Exploring the dynamic response and energy dissipation capacity of functionally graded EPS concrete

It is apparent that the dynamic response of a building dependson its energy dissipation capacity, hence damping ratio. Thedamping value experienced by a building during an earthquakediffers significantly from the value specified in the design step.This introduces uncertainties in the design process of the building.It would be desirable to consider not only the effects ofuncertainties in loading but also the uncertainties in the structuralparameters. In this paper, the effects of uncertainties in the estimation ofdamping ratio ξ, on the use of Damping Reduction Factors (DRF) for the evaluation of high damping response spectra,are examined. Damping uncertainties are described by a lognormalprobability distribution, and the Monte Carlo techniqueis used to generate the random values of damping. Theaverage of the distribution is the deterministic value of damping (taken equal to 5%, 7.5%, 10%, 20%, 30% and 40%) whilethree different values of coefficient of variation are considered (i.e. 10%, 20% and 40%, respectively). All the DRF formulations found in the literature are not able totake into consideration damping uncertainties, leading to significantdiscrepancies in the high damping response spectra. Based on the results of this study, a new DRF formulation, ableto account for uncertainties in damping estimation, is tentatively proposed.

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Influence of pore shape on impact dynamics characteristics of functionally graded brittle materials

The Journal of Strain Analysis for Engineering Design ◽

10.1177/03093247211029792 ◽

2021 ◽

pp. 030932472110297

Author(s):

Yongqiang Li ◽

Nianzhu Wang ◽

Wenkai Yao ◽

Tao Wang ◽

Mao Zhou

Keyword(s):

Energy Dissipation ◽

Impact Energy ◽

Elastic Limit ◽

Brittle Materials ◽

Functionally Graded ◽

Deformation Wave ◽

Hugoniot Elastic Limit ◽

Piston Velocity ◽

Energy Dissipation Capacity ◽

The Impact

Improving the impact energy dissipation capacity of functionally graded brittle materials through pore design will help avoid or delay failure. In order to improve the impact energy dissipation capacity of functionally graded brittle materials, pores with specific shapes can be implanted inside them. The effect of pore shape on the impact properties of functionally graded brittle materials was investigated using a lattice-spring model that can quantitatively represent the mechanical properties of functionally graded brittle materials. The calculated results show that the pores with negative Poisson’s ratio such as inner-concave triangle, fourth-order star, and inner-concave hexagon are easy to collapse under the impact, while the square and square-hexagon pores have the strongest resistance to deformation. For all seven pore shapes, the Hugoniot elastic limit of the samples decreased gradually with increasing porosity, and the Hugoniot elastic limit did not change with the change of piston velocity. The propagation velocity of the deformation wave increases with the piston velocity and the velocity of the particle corresponding to the Hugoniot state behind the deformation wave increases accordingly. The principle that pores can enhance the macroscopic impact energy dissipation capacity of functionally graded brittle material samples revealed in this paper will contribute to the prevention of sample impact failure and provide guidance for the optimal design of impact kinetic properties of samples.

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ENHANCEMENT OF ENERGY DISSIPATION CAPACITY OF OIL DAMPER BY INTRODUCING MULTISTEP ENERGY RECOVERY SYSTEM

Journal of Structural and Construction Engineering (Transactions of AIJ) ◽

10.3130/aijs.85.1407 ◽

2020 ◽

Vol 85 (777) ◽

pp. 1407-1417

Author(s):

Ryusuke FUKUDA ◽

Haruhiko KURINO

Keyword(s):

Energy Dissipation ◽

Energy Recovery ◽

Energy Recovery System ◽

Recovery System ◽

Energy Dissipation Capacity

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Experimental and Numerical Analysis of the Mechanical Properties of a Pretreated Shape Memory Alloy Wire in a Self-Centering Steel Brace

Processes ◽

10.3390/pr9010080 ◽

2021 ◽

Vol 9 (1) ◽

pp. 80

Author(s):

Bo Zhang ◽

Sizhi Zeng ◽

Fenghua Tang ◽

Shujun Hu ◽

Qiang Zhou ◽

...

