Types Of Armour Research Articles

Damage evolution in single-layer cube armoured breakwaters with a regular placement pattern

Single-layer cube (SLC) armoured breakwaters with a regular placement pattern are a relatively recent concept despite the cube being one of the oldest concrete units available. Limited investigation on the performance and hydraulic stability of this armour type is available to date. This work presents a quantitative assessment of the damage evolution for SLC armoured breakwaters with a regular placement pattern based on 2D physical modelling tests carried out at the University of Porto, Portugal. Tests were carried out for different armour porosities, wave steepnesses, and armour crest levels.A new method for automatically determining cube positions for each test was developed with image-processing techniques using advanced machine-learning tools. This method greatly reduces processing time since several images can be processed in batch mode.Innovative parameters to describe armour layer behaviour were derived and proposed for assessment and quantification of the damage evolution: exceedance probability of cube movements, mean grid orthogonality, and relative damage number for SLC. New damage level classification and criteria for initiation of damage are proposed for each of the parameters assessed. This analysis is focused on the initial stages of the damage, which are critical in designing new structures.

Structure Design and Energy Absorption Mechanism of a New Type of Armor Inspired from Armadillos

Structure Design and Energy Absorption Mechanism of a New Type of Armor Inspired from Armadillos

SASSANID ARMOR: BACKGROUND, DEVELOPMENT AND TECHNOLOGY

The aim of this article is to study the Sassanid armor types and their construction methods based on Sassanid rock reliefs, surviving fragments, armor depicted on Sassanid dishes and stone statues in Iran. The article explains the construction methods of different armor types used by the Sassanids during their rule and how Sassanids influenced the development of armor technology and were influenced by other cultures. Different types of armor used by Sassanids such as mail armor, scale armor, laminated armor (vambraces and greaves), and lamellar armor and their origins are discussed in the article. Hand, arm and leg protection as well as different helmet types used by Sassanids are also analyzed. These include simple bandhelm type, four-part bandhelm type, spangenhelm (strap helmets) type and lamellar helmet type. Different types of shields used by Sassanids are also discussed in the article. Next to archaeological finds, stone and rock reliefs as well as Sassanid iconography are analyzed to describe different types of armor used by Sassanids.

ROUGHNESS FACTOR FOR MULTI-LAYER ARMOUR AS OVERTOPPING ESTIMATOR

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

THE COMPARISON OF EMPIRICAL FORMULAE FOR THE PREDICTION OF MEAN WAVE OVERTOPPING RATE AT ARMORED SLOPED STRUCTURES

Armored sloped structures are generally used to provide the safety of their lee side, i. e. harbours and coastal regions against wave attacks and storm surge. Recently, due to the potential impact of climate change, increasing emphasis has been placed on their hydraulic performance (e.g. Pillai et al. 2019). Thus, accurate estimation of wave overtopping rate, as the hydraulic response of coastal structures, has an important role in design. Wave overtopping is a complex phenomenon and depends on structural geometry and wave characteristics. Hence, empirical formulae are generally used for estimation of mean overtopping rate. These formulae have been derived from laboratory measurements in which the dimensionless measured overtopping rates are correlated with the dimensionless structural and hydraulic parameters through physical arguments. The most well-known formulae for wave overtopping prediction can be found in the Coastal Engineering Manual (2012) and European Overtopping Manual (EurOtop, 2018). The CLASH database as one of the most comprehensive datasets, was initially provided by De Rouck and Geeraerts (2005). This data base was recently updated by including more test results (EurOtop, 2018). However, a detailed comparison of formulae proposed for the estimation of overtopping rates at rubble mound sloped structures is not reported. The present paper aims to evaluate the performance of existing empirical formulae namely EurOtop 2018 (hereafter ET18), Owen (1982), van der Meer and Janssen (1995) (hereafter VMJ) and Jafari and Etemad-Shahidi (2012) (hereafter JES) against EurOtop database (updated CLASH database). The analysis includes structures with different armor types (rock, concrete cubes etc.) with both impermeable and permeable cores, to evaluate the capability of used formulae under different conditions.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/0TL5zFCf6GU

Preparation and Impact Resistance Properties of Hybrid Silicone-Ceramics Composites

This article presents the method of preparation a new type of ballistic armor based on hybrid silicone-ceramic (HSC) composites with considerable flexibility. An experimental study on the ballistic behavior of HSC composites connected with soft body armor is presented against FSP.22 fragments. The effect of Al2O3 ceramics on the ballistic performance of HSC composite was investigated, and the fragmentation resistance process of the composite armor combining the HSC composite and soft aramid insert is clarified. Furthermore, impact resistance tests made with a drop tower which allows for a gravity drop of a mass along vertical guides onto a sample placed with an energy of 5 J were performed. The results presented in this paper show that the HSC composites can be successfully used as a hard body armor. However, they do not exhibit the properties of absorbing the impact energy generated during the drop tower tests. The test results show that the ballistic performance of composite armors is influenced by the hardness and Young modulus of ceramics and soft body armor panel. Additionally, in the article, the results of mechanical properties of silicones used for preparation of composites were presented and compiled to determine their role in the performance of impact protection.

