scholarly journals The Dynamic Response of the Vibrating Compactor Roller, Depending on the Viscoelastic Properties of the Soil

2020 ◽  
Vol 3 (2) ◽  
pp. 25
Author(s):  
Cornelia Dobrescu
Keyword(s):  
Dynamic Response ◽  
Soil Compaction ◽  
Viscoelastic Properties ◽  
Dynamic Effect ◽  
Pulse Response ◽  
Compaction Process ◽  
Response Curves ◽  
Soil Layers ◽  
Transmitted Force ◽  
Practical Engineering

The present paper addresses the problem of the dynamic response of a vibrating equipment for soil compaction. In essence, dynamic response vibrations are analysed by applying an inertial-type perturbing force. This is generated by rotating an eccentric mass with variable angular velocity, in order to reach the regime necessary to ensure the degree of compaction. The original character of the research is that during the compaction process, the soil layers with certain compositions of clay, sand, water and stabilizing substances change their rigidity and/or amortization. In this case, two situations were analysed, both experimentally and with numerical modelling, with special results and practical engineering conclusions, favourable to the evaluation of the interaction between vibrator roller–compacted ground. We mention that the families of amplitude–pulse and transmitted force–pulse response curves are presented, from which the dynamic effect in the compaction process results after each passage on the same layer of soil, until the necessary compaction state is reached.

Steady-State Dynamic Response of a Limited Slip System

1968 ◽  
Vol 35 (2) ◽  
pp. 322-326 ◽  
Author(s):  
W. D. Iwan
Keyword(s):  
Steady State ◽  
Dynamic Response ◽  
Slip System ◽  
External Load ◽  
Initial Conditions ◽  
Viscous Damping ◽  
Steady State Response ◽  
Response Curves ◽  
State Response ◽  
System Nonlinearity

The steady-state response of a system constrained by a limited slip joint and excited by a trigonometrically varying external load is discussed. It is shown that the system may possess such features as disconnected response curves and jumps in response depending on the strength of the system nonlinearity, the level of excitation, the amount of viscous damping, and the initial conditions of the system.

The Dynamic Response of a Simple Elastic System to Antisymmetric Forcing Functions Characteristic of Airplanes in Unsymmetric Landing Impact

1949 ◽  
Vol 16 (3) ◽  
pp. 310-316
Author(s):  
Joseph B. Woodson
Keyword(s):  
Dynamic Response ◽  
Sine Wave ◽  
Response Curves ◽  
Response Factors ◽  
Natural Period ◽  
Wave Pulse ◽  
Pulse Disturbance ◽  
Landing Impact ◽  
Forcing Functions ◽  
The Difference

Abstract This paper presents an analysis of the dynamic response of an undamped mechanical system with one degree of freedom subjected to disturbances which are described by antisymmetric forcing functions. The analysis was undertaken to throw light on the effect on the vibration of the wings caused by unsymmetric landing impact of an airplane. Two types of disturbances are considered; a full-sine-wave pulse, and a pulse which is the difference between two overlapping half sine waves. The results are presented in the form of dynamic-response curves and dynamic-response-factor curves. The numerically greatest dynamic-response factors, approximately 3.24 and −3.26, resulted for a full-sine-wave pulse disturbance with a ratio of duration of impact to natural period, Ti/T ≅ 1.11. When Ti/T is in the neighborhood of 1, the first positive peak of dynamic response is numerically less than the negative and positive peaks which follow it. For much of the range, the positive and negative dynamic-response factors are numerically approximately equal. The analysis was confined to values of Ti/T between 0.33 and 12. As Ti/T increases without limit, the positive and negative dynamic-response factors tend to 1 and −1, respectively.

scholarly journals Dynamic behaviour of an earthen material under different impact loading conditions

2018 ◽  
Vol 183 ◽  
pp. 02014
Author(s):  
Luigi Fenu ◽  
Francesco Aymerich ◽  
Luca Francesconi ◽  
Daniele Forni ◽  
Nicoletta Tesio ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Impact Loading ◽  
Dynamic Behaviour ◽  
Hopkinson Bar ◽  
Impact Response ◽  
Favourable Effect ◽  
Impact Loads ◽  
Response Curves ◽  
Hemp Fibres ◽  
Modified Hopkinson Bar