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Energy Dissipation ◽

Shape Memory Alloy ◽

Shape Memory ◽

Loading Rate ◽

Effective Elastic Modulus ◽

Maximum Energy ◽

Numerical Results ◽

Energy Dissipation Capacity

As a stimulus-sensitive material, the difference in composition, fabrication process, and influencing factors will have a great effect on the mechanical properties of a superelastic Ni-Ti shape memory alloy (SMA) wire, so the seismic performance of the self-centering steel brace with SMA wires may not be accurately obtained. In this paper, the cyclic tensile tests of a kind of SMA wire with a 1 mm diameter and special element composition were tested under multi-working conditions, which were pretreated by first tensioning to the 0.06 strain amplitude for 40 cycles, so the mechanical properties of the pretreated SMA wires can be simulated in detail. The accuracy of the numerical results with the improved model of Graesser’s theory was verified by a comparison to the experimental results. The experimental results show that the number of cycles has no significant effect on the mechanical properties of SMA wires after a certain number of cyclic tensile training. With the loading rate increasing, the pinch effect of the hysteresis curves will be enlarged, while the effective elastic modulus and slope of the transformation stresses in the process of loading and unloading are also increased, and the maximum energy dissipation capacity of the SMA wires appears at a loading rate of 0.675 mm/s. Moreover, with the initial strain increasing, the slope of the transformation stresses in the process of loading is increased, while the effective elastic modulus and slope of the transformation stresses in the process of unloading are decreased, and the maximum energy dissipation capacity appears at the initial strain of 0.0075. In addition, a good agreement between the test and numerical results is obtained by comparing with the hysteresis curves and energy dissipation values, so the numerical model is useful to predict the stress–strain relations at different stages. The test and numerical results will also provide a basis for the design of corresponding self-centering steel dampers.

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Experimental/Numerical Evaluation of Steel Trapezoidal Corrugated Infill Panels with an Opening

Applied Sciences ◽

10.3390/app11073275 ◽

2021 ◽

Vol 11 (7) ◽

pp. 3275

Author(s):

Majid Yaseri Gilvaee ◽

Massood Mofid

Keyword(s):

Energy Dissipation ◽

Ultimate Strength ◽

Steel Plate ◽

Shear Walls ◽

Experimental Results ◽

Structural Performance ◽

Initial Stiffness ◽

Infill Panels ◽

Energy Dissipation Capacity ◽

Ductility Ratio

This paper investigates the influence of an opening in the infill steel plate on the behavior of steel trapezoidal corrugated infill panels. Two specimens of steel trapezoidal corrugated shear walls were constructed and tested under cyclic loading. One specimen had a single rectangular opening, while the other one had two rectangular openings. In addition, the percentage of opening in both specimens was 18%. The initial stiffness, ultimate strength, ductility ratio and energy dissipation capacity of the two tested specimens are compared to a specimen without opening. The experimental results indicate that the existence of an opening has the greatest effect on the initial stiffness of the corrugated steel infill panels. In addition, the experimental results reveal that the structural performance of the specimen with two openings is improved in some areas compared to the specimen with one opening. To that end, the energy dissipation capacity of the specimen with two openings is obtained larger than the specimen with one opening. Furthermore, a number of numerical analyses were performed. The numerical results show that with increasing the thickness of the infill plate or using stiffeners around the opening, the ultimate strength of a corrugated steel infill panel with an opening can be equal to or even more than the ultimate strength of that panel without an opening.

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Dynamic response of a functionally graded cylindrical tube with power-law varying properties due to SH-waves

Waves in Random and Complex Media ◽

10.1080/17455030.2021.1948628 ◽

2021 ◽

pp. 1-19

Author(s):

Ning Zhang ◽

Yu Zhang ◽

Denghui Dai

Keyword(s):

Dynamic Response ◽

Power Law ◽

Cylindrical Tube ◽

Functionally Graded ◽

Sh Waves

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Estimation of Additional Equivalent Damping Ratio of the Damped Structure Based on Energy Dissipation

Advances in Civil Engineering ◽

10.1155/2019/8052413 ◽

2019 ◽

Vol 2019 ◽

pp. 1-14

Author(s):

Xiuyan Hu ◽

Qingjun Chen ◽

Dagen Weng ◽

Ruifu Zhang ◽

Xiaosong Ren

Keyword(s):

Energy Dissipation ◽

Damping Ratio ◽

Theoretical Concept ◽

Estimation Methods ◽

External Excitation ◽

Single Degree Of Freedom ◽

Equivalent Damping ◽

Seismic Motion ◽

Practical Engineering ◽

Energy Dissipation Capacity

In the design of damped structures, the additional equivalent damping ratio (EDR) is an important factor in the evaluation of the energy dissipation effect. However, previous additional EDR estimation methods are complicated and not easy to be applied in practical engineering. Therefore, in this study, a method based on energy dissipation is developed to simplify the estimation of the additional EDR. First, an energy governing equation is established to calculate the structural energy dissipation. By means of dynamic analysis, the ratio of the energy consumed by dampers to that consumed by structural inherent damping is obtained under external excitation. Because the energy dissipation capacity of the installed dampers is reflected by the additional EDR, the abovementioned ratio can be used to estimate the additional EDR of the damped structure. Energy dissipation varies with time, which indicates that the ratio is related to the duration of ground motion. Hence, the energy dissipation during the most intensive period in the entire seismic motion duration is used to calculate the additional EDR. Accordingly, the procedure of the proposed method is presented. The feasibility of this method is verified by using a single-degree-of-freedom system. Then, a benchmark structure with dampers is adopted to illustrate the usefulness of this method in practical engineering applications. In conclusion, the proposed method is not only explicit in the theoretical concept and convenient in application but also reflects the time-varying characteristic of additional EDR, which possesses the value in practical engineering.

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