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Mechanics of twisted and coiled tube-based artificial muscles driven by hydraulic pressure

Science China(Technological Sciences) 2025年第4期68卷 72-81页

作者： Hao LIU Zhiya ZHANG Lei LIU Dabiao LIU Department of Engineering Mechanics School of Aerospace EngineeringHuazhong University of Science and TechnologyWuhan430074China Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment Wuhan430074China

The twisted and coiled polymer(TCP)artificial muscles driven by hydraulic pressure offer high mechanical efficiency and power *** relation between geometry,mechanics,and actuation performance for this kind of muscle is *** this study,we study the mechanics and actuation characteristics of TCP tube-based muscles driven by hydraulic pressure through experiment,theory,and finite element *** for the helical geometry and transverse isotropy of the TCP muscles,we develop a phenomenological model to predict the actuation performance of TCP tube-based *** torsional and tensile actuation characteristics of the twisted and TCP tube-based muscle driven by hydraulic pressure are *** is found that the cold drawing enhances the anisotropy of the polyvinyl chloride tube,resulting in an improved actuation performance of the twisted and TCP *** torsional actuation in the twisted tube reaches the maximum at a critical bias angle for a given pressure,while the tensile actuation in TCP muscles increases with the coil *** theoretical predictions and simulations are in good agreement with experimental *** study is significant for guiding the design of TCP tube-based muscles and achieving their precise actuation control.

关键词： artificial muscles hydraulic pressure actuation characteristics anisotropy

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Nanoindentation creep behavior of high entropy superalloy with γ/γ′ microstructure under various loads and temperatures

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Journal of Alloys and Compounds 2025年 1031卷

作者： Han, Kangning Zhu, Yaxin Wang, Changwei Gao, Peng Liang, Shuang Zhao, Lv Huang, Minsheng Li, Zhenhuan Department of Engineering Mechanics School of Aerospace Engineering Huazhong University of Science and Technology Wuhan430074 China Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment Wuhan430074 China

High-entropy superalloys (HESAs) with a γ/γ′ microstructure similar to that of Ni-based single-crystal superalloys (NSCS) have emerged as promising candidates for high-temperature applications due to their high strength/density ratio and low cost. In this paper, the nanoindentation creep behaviors of HESA with the γ/γ′ microstructure under different loads and temperatures have been studied systematically. The HESA exhibits competitive creep resistance and structural stability as compared to NSCS. At low temperature and low load, the indentation features a shallow depth and a confined plastic deformation zone. However, at high temperature and high load, dislocations can progressively shear through multiple γ′ precipitates, resulting in an expanded plastic zone and a notable acceleration in the creep rate. With the increase of temperature and load, although the creep rate of this HESA increases gradually, it has higher stress exponent and superior creep resistance compared with most alloys. These new findings can provide guidance for the development of advanced HESAs and their engineering applications. © 2025 Elsevier B.V.

关键词： High temperature applications

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Method of reverberation-ray matrix for size effect on nano phononic crystals

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Applied Mathematical Modelling 2025年 146卷

作者： Xu, Haoyu Wang, Weiwei Hu, Ningdong Yao, Mingge Hu, Hongping Department of Mechanics School of Aerospace Engineering Huazhong University of Science and Technology Wuhan430074 China Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment Huazhong University of Science and Technology Wuhan430074 China Shanghai Institute of Satellite Engineering Shanghai201109 China Tianjin Aerospace Reliability Technology Co. Ltd Wuhan430074 China

With the proposal of the high-order nonlocal theories for studying size effect on nano structure, due to the poor numerical convergence, the traditional transfer matrix method (TMM) can no longer meet its requirements in the research of the size effect on nano phononic crystals (PnCs), which leads to the lack of research on nano PnCs. To overcome the shortcoming, a theoretical model is established for the analysis of size effect on the PnCs based on nonlocal strain gradient theory (NSGT). The method of reverberation-ray matrix (MRRM) is first introduced to obtain the analytical solution of size effect on band structures of the PnCs. Compared with TMM, MRRM shows excellent numerical stability in studying size effect on both finite and infinite nano PnCs with a wide parameter range, which is verified by finite element method (FEM). Numerical results reveal that softening effect will reduce the frequency, while the stiffening effect will increase the frequency, thereby leading to a complex size effect on the band structure and wave attenuation. The different mechanisms of softening and hardening effects on the bandwidth and wave attenuation of the first bandgap are investigated. The stiffening effect first widens the bandwidth and enhances wave attenuation at lower intensities, while narrowing the bandwidth and weakening wave attenuation at higher intensities. However, the softening effect only narrows the bandwidth and enhances wave attenuation. There exist specific optimal nonlocal parameters that maximize both bandwidth and wave attenuation. This study paves the way for investigating the size effect on nano PnCs with a numerical stable calculation method, and provides theoretical guidance for the design and application of nano PnCs. © 2025 Elsevier Inc.

