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Study on the damage-softening constitutive model of rock and experimental verification

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Acta Mechanica Sinica 2019年第4期35卷 786-798页

作者： Sheng-Qi Yang Bo hu peng Xu State Key Laboratory for Geomechanics and Deep Underground Engineering School of Mechanics and Civil Engineering China University of Mining and Technology Xuzhou 221116 China China Construction Third Engineering Design Bureau Co. Ltd Wuhan 430064 China

A damage-softening model is presented to describe the stress-strain curve of rock. By comparing the Hoek-Brown (H-B) and Mohr-Coulomb (M-C) yield criterion, the equivalent M-C yield criterion is selected as the strength criterion in this model. To better characterize the rock damage and failure processes with considering the relationship between damage and deformation, the concept of yield stress ratio is introduced to describe the yield strengthening deformation before rock peak stress. Damage events are described by two cumulative damage evolution laws. The evolution equations of tensile and shear damage are presented based on the equivalent plastic strains and the maximum value between tensile and shear damage represents the total damage for rock. Considering that rock cannot bear tensile load after tensile failure but still has a certain shear strength, its tensile and shear strengths are small after shear failure. The elastic modulus is affected by tensile damage, whereas the angle of internal friction, the cohesion, and dilation angles are influenced by shear damage. The proposed damage-softening model describes the strain-softening, brittle stress-drop, and residual strength of rock after peak stress, and finally the model is implemented in FLAC3D. Comparing the test and the numerical calculation results, the damage-softening model better describes the total stress-strain curve of rock.

关键词： Rock deformation Damage evolution Softening Numerical calculation

A High Consistency Wireless Key Generation Scheme for Vehicular Communication Based on Wiener Filter Extrapolation

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Automotive Innovation 2023年第4期6卷 547-557页

作者： Yiming Ma Linning peng Wenhao Yin hua Fu Aiqun hu peng Guo Hongxing hu School of Cyber Science and Engineering Southeast UniversityNanjingChina Purple Mountain Laboratories NanjingChina National Mobile Communications Research Laboratory Southeast UniversityNanjingChina China Automotive Innovation Co. LtdNanjingChina

Secret key generation from wireless channel is an emerging technology for communication network security,which exploits the reciprocity and time variability of wireless channels to generate symmetrical keys between the communication *** to the existing asymmetric key distribution methods,secret key generation from wireless channel has low complexity and high security,making it especially suitable for distributed *** vehicular communications,the reciprocity of wireless channel is degraded due to the movement of *** paper proposes a high consistency wireless key generation scheme for vehicular communication,especially applied to LTE-V2X(LTE vehicle to everything)systems.A channel reciprocity enhancement method is designed based on Wiener filter extrapolation,which can efficiently reduce the mismatch between the channels at the receiver and significantly reduce key disagreement rate.A real experimental system based on vehicle and universal software radio peripheral(USRP)platform is setup to verify the secret key generation in LTE-V2X *** effectiveness of the proposed method is verified in simulations and extensive practical tests.

关键词： Physical layer security Wireless key generation LTE-V2X Channel reciprocity Wiener filter

3D Printing of Tough Hydrogel Scaffolds with Functional Surface Structures for Tissue Regeneration

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Nano-Micro Letters 2025年第2期17卷 18-45页

作者： Ke Yao Gaoying Hong Ximin Yuan Weicheng Kong pengcheng Xia Yuanrong Li Yuewei Chen Nian Liu Jing He Jue Shi Zihe hu Yanyan Zhou Zhijian Xie Yong He State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical EngineeringZhejiang UniversityHangzhou 310027People’s Republic of China Liangzhu Laboratory Zhejiang UniversityHangzhou 310027People’s Republic of China Key Laboratory of 3D Printing Process and Equipment of Zhejiang Province College of Mechanical EngineeringZhejiang UniversityHangzhou 310027People’s Republic of China Stomatology Hospital School of StomatologyZhejiang University School of MedicineHangzhou 310027People’s Republic of China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001People’s Republic of China Institute of Digital Medicine Nanjing First HospitalNanjing Medical UniversityNanjing 210006People’s Republic of China

Hydrogel scaffolds have numerous potential applications in the tissue engineering ***,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical *** by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this ***,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent ***,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell ***,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT *** experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.

