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Layered metastructure containing freely-designed local resonators for wave attenuation

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Defence Technology（防务技术） 2024年第2期32卷 23-31页

作者： Yu Li Huguang He Jiang Feng Hailong Chen Fengnian Jin Hualin Fan State key laboratory for disaster prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing 210007China Rocket Force University of engineering Xi'an 710025China Henan International Joint laboratory of Dynamics of Impact and disaster of engineering Structures Department of Civil EngineeringNanyang Institute of TechnologyNanyang 473004China guangxi key laboratory of disaster prevention and engineering safety and Key Laboratory of Disaster Prevention and Structural Safety of Ministry of EducationCollege of Civil Engineering and ArchitectureGuangxi UniversityNanning 530004China Research Center of Lightweight Structures and Intelligent Manufacturing State Key Laboratory of Mechanics and Control of Mechanical StructuresNanjing University of Aeronautics and AstronauticsNanjing 210016China

Combining periodic layered structure with three-dimensional cylindrical local resonators,a hybrid metastructure with improved wave isolation ability was designed and investigated through theoretical and numerical *** metastructure is composed of periodic rubber layers and concrete layers embedded with three-dimensional resonators,which can be freely designed with multi local resonant frequencies to attenuate vibrations at required frequencies and widen the attenuation *** metastructure can also effectively attenuate seismic *** with layered rubber-based structures,the metastructure has more excellent wave attenuation effects with greater attenuation and wider bandgap.

关键词： Layered metastructure Local resonator Wave attenuation

Bond of Seawater Scoria Aggregate Concrete to Stainless Reinforcement

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Journal of Renewable Materials 2023年第1期11卷 209-231页

作者： Lei Yin Yijie Huang Yanfei Dang Qing Wang Shandong key laboratory of Civil engineering disaster prevention and Mitigation Shandong University of Science and TechnologyQingdao266590China

This study investigates the bond between seawater scoria aggregate concrete(SSAC)and stainless reinforcement(SR)through a series of pull-out tests.A total of 39 specimens,considering five experimental parameters—con-crete type(SSAC,ordinary concrete(OC)and seawater coral aggregate concrete(SCAC)),reinforcement type(SR,ordinary reinforcement(OR)),bond length(3,5 and 8 times bar diameter),concrete strength(C25 and C30)and concrete cover thickness(42 and 67 mm)—were *** typical bond properties(failure pattern,bond strength,bond-slip curves and bond stress distribution,etc.)of seawater scoria aggregate concrete-stainless rein-forcement(SSAC-SR)specimen were systematically ***,the failure pattern changed with the con-crete type used,and the failure surface of SSAC specimen was different from that of OC *** enhanced the bond strength of specimen,while its effect on the deformation of SSAC-SR was *** aver-age,the peak slip of SSAC specimens was 20%lower while the bond strength was 6.7%higher compared to OC specimens under the similar *** effects of variables on the bond strength of SSAC–SR in increasing order are concrete type,bond length,concrete strength and cover *** bond-slip curve of SSAC-SR specimen consisted of micro-slipping,slipping and declining *** can be obtained that SSAC reduced the curve curvature of bond-slip,and the decline of curve became steep after adopting *** typical distribution of bond stress along bond length changed with the types of concrete and reinforcement ***,a specific expression of the bond stress-slip curve considering the effects of various variables was established,which could provide a basis for the practical application of reinforced SSAC.

关键词： Bond properties seawater scoria aggregate concrete stainless reinforcements bond-slip curve bond stress distribution analytical model

Effect of Waste Marble Powder on Physical and Mechanical Properties of Concrete

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Journal of Renewable Materials 2022年第10期10卷 2623-2637页

作者： Yumei Wang Jianzhuang Xiao Jintuan Zhang Department of Structural engineering College of Civil EngineeringTongji UniversityShanghai200092China College of Earth Sciences Guilin University of TechnologyGuilin541004China College of Architecture and Civil engineering Nanning UniversityNanning541699China guangxi key laboratory of disaster prevention and engineering safety Guangxi UniversityNanning530004China

The emission of greenhouse gases from cement production is an obstacle for sustainable development of construction *** use of waste materials in constructions instead of cement could be a feasible solution to green *** marble powder with good cementing property can be used in concrete partially replace *** this research,the effects of using waste marble powder on the physical and mechanical properties of concrete have been *** groups of particle size and five levels of replacement ratio(5%,10%,15%,20%,25%)for each group have been *** the different stage of hydration process,the microstructure,phase composition and thermal properties of marble-cement paste have been investigated,the influence of particle size of marble powder on these properties has been *** compressive strength and stressstrain relation were tested for different series prepared by partially replacing cement at proportions of 5%–25%*** the data analysis,it was observed that the using of waste marble powder would affect the hydration products and further affect the mechanical properties of concrete,the addition of marble powder that partially replace the cement at particular proportions in concrete is feasible.

