scholarly journals Experimental Study on the Relationship between the Velocity of Surface Movements and Tilting Rate in Pre-Failure Stage of Rainfall-Induced Landslides

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 5988
Author(s):  
Jiren Xie ◽  
Taro Uchimura ◽  
Chao Huang ◽  
Zain Maqsood ◽  
Jingli Tian
Keyword(s):  
Linear Relationship ◽  
Slope Failure ◽  
Failure Time ◽  
Failure Process ◽  
Time History ◽  
Field Tests ◽  
Prediction Methods ◽  
Surface Displacements ◽  
History Of ◽  
Proportional Relationship

With the development of deformation measuring technology at slope surfaces, prediction methods for rainfall-induced landslides based on the surface movements and tilting of slopes in the pre-failure stage have been recognized as a promising technique for risk reduction of slope failure triggered by rainfall. However, the correlation and possible mechanism for these prediction methods were rarely discussed. In this study, the comparison between the prediction methods of slope failure based on the time history of surface displacements and tilting in the acceleration stage was carried out by conducting a series of laboratory tests and field tests under rainfall, in which the movements and tilting behaviors at the slope surface were measured. The results show that the predicted failure time of tested slopes obtained by different prediction methods is consistent, and the correlation between these landslide prediction methods were also detected. A proportional relationship between the velocity of surface displacements and tilting rate was observed, and a possible mechanism for the sliding behavior was discussed based on this linear relationship as well. In addition, an expression for the linear relationship between the rate of the surface tilting and displacement was also established in this study, and the results could have significance for the understanding of the sliding behavior in the failure process in rainfall-induced landslides.

Experimental Study and Numerical Analysis of Sihui Metro Depot and the Superstructure

2012 ◽  
Vol 226-228 ◽  
pp. 176-180
Author(s):  
Jing Zhang ◽  
Bin Zhang ◽  
Ying Hua Liu ◽  
Long Qi Wang ◽  
Yu Bin Wu
Keyword(s):  
Time History ◽  
Field Tests ◽  
Element Model ◽  
Test Analysis ◽  
3 Dimensional ◽  
Dimensional Finite Element ◽  
Calculation Results ◽  
History Of ◽  
The Given ◽  
The Waves

Field tests were carried out on Sihui metro depot of Beijing metro line 1 and its superstructure. The acceleration time history of sleepers and floors of the building was obtained, and the waves-propagation laws of building were studied through the tests. Test analysis shows that the structure vibrations show zigzag tendencies ascends with the height of the building. Based on current situation of Sihui metro depot, a metro-soil-building 3-dimensional finite element model is established on ANSYS. By using actual acceleration of sleepers as inputs, the dynamic responds rule of the superstructure is obtained. Compared calculation results with the experimental results, the given numerical model can predict the vibrations of the building induced by moving trains quite well. This method can provide guidance and technical support for future development of superstructure.

scholarly journals Modelling of the ice-edge failure process with curved failure surfaces

1994 ◽  
Vol 19 ◽  
pp. 158-164 ◽  
Author(s):  
Pentti Kujala
Keyword(s):  
Failure Process ◽  
Time History ◽  
Logarithmic Spiral ◽  
Failure Surface ◽  
Friction Angle ◽  
Good Correspondence ◽  
Crushing Force ◽  
History Of ◽  
Physical Background ◽  
Ice Edge

The failure process of a Wedge-shaped ice edge is modelled by dividing the process in crushing failures at the contact and flaking failures initiating from high pressure in the contact. This type of approach has been shown earlier by Daley to give an explanation of the physical background of the line-like contact observed in ice-crushing tests and in full-scale measurements. Daley's model is developed further by studying the stress field in ice in more detail when applying the Coulomb macroscopic failure criterion to determine the force required for flaking failures. The analysis indicates that the shape of the flaking failure surface to minimise the force required to cause failure follows a logarithmic spiral. The shape of the spiral is related to the inner friction angle of ice and to the geometry of the ice edge. The curved flaking surfaces require considerably less force than straight surfaces used previously, especially with wide wedge angles. Finally, the model developed is used to simulate the time history of a crushing force measured in laboratory crushing tests and a good correspondence is obtained.

