表明该模型的准确率最高、抗噪性方面更好,其中该研究算法准确率达到了99.82%并且在不同噪声条件下都能维持91%以上的准确率,高于其他选线模型,克服了传统故障选线方法准确率低、抗噪性差的问题。
基金supported by the National Natural Science Foundation of China(Nos.11572182,11232009,and 11402151) the Natural Science Foundation of Liaoning Province(No.2015020106)
文摘A mechanical-piezoelectric system is explored to reduce vibration and to harvest energy. The system consists of a piezoelectric device and a nonlinear energy sink （NES）, which is a nonlinear oscillator without linear stiffness. The NES-piezoelectric sys- tem is attached to a 2-degree-of-freedom primary system subjected to a shock load. This mechanical-piezoelectric system is investigated based on the concepts of the percentages of energy transition and energy transition measure. The strong target energy transfer occurs for some certain transient excitation amplitude and NES nonlinear stiffness. The plots of wavelet transforms are used to indicate that the nonlinear beats initiate energy transitions between the NES-piezoelectric system and the primary system in the tran- sient vibration, and a 1：1 transient resonance capture occurs between two subsystems. The investigation demonstrates that the integrated NES-piezoelectric mechanism can re- duce vibration and harvest some vibration energy.
文摘针对随机激励下振动系统的减振问题,提出了考虑摩擦与非线性阻尼的混联Ⅱ型惯容非线性能量阱(nonlinear energy sink,简称NES),建立了含新型NES主系统的动力学控制方程。首先,采用蒙特卡洛数值方法,研究了非线性刚度对减振性能的影响,当非线性刚度比κ_(21)逐渐增大时,主结构和混联Ⅱ型惯容NES的位移概率密度函数出现了双峰变为单峰,以及速度概率密度函数由单峰变为双峰的随机跳跃现象。主结构的位移概率密度函数对非线性刚度κ_(22)的敏感性比κ_(21)更高,κ_(22)最佳取值区间为200~1 000。其次,研究了噪声强度、阻尼比和惯质比对减振性能的影响,当噪声强度小于0.1或惯质比μ在0.1左右时,惯容NES的减振效果较好。虽然线性阻尼比λ_(1)和非线性阻尼比λ_(21)、λ_(22)增大会导致主结构和混联Ⅱ型惯容NES的概率密度函数出现分岔不稳定现象,但增大非线性阻尼比有助于改善惯容NES的减振性能。最后,采用差分进化法对惯容NES的参数进行了优化。本研究可为受随机激励的振动系统减振研究提供技术参考。
基金the Shanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant(No.20172005)。
文摘Closed thoracic drainage can be performed using a steel-needle-guided chest tube to treat pleural effusion or pneumothorax in clinics.However,the puncture procedure during surgery is invisible,increasing the risk of surgical failure.Therefore,it is necessary to design a visualization system for closed thoracic drainage.Augmented reality(AR)technology can assist in visualizing the internal anatomical structure and determining the insertion point on the body surface.The structure of the currently used steel-needle-guided chest tube was modified by integrating it with an ultrafine diameter camera to provide real-time visualization of the puncture process.After simulation experiments,the overall registration error of the AR method was measured to be within(3.59±0.53)mm,indicating its potential for clinical application.The ultrafine diameter camera module and improved steel-needle-guided chest tube can timely reflect the position of the needle tip in the human body.A comparative experiment showed that video guidance could improve the safety of the puncture process compared to the traditional method.Finally,a qualitative evaluation of the usability of the system was conducted through a questionnaire.This system facilitates the visualization of closed thoracic drainage puncture procedure and pro-vides an implementation scheme to enhance the accuracy and safety of the operative step,which is conducive to reducing the learning curve and improving the proficiency of the doctors.