关键词： 3D printing Tough hydrogel scaffold Functional surface structure Tissue regeneration Biomaterials

CNQ: Compressor-Based Non-uniform Quantization of Deep Neural Networks

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Chinese Journal of Electronics 2020年第6期29卷 1126-1133页

作者： YUAN Yong CHEN Chen hu Xiyuan peng Silong Institute of Automation Chinese Academy of Sciences University of Chinese Academy of Sciences School of Computer Science and Engineering Nanjing University of Science and Technology

Deep neural networks(DNNs) have achieved state-of-the-art performance in a number of domains but suffer intensive *** quantization can effectively reduce computation and memory costs without changing network structure,facilitating the deployment of DNNs on mobile *** the existing methods can obtain good performance,low-bit quantization without time-consuming training or access to the full dataset is still a challenging *** this paper,we develop a novel method named Compressorbased non-uniform quantization(CNQ) method to achieve non-uniform quantization of DNNs with few unlabeled ***,we present a compressor-based fast nonuniform quantization method,which can accomplish nonuniform quantization without ***,we propose to align the feature maps of the quantization model with the pre-trained model for accuracy *** the property difference between different activation channels,we utilize the weighted-entropy perchannel to optimize the alignment *** the experiments,we evaluate the proposed method on image classification and object *** results outperform the existing post-training quantization methods,which demonstrate the effectiveness of the proposed method.

关键词： entropy image classification learning (artificial intelligence) neural nets object detection optimisation quantisation (signal) network structure DNN low-bit quantization time-consuming training compressor-based fast nonuniform quantization method quantization model post-training quantization methods deep neural networks network quantization compressor-based nonuniform quantization CNQ Non-uniform quantization Knowledge distillation Unlabeled samples Network compression

Underwater Directional Acoustic Source Based on Pentamode Material

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Acta Mechanica Solida Sinica 2024年第1期37卷 1-9页

作者： Binghao Zhao peng Wang Dongwei Wang Gengkai hu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Wuhan Second Ship Design and Research Institute Wuhan 430205China

An underwater directional acoustic emitter is conceived with a highly anisotropic lattice material,whose acoustic characteristics manifest strong dependence on the orientation of the lattice material’s principal *** these features,a cylindrical structure made of such anisotropic lattice material is engineered to possess distinct impedance values in different directions,thereby facilitating wave emission along the principal axis while inducing reflection in other ***,through numerical simulations,it is demonstrated that the emission direction can be effectively manipulated by adjusting the principal axis orientation,concurrently enhancing the emitted *** contrast to previous directional acoustic structures,the compact emitter presented in this study can get rid of the size-wavelength constraint,enabling effective control of low-frequency waves.

关键词： Underwater Directional emission Pentamode material Broadband frequency

Modeling on mechanical behavior and damage evolution of single-lap bolted composite interference-fit joints under thermal effects

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Chinese Journal of Aeronautics 2021年第8期34卷 230-244页

作者： Junshan hu Kaifu ZHANG hui CHENG peng ZOU College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Mechanical Engineering Northwestern Polytechnical UniversityXi'an 710072China Aircraft Strength Research Institute of China Xi'an 710065China

This paper reports the modeling method and outcomes of mechanical performance and damage evolution of single-lap bolted composite interference-fit joints under extreme *** anisotropic continuum damage model involving thermal effects is established on continuum damage mechanics which integrates the shear nonlinearity constitutive relations characterized by Romberg-Osgood *** temperature-induced modification of thermal strains and material properties is incorporated in stress-strain analysis,extended 3 D failure criteria and exponential damage evolution *** proposed model is calibrated and employed to simulate behavior of composite joints in interference fitting,bolt preloading,thermal and bearing loading processes,during which the influence of interference-fit sizes,preload levels,laminate layups and service temperatures is thoroughly *** predicated interfacial behavior,bearing response and failure modes are in good agreement with experimental *** numerical model is even capable of reflecting some non-intuitive experimental findings such as residual stress relaxation and matrix softening at elevated temperatures.

