Stress densification and its evaluation

2004 ◽  
Vol 41 (1) ◽  
pp. 181-186 ◽  
Author(s):  
Sung-Sik Park ◽  
Peter M Byrne
Keyword(s):  
Physical Model ◽  
Applied Stress ◽  
Test Data ◽  
Model Test ◽  
Physical Model Test ◽  
Liquefaction Resistance ◽  
Physical Test ◽  
One Dimensional ◽  
Physical Model Tests ◽  
Stress Changes

Stress densification occurs in natural soils as well as manmade embankments and physical model tests. Such densification can increase stability and liquefaction resistance. One-dimensional compression test data from eight sands were examined. From these data a stress densification equation is developed to estimate the density increase due to applied stress changes. It is found that stress densification can lead to erroneous conclusions if not taken into consideration when evaluating physical model test results.Key words: stress, densification, embankments, physical test.

Prediction of Warship Manoeuvring Coefficients using CFD

2015 ◽  
Author(s):  
C. Oldfield ◽  
M. Moradi Larmaei ◽  
A. Kendrick ◽  
K. McTaggart
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Physical Model ◽  
Test Data ◽  
Model Test ◽  
Verification And Validation ◽  
Planar Motion ◽  
Physical Model Test ◽  
Motion Mechanism ◽  
Planar Motion Mechanism

Verification and validation has been completed for the use of computational fluid dynamics as a practical means of simulating captive manoeuvring model tests. Verification includes spatial and temporal refinement studies. Direct validation includes the comparison of individual steady drift and planar motion mechanism simulations to physical model test data. Rotating arm simulations are validated indirectly on the basis of manoeuvring derivatives developed from the PMM tests. The merits of steady and unsteady simulations are discussed.

scholarly journals STABILITY OF XBLOCPLUS ARMOUR LAYERS AFTER INITIAL DAMAGE

2020 ◽  
pp. 16
Author(s):  
Pieter Bakker ◽  
Tiemen de Hoop ◽  
Markus Muttray
Keyword(s):  
Physical Model ◽  
Model Test ◽  
Safety Margin ◽  
Single Layer ◽  
Physical Model Test ◽  
Stability Number ◽  
Random Orientation ◽  
Initial Damage ◽  
Physical Model Tests ◽  
Hydraulic Stability

XblocPlus is an interlocking single layer armour unit that is placed with uniform orientation. The unit is applied with a large safety margin. Physical model test were performed without damage up to stability numbers of Hs/dDn=5.5 whereas a design stability number of Hs/dDn=2.5 has been adopted. The behaviour of an XblocPlus armour layer after initial damage is has been investigated by physical model tests with broken and manually removed model units. XblocPlus armour layers (with uniform orientation) respond differently to initial damage than interlocking armour units with random orientation. The latter are moving and re-arranging in order to bridge a gap in the armour layer (de Rover et al., 2008). XblocPlus units in contrast hardly move and nonetheless maintain the hydraulic stability of the damaged section. Details of the experiments and findings as well as implications for design and maintenance of breakwater armour layers will be discussed in the final paper.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/izwm60IBx-4

scholarly journals Determining the Depth of Local Scouring in a Downstream Energy Dissipation in the Physical Model Test

2021 ◽  
Vol 930 (1) ◽  
pp. 012022
Author(s):  
R D Lufira’ ◽  
S Marsudi ◽  
S Agustien ◽  
A Khosin
Keyword(s):  
Energy Dissipation ◽  
Physical Model ◽  
Model Test ◽  
Design Model ◽  
Physical Model Test ◽  
Original Design ◽  
Physical Model Tests ◽  
Final Design ◽  
Concrete Blocks ◽  
River Bottom

