Search Results (17)

This paper presents the development of two solutions for sandwich panels composed of a thin-layer alkali-activated composite (AAc) layer and a thicker insulation layer, formed by extruded polystyrene foam or expanded cork agglomerate (panels named AP_XPS or AP_ICB, respectively). The AAc combined ceramic waste from clay bricks and roof tiles (75%) with ladle furnace slag (25%), activated with sodium silicate. The AAc layer was further reinforced with polyacrylonitrile (PAN) fibers (1% content). The mechanical behavior was assessed by measuring the uniaxial compressive strength of cubic AAc specimens, shear bond strength, pull-off strength between the AAc layer and the insulation material, and the flexural behavior of the sandwich panels. The thermal performance was characterized by heat flux, inner surface temperatures, the thermal transmission coefficient, thermal resistance, and thermal conductivity. Mechanical test results indicated clear differences between the two proposed solutions. Although AP_XPS panels exhibited higher tensile bond strength values, the AP_ICB panels demonstrated superior interlayer bond performance. Similar findings were observed for the shear bond strength, where the irregular surface of the ICB positively influenced the adhesion to the AAc layer. In terms of flexural behavior, after the initial peak load, the AP_XPS exhibited a deflection-hardening response, achieving greater load-bearing capacity and energy absorption capacity compared to the AP_ICB. Finally, thermal resistance values of 1.02 m² °C/W and 1.14 m² °C/W for AP_ICB and AP_XPS were estimated, respectively, showing promising results in comparison to currently available building materials. Full article

Armor composite structures have attracted interest in structural health monitoring (SHM) for their applications in damage localization. The signal propagation and the frequency dispersion features of the Lamb wave signal on thick armor composite structures are more complicated than their counterparts on other composite plates. In this research, a time-reversal localization and imaging method for impact localization of armor composite structures is proposed. First, composite sandwich structures were designed that are typically composed of ballistic-resistant ceramic materials as the face panel and a composite material as the core layer, sandwiched between metal materials serving as the backplate. The results show that the proposed method can validate the position of impact efficiently, and radial error is within 4.12 mm and 5.39 mm in single-damage and multi-damage imaging localization, respectively. Full article

The archaeological site of villa Horta da Torre in Portugal reveals distinctive architectural features within the context of Roman villae in Hispania. Notably, the triclinium was designed with an artificial cascade originating from a double apse wall, and the walls were adorned with mosaic tessellae panels and marble skirting. During the Roman era, the surrounding area belonged to the former province of Lusitania, with Augusta Emerita serving as its capital. This study examines 11 mortar samples from various contexts and functions, such as masonry, preparatory, render, and opus signinum mortars. A set of complementary analytical techniques was employed to determine the textural and mineralogical compositions of the mortars. The aim was to gain insights into the production techniques and the selection of raw materials within the geological context of this rural construction. It was observed that the processing of raw materials and production techniques did not always adhere to the rules of Vitruvius. A comparison with other villas revealed comparatively less meticulous attention to sand selection and precise layering for mural painting. Nevertheless, it was noted that in preparatory layers for the supranucleus and nucleus tesserae, ceramic pieces were intentionally added to improve the mortar. The binder used was calcitic lime, likely obtained from locally sourced limestone. The nature of aggregates is diversified but consistent with the local geological provenance within a radius of less than 3 km, in accordance with two sand exploration sites. This research aligns with the United Nations’ 2030 Agenda for Sustainable Development, contributing specifically to SDG 11 and Target 11.4, which “aims to strengthen efforts to protect and safeguard the world’s cultural and natural heritage”. Full article

Ceramic panel collapse will easily lead to the failure of traditional targets. One strategy to solve this problem is to use separate ceramic units as armor panels. Based on this idea, we propose an aluminum matrix composite using pressure infiltration, containing an array of ceramic balls, the reinforcement of which consists of centimeter-scale SiC balls and micron-scale B₄C particles. Three different array layouts were designed and fabricated: compact balls in the front panel (F-C), non-compact balls in the front panel (F-NC), and compact balls inside the target (I-C). The penetration resistance properties were tested using a 12.7 mm armor-piercing incendiary (API). The results show that there are no significant internal defects, and the ceramic balls are well-bonded with the matrix composite. The F-NC structure behaves the best penetration resistance with minimal overall damage; the I-C structure has a large area of spalling and the most serious damage. Finite element simulation reveals that the ceramic balls play a major role in projectile erosion; in the non-compact structure, the composite materials between the ceramic balls can effectively disperse the stress, thereby avoiding the damage caused by direct contact between ceramic balls and improving the efficiency of ceramic ball erosion projectiles. Furthermore, it is essential to have a certain thickness of supporting materials to prevent spalling failure caused by stress wave transmission during penetration. This multi-scale composite exhibits excellent ballistic performance, providing valuable insights for developing anti-penetration composite armor in future applications. Full article

