Articles de revues : « Armour layer »

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Agung, Ida Bagus. "PENGARUH DURASI SERANGAN GELOMBANG TERHADAP TINGKAT KERUSAKAN LAPIS LINDUNG PEMECAH GELOMBANG." Science Tech: Jurnal Ilmu Pengetahuan dan Teknologi 1, no. 1 (2015): 18–27. http://dx.doi.org/10.30738/jst.v1i1.471.

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this research tetrapodÂ have been utilized for breakwaterÂ cover layer or armour layer. The effect of wave duration on the armorÂ layer tetrapod stability wasÂ studied. The models were runÂ in the irregular wave flume, where Bretschneider spectrum may be generated attackingÂ the breakwater. The waves were set to break before reaching the breakwater. The test was conducted until the damage level of armour layer reached more than 5 %. The result of the research showed that waves duration and the highÂ of the wave attack affect the stability of armour layer, especially when the waveÂ was Rayleigh distributed. The effect of waves durationÂ reducedÂ as more and more waves broken before reaching the structure of the breakwater

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MAYSTRENKO, Anatoliy L., Volodymyr I. KUSHCH, Evgeniy A. PASHCHENKO, Vitaliy G. KULICH, Olecksiy V. NESHPOR, and Sergiy P. BISYK. "Ceramic Armour for Armoured Vehicles Against Large-Calibre Bullets." Problems of Mechatronics Armament Aviation Safety Engineering 11, no. 1 (2020): 9–16. http://dx.doi.org/10.5604/01.3001.0014.0279.

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Modelling the armour-piercing bullets B-32 calibre 12.7 mm penetration into the double-layer ceramic-composite armour has been performed for the armour blocks of two designs. The first one is a layer of ceramic square tiles supported by the glass or polyamide fabric. Modelling and subsequent ballistic tests have shown that the conical Hertz crack localized in the ceramic tile is formed. The tile is destroyed from the spread of radial cracks, and the entire armour unit becomes unable to sustain the repeated hit of the bullet. In the second case, the armour block consists of the discrete epoxy-filled cylindrical ceramic elements with spherical ends. The advantage of this "discrete" armour is localization of the damage zone and thus an ability to sustain the multiple bullet hits. The ballistic tests of the compared armour units have shown that both provide effective additional protection of light-armoured vehicles against the normal impact of the calibre 12.7 mm bullet.

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Mouton, le Fras, Alexander Flemming, Michael Bates, and Chris Broeckhoven. "The relationship between generation gland morphology and armour in Dragon Lizards (Smaug): a reassessment of ancestral states for the Cordylidae." Amphibia-Reptilia 39, no. 4 (2018): 457–70. http://dx.doi.org/10.1163/15685381-20181032.

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Abstract To substantiate the claim of a relationship between generation gland morphology and degree of body armour in cordylid lizards, we studied the nine species in the genus Smaug. We predicted that well armoured species in this clade will have multi-layer generation glands, and lightly armoured species two-layer glands. Gland type was determined using standard histological techniques after sectioning a glandular patch of one adult male per species. A total of 133 specimens were examined for data on tail and occipital spine lengths (which were used as indicators of armour). We found that species with multi-layer generation glands (S. giganteus, S. breyeri, and S. vandami) have relatively long tail and occipital spines, while species with two-layer glands (S. mossambicus, S. regius, S. barbertonensis, S. warreni, and an undescribed species) have relatively short spines. Smaug depressus possesses both multi-layer and two-layer glands, and this variation was linked to regional variation in spine length. An ancestral state reconstruction for the Cordylidae showed that the two-layer state always results from the reduction of layers from a multi-layer precursor, and that reduction always culminates in two-layer glands and not in one-layer glands. This finding suggests that the one-layer state in the Ninurta-Chamaesaura-Pseudocordylus clade is most probably plesiomorphic, and therefore the ancestral state at the Cordylidae and Cordylinae nodes. Given the observed relationship between type of generation gland and body armour, this finding would suggest that the most recent common ancestor of the Cordylidae was lightly armoured.

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Van den Bosch, Ilse, Erik Ten Oever, Pieter Bakker, and Markus Muttray. "STABILITY OF INTERLOCKING ARMOUR UNITS ON A BREAKWATER CREST." Coastal Engineering Proceedings 1, no. 33 (2012): 11. http://dx.doi.org/10.9753/icce.v33.structures.11.

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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.

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Santos, João Alfredo, Francisco Pedro, Mário Coimbra, et al. "3-D Scale Model Study of Wave Run-Up, Overtopping and Damage in a Rubble-Mound Breakwater Subject to Oblique Extreme Wave Conditions." Defect and Diffusion Forum 396 (August 2019): 32–41. http://dx.doi.org/10.4028/www.scientific.net/ddf.396.32.

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A set of scale-model tests carried out to enlarge the range of wave steepness values analysed in run-up, overtopping and armour layer stability studies, focusing on oblique extreme wave conditions and on their effects on a gentler slope breakwater’s trunk armour and roundhead, is presented in this paper. A stretch of a rubble mound breakwater (head and part of the adjoining trunk, with a slope of 1(V):2(H)) was built in a wave basin at the Leibniz University Hannover to assess, under extreme wave conditions (wave steepness of 0.055) with different incident wave angles (from 40º to 90º), the structure behaviour in what concerns wave run-up, wave overtopping and damage progression of the armour layer. Two types of armour elements (rock and Antifer cubes) were tested. Non-intrusive methodologies including a new application of laser scanning technique for the assessment of both armour layer damage and wave run-up and overtopping were used. It is expected that such work will contribute also with data to improve empirical formulas as well as to validate complex numerical model for wave-structure interaction.

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Lu, Jiang Ren, Xin Li Sun, Xing Hui Cai, San Qiang Dong, and Guo Liang Wang. "Numerical Study on the Ballistic Impact on Lightweight Composite Armour." Applied Mechanics and Materials 670-671 (October 2014): 824–28. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.824.

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A lightweight sandwich composite armours has been established by comparing the ballistic resistance of the potential component materials. The ballistic-resistance properties of the armours under impacting by the bullet with 12.7mm diameter are also numerically investigated by using finite element software LS-DYNA. Numerical modeling is used to obtain an estimate for the ballistic limit velocity (V50) and simulate penetration processes. The focus is placed on the energy absorption capabilities of different component layers with same density per unit area. The influence of stacking sequence and thickness ratio of ceramic/fiber layer has been analyzed in detail. Results indicate that the composite armour having optimal thickness ratio of ceramic/fiber layer in the same density and its mass is 29% lighter than of 4340 steel target.