The dynamic behaviour of earthen materials reinforced with natural fibres is little studied although earth buildings are often built in seismic areas. In this paper the dynamic behaviour of an earthen material reinforced with hemp fibres under different impact loadings has been experimentally investigated. The dynamic response of the material in 3-point bending was investigated through an instrumented dropweight device, while the response in tension and in compression was investigated through a modified Hopkinson bar device. Typical impact response curves for tension, compression and bending impact tests have been obtained. The favourable effect of fibres in dissipating fracture energy under impact loads has been observed in all these types of test.

DEVELOPMENT OF A HYBRID SOIL PRESSURE SENSOR AND ITS APPLICATION TO SOIL COMPACTION

2020 ◽  
Author(s):  
Mark Talesnick ◽  
Moti Ringel ◽  
Kyle Rollins
Keyword(s):  
Pressure Sensor ◽  
Soil Compaction ◽  
Compaction Pressure ◽  
Confining Pressure ◽  
Soil Pressure ◽  
Compaction Process ◽  
Vibratory Compaction ◽  
Soil Strain ◽  
The Relationship

A new soil pressure sensor based on a combination of the deflecting membrane and fluid filled approaches has been developed. The advantages of this combined approach are that issues of sensor compliance are eliminated without reducing the effectiveness of the sensor to be used for dynamic measurements. Calibration and verification testing performed under controlled laboratory conditions illustrate these benefits. The new system was implemented in a full-scale field trial which involved the construction of a compacted engineered fill 1.8 m in height. As each layer of fill was placed and compacted vertical in-soil pressure and vertical in-soil strain were continuously measured. During the vibratory compaction process both vertical soil pressure and vertical soil strain histories were captured in each layer. The data collected allowed for the determination of fill stiffness for both static and dynamic conditions. The results illustrate the effect of both confining pressure and strain level on fill stiffness. The relationship between compaction pressure and depth is clearly defined.

Dynamic response of a concrete dam impounding an ice-covered reservoir: Part II. Parametric and numerical study

2004 ◽  
Vol 31 (6) ◽  
pp. 965-976 ◽  
Author(s):  
Najib Bouaanani ◽  
Patrick Paultre ◽  
Jean Proulx
Keyword(s):  
Dynamic Response ◽  
Frequency Response ◽  
Parametric Study ◽  
Seismic Analysis ◽  
Numerical Study ◽  
Ice Cover ◽  
Concrete Dams ◽  
Response Curves ◽  
Concrete Dam ◽  
Structure Interaction

This paper presents a numerical and parametric study of the effect of an ice cover on the dynamic response of a concrete dam using the approach proposed in the companion paper in this issue. The method was programmed and implemented in a finite element code specialized for the seismic analysis of concrete dams. The 84-m-high Outardes 3 concrete gravity dam in northeastern Quebec was chosen as a model for this research. Some basic aspects of the numerical model are established in this paper and we show that the ice cover affects the dynamic response of the ice–dam–reservoir system. Main features of this influence are emphasized and discussed in a parametric study through the analysis of: (i) acceleration frequency response curves at the dam crest, (ii) hydrodynamic frequency response curves inside the reservoir, and (iii) the hydrodynamic pressure distribution on the upstream face of the dam. Key words: gravity dams, concrete dams, ice, reservoirs, mathematical models, ice–structure interaction, fluid–structure interaction, forced-vibration testing, finite elements modelling.

