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Tailored energy absorption for a novel auxetic honeycomb structure under large deformation

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Science china(Physics,mechanics & Astronomy) 2024年第5期67卷 63-80页

作者： xiuhui Hou Bin Wang zichen {2. school of mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710129China MIIT Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical UniversityXi'an 710072China school of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China

In comparison to conventional hexagonal honeycomb structures,auxetic metamaterials with re-entrant configurations have exhibited superior mechanical properties in terms of energy *** further enhance the energy absorption capacity of these materials,a novel re-entrant honeycomb configuration,named novel auxetic re-entrant honeycomb(NARH),is developed by incorporating“”-shaped cell walls into the conventional auxetic re-entrant honeycomb(ARH).Two analytical models for the plateau stress are formulated to consider the plastic deformation of NARH during quasi-static compression and the dynamic impact using the linear momentum ***-static compression tests on 3D printed NARH honeycomb specimens and finite element simulations are performed to verify the effectiveness of the theoretical *** exhibits higher plateau stresses compared with ARH during compression,which can be attributed to the presence of more plastic hinges formed in *** hinges,the embedded parts with inclined cell walls,not only improve stability by forming stable triangles during compression but also enhance the energy absorption capacity.A parametric study is conducted to analyze the effect of impact velocity,thickness,and incline angle of cell walls on *** simulations demonstrate higher sensitivity of the mechanical properties to impact velocity and cell wall *** ribs to the“”-shaped cell walls in NARH further reduces the initial peak force during dynamic crushing while maintaining high energy *** research provides valuable guidelines for the design of energy absorption metamaterials.

关键词： absorption walls shaped

Multi-symplectic method to analyze the mixed state of Ⅱ-superconductors

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Science china(Physics,mechanics & Astronomy) 2008年第12期51卷 1835-1844页

作者： hu weipeng1↑ & deng zichen1,2.1 school of mechanics, {2. Engineering and architecture, northwestern polytechnical university, xi’an 710072. china 2.State Key Laboratory of Structural Analysis of Industrial Equipment, Dalian university of Technology, Dalian 11602., china school of mechanics Civil Engineering and Architecture Northwestern Polytechnical University Xi’an China State Key Laboratory of Structural Analysis of Industrial Equipment Dalian University of Technology Dalian China

The mixed state of two-band II-superconductor is analyzed by the multi-symplectic method. As to the Ginzburg-Landau equation depending on time that describes the mixed state of two-band II-superconductor, the multi-symplectic formulations with several conservation laws: a multi-symplectic conservation law, an energy con- servation law, as well as a momentum conservation law, are presented firstly; then an eighteen points scheme is constructed to simulate the multi-symplectic partial differential equations (PDEs) that are derived from the Ginzburg-Landau equation; finally, based on the simulation results, the volt-ampere characteristic curves are obtained, as well as the relationships between the temperature and resistivity of a suppositional two-band II-superconductor model under different magnetic intensi- ties. From the results of the numerical experiments, it is concluded that the notable property of the mixed state of the two-band II-superconductor is that: The trans- formation temperature decreases and the resistivity ρ increases rapidly with the increase of the magnetic intensity B. In addition, the simulation results show that the multi-symplectic method has two remarkable advantages: high accuracy and excellent long-time numerical behavior.

关键词： two-band Ginzburg-Landau equation mixed state multi-symplectic conservation law

On Klein tunneling of low-frequency elastic waves in hexagonal topological plates

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Applied Mathematics and mechanics(English Edition) 2024年第7期45卷 1139-1154页

作者： Yuxin YAO Yuansheng MA Fang HONG Kai ZHANG Tingting WANG Haijun PENG zichen deng school of mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China MIIT Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical UniversityXi’an710072China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian116024Liaoning ProvinceChina

Incident particles in the Klein tunnel phenomenon in quantum mechanics can pass a very high potential *** the concept of tunneling into the analysis of phononic crystals can broaden the application *** this study,the structure of the unit cell is designed,and the low frequency(1 k Hz)valley locked waveguide is realized through the creation of a phononic crystal plate with a topological phase transition *** defect immunity of the topological waveguide is verified,that is,the wave can propagate along the original path in the cases of impurities and ***,the tunneling phenomenon is introduced into the topological valley-locked waveguide to analyze the wave propagation,and its potential applications(such as signal separators and logic gates)are further explored by designing phononic crystal *** research has broad application prospects in information processing and vibration control,and potential applications in other directions are also worth exploring.