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Young, Martin, John Hayman-Joyce, and Seok Hyeon Kim. "USE OF SINGLE LAYER CONCRETE ARMOUR UNITS AS TOE REINFORCEMENT." Coastal Engineering Proceedings 1, no. 33 (2012): 48. http://dx.doi.org/10.9753/icce.v33.structures.48.

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Detailing and optimization of the toe reinforcement is presented as a case study from the construction of the 5.2km long main breakwater for the new Colombo South Harbour in 18m water depth. During the breakwater design the environmental constraints on supply of large rock armour were recognized, and CORE-LOC™ single layer concrete armour units were selected for the primary armour protection. During construction, supply of relatively small quantities of 8-12t rock for use in the toe reinforcement became an issue, and use of CORE-LOC™ units placed on the flat rock armour apron as an alternative to rock armour toe reinforcement was investigated and implemented. This use is unusual as there is no in-plane compression between units as found when they are placed on the slope. A site based prototype scale trial was conducted to evaluate placing method and criteria, and an “alternate opposing cannon” pattern placement, in rows going seaward from the primary armour, was successful. Packing density and unit spacing is the same as for the primary armour. Hydraulic stability of this alternative toe reinforcement was verified in 2D physical hydraulic model testing.

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Bakker, Pieter, Tiemen de Hoop, and Markus Muttray. "STABILITY OF XBLOCPLUS ARMOUR LAYERS AFTER INITIAL DAMAGE." Coastal Engineering Proceedings, no. 36v (December 28, 2020): 16. http://dx.doi.org/10.9753/icce.v36v.structures.16.

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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

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Latham, John-Paul, Eleni Anastasaki, and Jiansheng Xiang. "A FEMDEM NUMERICAL MODEL STUDY OF RUBBLE-MOUND STRUCTURES ARMOURED WITH CONCRETE ARMOUR UNITS." Coastal Engineering Proceedings 1, no. 33 (2012): 37. http://dx.doi.org/10.9753/icce.v33.posters.37.

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A new method for the numerical creation of random single-layer systems of concrete armour units is illustrated. The armour layer pack is created by a FEMDEM solver that ensures mechanical equilibrium between all concrete units and rocks of the underlayer. The local and average packing density together with geometric constraints indicative of randomness and interlocking are assessed using analysis tools and shown to be in accordance with unit designer requirements. This solids modelling research is an essential pre-requisite to future simulation of the armour layer response to wave loading and more realistic modelling of wave run-up and overtopping on rubble-mound structures.

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Burcharth, Hans Falk, Thomas Lykke Andersen, and Josep R. Medina. "STABILITY OF CUBIPOD ARMOURED ROUNDHEADS IN SHORT-CRESTED WAVES. A COMPARISON BETWEEN CUBIPOD AND CUBE ARMOUR STABILITY." Coastal Engineering Proceedings 1, no. 32 (2011): 39. http://dx.doi.org/10.9753/icce.v32.structures.39.

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The paper presents a comparison of the stability of concrete cube armour and Cubipod armour in a breakwater roundhead with slope 1:1.5, exposed to both 2-D (long-crested) and 3-D (short-crested) waves. The model tests were performed at the Hydraulics and Coastal Engineering Laboratory at Aalborg University, Denmark. The model tests showed that Cubipod armour is more stable than cube armour when exposed to longer waves (steepness approx. 0.025) and has equal stability to cubes in shorter waves. The Cubipod armour layer contained due to its high porosity approximately 6-17% less concrete than the cube armour layer. Therefore, it was concluded that per used volume of concrete the Cubipods perform better than the cubes.

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Lemos, Rute, João A. Santos, and Conceição J. E. M. Fortes. "Damage Evolution Prediction during 2D Scale-Model Tests of a Rubble-Mound Breakwater: A Case Study of Ericeira’s Breakwater." Modelling 4, no. 1 (2022): 1–18. http://dx.doi.org/10.3390/modelling4010001.

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Melby presents a formula to predict damage evolution in rubble-mound breakwaters whose armour layer is made of rock, based on the erosion measured in scale-model tests and the characteristics of the incident sea waves in such tests. However, this formula is only valid for armour layers made of rock and for the range of tested sea states. The present work aims to show how the Melby methodology can be used to establish a similar formula for the armour layer damage evolution in a rubble-mound breakwater where tetrapods are employed. For that, a long-duration test series is conducted with a 1:50 scale model of the quay section of the Ericeira Harbour breakwater. The eroded volume of the armour layer was measured using a Kinect position sensor. The damage parameter values measured in the experiments are lower than those predicted by the formulation for rock armour layers. New and coefficients for the Melby formula for the tested armour layer were established based on the minimum root mean square error between the measured and the predicted damage. This work shows also that it is possible to assess the damage evolution in scale-model tests with rubble-mound breakwaters by computing the eroded volume and subsequently, the dimensionless damage parameter based on the equivalent removed armour units.

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Abtew, Mulat Alubel, Francois Boussu, Pascal Bruniaux, and Yan Hong. "Dynamic Impact Surface Damage Analysis of 3D Woven Para-Aramid Armour Panels Using NDI Technique." Polymers 13, no. 6 (2021): 877. http://dx.doi.org/10.3390/polym13060877.

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The effects of the yarn composition system inside 3D woven high-performance textiles are not well investigated and understood against their final ballistic impact behaviour. The current study aims to examine the ballistic impact performances of armour panels made of different 3D woven fabric variants through postmortem observations. Four high-performance five-layer 3D woven fabric variants were engineered based on their different warp yarn compositions but similar area density. A 50 × 50 cm2 armour system of each variant, which comprises eight nonbonded but aligned panels, namely, 3D-40-8/0 (or 8/0), 3D-40-8/4 (or 8/4), 3D-40-8/8 (or 8/8) and 3D-40-4/8 (or 4/8), were prepared and moulded to resemble female frontal morphology. The armour systems were then tested with nonperforation ballistic impacts according to the National Institute of Justice (NIJ) 0101.06 standard Level-IIIA. Two high-speed cameras were used to capture the event throughout the test. Nondestructive investigation (NDI) using optical microscopic and stereoscopic 3D digital images were employed for the analysis. The armour panels made of the 8/0 and 4/8 fabric variants were perforated, whereas the armour made of the 8/8 and 8/4 fabric variants showed no perforation. Besides, the armour made of the 8/4 fabric variant revealed higher local and global surface displacements than the other armours. The current research findings are useful for further engineering of 3D woven fabric for seamless women’s impact protective clothing.

