Resistance of Soil to a Vertically Vibrating Pile

2013 ◽  
Vol 712-715 ◽  
pp. 979-983
Author(s):  
Zhan Shi Gao ◽  
Qing Ren
Keyword(s):  
Slenderness Ratio ◽  
Damping Ratio ◽  
Large Diameter ◽  
Three Dimensional ◽  
Horizontal Displacement ◽  
Vertical Vibration ◽  
Vibration Model ◽  
Couple Effect ◽  
Soil Dynamic ◽  
Strain Model

Based on the plane strain model, a three-dimensional vibration model was setup for soil dynamic response of soil surrounding large diameter pile. An accurate analytical solution was got by considering the couple effect of vertical and horizontal displacement of soil. Through the discussion parameters slenderness ratio (L/d), hysteretic damping ratio (Ds,Dv) and soil Poisson's ratio (ν),it is concluded that they are very important for the vertical vibration propproperties of soil impedance.

Response Law and Influencing Factors of the Soil under Action of Pile Driving Vibration Based on Midas/GTS

2013 ◽  
Vol 353-356 ◽  
pp. 979-983
Author(s):  
Dong Zhang ◽  
Jing Bo Su ◽  
Hui De Zhao ◽  
Hai Yan Wang
Keyword(s):  
Damping Ratio ◽  
Large Diameter ◽  
Time History ◽  
Pile Driving ◽  
Analysis Model ◽  
Vibration Load ◽  
History Analysis ◽  
Study Results ◽  
Propagation Law ◽  
Dynamic Time

Due to the upgrade and reconstruct of a high-piled wharf, the piling construction may cause the damage of the large diameter underground pipe of a power plant nearby. For this problem, a dynamic time-history analysis model was established using MIDAS/GTS program. Based on the analysis of the pile driving vibration and its propagation law, some parameters, such as the modulus of the soil, the Poissons ratio of soil, the action time of vibration load and the damping ratio of the soil that may have an effect on the response law of the soil, were studied. The study results not only serve as an important inference to the construction of this case, but also accumulate experience and data for other similar engineering practices.

Split Vibration Modes in Acoustically-Coupled Disk Stacks

1995 ◽  
Author(s):  
Jung-Ge Tseng ◽  
Jonathan Wickert
Keyword(s):  
Natural Frequencies ◽  
Three Dimensional ◽  
System Level ◽  
Thin Plates ◽  
Mode Shapes ◽  
Design Parameters ◽  
Phase System ◽  
Acoustic Coupling ◽  
Annular Plates ◽  
Vibration Model

Abstract Vibration of an array of stacked annular plates, in which adjacent plates couple weakly through an acoustic layer, is investigated through experimental and theoretical methods. Such acoustic coupling manifests itself through split natural frequencies, beating in the time responses of adjacent or separated plates, and system-level modes in which plates in the array vibrate in- or out-of-phase at closely-spaced frequencies. Laboratory measurements, including a technique in which the frequency response function of all in-phase modes but no out-of-phase modes, or visa versa, is measured, demonstrate the contribution of coupling to the natural frequency spectrum, and identify the combinations of design parameters for which it is important. For the lower modes of primary interest here, the natural frequencies of the out-of-phase system modes decrease as the air layer becomes thinner, while those of the in-phase mode remain sensibly constant at the in vacuo values. A vibration model comprising N classical thin plates that couple through the three-dimensional acoustic fields established in the annular cavities between plates is developed, and its results are compared with measurements of the natural frequencies and mode shapes.

Absolute Measurement of Aspheric Surfaces Using White-Light Interferometry

2007 ◽  
Vol 364-366 ◽  
pp. 80-85
Author(s):  
Su Ping Chang ◽  
Tie Bang Xie ◽  
Xuang Ze Wang ◽  
Jun Guo
Keyword(s):  
High Precision ◽  
White Light ◽  
Spherical Surface ◽  
Three Dimensional ◽  
Influence Factors ◽  
Horizontal Displacement ◽  
Absolute Measurement ◽  
Aspheric Surfaces ◽  
Interferometric Technique ◽  
Main Influence

White-light interferometric technique has been widely applied in the measurement of three-dimensional profiles and roughness with high-precision. Based on the characteristic of interferometric technique, a new method combined with image location and a three-dimensional stage is proposed to achieve the non-contact absolute shape measurement for aspheric and spherical surface in a slarge range. The interference fringes vary with the horizontal displacement of the measured surface, the surface information was obtained by locating the transformation of the maximal intensity in the interferograms. Two main influence factors are discussed; they are performance of the inerferimetric microscope and the stage. Since the performance of the stage directly determines the measurement precision, a three-dimensional displacement stage with a large range and a high precision was developed. Some experiments were carried out to verify the performance of the three-dimensional displacement stage and the validity of the new measurement method with satisfactory results.