RPG‑7 — ​udivitel'nyj artefakt ote­chestvennogo oboronno-­promyshlennogo kompleksa

The article discusses the history of creation and combat use of rocket-propelled grenade launcher RPG-7, grenade launcher modernization in the Soviet Union (Russian Federation) and the countries operating this type of reactive armour. Some constructive and operational features of RPG-7, and its greatest modifications are presented.

Numerical simulation of steel tube array composite armor structure against rod projectile penetration

In order to explore the feasibility of the new type of armor against projectile penetration, a steel plate tube array composite armor was designed, and its effectiveness against projectile penetration was studied by numerical simulation. The results of simulation vividly reproduce the physical and mechanical processes of composite armor structure, such as deformation and breakage, penetration failure, and stress wave propagation under the impact of projectile. The time history characteristics of projectile residual velocity were accurately captured. The influence of key factors, such as the number of tube array layers, array combination form and projectile impact position on the damage mode of the composite armor structure was obtained. The related results can provide important support and scientific basis for the optimal design and accurate evaluation of the new composite armor.

«Шапки калмыцкие» в собрании Оружейной палаты Московского Кремля

Introduction. In the 17th century, the Kremlin Armoury (Moscow) stored the biggest collection of Central Asian helmets (‘Kalmyk caps’, Rus. shapka) in Europe. Introduction of the materials into scientific discourse remains a priority task. Goals. The paper seeks to identify stages in the formation of the ‘Kalmyk Caps’ Collection, describe the items in detail, and specify the actual conditions of their storage and maintenance in the museum. Results. The first richly decorated Central Asian helmets are reported to have arrived in the Kremlin Armoury since the early 17th century as diplomatic gifts from Mongol and Oirat rulers. In the mid-17th century, the collection grew through acquisitions of helmets made in Sothern Siberia and received by Russian authorities from Kuznetsk Tatars (historical ancestors of the Shors). The latter headgears were simpler and seem to resemble those delivered by Kuznetsk Tatars to Oirat warriors as alman (tribute) and in exchange for cattle. Arsenals of the Russian nobility proved the third and final source of the collection. As a result, in the late 17th century the Kremlin Armoury contained about 100 ‘Kalmyk shapkas’. The study shows the common opinion characterizing ‘Kalmyk caps’ as identical to ‘shapka bumazhnaya’ (cotton-wool helmets) is actually wrong. All the headgears constituting the collection are riveted iron helmets of different types. Moscow masters would modify ‘Kalmyk shapkas’ in the 1660-1670s through attaching plated aventails, arming caps, chinstraps, and plumes. At the same time, the Kremlin Armoury started producing plated kuyaks (body armors) that supposedly imitated Central Asian samples. From 1664 onwards, the Russian noblemen actively participated in military parades and diplomatic meetings wearing kuyaks and Kalmyk shapkas, vambraces and Kalmyk-style zarukavie (hand and arm protective gears). Conclusions. Particular attention to this type of Oirat armor in the late 1650-70s seems to have arisen not only from vivid interest of the Moscow nobility towards exotic Asian armory but rather due to active participation of the Kalmyks in Russian military campaigns. So, the fact the Russian nobility tended to wear Kalmyk shapkas and kuyaks during ceremonies or special events meant not only their desire to impress other attendees but was also to deliver the message — militant and victorious Kalmyks are now in the political orbit of the Tsardom of Muscovy.