Abstract Karangnongko Weir is planned to be located in the Bengawan Solo River (Lower Solo River Basin) about 15 km downstream of the confluence of Bengawan Solo River with the Madiun River in Ngelo Village, Margomulyo Sub-District, Bojonegoro Regency, and Ngrawoh Village in Kradenan Sub-District, Blora Regency. This study aims to determine the Depth and pattern of scouring in downstream energy dissipation through physical model tests based on initial planning. Downstream protection of energy dissipation in the original design model combines 50 m of riprap rocks and 50 m of riprap concrete for a total length of 100 m of protection. The maximum scouring pattern occurred at elevation + 17.64 m, where the scouring was 4.36 m deep, from the planned essential height of Height 00 m. Thus, the downstream protection of energy dissipation was extended to 112 m in riprap concrete blocks for the final design model. Scouring at the end of riprap was 3.04 m, the original elevation of the river bottom of + 22.00 m, down to + 18.96 m. It is concluded that the protection is effective in reducing scouring by up to 30.27%.

Model Test Study on Influences of Layered Rock Mass Dip Angle on Stability of Deep-Buried Tunnel

2011 ◽  
Vol 90-93 ◽  
pp. 2363-2371
Author(s):  
Bin Wei Xia ◽  
Ke Hu ◽  
Yi Yu Lu ◽  
Dan Li ◽  
Zu Yong Zhou
Keyword(s):  
Rock Mass ◽  
Physical Model ◽  
Model Test ◽  
Physical Models ◽  
Physical Model Test ◽  
Stress Distributions ◽  
Failure Characteristics ◽  
Layered Rock ◽  
Layered Rock Mass ◽  
Dip Angle

Physical models of layered rock mass with different dip angles are built by physical model test in accordance with the bias failure characteristics of surrounding rocks of layered rock mass in Gonghe Tunnel. Bias failure characteristics of surrounding rocks in thin-layered rock mass and influences of layered rock mass dip angle on stability of tunnel are studied. The research results show that failure characteristics of physical models generally coincide with those of surrounding rocks monitored from the tunnel site. The failure regions of surrounding rock perpendicular to the stratification planes are obviously larger than those parallel to. The stress distributions and failure characteristics in the surrounding rocks are similar to each physical model of different dip angles. The stress distributions and failure regions are all elliptic in shape, in which the major axis is in the direction perpendicular to the stratification planes while the minor axis is parallel to them. As a result, obvious bias failure of surrounding rocks has gradually formed. The physical model tests provide reliable basis for theoretical analysis on the failure mechanism of deep-buried layered rock mass.

A Joint-Industry Effort to Develop and Verify CFD Modeling Practice for Vortex-Induced Motion of a Deep-Draft Semi-Submersible

2021 ◽  
Author(s):  
Hyunchul Jang ◽  
Dae-Hyun Kim ◽  
Madhusuden Agrawal ◽  
Sebastien Loubeyre ◽  
Dongwhan Lee ◽  
...  
Keyword(s):  
Test Data ◽  
Model Test ◽  
Working Group ◽  
Cfd Modeling ◽  
Physical Model Test ◽  
Mooring Lines ◽  
Cfd Models ◽  
Induced Motion ◽  
Modeling Practice ◽  
Decay Tests

Abstract Platform Vortex Induced Motion (VIM) is an important cause of fatigue damage on risers and mooring lines connected to deep-draft semi-submersible floating platforms. The VIM design criteria have been typically obtained from towing tank model testing. Recently, computational fluid dynamics (CFD) analysis has been used to assess the VIM response and to augment the understanding of physical model test results. A joint industry effort has been conducted for developing and verifying a CFD modeling practice for the semi-submersible VIM through a working group of the Reproducible Offshore CFD JIP. The objectives of the working group are to write a CFD modeling practice document based on existing practices validated for model test data, and to verify the written practice by blind calculations with five CFD practitioners acting as verifiers. This paper presents the working group’s verification process, consisting of two stages. In the initial verification stage, the verifiers independently performed free-decay tests for 3-DOF motions (surge, sway, yaw) to check if the mechanical system in the CFD model is the same as in the benchmark test. Additionally, VIM simulations were conducted at two current headings with a reduced velocity within the lock-in range, where large sway motion responses are expected,. In the final verification stage, the verifiers performed a complete set of test cases with small revisions of their CFD models based on the results from the initial verification. The VIM responses from these blind calculations are presented, showing close agreement with the model test data.

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