Research on Damage Status of the Reinforced Concrete Ground Floor Columns

2012 ◽  
Vol 226-228 ◽  
pp. 1436-1440
Author(s):  
Li Jun Gao ◽  
Yong Sheng Zhang ◽  
Qin Li
Keyword(s):  
Reinforced Concrete ◽  
Measurement Method ◽  
Damping Ratio ◽  
Simple Calculation ◽  
Dynamic Measurement ◽  
Concrete Column ◽  
Destructive Testing ◽  
Reinforced Concrete Column ◽  
First Order ◽  
Vibration Model

In this paper, dynamic measurement method is applied to test the damage of the bottom reinforced concrete column. The comparison between the calculated first order frequency of the bottom reinforced concrete column and the measured first order frequency shows that the result is consistent. This indicates that this approach is feasible. However, in recent years, dynamic measurement method is widely used in non-destructive testing of bridges and floors. The principle of the dynamic measurement method for the detection of reinforced concrete column utilizes the measured natural frequency, vibration model and damping ratio of reinforced concrete column and such inherent dynamic characteristics of indicators to reflect the damage of reinforced concrete column. And there is no secondary injury for the column. The simplified method of structure dynamics is applied to calculate the frequency of the bottom reinforced concrete column. And the simple calculation method is verified by experiment and practice.

scholarly journals Vertebrobasilar Artery Geometry and Bisilar Artery Plaques: A High-Resolution Magnetic Resonance Imaging Stydy

2020 ◽  
Author(s):  
Jinmei Zheng ◽  
Bin Sun ◽  
Ruolan Lin ◽  
Yongqi Teng ◽  
Xihai Zhao ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Large Diameter ◽  
Three Dimensional ◽  
Resonance Imaging ◽  
Logistic Regression Models ◽  
Vertebrobasilar Artery ◽  
Number Of Bends ◽  
The Relationship

Abstract Background Atherosclerotic plaques are often present in regions with complicated flow patterns. Vascular morphology plays a role in hemodynamics. In this study, we investigate the relationship between the geometry of the vertebrobasilar artery system and the basilar artery (BA) plaque prevalence.Methods We enrolled 290 patients with posterior circulation ischemic stroke. We distinguished four configurations of the vertebrobasilar artery: Walking, Tuning Fork, Lambda, and No Confluence. The diameter of the vertebral artery (VA) and the number of bends in the intracranial VA segment was assessed using three-dimensional time-of-flight magnetic resonance angiography. We differentiated between multi-bending (≥ 3 bends) and oligo-bending (< 3 bends) VAs. High-resolution magnetic resonance imaging was used to evaluate BA plaques. Logistic regression models examined the relationship between the geometry type and BA plaque prevalence.Results After adjusting for sex, age, body mass index ≥ 28, hypertension, and diabetes mellitus, the Walking, Lambda, and No Confluence geometries were associated with the presence of BA plaque. Patients with multi-bending VAs in both the Walking (71.43%, P = 0.003) and Lambda group (40.43%, P = 0.018) had more plaques compared to patients with oligo-bending VAs in these groups. In the Lambda group, the diameter difference between the VAs was larger in patients with BA plaques than that in patients without BA plaques (1.4 mm vs. 0.9 mm, P < 0.001).Conclusions The Walking, Lambda, and No Confluence geometry, ≥ 3 bends in the VAs, and a large diameter difference between the VAs were associated with the presence of BA plaque.

scholarly journals Comparison of Dynamic Characteristics between Small and Super-Large Diameter Cross-River Twin Tunnels under Train Vibration

2021 ◽  
Vol 11 (16) ◽  
pp. 7577
Author(s):  
Lin Wu ◽  
Xiedong Zhang ◽  
Wei Wang ◽  
Xiancong Meng ◽  
Hong Guo
Keyword(s):  
Dynamic Characteristics ◽  
Large Diameter ◽  
Horizontal Displacement ◽  
Element Model ◽  
Vertical Displacement ◽  
Decisive Factor ◽  
Cross River ◽  
Static Responses ◽  
Train Vibration ◽  
Twin Tunnels

Train vibration from closely aligned adjacent tunnels could cause safety concerns, especially given the soaring size of the tunnel diameter. This paper established a two-dimensional discrete element model (DEM) of small (d = 6.2 m) and super-large (D = 15.2 m) diameter cross-river twin tunnels and discussed the dynamic characteristics of adjacent tunnels during the vibration of a train that runs through the tunnel at a speed of 120 km/h. Results in the D tunnel showed that the horizontal walls have the same horizontal displacement (DH) and the vertical walls have the same vertical displacement (DV). The stress state of the surroundings of the D tunnel is the decisive factor for DH, and the distance from the vibration point to the measurement point is the decisive factor for DV. Results in the comparison of the d and D tunnels showed that the D tunnel is more stable than the d tunnel with respect to two aspects: the time the tunnel reaches the equilibrium state and the vibration amplitude of the structure’s dynamic and static responses. The dynamic characteristic of the d and D tunnel is significantly different. This research is expected to guide the design and construction of large diameter twin tunnels.