基金Project supported by the National Science Fund for Distinguished Young Scholars(No.12025204)the China Scholarship Council(No.202206890066)。
文摘Designing,modeling,and analyzing novel nonlinear elastic elements for the nonlinear energy sink(NES)have long been an attractive research topic.Since gravity is difficult to overcome,previous NES research mainly focused on horizontal vibration suppression.This study proposes an origami-inspired NES.A stacked Miura-origami(SMO)structure,consisting of two Miura-ori sheets,is adopted to construct a nonlinear elastic element.By adjusting the initial angle and the connecting crease torsional stiffness,the quasi-zero stiffness(QZS)and load-bearing capacity can be customized to match the corresponding mass,establishing the vertical SMO-NES.The dynamic model of the SMO-NES coupled with a linear oscillator(LO)is derived for vibrations in the vertical direction.The approximate analytical solutions of the dynamic equation are obtained by the harmonic balance method(HBM),and the solutions are verified numerically.The parameter design principle of the SMO-NES is provided.Finally,the vibration reduction performance of the SMO-NES is studied.The results show that the proposed SMONES can overcome gravity and achieve quasi-zero nonlinear restoring force.Therefore,the SMO-NES has the ability of wide-frequency vibration reduction,and can effectively suppress vertical vibrations.By adjusting the initial angle and connecting the crease torsional stiffness of the SMO,the SMO-NES can be achieved with different loading weights,effectively suppressing the vibrations with different primary system masses and excitation amplitudes.In conclusion,with the help of popular origami structures,this study proposes a novel NES,and starts the research of combining origami and NES.
文摘地下粮仓具有充分利用地下空间和抵抗外部干扰能力强等优点。为研究地下粮仓结构与土场相互作用的动力学特征,以装配式地下粮仓结构中钢桩为研究对象,利用非线性能量阱(nonlinear energy sink,NES)理论,将地下粮仓周围简化为非线性Winkler地基,钢桩简化为简支的Euler-Bernoulli梁。利用Hamilton原理,建立梁-土系统的运动方程;引入地基反力系数,描述土体的非线性刚度;利用增量谐波平衡法,求得运动方程的半解析解,并与数值解对比验证。与不考虑NES效应的结果对比,分析阻尼、质量比和地基反力系数等参数对结构在简谐激励下动力响应的影响,分析不同参数条件下土场对结构振动响应的抑制效果。研究表明:选取合理的阻尼、质量比和地基反力系数等参数时,弹性土体能在宽频带范围内减小结构稳态振动能量,显著降低结构共振能量峰和响应幅值;在经分析所得到的最优参数条件下,振动能量衰减率达99.39%。研究成果进一步阐释了土-结构相互作用效应的减振吸能作用,并为基于NES理论的地下粮仓减振设计提供了理论依据。
文摘为拓宽非线性能量阱(nonlinear energy sink,NES)的频率变化范围,基于负刚度原理,通过预压弹簧构造负刚度系统,设计水平向的负刚度NES减震器。利用ABAQUS有限元软件对负刚度NES减震器进行数值模拟,在导杆无摩擦且弹簧不发生侧向屈曲的状态下,分析弹簧行程长宽比、预压缩量、刚度和阻尼比对负刚度NES减震器抗震性能的影响。研究结果表明:在固定弹簧行程长宽比的条件下,增加弹簧的预压缩量,可提高减震器的抗震性能;在固定弹簧预压缩量的条件下,随着弹簧行程长宽比的增大,减震器的承载力逐渐减小,抗震性能下降;弹簧刚度和阻尼比的增加可显著增大减震器的承载力,提高抗震性能。研究结果为负刚度NES减震器的工程应用提供参考。
基金supported by the National Basic Research Program of China(No.2014CB046805)the National Natural Science Foundation of China (Nos. 11372211,11672349)
文摘Aiming to decrease the vibration of wing induced by dual-rotor civil turbofan engines,the dynamic models of a single-degree of freedom (DOF) linear main oscillator coupled with single-DOF and two-DOF nonlinear energy sink (NES) are established.According to the related energy criteria for the optimization of the dynamic vibration absorber,focusing on the effects of external excitation on the kinetic energy of the primary mass and total system energy,the vibration suppression effects of single-DOF,two-DOF serial and parallel NES on the main oscillator system are studied.Under the condition that the characteristic parameters of the main oscillator system and additional total mass of the vibration absorber remain unchanged,results show that the two-DOF parallel NES has the best vibration energy suppression effects,which can provide data reference for the optimal design of NES vibration suppression under dual-frequency excitation.