Enhanced bi-layer mosaic armor: experiments and simulation

Three different alumina/aluminum bi-layer armors having different striking faces, i.e., monolithic alumina, mosaic alumina, and mosaic alumina enhanced by aluminum honeycomb, were fabricated and tested under the impact of the flat projectile. The ballistic performance of each armor type was also investigated using three-dimensional (3D) finite element (FE) simulations. Upon validating the FE simulation results with experimental measurements, the ballistic limit velocity and failure mechanisms for each type of armor, as well as the influence of ceramic tile size, impact position, border effect, and inter tile gap width were quantified. For the enhanced mosaic armor, the metallic honeycomb lattice performed as a cellular skeleton to confine the ceramic tiles and fragments, leading to enhanced ballistic resistance. Besides, the honeycomb enhanced mosaic armor was also found to have much improved multi-hit ballistic resistance in comparison with monolithic and mosaic alumina. The honeycomb preserved the structural integrity of the mosaic armor so that a high level of residual ballistic resistance remained even after impact. With the extended reliability calculation method, single shot ballistic data were used to estimate the performance of the honeycomb enhanced mosaic armor under multiple projectile impacts.

Ballistic performance of unidirectionally oriented carbon fiber reinforced composite armor with high-velocity impact

For the last few decades, composite materials have been more popular than other conventional metal materials in the aircraft industry. Having better mechanical properties (strength, fatigue life, impact strength, corrosion resistance, etc.) and being lighter than conventional engineering materials, composites have become very important in defense industry as well. In spite of the fact that some of the composite materials such as aramid-based composites have been effectively used in body protection, they have not been so successful in heavy armored vehicles which are generally equipped with different types of add-on armor blocks for protecting against threats. These add-on armors are mostly composed of armor steels and ceramics. This study specifically aims to investigate high-velocity impact behavior of unidirectionally oriented carbon fiber reinforced/epoxy layer sandwiched with armor steel plates that are exposed to kinetic energy projectile. Carbon fibers are normally very brittle to transverse loading direction, contrarily, to its axial tension or compression direction. This is the reason why it is claimed that this high compression strength property of carbon fibers could be used for manufacturing a layer in order to replace ceramics in add-on multilayer composite armor. In order to prove this hypothesis, an experimental analysis has been carried out by performing impact tests on these manufactured add-on armor test samples. Testing was carried out in accordance with the STANAG 4569 level-4 standard. The results indicated that the multilayer carbon fiber reinforced epoxy composite–armor steel hybrid panels can provide level-4 protection with a lower areal density compared to Rolled Homogenous Armor.

Ballistic performance of composite armor with dual layer piecewise ceramic tiles under sequential impact of two projectiles

A new type of composite armor, which is composed of the front steel plate, medium dual-layer piecewise ceramic tiles separated by steel grid and the Kevlar back plate, was designed based on the bio-inspiration. The failure mechanism, energy absorption, and the effect of the geometric parameters on ballistic response of composite armors were analyzed. The results show that the damage area of ceramic layer can be remarkably decreased by replacing a monolithic ceramic plate by the piecewise ceramic tiles, and the ballistic properties of armors can be enhanced by using multiple ceramic tiles separated by metal grids in composite armors.

해외박물관 소장 조선후기 면갑(綿甲) 유물 분석 : 메트로폴리탄박물관 소장 유물을 중심으로

In the late 19th century, a specific type of cotton armor was developed in order to protect from bullets of Western arms. Only one cotton armor exists in the collections of Korean museum. Therefore, comparative study of the artifacts in the museums overseas was critical. A set of the cotton armor was examined at The Met in New York and later studied in comparison with a cotton armor in the collection of the National Museum of Korea in Seoul. While the cotton armor is so rare to find in Korea, the author was able to locate several artifacts in the museum collections of other countries including the USA, France, Japan, and the UK. The examples abroad even include helmets, belts, and chest pads. The set of cotton armor of The Met has three components: a helmet, an armor, and a wide belt. The helmet and the armor were constructed with scores layers of cotton fabric overlay. There are a few amulet patterns including Om Mani Padme Hum and pomegranate, stamped on the fabric in black ink. Although Confucianism was the main philosophy of the Joseon Dynasty, the amulet patterns reflect people’s reliance on Buddhism and Taoism. They needed psychological protection for their life in addition to the physical protection. The name of the wearer was written in black ink inside of the helmet and the armor. The cotton armors in the collections of The Met and the National Museum of Korea showed great similarities with few minor differences. In conclusion, it is likely that the cotton armors were made by following an instruction regulated by authorities with the same specifications, such as structure, material, color and amulet patterns. They were possibly produced in large quantity for training soldiers under the initiative of the national authority or the military camp.

Effects of police body armour on overmatching ballistic injury.

Overmatching occurs when body armour that has been designed to resist perforation by a specified projectile is perforated by a greater threat. This may result in wounding to the body armour wearer. In this work, overmatching of two types of police body armour was studied using two types of ammunition. The use of a 250-mm-long gelatine block to represent the depth of the human torso combined with armour panels mounted on the anterior and posterior of the block allowed for a more realistic simulation to be completed. There was some evidence to suggest that overmatching events could lead to increased levels of damage during a survivable incident compared with no body armour being present. This information is of interest to armour designers and medical personnel that might treat such wounds.

