Dynamic Behavior of Nagawado Arch Dam in the Event of 1984 Naganoken Seibu Earthquake

1987 ◽  
Vol 3 (2) ◽  
pp. 347-364 ◽  
Author(s):  
T. Fujii ◽  
K. Egawa ◽  
I. Katayama
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Arch Dam ◽  
Scale Model ◽  
Small Scale ◽  
Vibration Modes ◽  
Band Pass ◽  
Small Scale Model ◽  
Good Agreement ◽  
Foundation Rock

Nagawado dam, a slender arch dam of 155 m height and 355.5 m chord length, recorded maximum accelerations of 193 and 242 gal at the crown and the 1/4 point of the crest arch, respectively, in the September 14, 1984 Naganoken Seibu earthquake of magnitude 6.8. The maximum accelerations in the foundation rock were in the range of 21 to 31 gal. Fourier analysis and band-pass filtering of corrected accelerograms, and spatial and temporal diagrams of the computed displacements of the dam and the foundation indicate the significant structural modes of peak frequencies 3.3, 3.6, 4.7, and 5.5 Hz. These frequencies correspond to the antisymmetric first, the symmetric first, the symmetric second, and the antisymmetric second modes of the dam. The first three peak frequencies were in good agreement with the values of corresponding vibration modes obtained by a small-scale model test. The derived frequencies and vibration modes were found also compatible with the results of eigenvalue analysis of a preliminary 3-D finite-element model as a whole. Orthogonal sets of accelerograms recorded at the points across a treated fracture zone in the foundation rock did not record any significant relative motions.

Examination of the Transferability of CTOA From Small-Scale DWTT to Full-Scale Pipe Geometries Using a Cohesive Zone Model

2020 ◽  
Author(s):  
Chris Bassindale ◽  
Xin Wang ◽  
William R. Tyson ◽  
Su Xu
Keyword(s):  
Finite Element ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Element Model ◽  
Full Scale ◽  
Opening Angle ◽  
Small Scale ◽  
Zone Model ◽  
Pipe Model ◽  
Good Agreement

Abstract In this work, the cohesive zone model (CZM) was used to examine the transferability of the crack tip opening angle (CTOA) from small-scale to full-scale geometries. The pipe steel STPG370 was modeled. A drop-weight tear test (DWTT) model and pipe model were studied using the finite element code ABAQUS 2017x. The cohesive zone model was used to simulate crack propagation in 3D. The CZM parameters were calibrated based on matching the surface CTOA measured from a DWTT finite element model to the surface CTOA measured from the experimental DWTT specimen. The mid-thickness CTOA of the DWTT model was in good agreement with the experimental value determined from E3039 and the University of Tokyo group’s load-displacement data. The CZM parameters were then applied to the pipe model. The internal pressure distribution and decay during the pipe fracture process was modeled using the experimental data and implemented through a user-subroutine (VDLOAD). The mid-thickness CTOA from the DWTT model was similar to the mid-thickness CTOA from the pipe model. The average surface CTOA of the pipe model was in good agreement with the average experimental value. The results give confidence in the transferability of the CTOA between small-scale specimens and full-scale pipe.

Displacement Properties of Newly Developed 3-Dimensional Piezoelectric Actuator at Various AC Frequencies

2007 ◽  
Vol 534-536 ◽  
pp. 1441-1444 ◽  
Author(s):  
Man Soon Yoon ◽  
Y.G. Choi ◽  
Soon Chul Ur
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Piezoelectric Actuator ◽  
Element Model ◽  
Vibration Modes ◽  
Maximum Strain ◽  
Electromechanical Properties ◽  
3 Dimensional ◽  
The Finite Element Model ◽  
Good Agreement

The electromechanical properties of a newly proposed 3-dimensional piezoelectric actuator have been investigated. Especially, the effects of 3-dimensional geometry on the maximum tip displacement were carefully investigated. As a result, it was found that the maximum strain of the 3-dimensional piezoelectric device was significantly enhanced up to 4.5 times higher than that of a disk shape device. This data was in good agreement with the finite element model analysis of strains and vibration modes. Moreover, the field -induced displacement stability of dome-shaped 3- dimensional piezoelectric actuator at various ac freguencies was superior to Rainbow actuator.