关键词： topological metamaterial elastic wave Klein tunneling valley-locked waveguide

Interaction effects of DNA, RNA-polymerase, and cellular fluid on the local dynamic behaviors of DNA

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Applied Mathematics and mechanics(English Edition) 2020年第4期41卷 623-636页

作者： weipeng hu {2. deng school of civil Engineering and {2. Xi’an University of TechnologyXi’an 710048China State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of china Xi’an University of TechnologyXi’an 710048China school of mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China

In view of the complex structure and environment,the dynamic analysis on deoxyribonucleic acid(DNA)is a challenge in the biophysics *** the local interaction with ribonucleic acid(RNA)-polymerase as well as the dissipative effect of cellular fluid,a coupling sine-Gordon-type dynamic model is used to describe the rotational motions of the bases in ***,the approximate symmetric form is ***,the wave form and the wave velocity of the kink solution to the proposed dynamic model are investigated by a Runge-Kutta structure-preserving scheme based on the generalized multi-symplectic *** numerical results indicate that,the strengthening of the local interaction between DNA and RNA-polymerase described by the coupling potential makes the form of the kink solution steep,while the appearance of the friction between DNA and cellular fluid makes the form of the kink solution *** addition,the appearance of the friction decreases the velocities of both the symplectic configuration and the anti-symplectic configuration with different *** above findings are beneficial to comprehend the DNA transcription mechanism.

关键词： deoxyribonucleic acid (DNA) dynamics local interaction generalized multisymplectic idea kink solution Runge-Kutta scheme

Minimum Control Energy of Spatial Beam with Assumed Attitude Adjustment Target

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Acta Mechanica Solida Sinica 2020年第1期33卷 51-60页

作者： weipeng hu Lingjun Yu {2. deng school of civil Engineering and {2. Xi’an University of TechnologyXi’an 710048China State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of china Xi’an University of TechnologyXi’an 710048China Department of Aeronautical Machinery Engineering of Army Aviation Institute Beijing 101123China school of mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China

The dynamic analysis on the ultra-large spatial structure can be simplified drastically by ignoring the flexibility and damping of the ***,these simplifications will result in the erroneous estimate on the dynamic behaviors of the ultra-large spatial *** the spatial beam as an example,the minimum control energy defined by the difference between the initial total energy and the final total energy in the assumed stable attitude state of the beam is investigated by the structure-preserving method proposed in our previous studies in two cases:the spatial beam considering the flexibility as well as the damping effect,and the spatial beam ignoring both the flexibility and the damping *** the numerical experiments,the assumed simulation interval of three months is evaluated on whether or not it is long enough for the spatial flexible damping beam to arrive at the assumed stable attitude *** then,taking the initial attitude angle and the initial attitude angle velocity as the independent variables,respectively,the minimum control energies of the mentioned two cases are investigated in *** the numerical results,the following conclusions can be *** the fixed initial attitude angle velocity,the minimum control energy of the spatial flexible damping beam is higher than that of the spatial rigid beam when the initial attitude angle is close to or far away from the stable attitude *** the fixed initial attitude angle,ignoring the flexibility and the damping effect will underestimate the minimum control energy of the spatial beam.

关键词： Spatial beam Structure-preserving method Generalized multi-symplectic Minimum control energy Hamiltonian

A review of dynamic analysis on space solar power station

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Astrodynamics 2023年第2期7卷 115-130页

作者： weipeng hu {2. deng school of civil Engineering and {2. Xi'an University of TechnologyXi'an 710048China State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of china Xi'an University of TechnologyXi'an 710048China school of mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China

The concept of a space solar power station(SSPS)was proposed in 1968 as a potential approach for solving the energy *** the past 50 years,several structural concepts have been proposed,but none have been sent into *** of the main challenges of the SSPS is dynamic behavior prediction,which can supply the necessary information for control strategy *** ultra-large size of the SSPS causes difficulties in its dynamic analysis,such as the ultra-low vibration frequency and large *** this paper,four approaches for the numerical analysis of the dynamic problems associated with the SSPS are reviewed:the finite element,absolute nodal coordinate,foating frame formulation,and structure-preserving *** the merits and shortcomings of the above four approaches are introduced when they are employed in dynamic problems associated with the *** the merits of the aforementioned four approaches,we believe that embedding the structure-preserving method into finite element software may be an effective way to perform a numerical analysis of the dynamic problems associated with the SSPS.

