Dynamic Elastic Modulus and Damping Ratio of Lignin-Modified Loess

The uniaxial cyclic fatigue tests on granite coming from the ChangJiang of Hainan nuclear power first-stage construction conventional island were done on the RMT-150B multi-function automatic rigid rock servo material testing machine. Stress amplitude of 10 MPa and sine wave cyclic loads with five different frequencies of 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, and 1 Hz were adopted as dynamic disturbance. The law between cyclic frequency and dynamic stress-dynamic strain hysteretic curve, dynamic elastic modulus and damping ratio are researched. The results showed that the curves of strain and stress for loading and unloading are not superposition under cyclic loading, but hysteretic loops. When cyclic frequency changes between 0.01 and 1.0 Hz, the granite hysteretic loop area, dynamic elastic modulus and damping ratio are increased with frequency increasing. The research result offered great reference value to seismic response analysis and site safety evaluation of the changjiang nuclear power.

Download Full-text

Study on the Cement-Improved Loess under the Vibratory Load by Dynamic Tests

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.838-841.1302 ◽

2013 ◽

Vol 838-841 ◽

pp. 1302-1308 ◽

Cited By ~ 2

Author(s):

Jia Ding Wang ◽

Shu Jun Peng ◽

Wan Li Xie

Keyword(s):

Elastic Modulus ◽

Dynamic Characteristics ◽

High Speed ◽

Dynamic Deformation ◽

Damping Ratio ◽

Test Method ◽

Dynamic Elastic Modulus ◽

Dynamic Tests ◽

Long Time ◽

Orthogonal Test Method

In this paper based on the foundation construction of Datong Xian high-speed railway, a large number of test samples have been taken. The order and contribution rate of every experiment factor like cement commingle ratio, depths, water dipping conditions, compacting factor and vibration frequency on the dynamic characteristics of cement-improved loess such as dynamic elastic modulus, dynamic deformation, damping ratio by dynamic triaxial test, which orthogonal test method has been applied to. The dynamic load was calculated according to the train vibration attenuation rule of different depth. The dynamic characteristics of cement-improved loess such as dynamic deformation, dynamic elastic modulus, damping ratio were got form the dynamic tests of long time and large number of cycles. The results showed that with the increase of cement ratio, the dynamic characteristics of cement-improved loess are more better, there is no optimal ratio of cement.

Download Full-text

Dynamic Behavior and Constitutive Relationship of Mudstone Slip Zone of Landslide with Weak Interlayer

Shock and Vibration ◽

10.1155/2021/3330127 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Jingjing Zhou ◽

Fasuo Zhao ◽

Yanbo Zhu ◽

Wenqi Dong ◽

Ziguang He

Keyword(s):

Elastic Modulus ◽

Dynamic Behavior ◽

Empirical Model ◽

Dynamic Stress ◽

Stress Amplitude ◽

Damping Ratio ◽

Constitutive Relationship ◽

Dynamic Elastic Modulus ◽

Loading Frequency ◽

Mountain Area

Sliding zone dynamics in the Qinling-Daba mountain area under different dynamic parameters have not been studied extensively. In this study, we investigated the dynamic behavior of the sliding zones of a high-steep rock landslide in the Qinling-Daba mountain area under the influence of dynamic stress amplitude and frequency and proposed an empirical model of the dynamic constitutive relationship. The dynamic behavior was studied based on a cyclic triaxial test system. The results indicated that an increase in the dynamic stress amplitude decreased the dynamic elastic modulus linearly, increased the damping ratio, and increased the axial strain exponentially. Among these properties, the elastic strain was found to be more sensitive to the increase in the dynamic stress amplitude than the plastic strain. As the loading frequency increased, the dynamic elastic modulus increased, whereas the damping ratio decreased. Furthermore, the proposed empirical model of the dynamic constitutive relationship between the vibration number and loading frequency based on the dynamic elastic modulus could satisfactorily describe the dynamic stress-strain relationships of the samples from test stability and failure zones. These findings are expected to make a significant contribution toward further revealing the sliding mechanism of such landslides.

Download Full-text

Evaluation Principles and Applications of Dynamic Elastic Modulus and Damping Ratio of Structural Materials Using the IET Method

Transactions of the Korean Society of Mechanical Engineers A ◽

10.3795/ksme-a.2019.43.4.261 ◽

2019 ◽

Vol 43 (4) ◽

pp. 261-266

Author(s):

Sun A Yoon ◽

Jung Kwon Lee ◽

Chang Soon Lee ◽

Tae Hwan Lim ◽

Chul Woon Han ◽

...

Keyword(s):

Elastic Modulus ◽

Damping Ratio ◽

Structural Materials ◽

Dynamic Elastic Modulus

Download Full-text

Sandstone Dynamical Characteristics Influenced by Water-Rock Interaction of Bank Slope

Advances in Civil Engineering ◽

10.1155/2019/3279586 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11 ◽

Cited By ~ 3

Author(s):

Huafeng Deng ◽

Yinchai Zhang ◽

Yongyan Zhi ◽

Lingling Duan ◽

Jianlin Li ◽

...