Pipeline plough performance in sand waves. Part 2: kinematic calculation method

2010 ◽  
Vol 47 (1) ◽  
pp. 65-77 ◽  
Author(s):  
Mark Fraser Bransby ◽  
Michael John Brown ◽  
Keith Lauder ◽  
Andrew Hatherley
Keyword(s):  
Calculation Method ◽  
Wave Amplitude ◽  
Scale Model ◽  
Sand Wave ◽  
Small Scale ◽  
Offshore Pipelines ◽  
Sand Waves ◽  
Calculation Methodology ◽  
Small Scale Model ◽  
Good Agreement

Offshore pipelines can be buried in the seabed by ploughing a trench, placing the pipe at its base, and then backfilling. The presence of sand waves or megaripples on the seabed surface can affect the progress of the plough and prevent the plough from generating a level trench with a uniform trench depth. A calculation method has been presented that makes assumptions about the motion of the plough to predict the kinematics of ploughs through regions of nonuniform seabeds. Results from the calculation methodology are compared with those from small-scale model tests with good agreement, and the detailed kinematics of ploughs are then examined. The calculation method suggests that as a plough moves through a sand-wave field, the oscillation of the plough about the skids results in the trench base being formed alternately by the share tip and heel. The new method allows prediction of likely offshore plough performance given known plough geometry, sand wavelength, and wave amplitude and may be used as a tool for assessing the feasibility of pipeline ploughing in zones of sand waves or megaripples.

Frustum confining vessel for testing model piles

1996 ◽  
Vol 33 (3) ◽  
pp. 499-504 ◽  
Author(s):  
Robert G Horvath ◽  
Dieter Stolle
Keyword(s):  
Finite Element ◽  
Soil Mass ◽  
Scale Model ◽  
Small Scale ◽  
Finite Element Analyses ◽  
Cone Penetration ◽  
Confining Stress ◽  
Testing Model ◽  
Physical Testing ◽  
Small Scale Model

A cone-shaped vessel, a frustum, has been developed for testing model piles. The magnitude of the confining stresses in the soil within the vessel can be controlled by applying pressure to a piston in the bottom of the device. A series of continous cone penetration tests was performed to determine approximate stress distributions with depth along the frustum axis. The penetration test results indicated that vertical stress within the soil mass increased with depth from zero at the top of the soil to a maximum value at the bottom, which is controlled by the stress applied to the bottom piston. Finite element analyses, which were carried out to establish stress patterns within the frustum confining vessel, confirmed the results obtained from the physical testing. This study demonstrates that the new confining vessel enables physical testing of small-scale model foundations under soil mass conditions that more closely reflect the in situ stress conditions encountered with full-scale foundations under in-service conditions. Key words: cone penetration resistance, confining stress, finite element analyses, frustum confining vessel, small-scale model testing, stress distribution.

scholarly journals The Pull-out Capacity of Suction Caissons in Model Investigations

2016 ◽  
Vol 63 (2-3) ◽  
pp. 157-171
Author(s):  
Andrzej Sawicki ◽  
Łukasz Wachowski ◽  
Marek Kulczykowski
Keyword(s):  
Model Experiment ◽  
Extraction Process ◽  
Experimental Results ◽  
Scale Model ◽  
Small Scale ◽  
Extensive Discussion ◽  
Pull Out ◽  
Small Scale Model ◽  
Suction Caissons ◽  
Good Agreement

AbstractA small-scale model experiment on the pull-out resistance of suction caissons is described. The pull-out force and suction developed within the caisson in the extraction process were recorded during the experiment. A simple breakout model, together with an elementary static formulae, is applied to predict the results obtained experimentally. There is a reasonably good agreement between the experimental results and predictions. An extensive discussion of the approach applied is included. The analysis presented in this paper is original, as it differs from other approaches mentioned in this paper, and leads to acceptable predictions. At the end, the results are also compared with another approach for predicting the capacity of suction caissons.

Low-Volume Road Bridge Alternative

2000 ◽  
Vol 1696 (1) ◽  
pp. 178-186
Author(s):  
B. M. Phares ◽  
F. W. Klaiber ◽  
T. J. Wipf
Keyword(s):  
Finite Element ◽  
Design Methodology ◽  
Structural Engineering ◽  
Element Model ◽  
Analytical Investigation ◽  
Bridge Engineering ◽  
Scale Model ◽  
Small Scale ◽  
Steel Beams ◽  
Concrete Deck