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Johnson, Andrew Allan, Guy Bingham, and Candice Majewski. "Laser sintered body armour – establishing single layer stab protection." Rapid Prototyping Journal 24, no. 1 (2018): 130–37. http://dx.doi.org/10.1108/rpj-11-2015-0173.

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Purpose The purpose of this paper is to establish the minimum thickness required to provide stab protection in accordance with the United Kingdom Home Office Scientific Development Branch (HOSDB) standards while testing a series of laser sintered (LS) planar specimens using instrumented test apparatus. Design/methodology/approach Planar test specimens were LS in single-layer thicknesses ranging from 1.00 to 15.00 mm in four material powder categories – DuraForm® virgin, DuraForm 50/50 mix, DuraForm EX® virgin and DuraForm EX 50/50 mix. All specimens were tested using instrumented drop test apparatus and were impacted with established Stanley Tools 1992 trimming blades to the UK HOSDB KR1-E1 stab impact energy level. Findings The research demonstrated that a minimum single planar specimen thickness of 11.00 mm, manufactured from DuraForm EX 50/50 mix powder, was required to provide protection against the HOSDB KR1-E1 level of stab impact energy. The alternative powder mixes tested within this experiment demonstrated poor levels of stab protection, with virgin powder specimens demonstrating no protection up to 15.00 mm, whereas DuraForm 50/50 mix specimens demonstrating inconsistent performances. Originality/value This paper enhances on existing literature surrounding the manufacturing and testing of additive manufacturing (AM) stab-resistant armour by adding further rigour to the testing of AM body armour specimens. In addition, this research establishes key foundation characteristics which could be utilised for the future development of bespoke AM body armour garments.

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Van Gent, Marcel R. A., Suzanna A. A. Zwanenburg, and Jan Kramer. "EFFECTS OF WATER LEVEL VARIATIONS ON THE STABILITY OF ROCK ARMOURED SLOPES." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 44. http://dx.doi.org/10.9753/icce.v36.papers.44.

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Physical model tests on the stability of rock armoured slopes have been performed to demonstrate the importance of water level variations during a storm, due to a tide or a storm surge. For the stability of rock armoured slopes also the importance of the sequence of storms at various water levels has been studied. The test results indicate that a smooth sinusoidal water level variation leads to an increase in damage compared to the same wave conditions at a constant water level. Furthermore, a stepwise approach of the sinusoidal water level elevation leads to other results than the approach with a continuous water level variation, whereas the continuous water level variation resembles the peak of a storm or the tidal water level variation better than a stepwise approach. If storms with different water levels attack the armour layer, the damage is generally smaller than if all storms attack the armour layer at the same water level. Furthermore, the results have been discussed based on earlier analyses where the statistics of rock armoured slopes have been addressed and the importance of the length effect has been illustrated using a method to apply results from physical model tests to real structures.

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Reedijk, Bas, Tamara Eggeling, Pieter Bakker, Robert Jacobs, and Markus Muttray. "HYDRAULIC STABILITY AND OVERTOPPING PERFORMANCE OF A NEW TYPE OF REGULAR PLACED ARMOR UNIT." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 111. http://dx.doi.org/10.9753/icce.v36.papers.111.

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The XblocPlus is a new type of interlocking single layer armour units that is placed with uniform orientation. This is novel and different from all other single layer, interlocking armouring systems. The hydraulic stability of the XblocPlus breakwater armour unit was tested in 2D and 3D hydraulic model tests. Wave overtopping tests were performed to determine the roughness coefficients of the EurOtop overtopping formula for the XblocPlus. Model tests on a rubble mound breakwater with XblocPlus armour included 2D tests with a 1:30 seabed slope and with 1:2 and 3:4 breakwater slopes and 3D model tests with a flat seabed and with a 3:4 breakwater slope. Wave heights up to 150% of the design wave height were tested in the 2D tests and up to 200% with wave directions 0Â° to 60Â° in the 3D tests. No armour unit displacements were observed in 2D tests with 1:2 slope. In the 2D tests with 3:4 slope one armour unit was displaced when the wave height reached 159% of the design wave height. No damage to the XblocPlus armour layer was observed in the 3D tests. A roughness coefficient of 0.45 was deduced from overtopping tests with wave heights of 60% to 100% of the design wave height. The model test results indicate little or no influence of wave steepness on XblocPlus stability and no adverse influence of wave obliquity while the seabed slope in front of the breakwater may have some impact on the XblocPlus armour layer stability.

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Wolters, Guido, and Marcel Van Gent. "OBLIQUE WAVE ATTACK ON CUBE AND ROCK ARMOURED RUBBLE MOUND BREAKWATERS." Coastal Engineering Proceedings 1, no. 32 (2011): 34. http://dx.doi.org/10.9753/icce.v32.structures.34.

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Stability formulae for armour layers of rubble mound breakwaters are usually being applied assuming perpendicular wave attack. Often it is assumed that for oblique wave attack the reduction in damage compared to perpendicular wave attack is small. This seems however a very conservative assumption. Wave basin tests at Deltares provide information to assess the effects of oblique waves on the stability of rock slopes and cube armoured rubble mound breakwaters. This includes cubes in a single layer and cubes in a double layer. The results show that the few available formulae that include wave obliquity underestimate the effects of oblique wave attack; the observed damage to breakwaters with armour layers of rock and cubes is lower and therefore new stability increase factors and mass reduction factors have been developed. The tests were performed for wave directions between perpendicular (0) and 70. The results show that large potential savings in diameter and mass can be obtained for large angles of wave obliquity.

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Jacobs, Robert, Pieter Bakker, Ineke Vos-Rovers, and Bas Reedijk. "XBLOC-PLUS â€“ DEVELOPMENT OF A REGULAR PLACED INTERLOCKING ARMOUR UNIT." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 45. http://dx.doi.org/10.9753/icce.v36.structures.45.

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Randomly placed single layer interlocking concrete armor units are currently the most advanced and cost-efficient option for the protection of breakwaters. The key feature of these units is the random orientation of the units, which requires the crane operator to assess the orientation of each individual unit during block placement. DMC noticed the desire for a block which can be placed in a regular pattern as this will increase the placement rates. Apart of this, regular placement of armor units can also be preferred for aesthetical reasons. Fifteen years after the introduction of Xbloc, DMC therefore introduces a new breakwater armour unit called XblocPlus which is placed with uniform block orientations.