关键词： Convergence of numerical methods

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Isogeometric analysis of the Nonlinear Deformation of Planar Flexible Beams with Snap-back

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Acta Mechanica Solida Sinica 2016年第4期29卷 379-390页

作者： Zheng Huang Zeng He Wen Jiang Hou Qiao Hui Wang Department of Mechanics Huazhong University of Science and Technology Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment

Based on the continuity of the derivatives of the Non-Uniform Rational B-Splines (NURBS) curve and the Jaumann strain measure, the present paper adopted the position coordinates of the control points as the degrees of freedom and developed a planar rotation-free Euler-Bernoulli beam element for isogeometric analysis, where the derivatives of the field variables with respect to the arc-length were expressed as the sum of the weighted sum of the position coordinates of the control points, and the NURBS basis functions were used as the weight functions. Furthermore, the concept of bending strip was used to involve the rigid connection between multiple patches. Several typical examples with geometric nonlinearities were used to demonstrate the accuracy and effectiveness of the proposed algorithm. The presented formulation fully accounts for the geometric nonlinearities and can be used to study the snap-through and snap-back phenomena of flexible beams.

关键词： isogeometric analysis NURBS rotation-free beam bending strip method snap-back

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A MODIFIED TORSION PENDULUM FOR MEASURING THE SHEAR MODULUS OF A SINGLE MICRO-SIZED FILAMENT

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Acta Mechanica Solida Sinica 2014年第3期27卷 221-233页

作者： Dabiao Liu Yuming He Peng Hu Zhipeng Gan Huaming Ding Department of Mechanics Huazhong University of Science and Technology Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment

A modified torsion pendulum apparatus is developed for measuring the shear modu- lus of single filaments with uniform micro-sized diameter. A single filament fixed at both ends and with a ring-shaped mass attached at the middle is used as a clamped-clamped torsion pendulum. The shear modulus of single filaments can be expressed as a function of the oscillation frequency of the torsion pendulum. The oscillation motion is measured with a CCD laser displacement sensor, and its frequency is determined by the Fast Fourier Transform （FFT） method. The shear moduli of three types of filaments： copper wires, tungsten wires and carbon fibers are accurately measured with this technique. It is found that the size effect in shear moduli of both copper wires and tungsten wires is minor. Finally, the error analysis of our measurement technique is presented in detail.

关键词： torsion pendulum shear modulus size effect single filament

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APPLICATION OF SURROGATE BASED PARTICLE SWARM OPTIMIZATION TO THE RELIABILITY-BASED ROBUST DESIGN OF COMPOSITE PRESSURE VESSELS

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Acta Mechanica Solida Sinica 2013年第5期26卷 480-490页

作者： Jianqiao Chen Yuanfu Tang Xiaoxu Huang Department of Mechanics Hubei Key Laboratory of Engineering Structural Analysis and Safety AssessmentHuazhong University of Science and Technology

A surrogate based particle swarm optimization （SBPSO） algorithm which combines the surrogate modeling technique and particle swarm optimization is applied to the reliability- based robust design （RBRD） of composite pressure vessels. The algorithm and efficiency of SBPSO are displayed through numerical examples. A model for filament-wound composite pressure vessels with metallic liner is then studied by netting analysis and its responses are analyzed by using Finite element method （performed by software ANSYS）. An optimization problem for maximizing the performance factor is formulated by choosing the winding orientation of the helical plies in the cylindrical portion, the thickness of metal liner and the drop off region size as the design variables. Strength constraints for composite layers and the metal liner are constructed by using Tsai-Wu failure criterion and Mises failure criterion respectively. Numerical examples show that the method proposed can effectively solve the RBRD problem, and the optimal results of the proposed model can satisfy certain reliability requirement and have the robustness to the fluctuation of design variables.