关键词： Waste marble powder concrete replacement ratio physical property mechanical property

Investigation of the seismic behavior of grouted sandy gravel foundations using shaking table tests

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Frontiers of Structural and Civil engineering 2022年第9期16卷 1196-1211页

作者： Tiancheng WANG Yu LIANG Xiaoyong ZHANG Zhihuan RUAN Guoxiong MEI key laboratory of disaster prevention and Structural safety.of Ministry of Education College of Civil Engineering and ArchitectureGuangxi UniversityNanning 530004China Ocean College Zhejiang UniversityZhoushan 316021China

Sandy gravel foundations exhibit non-linear dynamic behavior when subjected to strong ground motions,which can have amplification effects on superstructures and can reveal insufficient lateral resistance of *** methods can be used to improve the seismic performance of natural sandy gravel *** strength and stiffness of grouted sandy gravel foundations are different from those of natural foundations,which have unknown earthquake *** studies have investigated the seismic behavior of sandy gravel foundations before and after *** this study,two shaking table tests were performed to evaluate the effect of grouting reinforcement on seismic *** natural frequency,acceleration amplification effect,lateral displacement,and vertical settlement of the non-grouted and grouted sandy gravel foundations were measured and ***,the dynamic stress-strain relationships of the two foundations were obtained by a linear inversion method to evaluate the seismic energy *** test results indicated that the acceleration amplification,lateral displacement amplitude,and vertical settlement of the grouted sandy gravel foundation were lower than that of the non-grouted foundation under low-intensity ***,a contrasting result was observed under high-intensity *** demonstrated that different grouting reinforcement strategies are required for different sandy gravel *** addition,the dynamic stress-strain relationship of the two foundations exhibited two different energy dissipation *** results provide insights relating to the development of foundations for relevant engineering sites and to the dynamic behavior of grouted foundations prior to investigating soil-structure interaction problems.

关键词： sandy gravel foundation grouting-treated reinforcement shaking table test seismic behavior

Fracture Analysis of Cast Iron Materials with Cracks Based on Elastoplastic Extended Finite Element Method

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Acta Mechanica Solida Sinica 2019年第2期32卷 201-214页

作者： Yanjun Chang Qiao Song Zheng Kuang Keshi Zhang Zhanguang Zheng College of Civil engineering and Architecture Guangxi University Nanning 530004 China College of Mechanical engineering Guangxi University Nanning 530004 China guangxi key laboratory of disaster prevention and engineering safety Guangxi University Nanning 530004 China key laboratory of engineering disaster prevention and Structural safety.of Ministry of Education Guangxi University Nanning 530004 China

Based on the ABAQUS platform for finite element analysis, the extended finite element method (XFEM) considering elastoplastic constitutive relationship is developed, by which the displacement discontinuity across the crack surface and the strong nonlinearity near the crack tip can be described more accurately. The strip specimens with unilateral cracks and central cracks under uniaxial tension are simulated using the XFEM and the FEM, respectively. The J-integral across the crack on each incremen t is calcula ted using the equivale nt domain integral met hod (EDIM), the interaction integral met hod and the FEM, respectively. The effec ts of mesh size and mesh shape near the crack tip, element type and different calculation methods on the accuracy of J-integral are analyzed. The simulation results show that the XFEM is more accurate than the FEM with the same element size and type. The fracture tests of cast iron specimens with unilateral cracks under uniaxial tension are performed, and the J-integral criterion is valid to predict the fracture initiation in numerical simulation. The critical value of J-integral is calculated using the EDIM of the XFEM. The comparisons demonstrate that the simulated elastoplastic load-displacement curves with the XFEM are in good agreement with the experimental results.

关键词： J-Integral Extended finite element Elastoplasticity Fracture criterion

Effects of coarse and fine aggregates on long-term mechanical properties of sea sand recycled aggregate concrete

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Frontiers of Structural and Civil engineering 2021年第3期15卷 754-772页

作者： Jingwei YlNG Yijie HUANG Xu GAO Xibo QI Yuedong SUN Shandong key laboratory of Civil engineering disaster prevention and Mitigation Shandong University of Science and TechnologyQingdao266590China guangxi key laboratory of disaster prevention and engineering safety Guangxi UniversityNanning530004China

Typical effects of coarse and fine aggregates on the long-term properties of sea sand recycled aggregate concrete(SSRAC)are analyzed by a series of axial compression *** different types of fine(coarse)aggregates are considered:sea sand and river sand(natural and recycled coarse aggregates).Variations in SSRAC properties at different ages are investigated.A novel test system is developed via axial compression experiments and the digital image correlation method to obtain the deformation field and crack development of *** results show that the compressive strength of SSRAC increase with decreasing recycled coarse aggregate replacement percentage and increasing sea sand chloride ion *** elastic modulus of SSRAC increases with ***,the Poisson’s ratio reduces after 2 *** axial stress-strain curves of SSRAC vary with ***,the effect of coarse aggregates on the axial deformation of SSRAC is clear;however,the deformation differences between coarse aggregate and cement mortar reduce by adopting sea *** aggregate type changes the crack characteristics and propagation of ***,an analytical expression is suggested to construct the long-term stress-strain curve of SSRAC.