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Baird, William F., D. D. Davidson, Billy Edge, Orville T. Magoon, Charles I. Rauw, and Donald Treadwell. "DESIGN AND CONSTRUCTION OF BERM TYPE BREAKWATERS." Coastal Engineering Proceedings 1, no. 21 (1988): 178. http://dx.doi.org/10.9753/icce.v21.178.

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The standard design for a rubble-mound breakwater as reported in recent text books and manuals has consisted of a core of rubble quarry-run that is protected from wave action by two layers of relatively large quarried stone or concrete units. Filter layers of intermediate size stone are recommended beneath the armour layer to prevent loss of the core material through the armour. The pioneering work of Hudson provides coefficients for a formula that allowed widespread use of this design concept throughout the world. A breakwater of this form tends to require the smallest volume of stone; however, it may not represent the least cost structure for a specific location because of the cost and availability of local materials. Recently, design engineers and hydraulic laboratories have given considerable attention to alternative forms of rubble mound structures. The objective of this work has been to minimize cost while maintaining the same or improved level of stability when the breakwater is subjected to extreme wave conditions. Principally, emphasis has been given to the utilization of locally available quarried stone and to maximizing the use of the full yield of a local quarry. This has required the design of breakwaters using smaller armour stone and a wider range of sizes than was used in the more conventional breakwater. These designs have also given consideration to the realities of construction and the limitation of construction equipment on the assumption that cost savings will be achieved with relatively simple construction methods. Clearly the use of smaller armour stones requires a change in other properties or characteristics of the armour layer, compared to a conventional design, in order to achieve the same stability. The principal characteristics of a berm breakwater are the high permeability of the armour-layer and the significantly larger volume of armour. Berm breakwaters generally consist of a relatively large and permeable mass of armour stone (of smaller size than required for a conventional design).

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Castillo, Carmen, Rafael Molina, Rebeca Gómez, and Enrique Castillo. "A STATISTICAL MODEL FOR DAMAGE ACCUMULATION IN BREAKWATERS." Coastal Engineering Proceedings 1, no. 32 (2011): 19. http://dx.doi.org/10.9753/icce.v32.posters.19.

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Rehabilitation and maintenance studies are a great concern for Port Authorities and other Administrations.  For a complete risk analysis, probability of failure due to instability of the armour layer must be analyzed and therefore a knowledge on its deterioration rate is needed.  Breakwater armour stability is highly variable and difficult to quantify for many variables are involved in the problem.   Breakwater armour stability is stochastic in nature as both loading and armour conditions are. There is uncertainty in armour placing and shape and in loading by waves and water level.  Dimensionality, compatibility conditions and the central limit theorem are suggested to be considered for building consistent statistical models reproducing random breakwater damage progression due to general random wave actions.

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Leng, Sioh Ek. "Functional Graded Material with Nano Coating for Protection." Solid State Phenomena 136 (February 2008): 93–98. http://dx.doi.org/10.4028/www.scientific.net/ssp.136.93.

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Ceramic composite armour in general utilises a front layer of dense ceramic, typically backed by a second layer of metal. Thereby creating a sharp interface that is the weakest link within the material system and would result in cracking of the ceramic prematurely and hence not able to provide the requisite protection. One promising possibility has been found is the use of functionally gradient materials as armour materials. In such materials, the high hardness of ceramics is combined with the ductility of metals. Laboratory scale experiments were being performed to exhibit the potential of this material in terms of physical and mechanical properties. A comparison was made with the current ceramic armour system and it was found that the new material system had better ballistic properties.

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Chabera, P., A. Boczkowska, A. Morka, et al. "Comparison of numerical and experimental study of armour system based on alumina and silicon carbide ceramics." Bulletin of the Polish Academy of Sciences Technical Sciences 63, no. 2 (2015): 363–67. http://dx.doi.org/10.1515/bpasts-2015-0040.

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Abstract The main goal of this numerical and experimental study of composite armour systems was to investigate their ballistic behaviour. Numerical simulations were employed to determine the initial dimensions of panel layers before the actual ballistic test. In order to achieve this aim, multivariate computations with different thicknesses of panel layers were conducted. Numerical calculations were performed with the finite element method in the LS-DYNA software, which is a commonly used tool for solving problems associated with shock wave propagation, blasts and impacts. An axisymmetric model was built in order to ensure sufficient discretization. Results of a simulation study allowed thicknesses of layers ensuring assumed level of protection to be determined. According to the simulation results two armour configurations with different ceramics have been fabricated. The composite armour systems consisted of the front layer made of Al2O3 or SiC ceramic and high strength steel as the backing material. The ballistic performance of the proposed protective structures were tested with the use of 7.62 mm Armour Piercing (AP) projectile. A comparison of impact resistance of two defence systems with different ceramic has been carried out. Application of silicon carbide ceramic improved ballistic performance, as evidenced by smaller deformations of the second layer. In addition, one of armour systems was complemented with an intermediate ceramic-elastomer layer. A ceramic-elastomer component was obtained using pressure infiltration of gradient porous ceramic by elastomer. Upon ballistic impact, the ceramic body dissipated kinetic energy of the projectile. The residual energy was absorbed by the intermediate composite layer. It was found, that application of composite plates as a support of a ceramic body provided a decrease of the bullet penetration depth

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Franco, Leopoldo, Yuri Pepi, Stefano de Finis, Verdiana Iorio, Giorgio Bellotti, and Claudia Cecioni. "ROUGHNESS FACTOR FOR MULTI-LAYER ARMOUR AS OVERTOPPING ESTIMATOR." Coastal Engineering Proceedings, no. 36v (December 28, 2020): 25. http://dx.doi.org/10.9753/icce.v36v.structures.25.

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Nowadays one of the most challenging problem for engineers is to adapt existing coastal structures to climate changes. Wave overtopping is highly sensitive to the increasing extreme water depths due to higher storm surges coupled with sea level rise. One way to face these problems for rubble mound breakwaters is to add one or more layers to the existing armour. Prediction of wave overtopping of coastal structures is presently obtained from empirical formulae in EurOtop (2018). For the case of overtopping over multi-layer armour, no validated method exists, so prediction must be based upon assumptions and judgement, with related uncertainties. This study is focused on the effects of different types of armour, the number of layer and other structural characteristics on the roughness factor f. The main effects of porosity and roughness will be investigated. This paper analyzes the results of several new physical model tests of different rubble mound breakwaters reproduced at the new medium scale random wave flume of the Department of Engineering of Roma Tre University.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/8cOdqkqQ-9s

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Chabera, P., A. Boczkowska, A. Morka, T. Niezgoda, A. Oziębło, and A. Witek. "Numerical and experimental study of armour system consisted of ceramic and ceramic- elastomer composites." Bulletin of the Polish Academy of Sciences Technical Sciences 62, no. 4 (2014): 853–59. http://dx.doi.org/10.2478/bpasts-2014-0094.