关键词： structural optimization reliability based robust design composite pressure vessel,surrogate based particle swarm optimization sequential algorithm

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NONLINEAR DYNAMICS AND SYNCHRONIZATION OF TWO COUPLED PIPES CONVEYING PULSATING FLUID

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Acta Mechanica Solida Sinica 2014年第2期27卷 162-171页

作者： Qiao Ni Zilong Zhang Lin Wang Qin Qian Min Tang Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment Department of Mechanics Huazhong University of Science and Technology

In this paper, the nonlinear dynamical behavior of two coupled pipes conveying pulsating fluid is studied. The connection between the two pipes is considered as a distributed linear spring. Based on this consideration, the equations of motion of the coupled two-pipe system are obtained. The two coupled nonlinear partial differential equations, discretized using the fourth- order Galerkin method, are solved by a fourth-order Runge-Kutta integration algorithm. Results show that the connection stiffness has a significant effect on the dynamical behavior of the coupled system. It is found that for some parameter values the motion types of the two pipes might be synchronous.

关键词： pipe conveying pulsating fluid nonlinear dynamics coupled two-pipe system synchronization

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Typical transient effects in a piezoelectric semiconductor nanofiber under a suddenly applied axial time-dependent force

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Applied Mathematics and Mechanics(English Edition) 2021年第8期42卷 1095-1108页

作者： Wanli YANG Yuxing LIANG Department of Mechanics School of Aerospace EngineeringHubei Key Laboratory of Engineering Structural Analysis and Safety AssessmentHuazhong University of Science and TechnologyWuhan 430074China

Based on the mechanical motion equation,Gauss’s law,and the current continuity condition,we study a few typical transient effects in a piezoelectric semiconductor(PS)fiber to realize the startup and turning-off functions of common piezotronic *** this study,the transient extensional vibration induced by a suddenly applied axial time-dependent force is examined in a cantilevered n-type ZnO *** the magnitude of the loadings nor the doping concentration significantly affects the propagation caused by disturbance of the axial ***,both of the factors play an important role in the propagation caused by disturbance of the electron *** indicates that the electromechanical coupling effect can be expected to directly determine the electronic performance of the *** addition,the assumption of previous simplified models which neglect the charge carriers in Gauss’s law is discussed,showing that this assumption has a little influence on the startup state when the doping concentration is smaller than 1021 *** suggests that the screening effect of the carriers on the polarized electric field is much reduced in this situation,and that the state is gradually transforming into a pure piezoelectric ***,the carriers can provide a damping effect,which means that the previous simplified models do not sufficiently describe the turning-off *** numerical results show that the present study has referential value with respect to the design of newly multifunctional PS devices.

关键词： transient piezoelectric semiconductor(PS) extension vibration

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Dislocation Dissociation Strongly Influences on Frank-Read Source Nucleation and Microplasticy of Materials with Low Stacking Fault Energy

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Chinese Physics Letters 2014年第4期31卷 96-99页

作者： HUANG Min-Sheng Department of Mechanics Huazhong University of Science and Technology Wuhan 430074 Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment Wuhan 430074

The influence of dislocation dissociation on the evolution of Frank-Read （F-R） sources is studied using a three- dimensional discrete dislocation dynamics simulation （3D-DDD）. The classical Orowan nucleation stress and recently proposed Benzerga nucleation time models for F-R sources are improved. This work shows that it is necessary to introduce the dislocation dissociation scheme into 3D-DDD simulation, especially for simulations on micro-plasticity of small sized materials with low stacking fault energy.

关键词： NUCLEATION MOLECULAR dynamics DISLOCATION loops DISSOCIATION (Chemistry) NICKEL

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Modeling of Cyclic Bending of Thin Foils Using Higher-Order Strain Gradient Plasticity

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Acta Mechanica Solida Sinica 2022年第4期35卷 616-631页

作者： Tong Luo Fenfei Hua Dabiao Liu School of Aerospace Engineering Huazhong University of Science and TechnologyWuhan430074China Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment Wuhan430074China

The plastic behaviors of thin metallic foils,including size effect,Bauschinger effect,and passivation effect,are studied under cyclic bending condition using the strain gradient visco-plasticity *** finite element simulations are performed on the cyclic bending of the elasto-viscoplastic thin foils with passivated and unpassivated *** study is also conducted on the transition from a passivated surface to an unpassivated *** roles of the dissipative and energetic gradient terms are *** the results,it is found that the dissipative gradient terms increase the yield strength,while the energetic gradient terms increase the strain hardening,resulting in an anomalous Bauschinger ***,it is observed that the surface passivation effect increases both the normalized bending moment at initial yielding and strain *** comparison between the numerical results of cases with and without passivation demonstrates that the switching of boundary conditions significantly affects the plastic behavior of the foils under cyclic bending.

关键词： Strain gradient plasticity Size effect Bauschinger effect Geometrically necessary dislocations Bending

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