The Effect of Structure Bury Depth on Dynamic Response of Underground Tunnel under Longitudinal Shearing Seismic Action

2014 ◽  
Vol 1020 ◽  
pp. 415-422
Author(s):  
Ying Qian Xu ◽  
Cheng Zhi Qi ◽  
Guo Xing Chen
Keyword(s):  
Dynamic Response ◽  
Rayleigh Wave ◽  
Elastic Foundation ◽  
Hyperbolic Type ◽  
Seismic Action ◽  
Linear Type ◽  
Underground Tunnel ◽  
Practical Engineering ◽  
S Curve ◽  
Effect Of Structure

In the present paper the model of beam on Winkler-type elastic foundation is used to model the underground tunnel. The soil displacement (mm)-stress (kpa) curve (p-s curve) is approximated in the form of hyperbolic type function by fitting the existing experimental data and then equivalent linear type of nonlinear bedding coefficient of foundation is derived from the fitting curve. Substitute the equivalent coefficient into the vibration equation of beam on Winkler-type elastic foundation, and we may assess the nonlinear effect of soil. Based on the hypothesis of large distance to earthquake source, Rayleigh wave is used to simulate the longitudinal shearing seismic wave. According to the amplitude attenuation law of Rayleigh wave in elastic half place, the effect of structure bury depth on dynamic response of underground tunnel is considered and the conception of critical bury depth is put forward. Finally the vibration differential equation of beam on Winkler-type elastic foundation is solved by using Matlab software, and the dynamic response of underground tunnel at different structure bury depth are compared. The results may provide a reference for practical engineering.

scholarly journals Investigation of the Effects of Anisotropic Flow of Pore Water and Multilayered Soils on Three-Dimensional Consolidation Characteristics

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Arpan Laskar ◽  
Sujit Kumar Pal
Keyword(s):  
Pore Water ◽  
Three Dimensional ◽  
Surface Settlement ◽  
Coefficient Of Consolidation ◽  
Consolidation Process ◽  
Soil Layers ◽  
Anisotropic Flow ◽  
Practical Engineering ◽  
Consolidating Soil ◽  
Multilayered Soils

Many practical engineering problems are seriously different from the assumptions which are considered for one-dimensional consolidation test and need to concentrate on three-dimensional consolidation of soil under different boundary conditions. In this study three-dimensional consolidation tests are performed with four different anisotropic flow conditions of pore water and fifteen different combinations of horizontal layered soils. Twelve different three-dimensional consolidation tests are also performed with different soils, surrounded by anisotropic vertical soil layers on two opposite sides. From these studies, it is observed that the anisotropic flow of pore water does not have any effect on initial and final surface settlement of soil but has a significant effect during the consolidation process. The anisotropic flow of pore water during the consolidation process has an immense effect on the coefficient of consolidation. Horizontal layered soil has a great effect on both surface settlement and the rate of settlement. Vertical soil layers on two opposite sides of consolidative soil have an immense effect on the horizontal movements of consolidating soil, finally affecting the resultant vertical settlement of soil. Vertical anisotropic surrounding soil layers also have an effect on the rate of consolidation settlement.

Three-dimensional analyses of two high-speed trains crossing on a bridge

2003 ◽  
Vol 217 (2) ◽  
pp. 99-110
Author(s):  
H-T Lin ◽  
S-H Ju
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
High Speed ◽  
Three Dimensional ◽  
Dynamic Effect ◽  
Response Ratio ◽  
Element Analysis ◽  
Dynamic Finite Element Analysis ◽  
High Speed Trains ◽  
The One

This paper investigates the dynamic characteristics of the three-dimensional vehicle-bridge system when two high-speed trains are crossing on a bridge. Multispan bridges with slender piers and simply supported beams were used in the dynamic finite element analysis. A response ratio (RR) was defined in this study to represent the ratio of the vehicle-bridge interaction of two-way trains to that of a one-way train. The finite element results indicate that this ratio increases significantly when two-way trains run near the same speed, and the maximum value is approximately equal to or smaller than two for the vertical dynamic response. This means that the maximum dynamic response of the two-way trains is at most twice that of the one-way train. When the two-way train speeds are sufficiently different, the response ratio approaches one on average, which means that the dynamic effect of the two-way train is similar to that of the one-way train. Finite element results also indicate that the averaged response ratio in the three global directions is about 1.65 when the two-way trains run at the same speed.

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