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Abstract The paper presents numerical and experimental results in the study of composite armour systems for ballistic protection. The modelling of protective structures and simulation methods of experiment as well as the finite elements method were implemented in LS DYNA software. Three armour systems with different thickness of layers were analyzed. Discretization for each option was built with three dimensional elements guaranteeing satisfactory accuracy of the calculations. Two selected armour configurations have been ballistically tested using the armour piercing (AP) 7.62 mm calibre. The composite armour systems were made of Al2O3 ceramics placed on the strike face and high strength steel as a backing material. In case of one ballistic structure system an intermediate ceramic- elastomer layer was applied. Ceramic- elastomer composites were obtained from porous ceramics with porosity gradient using pressure infiltration of porous ceramics by elastomer. The urea-urethane elastomer, as a reactive liquid was introduced into pores. As a result composites, in which two phases were interconnecting three-dimensionally and topologically throughout the microstructure, were obtained. Upon ballistic impact, kinetic energy was dissipated by ceramic body The residual energy was absorbed by intermediate composite layer. Effect of the composite shell application on crack propagation of ceramic body was observed.

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van der Wal, Rogier, Erik Carton, and Frits Hilvers. "The performance of armour steels with pre-layers against fragment simulating projectiles." EPJ Web of Conferences 183 (2018): 04015. http://dx.doi.org/10.1051/epjconf/201818304015.

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Armour steels have proven to be promising solutions for protection against fragments from threat weapons. The area to cover for ship bulkheads is usually large, so cost of the raw material is an important driver. For new ships, additional mass can be compensated for in the design. Past research by TNO and other workers has shown that the ballistic limit V50 of armour steels against fragments is increased significantly by adding a front or pre-layer. This layer can be a variety of materials ranging from cardboard to glass. In TNO’s Laboratory for Ballistics Research a test program was conducted to study the effect of high pressure laminate, polymer and fire insulation pre-layers at the V50 and well above the ballistic limit. The high velocities are typically associated with fragments from relevant threats for warships. Fragment simulating projectiles were fired on armour steel plates of varying type and thickness with these pre-layers and measured the residual velocity and resulting hole sizes. The tests resulted in clear dependencies of the residual velocity as a function of impact velocity and pre-layer (type and thickness). Analysis of the data showed that there are several counteracting effects interacting when a pre-layer is applied to armour steel. The failure mechanism of the steel as well as the hardness and thickness of the pre-layer seem to influence the outcome of this interaction and hence the response of the steel to various pre-layers. The results of this research will be used in the design of fragment and blast resistant bulkheads for future naval ships.

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Kędzierski, P., A. Morka, G. Sławiński, and T. Niezgoda. "Optimization of two-component armour." Bulletin of the Polish Academy of Sciences Technical Sciences 63, no. 1 (2015): 173–79. http://dx.doi.org/10.1515/bpasts-2015-0020.

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Abstract The paper presents research on optimization of two-layer armour subjected to the normal impact of the 7.62x54 B32 armour piercing (AP) projectile. There were analysed two cases in which alumina Al2O3 was supported by aluminium alloy AA2024-T3 or armour steel Armox 500T. The thicknesses of layers were determined to minimize the panel areal density whilst satisfying the constraint, which was the maximum projectile velocity after panel perforation. The problem was solved through the utilization of LS-DYNA, LS-OPT and HyperMorph engineering software. The axisymmetric model was applied to the calculation in order to provide sufficient discretization. The response of the aluminium alloy, armour steel and projectile material was described with the Johnson-Cook model, while the one of the alumina with the Johnson-Holmquist model. The study resulted in the development of a panel optimization methodology, which allows the layer thicknesses of the panel with minimum areal density to be determined. The optimization process demonstrated that the areal density of the lightest panel is 71.07 and 71.82 kg/m2 for Al2O3-Armox 500T and Al2O3-AA2024-T3, respectively. The results of optimization process were confirmed during the experimental investigation.

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Namaee, Mohammad Reza, and Jueyi Sui. "Impact of armour layer on the depth of scour hole around side-by-side bridge piers under ice-covered flow condition." Journal of Hydrology and Hydromechanics 67, no. 3 (2019): 240–51. http://dx.doi.org/10.2478/johh-2019-0010.

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Abstract In the present study, experiments were conducted in a large-scale flume to investigate the issue of local scour around side-by-side bridge piers under both ice-covered and open flow conditions. Three non-uniform sediments were used in this experimental study. Analysis of armour layer in the scour holes around bridge piers was performed to inspect the grain size distribution curves and to study the impact of armour layer on scour depth. Assessments of grain size of deposition ridges at the downstream side of bridge piers have been conducted. Based on data collected in 108 experiments, the independent variables associated with maximum scour depth were assessed. Results indicate that the densi-metric Froude number was the most influential parameter on the maximum scour depth. With the increase in grain size of the armour layer, ice cover roughness and the densimetric Froude number, the maximum scour depth around bridge piers increases correspondingly. Equations have been developed to determine the maximum scour depth around bridge piers under both open flow and ice covered conditions.

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Kulakov, N. A., and A. N. Lyubin. "Features of composite armour design." Izvestiya MGTU MAMI 5, no. 1 (2011): 46–51. http://dx.doi.org/10.17816/2074-0530-69841.

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The article examines the design of protection composite armour panel. This panel consists of two parts. The first part is a layer of cylindrical shape with crushing ceramics elements. The second part is a metal plate. The metal plate is a place for crushing elements. This protection panel is used for bullet protection of a car.

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Zhao, Xiao Dong, Xue Song Xu, Xiao Xiao Li, and Xing Chen. "Stability Experiment of Revetment Blocks for Regulation Project of Mulan Creek River." Applied Mechanics and Materials 212-213 (October 2012): 789–95. http://dx.doi.org/10.4028/www.scientific.net/amm.212-213.789.

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The anti-scour velocity of revetment blocks for flood control project of Mulan Creek river was studied through flume experiments. The results show that the revetment stability is related to the surface smoothness of revetment blocks. If they are paved smoothly, the incipient velocity of the blocks is greater than 4.0m/s, otherwise it is smaller than 3.2m/s. Hence, the smooth armour layer of revetment blocks are more stable than the others. According to distributions of flow velocities during flood in the river, the armor block types for different reaches of Mulan Creek river are suggested.