Renesansowe zbroje płytowe z napierśnikiem bombiastym w dawnym księstwie pomorskim w świetle wybranych zabytków sztuki

The article discussed eleven works of art with images of the most prominent men of the Duchy of Pomerania, shown in suits of armour, which were among the most impressive types of wear of the epoch. All the images are reliefs, ten of them carved in stone (Figures 1–4, 6–11; Catalogue no. 1–4, 6–11) and one in wood (Fig. 5a–5b; Cat. no. 5). Three are foundation plaques (Fig. 1–2, 8; Cat. no. 1–2, 8), seven are tombstones (Fig. 3–4, 6–7, 9–11; Cat. no. 3–4, 6–7, 9–11) and one is an epitaph (Fig. 5a–5b; Cat. no. 5). Three show dukes of Pomerania (Fig. 1–2, 5a–5b; Cat. no. 1–2, 5) and eight — Pomeranian nobles (Fig. 3–4, 6–11; Cat. no. 3–4, 6–11). Eight have survived until today (Fig. 1–3, 7–11; Cat. no. 1–3, 7–11), while the remaining three are known from archival photographs (Fig. 4–6; Cat. no. 4–6). All were intended for places treated as family memorials, such as residences or churches. Of the surviving reliefs five remain in their original locations (Fig. 3, 8–11; Cat. no. 3, 8–11) and three have been transferred (Fig. 1–2, 7; Cat. no. 1–2, 7). The images discussed in this article provide a starting point for research on plate armour in Pomerania in the early decades of the 16th century. All the figures are shown in plate armour with a deep–bellied breastplate, some of them in the most characteristic richly decorated Maximilian suits of armour, which reflected the men’s fashion of the time. Maximilian armour is depicted in four of the cases analysed (Cat. no. 1–3, 6). Another type of armour used at the time had similarly harmonious proportions but was plain (Cat. no. 4, 7–11). The first one of these has a tucked skirt. One of the reliefs shows a costume suit of armour (Cat. no. 5). The analysed iconographic sources bring valuable data on historical armour. The plate armour in the epitaph of Duke Boguslaw X is represented in such detail that it was possible to compare it with a costume suit of armour preserved in Deutsche Historisches Museum in Berlin (inventory no. W 2327) and to conclude that the latter is the armour that used to belong to the Pomeranian Duke and was brought to Berlin in 1731 by King Frederic William I of Prussia.

Simulation of the Lightweight Ceramic/Aluminum Alloy Composite Armor for Optimizing Component Thickness Ratios

The lightweight ceramic/aluminum alloy composite armor design is examined and optimized to get better protective performance. The armor penetrability is simulated via the smooth particle hydromechanics approach using the ANSYS/AUTODYN software. The accuracy of the program was verified by comparing with known data. Three composite armor types with the total thickness of 30, 40, and 50 mm, and five different ceramic/metal thickness ratios were analyzed in simulation of the residual bullet speed and the final distance. Simulation results are compared with the theoretical model. The best bullet protective performance of the three armor types was obtained with the ceramic/aluminum alloy thickness ratio of 4:1.

Optimization of Soft Body Armor with Laminates of Carbon–aramid Fiber and Polyester Fiber Using the Taguchi Method

Body armor is a vital instrument for Tentara Nasional Indonesia-Indonesian National Armed Forces (TNI) and Polisi Republik Indonesia-Indonesian National Police (POLRI) to protect themselves from any projectile penetration and the spread of explosive material. One type of body armor is soft body armor, commonly used for handling community riots. The forming material of soft body armor should be strong and flexible. For that, selecting appropriate materials to optimize their ability is necessary. This research aims to develop soft body armor with carbon–aramid and polyester laminate as materials using a quasi–static impact test. The method used was the Taguchi experiment, the advantage of which is its ability to optimize the desired quality characteristics based on the best factor. The results showed that the optimal combination of polyester and carbon–aramid composite materials showed a median result from the quasi–static impact test of 61 259.91 N with the optimum compositions of factor D level 1, factor A level 2, factor B level 1, factor E level 2, factor C level 2, factor F level 1, and factor G level 2.

