scholarly journals DAMAGE CRITERIA IN ROUNDHEADS ARMOURED WITH A SINGLE LAYER OF CUBIPOD ARMOR UNITS

2017 ◽  
pp. 13 ◽  
Author(s):  
José Sande ◽  
Enrique Peña ◽  
Enrique Maciñeira
Keyword(s):  
Active Zone ◽  
Sea Water ◽  
Single Layer ◽  
Relevant Parameter ◽  
Wave Steepness ◽  
Principal Parameter ◽  
Physical Model Tests ◽  
The Stability ◽  
Damage Criteria ◽  
Vertical Size

The present paper covers the analysis of damage in a single-layer roundhead armored with Cubipods. This study was carried through physical model tests. Firstly, the analysis of the damage in these structures has not been an intensive studied topic. It is normally defined when a piece doesn’t contribute in the stability on the single layer armor and, due to, a new damage criteria was proposed. In addition, vertical and sectorial size of active zone was defined. It could be possible defined three different phases in the evolution of damage due to the homogenous behavior for the roundhead. The most damage sector is 90-135º, and the neighbors, 45-90º and 135-180º, but damage in 45-90º is greater in frequency and value. Also, the dimensionless parameters of roundhead size (Rn, R/H and R/L) are involved in this phenomenon. Besides, the vertical size of active zone is defined in ±1.5Hs since sea water level (SWL), being the wave steepness is the principal parameter involved. It was proposed two level of damage: start of damage (D [%] =0.4) and failure (D [%] =11). Finally, it has been measure the reserve of stability. It is defined like the percentage of wave that the roundhead is able to resists between 2 levels of damage. This parameter allows analyzes the rigid behavior of the roundhead single layer armor. The value of this parameter, except one case, is RE [%] =9. It was conclude that wave steepness is a relevant parameter, when it increased the reserve is reduces.

scholarly journals STABILITY OF INTERLOCKING ARMOUR UNITS ON A BREAKWATER CREST

2012 ◽  
Vol 1 (33) ◽  
pp. 11 ◽  
Author(s):  
Ilse Van den Bosch ◽  
Erik Ten Oever ◽  
Pieter Bakker ◽  
Markus Muttray
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Packing Density ◽  
Single Layer ◽  
Hydraulic Model ◽  
Model Tests ◽  
Wave Steepness ◽  
Design Wave Height ◽  
The Stability ◽  
Hydraulic Stability

The hydraulic stability of single layer, interlocking armour units on low crested and submerged breakwaters was investigated in 2D hydraulic model tests. Displacements of armour units and rocking were monitored and have been applied as indicators for the armour layer stability on the crest, front and rear slope. The effect of freeboard, packing density and wave steepness on the armour layer stability have been investigated. The stability of interlocking concrete armour units on low crested and submerged structures is qualitatively different from rock armour. About 40% to 50% larger armour units are required on the seaward slope and crest of low crested structures (as compared to conventional high crested breakwaters). About 35% larger armour units are required on the rear slope. Larger armour units are not required on submerged breakwaters if the water depth on the crest exceeds 50% of design wave height.

Bamboo Waste-based Bio-composite Substance: An application for Low-cost Construction Materials

2020 ◽  
Vol 4 (1) ◽  
pp. 41-48
Author(s):  
Teodoro Astorga Amatosa ◽  
Michael E. Loretero
Keyword(s):  
Composite Materials ◽  
Sea Water ◽  
Raw Materials ◽  
Low Cost ◽  
Construction Materials ◽  
Single Layer ◽  
High Strength ◽  
Green Technology ◽  
Experimental Medium ◽  
Natural Treatment

Bamboo is a lightweight and high-strength raw materials that encouraged researchers to investigate and explore, especially in the field of biocomposite and declared as one of the green-technology on the environment as fully accountable as eco-products. This research was to assess the technical feasibility of making single-layer experimental Medium-Density Particleboard panels from the bamboo waste of a three-year-old (Dendrocalamus asper). Waste materials were performed to produce composite materials using epoxy resin (C21H25C105) from a natural treatment by soaking with an average of pH 7.6 level of sea-water. Three different types of MDP produced, i.e., bamboo waste strip MDP (SMDP), bamboo waste chips MDP (CMDP) and bamboo waste mixed strip-chips MDP (MMDP) by following the same process. The experimental panels tested for their physical-mechanical properties according to the procedures defined by ASTM D1037-12. Conclusively, even the present study shows properties of MDP with higher and comparable to other composite materials; further research must be given better attention as potential substitute to be used as hardwood materials, especially in the production, design, and construction usage.

