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The hybrid sandwich structure consistes of tooth-plate-glass-fiber facesheets and a foam core. Tooth plate was connected with foam core through tooth nails. Tooth-plate-glass-fiber hybrid sandwich beams were made by vacuum assisted resin transfer molding. Compared with the normal sandwich structures, the failure mode and flexural performance with different spans and core densities were investigated by three-point bending tests. Meanwhile, the influence of the tooth plate on the interfacial property was also studied. The test results show that in the case of foam core density of 35 kg/m ³ 80 kg/m³ and 150 kg/m³, the ultimate bending strength increases by 168%, 211% and 258%, respectively, compared with the normal sandwich beams and the interfacial shear strength are 0.09 MPa 0.21 MPa and 0.45 MPa in turn. With the change of core density and span, the structures mainly occur two kinds of failure modes, which are core shear and core indentation. The tooth plate suppresses shear failure effectively. In addition, the analytical model used to predict the ultimate bearing capacity of specimen was proposed. The calculated results are in good accordance with the experimented results. [ABSTRACT FROM AUTHOR]

The flexural behavior of twelve glulam beams reinforced with vertical CFRP lath under different reinforcement ratio and three comparison beams were tested to failure to investigate the failure modes, failure mechanism and flexural behaviors. The ultimate load, flexural stiffness and ductility of CFRP lath reinforced laminated timber beams were compared with those of unreinforced control beams. The test results show that reinforced laminated timber beams with CFRP lath can increase the ultimate load by 34. 2%-52. 3%, and bending stiffness by 8 .0% - 28.5%. Furthermore, the failure modes of the reinforced beams show ductile compression failures. Meanwhile, the comparison of two CFRP lath enhancement methods shows that the ultimate load and the maximum displacement of beams reinforced with vertical CFRP lath inlay are significantly improved. Based on the linear elastic theory and the mechanical model of the isolated elements, the equations for ultimate loads of three different destructive forms were developed. Compared with a large number of test data, the formula shows a satisfied accuracy. [ABSTRACT FROM AUTHOR]

The performance-based seismic design can hardly reflect the changes of global structure and local components performance by single software. Combined application of PERFORM-3D and ABAQUS can use their characteristics to make a comprehensive assessment of the structure seismic performance. Taking a tall building beyond code-specification as an example, performance levels and performance goals of tall buildings beyond the code-specification under major earthquake were established. The performance goals of all components under different levels can be defined in PERFORM-3D, and the stress-strain state of the steel in important components can be analyzed by ABAQUS. A comprehensive assessment of the structure seismic performance can be obtained by judging the global performance goals and the local stress-strain state. The result shows that combined using of these two kinds of software can reflect the seismic resistance of the structure, and the stress-strain state of local components. The assessment of seismic performance of the structure is more comprehensive and reliable by the combined application of the two kinds of software. [ABSTRACT FROM AUTHOR]

In order to investigate the seismic behavior and isolation effectiveness of a high-rise isolated structure on soft soil foundation, the shaking table tests of a high-rise isolated model on rigid and soft soil foundation were conducted. A laminar shear soil container was fabricated to minimize the boundary effects. With the similitude of the soil pressure, five-story steel frame models of aspect ratio 4, either with or without rubber bearings, supported by a pile group, and seated on a silty clay deposit, were subjected to different strong ground motions. From the results, it is found that soil-structure interaction (SSI) effects on high-rise isolated structure models are not as important as those in unisolated counterpart. Due to SSI, the natural frequency of the isolated model system is obviously reduced, and damping ratio largely increased. The efficiency of the presented isolation system on soft soil is confirmed. However, the ratio of peak acceleration of the isolated model to the unisolated one on soft soil is increased, with the isolation effectiveness reduced relatively. SSI can increase or decrease the seismic response of high-rise isolated model, depending on not only the type but also the intensity of the earthquake motion. It is also observed that the acceleration response spectrum of the foundation input motion agrees well with that of the free-field motion for the isolated structure. While, for the unisolated one, it is close to those of the ground motions at greater depths of soil. [ABSTRACT FROM AUTHOR]

The influence of soil-structure interaction (SSI) on Park-Ang damage index (PADI) of energy dissipating structures was investigated under seismic excitation. A systematic lumped-parameter model was used to represent dynamic impedance function of foundation-soil. The structure was assumed to be shear-type system which was based on the Takeda hysteretic model. Two parameters were used as the key parameters: peak ground motion acceleration of earthquakes and soil shear wave velocity. It is found in this study that, for the structures without energy dissipation devices, decreasing soil shear wave velocity has very little effect on PADI when peak ground motion acceleration is 0.1g. However, for the structures with energy dissipation devices, decreasing soil shear wave velocity increases PADI when peak ground motion acceleration is 0.1g. In addition, for the structures with energy dissipation devices and without energy dissipation devices, decreasing soil shear wave velocity increases PADI when peak ground motion acceleration is 0.3g. [ABSTRACT FROM AUTHOR]