Lower-limb joint work and power are modulated during load carriage based on load configuration and walking speed

Soldiers regularly transport loads weighing >20 kg at slow speeds for long durations. These tasks elicit high energetic costs through increased positive work generated by knee and ankle muscles, which may increase risk of muscular fatigue and decrease combat readiness. This study aimed to determine how modifying where load is borne changes lower-limb joint mechanical work production, and if load magnitude and/or walking speed also affect work production. Twenty Australian soldiers participated, donning a total of 12 body armor variations: six different body armor systems (one standard-issue, two commercially available [cARM1-2], and three prototypes [pARM1-3]), each worn with two different load magnitudes (15 and 30 kg). For each armor variation, participants completed treadmill walking at two speeds (1.51 and 1.83 m/s). Three-dimensional motion capture and force plate data were acquired and used to estimate joint angles and moments from inverse kinematics and dynamics, respectively. Subsequently, hip, knee, and ankle joint work and power were computed and compared between armor types and walking speeds. Positive joint work over the stance phase significantly increased with walking speed and carried load, accompanied by 2.3–2.6% shifts in total positive work production from the ankle to the hip (p < 0.05). Compared to using cARM1 with 15 kg carried load, carrying 30 kg resulted in significantly greater hip contribution to total lower-limb positive work, while knee and ankle work decreased. Substantial increases in hip joint contributions to total lower-limb positive work that occur with increases in walking speed and load magnitude highlight the importance of hip musculature to load carriage walking.

Tibiofemoral joint contact forces increase with load magnitude and walking speed but remain almost unchanged with different types of carried load.

Musculoskeletal injuries (MSI) in the military reduce soldier capability and impose substantial costs. Characterizing biomechanical surrogates of MSI during commonly performed military tasks (e.g., load carriage) is necessary for evaluating the effectiveness of possible interventions to reduce MSI risk. This study determined the effects of body-borne load distribution, load magnitude, and walking speed on tibiofemoral contact forces. Twenty-one Australian Army Reserve soldiers completed a treadmill walking protocol in an unloaded condition and wearing four armor types (standard-issue and three prototypes) with two load configurations (15 and 30 kg) for a total of 8 armor x load ensembles. In each ensemble, participants completed a 5-minute warm-up, and then walked for 10 minutes at both moderate (1.53 m⋅s-1) and fast (1.81 m⋅s-1) speeds. During treadmill walking, three-dimensional kinematics, ground reaction forces, and muscle activity from nine lower-limb muscles were collected in the final minute of each speed. These data were used as inputs into a neuromusculoskeletal model, which estimated medial, lateral and total tibiofemoral contact forces. Repeated measures analyses of variance revealed no differences for any variables between armor types, but peak medial compartment contact forces increased when progressing from moderate to fast walking and with increased load (p<0.001). Acute exposure to load carriage increased estimated tibiofemoral contact forces 10.1 and 19.9% with 15 and 30kg of carried load, respectively, compared to unloaded walking. These results suggest that soldiers carrying loads in excess of 15 kg for prolonged periods could be at greater risk of knee MSI than those with less exposure.

Primarily hip-borne load carriage does not alter biomechanical risk factors for overuse injuries in soldiers

ObjectivesTo determine the effects of different body armour types, carried loads, and walking speeds on trunk and lower-limb joint biomechanics. DesignWithin-subjects repeated measures to determine the effects of different body armour types, carried loads, and walking speeds on trunk and lower-limb joint biomechanics. MethodsTwenty soldiers (29.5±7.1yrs) completed a treadmill walking protocol in an unloaded (baseline) condition and wearing a control, Tiered Body Armour System (TBAS) and five different armour types (cARM1-2, pARM1) with two load configurations (15 and 30kg) for a total of eight armour×load ensembles. In each ensemble, participants walked for 10min at 1.53ms−1 and 1.81ms−1 speeds. Whole-body marker kinematics and ground reaction forces were used, along with a scaled anatomic model, to determine peak lower-limb joint angles, net joint moments, and negative knee work. Peak parameters were compared between armour types, walking speeds, and carried loads using repeated measures ANOVAs. ResultsPeak plantarflexion and hip abduction moments were reduced when wearing cARM1 (p=0.040, p=0.045) and cARM2 (p=0.045, p=0.003) compared to TBAS, while carrying 30kg and/or walking fast. This suggests positive benefits of load distribution at higher task demands. Joint moments increased when participants carried greater load and/or walked faster, and the combined effects of carried load and walking speed were mostly additive. ConclusionsPrimarily hip-borne load carriage does not negatively alter joint kinetics, and some positive adaptations occurred during tasks with higher demands. These results can inform equipment design and physical training programs for load carriage.