scholarly journals Development of a finite element human vibration model for use in spacecraft coupled loads analysis

2018 ◽  
Vol 38 (2) ◽  
pp. 839-851 ◽  
Author(s):  
Nancy J Currie-Gregg ◽  
Kelly Carney
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Joint Stiffness ◽  
Low Frequency ◽  
Nonlinear Dynamic Response ◽  
Vibration Model ◽  
Loads Analysis ◽  
Impact Attenuation ◽  
Coupled Loads Analysis ◽  
Coupled Loads

Finite element human vibration models were developed and implemented for use in human-tended spacecraft-coupled loads analysis, an analytical process used to predict low-frequency spacecraft loads which occur during dynamic phases of flight of such as launch, ascent, or ascent aborts. Human vibration may also affect stress predictions for spacecraft systems which the crew interacts with, such as crew seats and crew impact attenuation systems. These human vibration models are three-dimensional, distributed-mass representations of 1st-percentile female, 50th-percentile male, and 99th-percentile male American crew members and provide a relatively simple linear and low-load representation of the nonlinear dynamic response of a seated human. The most significant features of these finite element models are anthropometrically based geometric human mass distribution, soft tissue vibration attributes, and skeleton and joint stiffness.

Study on the Method of Construction of Large Section Tunnel Crossing the Ancient Great Wall

2012 ◽  
Vol 226-228 ◽  
pp. 1504-1508
Author(s):  
Ai Bing Jin ◽  
Long Fu Li ◽  
Fu Gen Deng ◽  
Min Zhe Zhang
Keyword(s):  
High Efficiency ◽  
Surface Deformation ◽  
Ground Deformation ◽  
Three Dimensional ◽  
Horizontal Displacement ◽  
Tunnel Excavation ◽  
Construction Scheme ◽  
Construction Experience ◽  
Strata Deformation ◽  
Great Wall

While the tunnel crossing the ancient Great Wall, we must take effective measures to control ground deformation, prevent ground deformation is too large, destroying the heritage. In order to study the effects of tunnel excavation types on strata deformation, a three-dimensional computational model is built to simulate surface settlement and horizontal displacement by three different excavation types which are both-side heading method, CRD method, and hole pile method. Following comparative analysis, in line with the realistic program is recommended. The results show that both-side heading method can better control the surface deformation, and has a high efficiency of construction, which was selected as the construction scheme of tunnel crossing the ancient great wall. The results of this study are expected to provide construction experience to the works of a similar background.

The adaptable amphibious wheel-legged robot

2018 ◽  
Vol 42 (3) ◽  
pp. 323-339
Author(s):  
Jicheng Liu ◽  
Jinshuai Yang ◽  
Binglu Yan ◽  
Zheng Liu
Keyword(s):  
Large Diameter ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Legged Robot ◽  
Loop Control ◽  
Walking Gait ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Amphibious Robot ◽  
Foot Trajectory

A new category of large-diameter adaptable amphibious wheel-legged robot is proposed in this paper. The proposed mechanism can climb obstacles better than existing designs. The Denavit–Hartenberg (D–H) coordinate system is used for kinematic analysis, and the constructed kinematic model is used to solve for these joint variables for a redundant robot. The control strategy is to plan both the foot trajectory of the amphibious robot, to optimize the operational performance in special environments, as well as the walking gait. Then the closed-loop control system is used. A simulation is used to verify the usefulness of the planned foot trajectory and walking gait for an entire running cycle, and a circuit is designed to solve a communication problem between the Arduino and the AX-12 servo. Finally, the foot trajectory of a single robot leg is captured by a three-dimensional motion-capture system to verify the rationality of the foot trajectory and walking gait.

Three-Dimensional Nonlinear Dynamics of Nonintegral Riser Bundle

1991 ◽  
Vol 35 (01) ◽  
pp. 40-57
Author(s):  
Nickolas Vlahopoulos ◽  
Michael M. Bernitsas
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Small Strain ◽  
Computer Code ◽  
Three Dimensions ◽  
Central Processor ◽  
Beam Columns ◽  
Central Processor Unit ◽  
Processor Unit ◽  
Strain Model

The dynamic behavior of a nonintegral riser bundle is studied parametrically. The dynamics of each component-riser is analyzed by a three-dimensional, nonlinear, large deflection, small strain model with coupled bending and torsion. Component-risers are slender, thin-walled, extensible or inextensible tubular beam-columns, subject to response and deformation dependent hydrodynamic loads. The con-nector equations of equilibrium are used to derive the connector forces and moments. Substructuring can thus be achieved even though in three dimensions connectors do not impose linearly dependent deflections at substructure interfaces. The developed time incremental and iterative finite-element computer code is used to analyze the effects of water depth, distribution of connectors, distance between component risers and number of finite elements in the numerical model. The problem of total CPU (central processor unit) time and the advantages of substructuring are discussed by running cases of up to 1094 degrees of freedom.

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