The low-light condition brings huge challenges to the traffic object detection, limiting its application in complex scenarios such as the round-the-clock traffic monitoring and automatic driving. To address this issue...
详细信息
The surrounding rock experiences the combined impacts of elevated ground stress, high water pressure, and hot groundwater during the deep-buried tunnels with high water temperatures. The stress in the surrounding rock...
详细信息
The effective fault diagnosis method is crucial for the engineering. At present, the fault diagnosis methods based on data-driven have achieved much attention. The traditional methods only utilize one sensor or one ch...
详细信息
The shear bond of interface between concrete and basalt fiber reinforced polymer(BFRP)bars during freeze–thaw(F–T)cycles is crucial for the application of BFRP bar-reinforced concrete structures in cold *** this stu...
详细信息
The shear bond of interface between concrete and basalt fiber reinforced polymer(BFRP)bars during freeze–thaw(F–T)cycles is crucial for the application of BFRP bar-reinforced concrete structures in cold *** this study,48 groups of pull-out specimens were designed to test the shear bond of the BFRP-concrete interface subjected to F–T *** effects of concrete strength,diameter,and embedment length of BFRP rebar were investigated under numerous F–T *** results showed that a larger diameter or longer embedment length of BFRP rebar resulted in lower interfacial shear bond behavior,such as interfacial bond strength,initial stiffness,and energy absorption,after the interface goes through F–T ***,higher concrete strength and fewer F–T cycles were beneficial for enhancing the interfacial bond ***,a three-dimensional(3D)interfacial model based on the finite element method was developed,and the interfacial bond behavior of the specimens was analyzed ***,a degradation bond strength subjected to F–T cycles was predicted by a proposed mechanical *** predictions were fully consistent with the tested *** model demonstrated accuracy in describing the shear bond behavior of the interface under numerous F–T cycles.
The mesh stiffness and vibration characteristics of a spur gear system are investigated when the crack propagates beyond the central line of the tooth. The time-varying mesh stiffness (TVMS) in the single-tooth engage...
详细信息
It is widely acknowledged that the radiation-induced volumetric expansion (RIVE) of aggregates is the primary mechanism responsible for the degradation of mechanical properties of concrete under neutron irradiation, w...
详细信息
Flexoelectricity is a two-way coupling effect between the strain gradient and electric field that exists in all dielectrics,regardless of point group ***,the high-order derivatives of displacements involved in the str...
详细信息
Flexoelectricity is a two-way coupling effect between the strain gradient and electric field that exists in all dielectrics,regardless of point group ***,the high-order derivatives of displacements involved in the strain gradient pose challenges in solving electromechanical coupling problems incorporating the flexoelectric *** this study,we formulate a phase-field model for ferroelectric materials considering the flexoelectric effect.A four-node quadrilateral element with 20 degrees of freedom is constructed without introducing high-order shape *** microstructure evolution of domains is described by an independent order parameter,namely the spontaneous polarization governed by the time-dependent Ginzburg–Landau *** model is developed based on a thermodynamic framework,in which a set of microforces is introduced to construct the constitutive relation and evolution *** the flexoelectric part of electric enthalpy,the strain gradient is determined by interpolating the mechanical strain at the node via the values of Gaussian integration points in the isoparametric *** model is shown to be capable of reproducing the classic analytical solution of dielectric materials incorporating the flexoelectric *** model is verified by duplicating some typical phenomena in flexoelectricity in cylindrical tubes and truncated pyramids.A comparison is made between the polarization distribution in dielectrics and *** model can reproduce the solution to the boundary value problem of the cylindrical flexoelectric tube,and demonstrate domain twisting at domain walls in ferroelectrics considering the flexoelectric effect.
External sulfate attack is one of the main reasons responsible for the performance deterioration of concrete. Accurate prediction of the temporal and spatial distribution of sulfate ions in concrete is the basis for r...
详细信息
Because heat dissipation of the traffic can accumulate along the tunnels, the temperature near the exit of an ultra-long underwater tunnel can be elevated significantly than that of the entrance. In this paper, method...
详细信息
Single phase 0.76(Bi_(0.5)Na_(0.5))TiO_(3)–0.24SrTiO_(3) ferroelectric ceramics have been synthesized with homogenous anatase and hierarchical rutile TiO_(2) raw reactants(BNST-A and BNST-R).Either calcined powder pe...
详细信息
Single phase 0.76(Bi_(0.5)Na_(0.5))TiO_(3)–0.24SrTiO_(3) ferroelectric ceramics have been synthesized with homogenous anatase and hierarchical rutile TiO_(2) raw reactants(BNST-A and BNST-R).Either calcined powder persists the microstructure characteristics of raw *** the result,when the sintering temperature increases from 1000 to 1200℃,the average grain size and density of BNST-A increase from 0.49 to 1.48μm and 5.02 to 5.61 g/cm^(3),while those of BNST-R from 0.86 to 1.44μm and 5.37 to 5.61 g/cm^(3).BNST-A illustrates a predominant ergodic relaxor state,and BNST-R prefers a non-ergodic relaxor state,as evidenced by the distinct polarization-electric field loops and current-electric field ***,such a distinct ferroelectric state is independent of sintering *** is believed that the special hierarchical microstructure of rutile TiO_(2) reactant is beneficial to form denser ceramics with larger grains,and thus suppresses the contributions of polar nanoregions and defect-induced built-in field to ferroelectric property,leading to non-ergodic relaxor *** work clearly demonstrates the nonnegligible effects of TiO_(2) reactants on the microstructure and properties of BNST ferroelectric ceramics.
暂无评论