Dynamic shear stiffness and damping ratio of marine calcareous and siliceous sands

2018 ◽  
Vol 38 (4) ◽  
pp. 315-322 ◽  
Author(s):  
Hamed Javdanian ◽  
Yaser Jafarian
Keyword(s):  
Damping Ratio ◽  
Shear Stiffness ◽  
Dynamic Shear ◽  
Stiffness And Damping

scholarly journals Experimental Investigation of Dynamic Characteristics of Subsea Sand-Silt Mixtures

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Tugen Feng ◽  
Yu Tang ◽  
Qiyenan Wang ◽  
Jian Zhang ◽  
Jian Song
Keyword(s):  
Cement Content ◽  
Damping Ratio ◽  
Shear Stiffness ◽  
Confining Pressure ◽  
Dynamic Responses ◽  
Resonant Column ◽  
Dynamic Shear ◽  
Column Tests ◽  
Mixture Ratio ◽  
Curing Age

In this paper, extensive resonant column tests were conducted to investigate dynamic responses of subsea sand-silt mixtures. The effects of confining pressure, mixture ratio, curing age, and cement content were evaluated. For the test condition considered in this study, the measured damping ratio is the smallest when the ratio of subsea sand to silt is in a range of 1.5 to 2.0. Moreover, unsolidified subsea sand-silt mixed at a ratio of 1.5 has almost the same maximum shear stiffness as the pure sand. For solidified subsea sand-silt mixture, cement can significantly increase the dynamic shear stiffness when the curing age is less than 14 days. However, the increase of the maximum dynamic shear stiffness is negligible when the curing age is longer than 14 days. When the cement content is 2%, the damping ratio of the solidified mixtures is very close to that of the unsolidified mixture. When the cement content is higher than 4%, the damping ratio of the solidified mixtures reduces significantly. This is mainly due to hydration reactions occurring in the solidified mixtures.

scholarly journals Experimental study on the shear stiffness and damping ratio of the coarse-grained soil against geogrid interface

2020 ◽  
Vol 22 (7) ◽  
pp. 1606-1617
Author(s):  
Chunhui Su ◽  
Aijun Chen ◽  
Junhua Chen ◽  
Xianyuan Tang ◽  
Zhaoyao Yuan
Keyword(s):  
Experimental Study ◽  
Damping Ratio ◽  
Shear Stiffness ◽  
Coarse Grained ◽  
Stiffness And Damping ◽  
Coarse Grained Soil

scholarly journals Identification of Dynamic Parameters of Pedestrian Walking Model Based on a Coupled Pedestrian–Structure System

2021 ◽  
Vol 11 (14) ◽  
pp. 6407
Author(s):  
Huiqi Liang ◽  
Wenbo Xie ◽  
Peizi Wei ◽  
Dehao Ai ◽  
Zhiqiang Zhang
Keyword(s):  
Negative Correlation ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Field Testing ◽  
The Body ◽  
Structural Vibration ◽  
Pedestrian Dynamics ◽  
Structure Interaction ◽  
Mass Spring ◽  
Stiffness And Damping

As human occupancy has an enormous effect on the dynamics of light, flexible, large-span, low-damping structures, which are sensitive to human-induced vibrations, it is essential to investigate the effects of pedestrian–structure interaction. The single-degree-of-freedom (SDOF) mass–spring–damping (MSD) model, the simplest dynamical model that considers how pedestrian mass, stiffness and damping impact the dynamic properties of structures, is widely used in civil engineering. With field testing methods and the SDOF MSD model, this study obtained pedestrian dynamics parameters from measured data of the properties of both empty structures and structures with pedestrian occupancy. The parameters identification procedure involved individuals at four walking frequencies. Body frequency is positively correlated to the walking frequency, while a negative correlation is observed between the body damping ratio and the walking frequency. The test results further show a negative correlation between the pedestrian’s frequency and his/her weight, but no significant correlation exists between one’s damping ratio and weight. The findings provide a reference for structural vibration serviceability assessments that would consider pedestrian–structure interaction effects.

Influencing Factors on Dynamic Response of Hydrostatic Guideways

2011 ◽  
Vol 418-420 ◽  
pp. 2095-2101 ◽  
Author(s):  
Zhi Wei Wang ◽  
Wan Hua Zhao ◽  
Bing Heng Lu
Keyword(s):  
Film Thickness ◽  
Damping Ratio ◽  
Pressure Ratio ◽  
Settling Time ◽  
Lubricating Oil ◽  
Oil Viscosity ◽  
Supply Pressure ◽  
Maximum Value ◽  
Small Perturbation Method ◽  
Stiffness And Damping

Stiffness and damping of hydrostatic guideways are calculated by small perturbation method based on Reynolds equation in dynamic regime. The hydrostatic guideway is considered as a system which consists of the mass, the spring and the damper. The effects of some main parameters on stiffness, damping and damping ratio are analyzed which include the supply pressure, the film thickness, the pad dimension, the pressure ratio, the lubricating oil volume and the lubricating oil viscosity. The relationships between the settling time of the hydrostatic guideways and these parameters are investigated under a step load. It is shown that the slide block returns to equilibrium without overshooting under a step load, and the amplitude of the block vibration has not a maximum value under a cyclic load, due to the large damping effect( ξ>1). In addition, the settling time can be shorten with the increase of the supply pressure, the film thickness and the lubricating oil volume, and also with the decrease of the pressure ratio and the lubricating oil viscosity. The settling time get the shortest value when recess parameter( α) is 0.55.