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Cuimbra, Salestiano, Haryo Dwito Armono, and Wahyudi. "Hydraulic Stability of BPPT – lock on Breakwater Head." IOP Conference Series: Earth and Environmental Science 1081, no. 1 (2022): 012026. http://dx.doi.org/10.1088/1755-1315/1081/1/012026.

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Abstract Breakwater is one of the coastal buildings built by humans to protect coastal areas such as ports, settlements, and tourist attractions from wave attacks. This test aims to determine the condition damage of BPPT – lock in one- and two-layers placements in the head of the rubble mound breakwater. The method used to conduct this research was physical model test and carried out at laboratory of Balai Teknologi Infrastruktur Pelabuhan dan Dinamika Pantai (BTIPDP) Yogyakarta – Indonesia. The armour unit model used BPPT–locks were 66.048 grams or equivalent to 2.268 tons in prototype and tested in various wave heights, starting from 7.5 cm, 9.2 cm, and 11.4 cm with period 1.5 S or equal to 4 meters of wave height in the prototype. Based on the laboratory results of testing, installing a double armour layer was recommended because the percentage of damage of the double armour layer was lower, and the coefficient of damage was higher.

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Donnelly, James, Pieter Bakker, Bas Reedijk, and Yang Zi Qian. "XBLOC-PLUS: THE INTERLOCKING, PATTERN PLACED AND EFFICIENT ARMOUR UNIT." Coastal Engineering Proceedings, no. 36v (December 28, 2020): 18. http://dx.doi.org/10.9753/icce.v36v.structures.18.

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Most breakwaters are built with randomly placed single layer armour units as these are most cost-efficient. Most single layer blocks require random unit orientations, which requires the crane operator to assess the orientation of each individual unit during placement. DMC noticed the desire for an interlocking block which can be placed in a regular pattern as many crane operators find it easier to place units uniformly, which requires less intuition. Fifteen years after the introduction of Xbloc, DMC introduces a new interlocking breakwater armour unit called XblocPlus which is placed with uniform block orientations.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/oEb1vsYfjL8

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Kobylkin, I. F., and V. V. Shakirzyanova. "Numerical Simulation of Projectile Penetration into Laminated Transparent Armour." Herald of the Bauman Moscow State Technical University. Series Mechanical Engineering, no. 1 (130) (February 2020): 16–28. http://dx.doi.org/10.18698/0236-3941-2020-1-16-28.

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The paper shows that the main reasons behind a laminated glass panel failing while penetrated by a high-velocity projectile are the high stresses in the region affected by the projectile and tensile stresses at the interface that are caused by the glass layers bending. For all the glass layers but the frontal one, intense fracturing does not start at the interface with the previous layer but at the interface with the subsequent layer, in the region of the tensile stresses generated by the current layer bending. The fracturing propagates towards the impact. A low-strength adhesive layer between glass layers inhibits and even stops the fracture-inducing wave propagating from the previous layer into the subsequent one. Analysis of the projectile deceleration plots in laminated glass panels of the same total thickness showed that the projectile undergoes more dramatic deceleration in a single-layer barrier and in barriers consisting of fewer layers.

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Chen, Weiqiu, Alberto Marconi, Marcel R. A. van Gent, Jord J. Warmink, and Suzanne J. M. H. Hulscher. "Experimental Study on the Influence of Berms and Roughness on Wave Overtopping at Rock-Armoured Dikes." Journal of Marine Science and Engineering 8, no. 6 (2020): 446. http://dx.doi.org/10.3390/jmse8060446.

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The average overtopping discharge is an important parameter for the design and reinforcement of dikes. Rock armour on the waterside slopes and berms of dikes is widely used to reduce the wave overtopping discharge by introducing slope roughness and dissipation of energy in the permeable armour layer. However, methods for estimating the influence of a rock berm and roughness of rock armour at dikes on the average overtopping discharge still need to be developed and/or validated. Therefore, this study aims to develop empirical equations to quantify the reductive influence of rock armour on wave overtopping at dikes. Empirical equations for estimating the effects of rock berms and roughness are derived based on the analysis of experimental data from new physical model tests. The influence of roughness of the rock armour applied on parts of waterside slopes is estimated by introducing the location weighting coefficients. Results show that the newly derived equations to predict the average overtopping discharge at dikes lead to a significantly better performance within the tested ranges compared to existing empirical equations.

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Fras, Teresa. "Experimental and Numerical Study on a Non-Explosive Reactive Armour with the Rubber Interlayer Applied against Kinetic-Energy Penetrators—The ‘Bulging Effect’ Analysis." Materials 14, no. 12 (2021): 3334. http://dx.doi.org/10.3390/ma14123334.

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The study concerns a protection system applied against kinetic-energy penetrators (KEPs) composed of steel plates sandwiching a rubber layer. Laminated steel-elastomer armours represent non-explosive reactive (NERA) armours that take advantage of a so-called ‘bulging effect’ to mitigate KEP projectiles. Upon an impact, the side steel plates deform together with the deforming rubber interlayer. Their sudden deformation (bulging) in opposite directions disturbs long and slender KEP projectiles, causing their fragmentation. The presented discussion is based on the experimental investigation, confirming that the long-rod projectiles tend to fracture into several pieces due to the armour perforation. A numerical simulation accompanies the ballistic test providing an insight into the threat/target interactions. The presented experimental–numerical study explains the principles of the analysed protection mechanism and proves the efficiency of the materials composition making up the laminated non-reactive protection system.

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Paman, Ashish, Govindan Sukumar, B. Ramakrishna, and Vemuri Madhu. "An optimization scheme for a multilayer armour module against 7.62 mm armour piercing projectile." International Journal of Protective Structures 11, no. 2 (2019): 185–208. http://dx.doi.org/10.1177/2041419619860533.