关键词： sea sand recycled aggregate concrete recycled coarse aggregate replacement percentage sea sand chloride ion content long-term mechanical properties stress-strain curve

Neural network and support vector machine models for the prediction of the liquefaction-induced uplift displacement of tunnels

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Underground Space 2021年第2期6卷 126-133页

作者： Gang Zheng Wenbin Zhang Wengang Zhang Haizuo Zhou Pengbo Yang School of Civil engineering Tianjin UniversityTianjin 300072China key laboratory of Coast Civil Structure safety Tianjin UniversityMinistry of EducationTianjin 300072China State key laboratory of Hydraulic engineering Simulation and safety Tianjin UniversityTianjin 300072China National Joint engineering Research Center of Geohazards prevention in Reservoir Area Environment School of Civil EngineeringChongqing UniversityChongqing 400045China

Tunnels buried in liquefiable deposits are vulnerable to liquefaction-induced uplift damage during *** paper presents support vector machine(SVM)and artificial neural network(ANN)models to predict the liquefaction-induced uplift displacement of tunnels based on artificial databases generated by the finite difference *** performance of the SVM and ANN models was assessed using statistical parameters,including the coefficient of determination R^(2),the mean absolute error,and the root mean squared *** for the above-mentioned approaches are compared and discussed.A relative importance analysis was adopted to quantify the sensitivity of each input *** precision of the presented models is demonstrated using centrifuge test results from previous studies.

关键词： Artificial neural network Support vector machine Liquefaction Uplift displacement

Creep damage properties of sandstone under dry-wet cycles

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Journal of Mountain Science 2020年第12期17卷 3112-3122页

作者： WANG Xin-gang LIAN Bao-qin WANG Jia-ding FENG Wen-kai GU Tian-Feng State key laboratory of Continental Dynamics Department of GeologyNorthwest UniversityXi’an 710069China guangxi key laboratory of disaster prevention and engineering safety Guangxi UniversityNanning 530004China State key laboratory of Geohazard prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China

Rock creep properties can be used to predict the long-term stability in rock *** reservoir bank slopes,sandstones which are frequently used in the bank slope undergoing longterm effects of dry-wet(DW) cycles due to periodic water inundation and drainage may gradually accumulate creep deformation,resulting in rock structure’s damage or even geological hazards such as *** fully investigate the effect of DW cycles on the creep damage properties of sandstone,triaxial creep tests were conducted on saturated sandstone with different DW cycles by using a triaxial rheometer *** experimental results show that both the instantaneous strain and the stabilized strain increase with the DW *** addition,using the Burgers model,four kinds of functions including an exponentially decreasing function,a linearly decreasing function,a linearly increasing function and an exponentially increasing function were proposed to express the relationships between the shear modulus,viscoelastic parameters of the Burgers model and the deviatoric stress under different DW *** comparative analysis,it is found that the theoretical curves generated using proposed four kinds of functions are in good agreement with the experimental ***,macromorphological and microstructural observations were performed on specimens after various triaxial rheological *** samples with small number of DW cycles,approximately X-shaped fracture surfaces were observed in shear failure zones,whereas several shear fractures including obvious axial and horizontal tensile cracks,and flaws were found for samples with relatively large DW cycles due to long-term propagation and evolution of micro-fissures and ***,as the DW cycles increases,the variation in micro-structure of samples after creep failure was summarized into three stages,namely,a stage with good and dense structure,a stage with pore and fissure propagation,and a stage with extensive in

关键词： Creep damage property Sandstone Drywet cycles Triaxial rheological test Microstructure

Mechanical Properties of Sea Water Sea Sand Coral Concrete Modified with Different Cement and Fiber Types

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Journal of Renewable Materials 2020年第8期8卷 915-937页

作者： Xibo Qi Yijie Huang Xiaowei Li Zhenhua Hu Jingwei Ying Dayong Li Department of Building engineering Shandong University of Science&TechnologyQingdao266590China Shandong key laboratory of Civil engineering disaster prevention and Mitigation Shandong University of Science and TechnologyQingdao266590China guangxi key laboratory of disaster prevention and engineering safety Guangxi UniversityNanning530004China

The mechanical properties of modified sea water sea sand coral concrete(SWSSCC)under axial compression were experimentally *** different parameters were considered in this test:types of cement and *** experimental campaign was developed involving uniaxial compression tests and the use of digital image correlation(DIC)method to analyze the strain distribution and crack propagation of *** results indicated that the compressive strength and elastic modulus of SWSSCC were improved by adding stainless steel fibers(SSF),while polypropylene fibers(PF)enhanced the SWSSCC peak *** was found that the elastic modulus and strength of SWSSCC using ordinary Portland cement(OPC)were higher compared to specimen with low alkalinity sulphoaluminate cement(LAS).Typical strain distribution changed with the variation of fiber *** propagation and characteristics of cracks in SWSSCC containing PF were similar to those of cracks in ***,the propagation of cracks and the development of plastic deformation in SWSSCC were effectively hindered by adopting ***,an analytical stress-strain expression of specimen considering the influences of fibers was *** obtained results would provide a basis for the application of SWSSCC.

关键词： Sea water sea sand coral concrete modified concrete mechanical properties stress-strain curve crack propagation strain distribution