Electrolysis soy protein isolate-based oleogels prepared with an emulsion-templated approach

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Dianyu Yu ◽  
Yan Chen ◽  
Xing Chen ◽  
Yunyan Huang ◽  
Liqi Wang ◽  
...  
Keyword(s):  
Soy Protein ◽  
Xanthan Gum ◽  
Binding Capacity ◽  
Soy Protein Isolate ◽  
Single Layer ◽  
Protein Isolate ◽  
Regulatory Limits ◽  
Order Of Magnitude ◽  
The Stability ◽  
Oil Binding

Abstract This research focuses on the use of protein-polyphenol complex and protein-polyphenol: polysaccharide complexes to prepare oleogels through an emulsion-templated approach. Electrolysis soy protein isolate (ESPI) could be effectively adsorbed on the surface of a single-layer emulsion to increase the particle size. The order of the negative charges of the emulsion after adding polysaccharides was xanthan gum (XG)> pectin> carboxymethyl cellulose (CMC). Rheological behavior showed that the stability of the double-layer emulsions increased, and the viscoelasticity increased around one order of magnitude with the addition of polysaccharides. The oil binding capacity (OBC) of the oleogel prepared by adding polysaccharides increased to more than 97%. The peroxide value (PV) and anisidine value (AV) of XG oleogel were the minimum values in all samples. The AV and POV were within the regulatory limits of China after storage for 21 days. This provides a reference to design of ESPI-based oleogel for different applications.

Analysis of Nonlinear Buckling of a Long-Span Elliptic Paraboloid Suspended Dome Structure

2013 ◽  
Vol 639-640 ◽  
pp. 191-197 ◽  
Author(s):  
Zheng Rong Jiang ◽  
Kai Rong Shi ◽  
Xiao Nan Gao ◽  
Qing Jun Chen
Keyword(s):  
Single Layer ◽  
Buckling Mode ◽  
Nonlinear Buckling ◽  
Elliptic Paraboloid ◽  
Geometric Imperfection ◽  
Long Span ◽  
Initial Geometric Imperfection ◽  
Dome Structure ◽  
Unsymmetrical Loading ◽  
The Stability

The suspended dome structure, which is a new kind of hybrid spatial one composed of the upper single layer latticed shell and the lower cable-strut system, generally has smaller rise-to-span ratio, thus the overall stability is one of the key factors to the design of the structure. The nonlinear buckling behavior of an elliptic paraboloid suspended dome structure of span 110m80m is investigated by introducing geometric nonlinearity, initial geometric imperfection, material elastic-plasticity and half-span distribution of live loads. The study shows that the coefficient of stable bearing capacity usually is not minimal when the initial geometric imperfection configuration is taken as the first order buckling mode. The unsymmetrical loading distribution and the material nonlinearity might have significant effects on the coefficient. The structure is sensitive to the changes of initial geometric imperfection, and the consistent mode imperfection method is not fully applicable to the stability analysis of suspended dome structure.

scholarly journals Influence of Snow Load Distribution on the Stability of Single-layer Reticulated Shells

2020 ◽  
Vol 10 (1) ◽  
pp. 141-147
Author(s):  
Junlin Wang ◽  
Wei Lu ◽  
Chenyang Dun ◽  
Hua Guo ◽  
Jianheng Sun
Keyword(s):  
Load Distribution ◽  
Single Layer ◽  
Snow Load ◽  
The Stability

scholarly journals THE VARIATION OF ELECTRICAL RESISTANCE WITH APPLIED POTENTIAL

1930 ◽  
Vol 14 (1) ◽  
pp. 139-162 ◽  
Author(s):  
L. R. Blinks
Keyword(s):  
Electrical Resistance ◽  
Sea Water ◽  
Single Layer ◽  
Applied Potential ◽  
Intact Cells ◽  
Outward Currents ◽  
Toxic Agents ◽  
Constant State ◽  
Inward Currents ◽  
Apparent Resistance

Electrical resistance and polarization were measured during the passage of direct current across a single layer of protoplasm in the cells of Valonia ventricosa impaled upon capillaries. These were correlated with five stages of the P.D. existing naturally across the protoplasm, as follows: 1. A stage of shock after impalement, when the P.D. drops from 5 mv. to zero and then slowly recovers. There is very little effective resistance in the protoplasm, and polarization is slight. 2. The stage of recovery and normal P.D., with values from 8 to 25 mv. (inside positive). The average is 15 mv. At first there is little or no polarization when small potentials are applied in either direction across the protoplasm, nor when very large currents pass outward (from sap to sea water). But when the positive current passes inward there is a sudden response at a critical applied potential ranging from 0.5 to 2.0 volts. The resistance then apparently rises as much as 10,000 ohms in some cases, and the rise occurs more quickly in succeeding applications after the first. When the potential is removed there is a back E.M.F. displayed. Later there is also an effect of such inward currents which persists into the first succeeding outward flow, causing a brief polarization at the first application of the reverse potential. Still later this polarization occurs at every exposure, and at increasingly lower values of applied potentials. Finally there is a "constant" state reached in which the polarization occurs with currents of either direction, and the apparent resistance is nearly uniform over a considerable range of applied potential. 3. A state of increased P.D.; to 100 mv. (inside positive) in artificial sap; and to 35 or 40 mv. in dilute sea water or 0.6 M MgSO4. The polarization response and apparent resistance are at first about as in sea water, but later decrease. 4. A reversed P.D., to 50 mv. (outside positive) produced by a variety of causes, especially by dilute sea water, and also by large flows of current in either direction. This stage is temporary and the cells promptly recover from it. While it persists the polarization appears to be much greater to outward currents than to inward. This can largely be ascribed to the reduction of the reversed P.D. 5. Disappearance of P.D. caused by death, and various toxic agents. The resistance and polarization of the protoplasm are negligible. The back E.M.F. of polarization is shown to account largely for the apparent resistance of the protoplasm. Its calculation from the observed resistance rises gives values up to 150 mv. in the early stages of recovery, and later values of 50 to 75 mv. in the "constant" state. These are compared with the back E.M.F. similarly calculated from the apparent resistance of intact cells. The electrical capacitance of the protoplasm is shown by the time curves to be of the order of 1 microfarad per cm.2 of surface.