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This study presents a methodology to find the optimal sequence and thicknesses of individual material layers in a multilayer armour module. The methodology is demonstrated with application to three different metal alloys: Armox-500T, Ti-6Al-4V and Al-2024. Numerical simulations are performed first to study the ballistic impact behaviour of these three materials using AUTODYN-3D code. The results of numerical simulations are compared with experimental results for validating the numerical models. Thereafter, a three-layer armour module consisting of these three materials is optimized to defeat 7.62 armour piercing projectile with minimum weight. The optimization process involves carrying a set of numerical simulations based on the design of experiment approach to generate a response surface for the ballistic performance of a composite module. A new ballistic performance parameter is introduced to measure the ballistic response of the module by combining depth of penetration and residual velocity of the projectile to bring uniformity between two cases of partial and complete penetration. The proposed parameter provides more information on ballistic performance. The response surface for ballistic performance parameter is generated in terms of thicknesses for six possible combinations of three material layers. The adequacy of the proposed optimization scheme is confirmed with ballistic experiments. The sequence Armox-500T/Ti-6Al-4V/Al-2024 with thicknesses 5.5, 8.5 and 13 mm, respectively, is found to be the best against 7.62 mm armour piercing projectile. Furthermore, the performance of each individual material is compared with an optimized three-layer armour module. The composite module is found to be weight efficient over Armox-500T, Al-2024 and provides better thickness efficiency over Al-2024. The weight efficiency and thickness efficiency of Ti-6Al-4V are found to be comparable to the composite module. This study emphasizes the necessity of developing new procedures to provide reliable estimates of design parameters for a multilayer armour module.

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Burcharth, Hans F., and Torben Brejnegaard-Neilsen. "THE INFLUENCE OF WAIST THICKNESS OF DOLOSSE ON THE HYDRAULIC STABILITY OF DOLOSSE ARMOUR." Coastal Engineering Proceedings 1, no. 20 (1986): 130. http://dx.doi.org/10.9753/icce.v20.130.

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The paper presents results from experiments with Dolosse having the same mass and volume but with different waist thickness to height ratios. The armour was exposed to irregular waves simulating one storm with increasing wave heights and the effect of waist to height ratio on the hydraulic stability was studied. A low packing density of approximately 0.65 was used corresponding to a two-layer armour with high porosity. From the results it is concluded that the hydraulic stability of Dolos armour is not very sensitive to variations in the waist to height ratio. Only for damage levels exceeding displacement of approximately 5% of the armour blocks in the most exposed area there seems to be a significant decrease in hydraulic stability with increasing waist to height ratio. Thus the waist ratio only influences the residual hydraulic stability. Based on a short discussion of stressed in armour units it is concluded that design criteria solely based on movements of armour units as observed in hydraulic models are not adequate for the assessment of structural integrity of the units. The paper also presents the results of each stability test as well as the scatter and the distributions. The large scatter found underlines the need for adoption of more restrictive safety factors than generally used in rubble mound breakwater design. It also supports the idea of a probabilistic approach in the design process.

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Anastasaki, Eleni, John-Paul Latham, and Jiansheng Xiang. "Numerical test for single concrete armour layer on breakwaters." Proceedings of the Institution of Civil Engineers - Maritime Engineering 169, no. 4 (2016): 174–87. http://dx.doi.org/10.1680/jmaen.2014.25.

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TAKAGAKI, Kiyokazu, Ahn SUNGMO, Hochan LEE, et al. "RESEARCH AND DEVELOPMENT OF NEW SINGLE LAYER ARMOUR UNIT." Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 72, no. 2 (2016): I_889—I_894. http://dx.doi.org/10.2208/kaigan.72.i_889.

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Aberle, Jochen. "Measurements of armour layer roughness geometry function and porosity." Acta Geophysica 55, no. 1 (2007): 23–32. http://dx.doi.org/10.2478/s11600-006-0036-5.

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Hawass, Ahmed, Hosam Mostafa, and Ahmed Elbeih. "Multi-layer protective armour for underwater shock wave mitigation." Defence Technology 11, no. 4 (2015): 338–43. http://dx.doi.org/10.1016/j.dt.2015.04.006.

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Kik, Rémon, Jeroen P. Van den Bos, Jonas Maertens, Henk Jan Verhagen, and Jentsje W. Van der Meer. "NOTIONAL PERMEABILITY." Coastal Engineering Proceedings 1, no. 33 (2012): 84. http://dx.doi.org/10.9753/icce.v33.structures.84.

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Different layer design of a rock slope and under layers has a large effect on the strengths on the rock slope itself. In the stability formula developed of VAN DER MEER [1988] this effect is represented by the term Notional Permeability with symbol P. A more open, or permeable, structure underneath the armour layer has the ability to dissipate more wave energy and therefore requires less weight of the armour layer. The influence of this parameter is thus very important in economic sense. Up until now only three configurations have been tested. In practice often intermediate structures were designed which do not correspond to the standard situations. P-values then have to be estimated in comparison with the known structures, which gives some uncertainty around the P-value. Therefore there is the demand for more validated values of the notional permeability representing other structures. During this study physical scale modelling is used to produce a value of P for a new structure.

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Reis, Maria Teresa, Joao Alfredo Santos, Conceicao Juana Fortes, et al. "WAVE RUN-UP AND OVERTOPPING IN RUBBLE-MOUND BREAKWATERS UNDER OBLIQUE WAVE INCIDENCE." Coastal Engineering Proceedings, no. 36v (December 28, 2020): 23. http://dx.doi.org/10.9753/icce.v36v.structures.23.

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The existing data gaps triggered the interest in developing the present experimental work, whose main goal is to contribute to a new whole understanding of the phenomena to mitigate future sea level rise impacts in European coastal structures, including the run-up and overtopping characterization on rough and permeable slopes. The key point is to extend the range of wave steepness values in run-up, overtopping and armour layer stability studies, focusing on oblique extreme wave conditions and on their effects on a sloping breakwater's trunk armour and roundhead. Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/sHxoaocYuL0

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Duplan, Yannick, Dominique Saletti, and Pascal Forquin. "Identification of the Quasi-Static and Dynamic Behaviour of Projectile-Core Steel by Using Shear-Compression Specimens." Metals 9, no. 2 (2019): 216. http://dx.doi.org/10.3390/met9020216.

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Armour-Piercing (AP) projectiles constitute a major threat to be considered for the design of bi-layer-armour configurations constructed using a ceramic front plate backed with a composite/metal layer. When they are not made of tungsten-carbide the cores of these projectiles are made of hard steel, and are the main part that defines the penetration performance of the projectile. However, due to specific testing difficulties, the dynamic behaviour of these high-strength steel AP projectiles has not been investigated in sufficient detail. In this study, a detailed experimental investigation of the dynamic behaviour of the steel used for the steel core of 7.62 mm BZ-type AP projectiles was analysed through the use of Shear-Compression Specimens (SCS). In this study, results from both quasi-static and dynamic experiments were examined. The data processing method employed was set and validated based on numerical simulations. Both quasi-static and dynamic SCS experiments were done with the steel tested which clearly indicated the steel cores exhibit a very high elastic limit, little strain-hardening, and very little strain-rate sensitivity despite the wide range of strain-rates considered. This experimental characterisation paves the way to the numerical modelling for the analysis of ballistic impact of 7.62 mm AP projectile against lightweight armour configurations.