Shear Modulus and Damping Ratio of Gravel Material

2011 ◽  
Vol 105-107 ◽  
pp. 1426-1432 ◽  
Author(s):  
De Gao Zou ◽  
Tao Gong ◽  
Jing Mao Liu ◽  
Xian Jing Kong
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Strain Amplitude ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Dynamic Shear Modulus ◽  
Test Results ◽  
Dynamic Shear ◽  
Data Points ◽  
Shear Strain Amplitude

Two of the most important parameters in dynamic analysis involving soils are the dynamic shear modulus and the damping ratio. In this study, a series of tests were performed on gravels. For comparison, some other tests carried out by other researchers were also collected. The test results show that normalized shear modulus and damping ratio vary with the shear strain amplitude, (1) normalized shear modulus decreases with the increase of dynamic shear strain amplitude, and as the confining pressure increases, the test data points move from the low end toward the high end; (2) damping ratio increases with the increase of shear strain amplitude, damping ratio is dependent on confining pressure where an increase in confining pressure decreased damping ratio. According to the test results, a reference formula is proposed to evaluate the maximum dynamic shear modulus, the best-fit curve and standard deviation bounds for the range of data points are also proposed.

Experimental Study on Dynamic Characteristics of Ionic Soil Stabilizer Reinforcing Red Clay

2011 ◽  
Vol 374-377 ◽  
pp. 1391-1395
Author(s):  
Xue Song Lu ◽  
Wei Xiang
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Dynamic Condition ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Natural Soil ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Red Clay ◽  
Soil Stabilizer

Based on the red clay of Wuhan reinforced by Ionic Soil Stabilizer, the red clay soil is treated by different matches of ISS at first, then is tested in the Atterberg limits test and dynamic triaxia test. The results show that the plastic index decreases, and the red clay were greatly improved under the dynamic condition, the maximum dynamic shear modulus ratio acquired an incensement of 27.72% on average after mixing the ISS into the red clay. In addition, It was concluded that the confining pressure influenced the dynamic shear modulus and damping ratio to a certain extent. Given the same strain conditions, with the incensement of confining pressure increases, the dynamic shear modulus increased and the damping ratio decreased. Moreover, when plotting the dynamic shear modulus versus the dynamic shear strain, the similar curve can be formed for both the natural soil and the modified one, the dynamic shear modulus monotonously decreased with the incensement of the dynamic shear strain. However, the value of dynamic shear modulus differed in the same shear strain between the natural soil and the soil modified by ISS.

scholarly journals Characterization of the Dynamic Properties of Clay–Gravel Mixtures at Low Strain Level

2020 ◽  
Vol 12 (4) ◽  
pp. 1616 ◽  
Author(s):  
Xianwen Huang ◽  
Aizhao Zhou ◽  
Wei Wang ◽  
Pengming Jiang
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Mechanical Performance ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Strain Level ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Gravel Content

In order to support the dynamic design of subgrade filling engineering, an experiment on the dynamic shear modulus (G) and damping ratio (D) of clay–gravel mixtures (CGMs) was carried out. Forty-two groups of resonant column tests were conducted to explore the effects of gravel content (0%, 10%, 20%, 30%, 40%, 50%, and 60%, which was the mass ratio of gravel to clay), gravel shape (round and angular gravels), and confining pressure (100, 200, and 300 kPa) on the dynamic shear modulus, and damping ratio of CGMs under the same compacting power. The test results showed that, with the increase of gravel content, the maximum dynamic shear modulus of CGMs increases, the referent shear strain increases linearly, and the minimum and maximum damping ratios decrease gradually. In CGMs with round gravels, the maximum dynamic shear modulus and the maximum damping ratio are greater, and the referent shear strain and the minimum damping ratio are smaller, compared to those with angular gravels. With the increase of confining pressure, the maximum dynamic shear modulus and the referent shear strain increase nonlinearly, while the minimum and maximum damping ratios decrease nonlinearly. The predicting equation for the dynamic shear modulus and the damping ratio of CGMs when considering confining pressure, gravel content, and shape was established. The results of this research may put forward a solid foundation for engineering design considering low-strain-level mechanical performance.

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