scholarly journals Modelling of the ice-edge failure process with curved failure surfaces

1994 ◽  
Vol 19 ◽  
pp. 158-164
Author(s):  
Pentti Kujala
Keyword(s):  
Failure Process ◽  
Time History ◽  
Logarithmic Spiral ◽  
Failure Surface ◽  
Friction Angle ◽  
Good Correspondence ◽  
Crushing Force ◽  
History Of ◽  
Physical Background ◽  
Ice Edge

The failure process of a Wedge-shaped ice edge is modelled by dividing the process in crushing failures at the contact and flaking failures initiating from high pressure in the contact. This type of approach has been shown earlier by Daley to give an explanation of the physical background of the line-like contact observed in ice-crushing tests and in full-scale measurements. Daley's model is developed further by studying the stress field in ice in more detail when applying the Coulomb macroscopic failure criterion to determine the force required for flaking failures. The analysis indicates that the shape of the flaking failure surface to minimise the force required to cause failure follows a logarithmic spiral. The shape of the spiral is related to the inner friction angle of ice and to the geometry of the ice edge. The curved flaking surfaces require considerably less force than straight surfaces used previously, especially with wide wedge angles. Finally, the model developed is used to simulate the time history of a crushing force measured in laboratory crushing tests and a good correspondence is obtained.

PROGRAM OF PREDICTION AND MANAGEMENT OF COINTEGED DYNAMIC ECONOMIC PROCESSES BASED ON THE CYBERNETIC APPROACH

2019 ◽  
Author(s):  
Olena Bundak ◽  
Nataliia Zubovetska
Keyword(s):  
Computer Program ◽  
Pair Correlation ◽  
Time History ◽  
Critical Area ◽  
Concrete Object ◽  
Graphic Arts ◽  
Ex Post ◽  
History Of ◽  
Successive Change ◽  
Rms Errors

A method and computer program ConRow, which prognostication of development of the dynamically CPLD economic transients is executed by, is described in the article. Such prognostication of economic processes is very important in the cases when their development can result in undesirable consequences, that to go out in the so-called critical area. Extrapolation in a critical area with the use of information about the conduct of the system at an area, near to it, allows to estimate to the lead through of experiment in the critical area of his consequence. For the imitation of conduct of object the function of review is set on entrance influence. For a concrete object this function can express, for example, dependence of change of level sale from time-history of charges on advertising and set as a numeral row. Statistics as a result of analysis of row are represented in a table, where the level of meaningfulness is set statistician, and also parameters of the handed over criteria. The graphic reflection of information is intended for visualization of analysis. Here represented on the points of graphic arts, the crooked smoothing which are calculated as полиномиальные regressions is added. The best approaching is controlled by sight on the proper graph, and also by minimization of their rms errors. Models of prognostication by sight and as formulas represented on graphic arts, the middle is here determined tailings and their chance is checked up on statistics of signs. After the got models determined also and prognosis values of influences and reviews. Establishing an order models of Сr(p) of co integrate regression is carried out separate custom controls. The coefficient of clay correlation of ruФ shows by itself pair correlation between lines with a successive change in relation to each other on a size to лагу of l = 1, 2, 3 . The program was tested on the example of ex-post prognosis at establishing an integration connection and possibility of prognostication of growth of nominal average monthly settlings on the basis of these statistical indexes of consumer inflation in Ukraine.

scholarly journals Comparison of Novel Seismic Protection Devices to Attenuate the Earthquake Induced Energy

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 73
Author(s):  
Osman Hansu ◽  
Esra Mete Güneyisi
Keyword(s):  
Lateral Displacement ◽  
Time History ◽  
Seismic Protection ◽  
Base Shear ◽  
Seismic Demands ◽  
Nonlinear Time History Analyses ◽  
History Of ◽  
Protection Devices ◽  
Nonlinear Time History ◽  
Better Than