Quasi-static tests on four reinforced concrete composite shear walls with opening and two reinforced concrete shear walls with opening under cyclic loading were reported. The deformation properties, failure mode were discussed, and the bearing capacity, hysteretic loops, skeleton curves, rigidity degradation curves, ductility and energy-dissipation were investigated. Test results indicate that the mechanical behavior of the reinforced concrete composite shear walls with opening is the same as that of the reinforced concrete shear walls with opening. The study shows that the reinforced concrete composite shear walls with opening have good seismic behavior. The prefabricated reinforced concrete cover for the thermal insulation can provide a certain extent of load carrying capacity, and the bearing capacity of the reinforced concrete composite shear walls with opening is higher than that of the reinforced concrete shear walls with opening about 7%. The prefabricated parts and the cast-in-situ concrete parts of the reinforced concrete composite shear walls with opening can work together in coordination very well under loading. [ABSTRACT FROM AUTHOR]

Quasi-static tests on three reinforced concrete composite shear walls with level splice and one reinforced concrete composite shear wall without level splice under cyclic loading were reported. Quasi-static test on one reinforced concrete shear wall under cyclic loading was reported too. The deformation properties and failure mode were discussed. The bearing capacity, hysteretic loops, skeleton curves, ductility and energy-dissipation were analyzed. Test results indicate that the mechanical behavior of the reinforced concrete composite shear walls with level splice and the reinforced concrete composite shear wall without level splice is the same as that of the reinforced concrete shear wall. The study shows that the reinforced concrete composite shear walls with level splice have good seismic behavior. The detailing requirements of the level splice are reasonable, and the load-carrying capacity of the reinforced concrete composite shear walls with level splice is greater than that of the reinforced concrete composite shear wall without level splice. The prefabricated parts and the cast-in-situ concrete parts of the reinforced concrete composite shear walls can work together very well under loading. [ABSTRACT FROM AUTHOR]

In order to explore the effect of the composite filling wall on the frame under earthquake, quasi-static tests on three composite filling wall frames with flexible connection and one pure RC frame under cyclic loading were conducted. A comparative study of the load process, crack development, failure mode was carried out. The differences between composite filling wall frames and fare frame in load carrying capacity, hysteretic behavior, ductility, stiffness and so on were focused on. To reduce the impact of the wallboard' s stiffness on the framework, a type of flexible connection between wall and frame was designed. The study shows that the hysteretic curves of composite filling wall frames were similar with pure RC frame, which indicate that the frame with the new type of composite wall has good seismic behavior. The ductility of the frame with the new type of composite wall with a side opening is the same as that of the bare frame. The connection between frame and wall has a reasonable design, with which the rigidity degradation of the frames with the new type of composite wall is the same as that of the bare frame. The connection also can effectively reduce the adverse effects of the wallboard, weaken the restraints between the wall and the column, and prevent the short column from damage. The connection can improve the walls' reliability and seismic resistance well. [ABSTRACT FROM AUTHOR]

This paper describes an experimental program of 25 glulam specimens with glued-in rebar which aim to investigate the influence of slenderness ratio (λ = la/d) of rebar and glue-line thickness on the pull out load, and bond behavior of glued-in rebar axially loaded parallel to the grain. The failure modes and mechanics of specimens were analyzed. Moreover, in order to obtain the bond stress distribution along the anchorage length of rebar, specimens with strain gauges attached to steel rebar internally were designed. The experimental results show that failure occurs mainly due to pull-out of rebar, shear failure of timber around the glue-line, splitting of timber and yielding of rebar. The pull out load of glued-in rebar increases with the increasing of both the anchorage length and glue-line thickness. The ductile failure of yielding rebar occurs with the slenderness ratio of rebar up to 12.5. Anchorage length and glue-line thickness have obvious influence on the bond behavior of glued-in rebar. The distribution of bond stress at rebar/ adhesive interface is not uniform, but rather accentuated near both the loading end and the anchorage end, which confirms the theory of Volkersen (1938). The variation of bond stress at rebar/adhesive interface is different from adhesive/timber interface with the increasing of glue-line thickness. With glue-line thickness increased from 2 mm to 6 mm, bond stress at rebar/adhesive interface increases, while decreases at adhesive/timber interface. Appropriate increasing of glue-line thickness is beneficial to the decreasing of peak value of bond stress. [ABSTRACT FROM AUTHOR]