关键词： Composite joints Damage evolution Interference fit Mechanical behavior Thermal effects

Design of Low-Power Turbo Encoder and Decoder for NB-IoT

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Chinese Journal of Electronics 2024年第2期33卷 403-414页

作者： chong ZHANG Yuhang LIN Deming WANG Jianguo hu School of Microelectronics Science and Technology Sun Yat-sen University School of Physics and Telecommunication Engineering South China Normal University School of Electronics and Information Engineering South China Normal University Development Research Institute of Guangzhou Smart City Shenzhen Research Institute of Sun Yat-sen University

Turbo code is an error correction coding scheme close to the Shannon limit, usually used in wireless data transmission. Based on the parallel Turbo code algorithm, a parallel Turbo code circuit design scheme is *** the encoder, the recursive systematic convolutional encoder is multiplexed. The decoder is divided into branch metric, recursive, maximum likelihood ratio, and external information calculation modules. The decoding algorithm is based on Max-Log-MAP, controlling the component decoder in parallel. And the state metric calculation in the decoding circuit is combined to reduce the overall power consumption effectively, enabling the encoder and decoder to be used in narrowband Internet of things(NB-IoT). Finally, the hardware scheme of the main functional modules of Turbo code encoding and decoding is designed and implemented. The results show that the dynamic power consumption is less than 50 m W. The overall on-chip power consumption is reduced by 40% at the frequency of 125 MHz compared with previous jobs.

关键词： Measurement Wireless communication Power demand Systematics Turbo codes System-on-chip Power dissipation

Nitrogen incorporated nickel molybdenum sulfide as efficient electrocatalyst for overall water splitting

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Journal of Materials Science & Technology 2022年第4期99卷 270-276页

作者： Kena Wu Xiaonan Wei Deng Li peng hu Beijing Bioprocess Key Laboratory State Key Laboratory of Chemical Resource EngineeringBeijing University of Chemical TechnologyBeijing 100029China Amoy-BUCT Industrial Bio-technovation Institute Amoy 361022China Key Laboratory of Advanced Functional Materials Education Ministry of ChinaFaculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China

Developing bifunctional electrocatalysts with improved efficiency and stability in overall water splitting is of extreme importance for renewable energy *** this work,an in situ N doping strategy was demonstrate to boost the efficiency and stability of nickel molybdenum sulfide both in electrocatalytic hydrogen evolution reaction and oxygen evolution *** and theoretical results indicate that such modification offers enriched active sites for electrochemical reaction,and further increases the kinetic driven force of water *** a result,the N–NiMoS electrode exhibits a remarkably improved performance with rather low potential of 1.54 V to offer a current density of 10 mA cm;for overall water splitting,which is 130 mV decrease than that of pristine *** addition,impressive electrochemical stability also reveals a 76.6%preservation of initial current density after 100 h test,which is superior than that of pristine one after 25 h ***,the potential to enhance the performance of electrocatalysts by as-proposed route promises a valuable way to develop efficient catalysts with enhanced property for electrochemical applications.

关键词： Bifunctional electrocatalyst Water splitting Nitrogen incorporation Nickel molybdenum sulfide

Higher-order electroelastic modelling of piezoelectric cylindrical nanoshell on elastic matrix

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Defence Technology（防务技术） 2022年第5期18卷 781-796页

作者： Xiao-ping huang peng-fei hu Mohammad Arefi College of Mechanical and Electrical Engineering Nanning UniversityNanning530000GuangxiChina School of Materials Science and Engineering Luoyang Institute of TechnologyLuoyang471023HenanChina Department of Solid Mechanics Faculty of Mechanical EngineeringUniversity of KashanKashan87317-51167Iran

This paper develops electro-elastic relations of functionally graded cylindrical nanoshell integrated with intelligent layers subjected to multi-physics loads resting on elastic *** piezoelectric layers are actuated with external applied *** nanocore is assumed in-homogeneous in which the material properties are changed continuously and gradually along radial ***-order shear deformation theory is used for the description of kinematic relations and electric potential distribution is assumed as combination of a linear function along thickness direction to show applied voltage and a longitudinal ***-elastic size-dependent constitutive relations are developed based on nonlocal elasticity theory and generalized Hooke’s *** principle of virtual work is used to derive governing equations in terms of four functions along the axial and the radial directions and longitudinal electric potential *** numerical results including radial and longitudinal displacements are presented in terms of basic input parameters of the integrated cylindrical nanoshell such as initial electric potential,small scale parameter,length to radius ratio and two parameters of *** is concluded that both displacements are increased with an increase in small-scale parameter and a decrease in applied electric potential.

关键词： Higher-order shear deformation theory Electro-elastic bending Functionally graded materials Size-dependent analysis Nonlocal parameter Cylindrical nano shell