This study addresses an alternative use of viscous dampers (VDs) associated with buckling restrained braces (BRBs) as innovative seismic protection devices. For this purpose, 4-, 8- and 12-story steel bare frames were designed with 6.5 m equal span length and 4 m story height. Thereafter, they were seismically improved by mounting the VDs and BRBs in three patterns, namely outer bays, inner bays, and all bays over the frame heights. The structures were modeled using SAP 2000 software and evaluated by the nonlinear time history analyses subjected to the six natural ground motions. The seismic responses of the structures were investigated for the lateral displacement, interstory drift, absolute acceleration, maximum base shear, and time history of roof displacement. The results clearly indicated that the VDs and BRBs reduced seismic demands significantly compared to the bare frame. Moreover, the all-bay pattern performed better than the others.

scholarly journals Development of a Field Deployable Firebrand Flux and Condition Measurement System

2020 ◽  
Author(s):  
Simone Zen ◽  
Jan C. Thomas ◽  
Eric V. Mueller ◽  
Bhisham Dhurandher ◽  
Michael Gallagher ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Time History ◽  
Infrared Camera ◽  
Thermal Conditions ◽  
Particle Characterization ◽  
Fire Dynamics ◽  
Rate Of Spread ◽  
New Instrument ◽  
History Of

AbstractA new instrument to quantify firebrand dynamics during fires with particular focus on those associated with the Wildland-Urban Interface (WUI) has been developed. During WUI fires, firebrands can ignite spot fires, which can rapidly increase the rate of spread (ROS) of the fire, provide a mechanism by which the fire can pass over firebreaks and are the leading cause of structure ignitions. Despite this key role in driving wildfire dynamics and hazards, difficulties in collecting firebrands in the field and preserving their physical condition (e.g. dimensions and temperature) have limited the development of knowledge of firebrand dynamics. In this work we present a new, field-deployable diagnostic tool, an emberometer, designed to provide measurement of firebrand fluxes and information on both the geometry and the thermal conditions of firebrands immediately before deposition by combining a visual and infrared camera. A series of laboratory experiments were conducted to calibrate and validate the developed imaging techniques. The emberometer was then deployed in the field to explore firebrand fluxes and particle conditions for a range of fire intensities in natural pine forest environments. In addition to firebrand particle characterization, field observations with the emberometer enabled detailed time history of deposition (i.e. firebrand flux) relative to concurrent in situ fire behaviour observations. We highlight that deposition was characterised by intense, short duration “showers” that can be reasonably associated to spikes in the average fire line intensity. The results presented illustrate the potential use of an emberometer in studying firebrand and spot fire dynamics.

Stationary and Transient Response of Cylindrical Shells Under Random Excitation

1988 ◽  
Vol 110 (2) ◽  
pp. 205-209
Author(s):  
A. V. Singh
Keyword(s):  
Transient Response ◽  
Random Vibration ◽  
Time History ◽  
Wide Band ◽  
Random Excitation ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
History Of ◽  
The Mean ◽  
Random Vibration Analysis

This paper presents the random vibration analysis of a simply supported cylindrical shell under a ring load which is uniform around the circumference. The time history of the excitation is assumed to be a stationary wide-band random process. The finite element method and the condition of symmetry along the length of the cylinder are used to calculate the natural frequencies and associated mode shapes. Maximum values of the mean square displacements and velocities occur at the point of application of the load. It is seen that the transient response of the shell under wide band stationary excitation is nonstationary in the initial stages and approaches the stationary solution for large value of time.

Second Paper: Deep Drawing and Free Forming Using a Water Hammer Technique

1964 ◽  
Vol 179 (1) ◽  
pp. 222-233 ◽  
Author(s):  
A. P. Vafiadakis ◽  
W. Johnson ◽  
I. S. Donaldson
Keyword(s):  
Deep Drawing ◽  
Time History ◽  
Water Hammer ◽  
High Rate ◽  
Pressure Time ◽  
Order Of Magnitude ◽  
History Of ◽  
Overall Efficiency ◽  
Initial Movement ◽  
Better Than

Earlier work on a water-hammer technique for high-rate forming of sheet metal has been extended to include work on deep drawing using lead plugs. A study of the pressure-time history of a deforming blank during its initial movement is reported. An assessment of the overall efficiency of the process has been made and is found to be about 50 per cent; this is an order of magnitude better than that found with comparable electro-hydraulic and explosive methods.

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