Low-cycle reversed loading tests were conducted on five 1: 1. 67 scaled specimens without reinforcement, which were strengthened by curved steel dampers with different radius and thickness. The structure behaviors, such as the failure characteristics, P-Δ hysteretic loops, skeleton curves and energy dissipation capacity were analyzed. The low-cycle reversed loading tests were conducted only on the curved steel dampers to obtain the hysteretic loops as well as skeleton curves. The test results indicate that strengthened frames also obtain good deformation capacity. Dampers can enhance strength and stiffness, develop energy disipation of the frames. Strength and stiffness of strengthened frames are mostly provided by curved steel dampers. Their capacity will increase with the bigger thickness within a certain range. With the increase of radius, the strength and stiffness is weakened in the early loading stage, while the energy dissipation capacity will increase more in the later loading stage. [ABSTRACT FROM AUTHOR]

In order to research the reinforcement effects on masonry structure strengthened with external prefabricated reinforced concrete wall and investigate the possibility of added story isolation on the top of reinforced masonry structure, the shaking table tests of three 1/4 scaled models were conducted. These three models were reinforced masonry structure model, reinforced masonry structure with added story model and reinforced masonry structure with added story isolation model. The dynamic characteristics and seismic response of models were evaluated under different levels of earthquakes. And then, the models subjected to rare seismic cases were tested again to analyze the dynamic responses of damaged structures. The results indicate that added story isolation structure can prolong the structural vibration periods efficiently and increase the damping ratio. Whiplash effect of superstructure of added story non-isolation structure is very obvious. Added story isolation structure can not only reduce seismic response of the substructure effectively, but also reduce the seismic response of the superstructure; therefore, reinforcement effect and seismic performance of added story isolation structure are significant. On the other hand, the isolating effect of seismic damaged structure will be decreased obviously. Acceleration of lower masonry may be larger than those of the other two models. The negative impact must be taken into account in the design. [ABSTRACT FROM AUTHOR]

In order to obtain comprehensive brain activity information conveniently in real time, this study designs a portable EEG and blood oxygen synchronous acquisition system for real-time monitoring of brain functional activities. The EEG electrodes filter and amplify the detected EEG signals, and send them to the microprocessor via Bluetooth to analyze the EEG data; the photoelectric probe converts the optical signals into electrical signals, which are amplified and separated, filtered, and AD converted, calculates the brain's oxygenation and blood-red protein (ΔHbO 2 ) and blood-red protein (ΔHb) by amplification of Lambert-Beer law. Finally, experiments with commercial instruments NuAmps and Oximeter show that the system can calculate ΔHbO 2 and ΔHb while collecting EEG signals.

In order to diagnose and evaluate the human spinal lesions through the paravertebral muscles, a paravertebral muscle monitoring system based on surface EMG signals was designed. The system used surface mount electrodes to obtain the surface myoelectric signal (sEMG) of paravertebral muscle. The signal was filtered and amplified by the conditioning circuit. The signal was collected by the microcontroller NRF52832 and was sent to the mobile APP. After the signal was preprocessed by the wavelet threshold denoising algorithm in APP, the time and frequency characteristics of the sEMG signal reflecting the functional state of the muscle were extracted. The calculated characteristic parameters was displayed in real time in the application interface. The experimental results show that the system meets the design requirements in analog signal acquisition, digital processing of signals and calculation of characteristic parameters. The system has certain application value.

Objective: To explore the regional homogeneity of resting state brain activity in early onset schizophrenia using functional magnetic resonance imaging., Methods: Schizophrenia or schizophreniform disorder was diagnosed according to DSM-IV-TR (diagnostic and statistical manual of mental disorders, fourth edition, text revision). A total of 18 adolescents with early-onset schizophrenia (EOS; onset of psychotic symptoms by age 18) and 18 age- and gender-matched healthy volunteers were tested in a resting-state fMRI scan. Regional homogeneity approach was used to analyze the functional imaging data,and statistical parametric mapping 5 (SPM5)was used to perform t-test in ReHo maps between the patients and controls., Results: In comparison with the controls, the early-onset patients showed significantly decreased regional homogeneity in bilateral medial prefrontal cortex(P<0.001,uncorrected; voxel>20), but no brain regions showed significantly increased regional homogeneity in the patients., Conclusion: Regional homogeneity of resting state brain activities in EOS was decreased in bilateral medial prefrontal cortex. These abnormal changes may be involved in the psychopathology of schizophrenia.