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Kulakov, N. A., and A. N. Lyubin. "Research of the Punch Interaction with Composite Protective Panel." Izvestiya MGTU MAMI 2, no. 1 (2008): 53–56. http://dx.doi.org/10.17816/2074-0530-69550.

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The work examines the structure of a protection composite panel consisting of a crushing layer (ceramic discrete elements of a cylindrical shape) and a restraining layer below (metallic leaf). This protection panel can be used for an armour-piercing bullet protection of the car. Here is the strength calculation of ceramic elements and metallic protective layer dynamic interaction under bullet impact. The problem was solved under a variety of protection panel parameters in order to define their proper values.

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Lemos, Rute, Vera Pina, João Alfredo Santos, Conceição Fortes, Maria Teresa Reis, and Antje Bornschein. "Wave RUN-UP Measurements under very oblique wave incidence." Revista Recursos Hídricos 42, no. 1 (2021): 81–90. http://dx.doi.org/10.5894/rh42n1-cti9.

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Under the scope of the HYDRALAB+ transnational access project, the so-called RODBreak experiment was conducted in the multidirectional wave basin at the Marienwerden facilities of the Leibniz University Hannover (LUH). A stretch of a rubble-mound breakwater was built in the wave basin with a very gentle slope. Its armour layer was made of Antifer cubes, at the roundhead and adjoining trunk, and of rock, at the rest of the trunk. A set of tests was carried out to extend the range of wave steepness values analysed in wave run-up, overtopping and armour layer stability studies, focusing on oblique extreme wave conditions, with incident wave angles from 40º to 90º. The present study focuses on the analysis of measured wave run-up values obtained in the tests and on their on their variability as well as the influence of the wave obliquity and directional spreading. Keywords: rubble-mound breakwaters; run-up; oblique waves; physical modelling; RODbreak.

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Jensen, Bjarne, Erik Damgaard Christensen, and B. Mutlu Sumer. "WAVE INTERACTION WITH LARGE ROUGHNESS ELEMENTS ON AN IMPERMEABLE SLOPING BED." Coastal Engineering Proceedings 1, no. 33 (2012): 23. http://dx.doi.org/10.9753/icce.v33.waves.23.

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The present paper presents the results of an experimental and numerical investigation of the flow between large roughness elements on a steep sloping impermeable bed during wave action. The setup is designed to resemble a breakwater structure. The work is part of a study where the focus is on the details in the porous core flow and the armour layer flow i.e. the interaction between the two flow domains and the effect on the armour layer stability. In order to isolate the processes involved with the flow in the porous core the investigations are first carried out with a completely impermeable bed and successively repeated with a porous bed. In this paper the focus is on the impermeable bed. Results are obtained experimentally for flow and turbulence between the roughness elements on the sloping bed. Numerical simulations have reproduced the experimental results with good agreements and can hereby add more details to the understanding of the fluid-structure interaction.

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Van de Koppel, Michael Alexander, Michiel Muilwijk, and Henk Jan Verhagen. "STATIC AND DYNAMIC LOADS ON THE BOTTOM ROW OF ARMOUR UNITS: A THEORETICAL AND PHYSICAL MODEL STUDY." Coastal Engineering Proceedings 1, no. 33 (2012): 44. http://dx.doi.org/10.9753/icce.v33.structures.44.

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A physical model study on the row averaged static and dynamic load on the bottom row of single layer armour units in order to investigate the influence of various parameters such as the number of rows on the slope of a breakwater and the initial relative packing density.

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Nielsen, Anders W., B. Mutlu Sumer, Jørgen Fredsøe, and Erik D. Christensen. "Sinking of armour layer around a cylinder exposed to a current." Proceedings of the Institution of Civil Engineers - Maritime Engineering 164, no. 4 (2011): 159–72. http://dx.doi.org/10.1680/maen.2011.164.4.159.

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Rahman, Najihah, Shahrum Abdullah, Mohamad Abdullah, Wan Zamri, Mohd Omar, and Zainuddin Sajuri. "Experimental and Numerical Investigation on the Layering Configuration Effect to the Laminated Aluminium/Steel Panel Subjected to High Speed Impact Test." Metals 8, no. 9 (2018): 732. http://dx.doi.org/10.3390/met8090732.

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This paper presents the effect of laminated aluminium-steel panel with different configurations in a high-speed impact test. Layering aluminium plate with high strength steel has become an interest in reducing the overall density of armour vehicle body while improving the ballistic resistance. Different layering configurations differ in laminated panel performance. Two layering configurations of double-layered panel achieving 25% of existing panel weight reduction were tested using experiment and computational method to investigate their behaviours when impacted with 7.62-mm full metal jacket at velocity range of 800–850 m/s. The ballistic performance of each configuration plate in terms of ballistic limit velocity, penetration process and permanent deformation was quantified and considered. Laminated panel with aluminium as the front layer reduced the ballistic performance of existing panel to 50% and the other panel maintained its performance. Thus, the laminated panel with aluminium as the back layer can be used in designing a protective structure for armoured vehicle while maintaining the performance of the existing vehicle in achieving weight reduction.

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Nguyen, Huu Hue, Manh Truong Nguyen, and Huu Thanh Nguyen. "A Formula for the Relationship between Penetration Depth, Viscosity of Asphalt Grouting and Diameter of Stone, Apply for Designing Asphalt-Grouted Stone Revetments." Materials Science Forum 987 (April 2020): 20–26. http://dx.doi.org/10.4028/www.scientific.net/msf.987.20.

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Where suitable rock of only a limited size is scarce, asphalt grouting can be used to provide an impermeable armour layer of greater resistance to wave action than the component rock alone. Asphalt-grouted stone revetments provide a flexible and durable cover layer which can resists abrasion, is indifferent to chemical attack by salt water etc.The paper presents the research on the relationship between the depth of asphalt grouting penetration with the diameter of stone and asphalt viscosity to apply for designing asphalt-grouted stone revetments to protect sea dykes.

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O’Halloran, S. M., A. D. Connaire, A. M. Harte, and S. B. Leen. "Modelling of fretting in the pressure armour layer of flexible marine risers." Tribology International 100 (August 2016): 306–16. http://dx.doi.org/10.1016/j.triboint.2016.02.040.

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