Recent reports indicate that a significant number of the nation’s bridges are either structurally deficient or functionally obsolete. A large number of these bridges are on the secondary road system and fall under the jurisdiction of county engineers with limited budgets and engineering staff. In response to this problem, a bridge replacement system was developed for simple span bridges with minimal to no skew that county engineers can design and build with limited resources. The bridge system involves fabrication of precast units consisting of two steel beams connected with a thin reinforced concrete deck. The precast deck thickness is limited to reduce the weight of the units so that they can be fabricated at one site and then easily transported to the bridge site. Multiple units are then connected on site to give the desired width of bridge, after which a reinforced cast-in-place concrete deck is placed over the entire bridge. Development of the design methodology for the steel beam precast unit bridge consisted of four phases. During the initial phase, small-scale bridge components and a full-scale model bridge were constructed and tested in the Iowa State University Structural Engineering Laboratory. These specimens were tested under a variety of loading configurations under service and ultimate loads. After completion of the laboratory testing, finite-element models of the laboratory bridge were developed and validated with data collected during the first phase. The validated finite-element model was then used to extrapolate analyses of common bridge configurations. The results of the analytical investigation were then combined with classic bridge engineering principles into a design methodology that is easy to use and understand. Although it is not discussed in detail, a demonstration project in which this concept was used has recently been completed and tested.

Plastic Response and Failure Prediction of Stiffened Plates Punched by a Wedge

2013 ◽  
Author(s):  
Bin Liu ◽  
Richard Villavicencio ◽  
C. Guedes Soares
Keyword(s):  
Finite Element ◽  
Experimental Tests ◽  
Element Model ◽  
Small Scale ◽  
Stiffened Plates ◽  
Tension Tests ◽  
Highly Sensitive ◽  
Force Displacement ◽  
The Finite Element Model ◽  
Good Agreement

Experimental tests have been performed to examine the response of small-scale stiffened plates laterally punched by a wedge. The specimens are supported at two opposite edges and the indenter is located at the mid-span. In the unsupported edges, the ends of the stiffeners are either connected to transverse stiffeners or remain free. The obtained force-displacement responses show a good agreement with the simulations performed by the LS-DYNA finite element solver. The finite element model includes defining the experimental boundary condition so as to simulate small axial displacements of the specimen at the supports. The strain hardening of the material is defined using experimental data of quasi-static tension tests and the critical failure strain is evaluated using tensile test simulations. The results show that the response of the specimens is highly sensitive to the amount of restraint provided at the supports. In addition, simplified calculations are proposed to evaluate the contribution of each structural component on the energy absorbed by the stiffened plate specimens.

Missile Firing Tests at Stationary Targets in Support of Blade Containment Design

1976 ◽  
Vol 98 (2) ◽  
pp. 159-164 ◽  
Author(s):  
J. I. Goatham ◽  
R. M. Stewart
Keyword(s):  
Minimum Weight ◽  
Turbine Blades ◽  
Scale Model ◽  
Small Scale ◽  
Satisfactory Explanation ◽  
Containment Problem ◽  
Compressor And Turbine Blades ◽  
Small Scale Model ◽  
Firing Tests ◽  
Good Agreement

Compressor and turbine blades of aircraft engines are liable to failure from a number of causes. Their subsequent containment within the immediate confines of the engine has long posed problems for the designer aiming for minimum weight designs. To assist the understanding of the dynamics of the containment problem, a series of small scale model tests have been conducted. The particular tests reported, deal with the failure mechanism at the point of impact. A theoretical analysis in support of the results obtained is developed. Fairly good agreement is obtained between tests and theory and the read-across to full scale containment tests indicates that the containment problem is capable of scaling if linear velocities are kept constant. A discontinuity in the behavior of materials with respect to their just contained energy capacity has been identified. While several contributory factors can be suggested, a fully satisfactory explanation is not found.

Wave Energy Hyperbaric Device for Electricity Production

2007 ◽  
Author(s):  
Segen F. Estefen ◽  
Paulo Roberto da Costa ◽  
Eliab Ricarte ◽  
Marcelo M. Pinheiro
Keyword(s):  
Power Generation ◽  
Wave Energy ◽  
Experimental Results ◽  
Electricity Production ◽  
Scale Model ◽  
Small Scale ◽  
Regular Waves ◽  
Hyperbaric Chamber ◽  
Small Scale Model

Wave energy is a renewable and non-polluting source and its use is being studied in different countries. The paper presents an overview on the harnessing of energy from waves and the activities associated with setting up a plant for extracting energy from waves in Port of Pecem, on the coast of Ceara State, Brazil. The technology employed is based on storing water under pressure in a hyperbaric chamber, from which a controlled jet of water drives a standard turbine. The wave resource at the proposed location is presented in terms of statistics data obtained from previous monitoring. The device components are described and small scale model tested under regular waves representatives of the installation region. Based on the experimental results values of prescribed pressures are identified in order to optimize the power generation.

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