关键词： space solar power station(SSPS) finite element method absolute nodal coordinate method floating frame formulation method structure-preserving method

Structure-preserving properties of Strmer-Verlet scheme for mathematical pendulum

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Applied Mathematics and mechanics(English Edition) 2017年第9期38卷 1225-1232页

作者： weipeng hu Mingzhe SONG {2. deng school of mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Structural Analysis of Industrial Equipment Dalian University of TechnologyDalian 116023Liaoning ProvinceChina

The structure-preserving property, in both the time domain and the frequency domain, is an important index for evaluating validity of a numerical method. Even in the known structure-preserving methods such as the symplectic method, the inherent conser- vation law in the frequency domain is hardly conserved. By considering a mathematical pendulum model, a Stormer-Verlet scheme is first constructed in a Hamiltonian frame- work. The conservation law of the StSrmer-Verlet scheme is derived, including the total energy expressed in the time domain and periodicity in the frequency domain. To track the structure-preserving properties of the Stormer-Verlet scheme associated with the con- servation law, the motion of the mathematical pendulum is simulated with different time step lengths. The numerical results illustrate that the StSrmer-Verlet scheme can preserve the total energy of the model but cannot preserve periodicity at all. A phase correction is performed for the StSrmer-Verlet scheme. The results imply that the phase correction can improve the conservative property of periodicity of the Stormer-Verlet scheme.

关键词： Strmer-Verlet scheme symplectic mathematical pendulum structure-preserving Hamiltonian system phase correction

Coupling Vibration of Simply-Supported Damping Beam Carrying a Moving Mass

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Acta Mechanica Solida Sinica 2022年第6期35卷 972-978页

作者： Jingjing hu weipeng hu Chuan xiao zichen deng school of mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China school of civil Engineering and {2. Xi’an University of TechnologyXi’an710048China State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of china Xi’an University of TechnologyXi’an710048China china Research and Development Academy of Machinery Equipment Beijing100089China

The coupling dynamic problems,such as the vehicle-bridge interaction problem,are difficult to be *** this paper,the generalized multi-symplectic approach is employed to investigate the coupling dynamic behaviors in the vehicle-bridge interaction system.A simply-supported damping beam model carrying a moving mass is considered and the generalized multi-symplectic form with the dynamical symmetry breaking factors is deduced *** then,Preissmann’s scheme is employed to discretize the generalized multi-symplectic form,and the discrete structure-preserving condition for the numerical scheme is *** to the discrete structure-preserving condition,the permitted moving speed of the mass with different damping factors and different time step lengths is obtained to ensure the structure-preserving properties of the numerical ***,the effects of the damping factor of the beam and the moving speed of the mass on the vibration of the beam are investigated by Preissmann’s *** main contribution of this work is to provide a structure-preserving analysis approach for the vehicle-bridge interaction problem.

关键词： Vehicle-bridge interaction Dynamical symmetry breaking Generalized multi-symplectic Hamiltonian Moving mass

Symplectic Analysis on Coupling Behaviors of Spatial Fiexible Damping Beam

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Acta Mechanica Solida Sinica 2022年第4期35卷 541-551页

作者： weipeng hu xiaojian xi Zhe Zhai Pengfei Cui Fan Zhang {2. deng school of civil Engineering and {2. Xi’an University of TechnologyXi’an710048China State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of china Xi’an University of TechnologyXi’an710048China china Academy of Ordnance Science Beijing100089China school of mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China

Although the complex structure-preserving method presented in our previous studies can be used to investigate the orbit–attitude–vibration coupled dynamic behaviors of the spatial flexible damping beam,the simulation speed still needs to be *** this paper,the infinite-dimensional dynamic model describing the orbit–attitude–vibration coupled dynamic problem of the spatial flexible damping beam is pretreated by the method of separation of variables,and the second-level fourth-order symplectic Runge–Kutta scheme is constructed to investigate the coupling dynamic behaviors of the spatial flexible damping beam *** with the simulation speed of the complex structure-preserving method,the simulation speed of the symplectic Runge–Kutta method is faster,which benefits from the pretreatment *** effect of the initial radial velocity on the transverse vibration as well as on the attitude evolution of the spatial flexible damping beam is presented in the numerical *** the numerical results about the effect of the initial radial velocity,it can be found that the appearance of the initial radial velocity can decrease the vibration frequency of the spatial beam and shorten the evolution interval for the attitude angle to tend towards a stable value *** addition,the validity of the numerical results reported in this paper is verified by comparing with some numerical results presented in our previous studies.

关键词： Symplectic Runge-Kutta method Spatial fexible damping beam Orbit-attitudevibration coupled dynamic behavior Structure-preserving