The stability of boundary-layer flow over single-and multi-layer viscoelastic walls

1988 ◽  
Vol 196 ◽  
pp. 359-408 ◽  
Author(s):  
K. S. Yeo
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Flow ◽  
Single Layer ◽  
Viscous Sublayer ◽  
Rigid Base ◽  
Theoretical Treatment ◽  
Dynamical Condition ◽  
Compliant Walls ◽  
Layer Flow ◽  
The Stability

In this paper, we are concerned with the linear stability of zero pressure-gradient laminar boundary-layer flow over compliant walls which are composed of one or more layers of isotropic viscoelastic materials and backed by a rigid base. Wall compliance supports a whole host of new instabilities in addition to the Tollmien-Schlichting mode of instability, which originally exists even when the wall is rigid. The perturbations in the flow and the compliant wall are coupled at their common interface through the kinematic condition of velocity continuity and the dynamical condition of stress continuity. The disturbance modes in the flow are governed by the Orr-Sommerfeld equation using the locally-parallel flow assumption, and the response of the compliant layers is described using a displacement-stress formalism. The theoretical treatment provides a unified formulation of the stability eigenvalue problem that is applicable to compliant walls having any finite number of uniform layers; inclusive of viscous sublayer. The formulation is well suited to systematic numerical implementation. Results for single- and multi-layer walls are presented. Analyses of the eigenfunctions give an insight into some of the physics involved. Multi-layering gives a measure of control over the stability characteristics of compliant walls not available to single-layer walls. The present study provides evidence which suggests that substantial suppression of disturbance growth may be possible for suitably tailored compliant walls.

scholarly journals Stability of Rubble Mound Breakwaters—A Study of the Notional Permeability Factor, Based on Physical Model Tests

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 934 ◽  
Author(s):  
Mads Røge Eldrup ◽  
Thomas Lykke Andersen ◽  
Hans Falk Burcharth
Keyword(s):  
Physical Model ◽  
Slope Angle ◽  
Model Tests ◽  
Permeability Factor ◽  
Physical Model Tests ◽  
Stability Model ◽  
The Stability ◽  
Rubble Mound Breakwaters ◽  
Layer Composition

The Van der Meer formulae for quarry rock armor stability are commonly used in breakwater design. The formulae describe the stability as a function of the wave characteristics, number of waves, front slope angle and rock material properties. The latter includes a so-called notional permeability factor characterizing the permeability of the structure. Based on armor stability model tests with three armor layer compositions, Van der Meer determined three values of the notional permeability. Based on numerical model results he added for a typical layer composition one more value. Based on physical model tests, the present paper provides notional permeability factors for seven layer compositions of which two correspond to the compositions tested by Van der Meer. The results of these two layer compositions are within the scatter of the results by Van der Meer. To help determination of the notional permeability for non-tested layer compositions, a simple empirical formula is presented.

scholarly journals Statistical Analysis of the Stability of Rock Slopes

2019 ◽  
Vol 7 (3) ◽  
pp. 60 ◽  
Author(s):  
Marcel van Gent ◽  
Ermano de Almeida ◽  
Bas Hofland
Keyword(s):  
Statistical Analysis ◽  
Physical Model ◽  
Model Tests ◽  
Water Levels ◽  
Test Series ◽  
Length Effect ◽  
Wave Flume ◽  
Physical Model Tests ◽  
Erosion Area ◽  
The Stability

Physical model tests were performed in a wave flume at Deltares with rock armoured slopes. A shallow foreshore was present. At deep water, the same wave conditions were used, but by applying different water levels, the wave loading on the rock armoured slopes increased considerably with increasing water levels. This allowed an assessment of the effects of sea level rise. Damage was measured by using digital stereo photography (DSP), which provides information on each individual stone that is displaced. Two test series were performed five times. This allowed for a statistical analysis of the damage to rock armoured slopes, which is uncommon due to the absence of statistical information based on a systematic repetition of test series. The statistical analysis demonstrates the need for taking the mean damage into account in the design of rock armoured slopes. This is important in addition to characterising the damage itself by erosion areas and erosion depths. The relation between damage parameters, such as the erosion area and erosion depth, was obtained from the tests. Besides tests with a straight slope, tests with a berm in the seaward slopes were also performed. A new method to take the so-called length effect into account is proposed to extrapolate results from physical model tests to real structures. This length effect is important, but is normally overlooked in the design of rubble mound structures. Standard deviations based on the presented model tests were used.

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