Keyword(s):

Elastic Modulus ◽

Dynamic Response ◽

Stress Amplitude ◽

Damping Ratio ◽

Dynamic Parameter ◽

Interaction Process ◽

Dynamic Elastic Modulus ◽

Rock Interaction ◽

Bank Slope ◽

Water Rock Interaction

During the long-term reservoir operation, the seismic capability and dynamic response characteristics of the bank slope are of great importance to its safety evaluation content. Aimed at typical bank slopes, considering reservoir water level fluctuation and soaking-air drying cyclic interaction, an experiment has been designed and conducted. In addition, the cyclic loading test with different stress amplitudes was carried out in different water-rock cycles. The laboratory results indicate that (1) during the immersion-air dry circulation process, the damping ratio and damping coefficient of sandstone gradually increased while the dynamic elastic modulus decreased. It is obvious that the dynamic elastic modulus of sandstone decreases dramatically during the immersion-air dry circulation process, especially in the first six periods. Also, its variation curve fits with the logarithmic curve. (2) When the cyclic load stress amplitude increases from 10 MPa to 35 MPa, the damping ratio and coefficient of the rock sample gradually decreased while dynamic elastic modulus increased. each dynamic parameter shows a more obvious variation trend when the stress amplitude is lower than 25 MPa. (3) During the water-rock interaction process, the closely knit microstructure of rock gradually becomes loose and porous, which resulted in the degradation of macroscopic physical and mechanical properties of sandstone. (4) In the analysis of the seismic response of the bank slope, the actual water-rock interaction process and the seismic level of the bank slope should be more considered. To find out further accurate reflection in the earthquake resistance and dynamic response of the bank slope, it is necessary to select the reasonable dynamic parameter to carry out seismic research.

Download Full-text

Natural stone test methods. Determination of the dynamic elastic modulus of elasticity (by measuring the fundamental resonance frequency)

10.3403/03027526 ◽

2004 ◽

Cited By ~ 3

Keyword(s):

Elastic Modulus ◽

Resonance Frequency ◽

Modulus Of Elasticity ◽

Test Methods ◽

Natural Stone ◽

Dynamic Elastic Modulus ◽

Fundamental Resonance ◽

Fundamental Resonance Frequency

Download Full-text

Studies the Properties of Polyaspartic Polyurea Coated Concrete under Coaction of Salt Fog and Freeze-Thaw

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.455-456.781 ◽

2012 ◽

Vol 455-456 ◽

pp. 781-785

Author(s):

Ping Lu ◽

Xin Mao Li ◽

Xue Qiang Ma ◽

Wei Bo Huang

Keyword(s):

Elastic Modulus ◽

Frost Resistance ◽

Dynamic Elastic Modulus ◽

Freeze Thaw ◽

Decrease Rate ◽

Thaw Cycle ◽

Freeze Thaw Cycle ◽

Salt Fog

. This paper mainly studied the properties of PAE polyurea coated concrete under coactions of salt fog and freeze-thaw. After exposed salt fog conditions for 200d, T3, B2, F2 and TM four coated concrete relative dynamic elastic modulus have small changes, but different coated concrete variation amplitude is different. T3 coated concrete after 100 times of freeze-thaw cycle the relative dynamic elastic modulus began to drop, 200 times freeze-thaw cycle ends, relative dynamic elastic modulus variation is the largest, decrease rate is 95%, TM concrete during 200 times freeze-thaw cycle, relative dynamic elastic modulus almost no change, B2 concrete and F2 concrete the extent of change between coating T3 and TM. After 300 times the freeze-thaw cycle coated concrete didn't appear freeze-thaw damage phenomenon. Four kinds of coating concrete relative dynamic elastic modulus variation by large to small order: T3 coated concrete > B2 coated concrete >F2 coated concrete > TM coated concrete, concrete with the same 200d rule. Frost resistance order, by contrast, TM coated concrete > B2 coated concrete > F2 coated concrete > T3 coated concrete.

Download Full-text

Use of Silica Fume and GGBS to Improve Frost Resistance of ECC with High-Volume Fly Ash

Advances in Civil Engineering ◽

10.1155/2018/7987589 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Yushi Liu ◽

Xiaoming Zhou ◽

Chengbo Lv ◽

Yingzi Yang ◽

Tianan Liu

Keyword(s):

Elastic Modulus ◽

Sodium Chloride ◽

Mass Loss ◽

Frost Resistance ◽

Chloride Solution ◽

Sodium Chloride Solution ◽

Tap Water ◽

High Volume ◽

Dynamic Elastic Modulus ◽

Freeze Thaw

Fly ash (FA) has been an important ingredient for engineered cementitious composite (ECC) with excellent tensile strain capacity and multiple cracking. Unfortunately, the frost resistance of ECC with high-volume FA has always been a problem. This paper discusses the influence of silica fume (SF) and ground-granulated blast-furnace slag (GGBS) on the frost resistance of ECC with high volume of FA. Four ECC mixtures, ECC (50% FA), ECC (70% FA), ECC (30% FA + 40% SL), and ECC (65% FA + 5% SF), are evaluated by freezing-thawing cycles up to 200 cycles in tap water and sodium chloride solution. The result shows the relative dynamic elastic modulus and mass loss of ECC in sodium chloride solution by freeze-thaw cycles are larger than those in tap water by freeze-thaw cycles. Moreover, the relative dynamic elastic modulus and mass loss of ECC by freeze-thaw cycles increase with FA content increasing. However, the ECC (30% FA + 40% SL) shows a lower relative dynamic elastic modulus and mass loss, but its deflection upon four-point bending test is relatively smaller before and after freeze-thaw cycles. By contrast, the ECC (65% FA + 5% SF) exhibits a significant deflection increase with higher first cracking load, and the toughness increases sharply after freeze-thaw cycles, meaning ECC has good toughness property.

Download Full-text