Photoluminescent (PL) layers and electroluminescent (EL) systems have gained significant attention for their applications in constructing flat panels, screen monitors, and lighting systems. In this study, we present a groundbreaking approach to fabricating temperature sensors using barium-calcium zirconium titanate (BCZT) with thermo-optic properties, leading to the development of opto-thermal sensors for electric vehicle battery packs. We prepared zinc sulfide (ZnS) fluorescent films on BCZT ceramics, specifically two optimal compositions, BCZT0.85 (Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃) and BCZT0.9 (Ba_0.9Ca_0.1Zr_0.1Ti_0.9O₃), via the solid-state reaction method for the dielectric layer. The BCZT powders were calcined at varying temperatures (1200 and 1250 °C) and dwell times (2 and 4 h). The resulting phase formation and microstructure characteristics were analyzed using X-ray diffraction and scanning electron microscopy, respectively. Our investigation aimed to establish a correlation between the dielectric behavior and optical properties to determine the optimal composition and conditions for utilizing BCZT as thermal detectors in electric vehicle battery packs. All BCZT powders exhibited a tetragonal phase, as confirmed by JCPDS No. 01-079-2265. We observed an increase in the dielectric constant with higher calcining temperatures or longer dwell times. Remarkably, BCZT0.85 ceramic sintered at 1250 °C for 4 h displayed the highest dielectric constant of 15,342, establishing this condition as optimal for preparing the dielectric film with a maximum dielectric constant of 42. Furthermore, we investigated the temperature-dependent electroluminescence intensity of the samples, revealing a significant enhancement with increasing temperature, reaching its peak at 80 °C. Additionally, we observed a positive correlation between electroluminescence intensity and dielectric constant, indicating the potential for improved opto-thermal sensors. The findings from this study offer promising opportunities for the development of advanced opto-thermal sensors with potential applications in electric vehicle battery packs. Our work contributes to the expanding field of photoluminescent and electroluminescent systems by providing novel insights into the design and optimization of efficient and reliable sensors for thermal monitoring in electric vehicle technologies. Full article

In this study, for the first time, a cluster-plus-glue-atom model was used to optimize the composition of lithium aluminosilicate glass-ceramics. Basic glass in glass-ceramics was considered to be a 16-unit combination of three-valence {M₂O₃} and one-valence {Li₂O} units. By adjusting the ratio of {M₂O₃} and {Li₂O}, the composition of basic glass could be optimized. After optimization, the average cation valence of the base glass was increased to 2.875. After heat treatment of the optimized base glass, it is found that the crystal size, proportion, and crystallinity changed obviously compared with that before optimization. The main crystalline phases of all the lithium aluminosilicate glass-ceramics prepared in this work were Li₂Si₂O₅ and LiAlSi₄O_10. All optimized glass-ceramics had an obvious improvement in the crystallinity, with one of the largest having a crystallinity of over 90%. Furthermore, its bending strength was 159 MPa, the microhardness was 967 Hv, and the visible light transmission rate exceeded 90%. Compared with the widely used touch panel cover glass, the optical properties were close, and the mechanical properties were greatly improved. Due to its excellent performance, it could be used in microelectronics, aerospace, deep-sea exploration, and other fields. Full article

A study was undertaken to develop a methodology for assessing the residual strength of C/SiC ceramic matrix composite panels subjected to combined thermal-acoustic loadings. A 2D plain-woven C/SiC ceramic matrix composite panel subjected to spatially uniform thermal loading and band-limited Gaussian white noise is chosen as the computational test article, with its geometric nonlinear response determined via numerical simulation. As the input, the material properties (static strength, residual strength, and fatigue life) of this material are fully characterized under tensile and compression loads, for fiber direction at elevated temperature in static and fatigue loading conditions. Based on the methodology, a computer code is developed that simulates the cycle-by-cycle behavior of composite panels under fatigue loadings. The methodology is validated with the residual strength test of 2D plain-woven C/SiC composite panel subjected to combined thermal-acoustic loadings. It has been shown that the results of residual strength predicted by the methodology are well correlated with the experimental results. Full article

Ceramic/fiber composite armor is a hot research topic of bulletproof equipment. The lightweight design of ceramic materials and structures has attracted much attention. In this work, in the light of the remarkable performance of ceramic against elastic and oblique penetration, a novel honeycomb ceramic panel with a hexagonal prism and spherical body was designed. The splicing ceramic/fiber composite plate was bonded with a PE plate. The splicing ceramic/fiber composite was prepared, and the target test of the composite was conducted. The results show that the bulletproof performance of the hexagonal prism spherical crown ceramic/fiber composite plate is better than that of the conventional ceramic/fiber composite plate of the same thickness. The honeycomb spherical crown structure of the ceramic surface can convert the nominal forward penetration into the actual oblique penetration. This surface structure provides an effective lightweight design of ceramic/fiber composite armor. Full article

Foamed ceramic foam concrete composite wall was prepared by a direct casting method. Compressive and tensile tests were carried out on different densities of foamed ceramic boards. Changing rules of interface bonding properties of the composite wall under the influence of foamed concrete age, the surface treatment of foamed ceramic boards, and exposure to freeze–thaw cycles were studied; and the failure mechanism was analyzed and discussed. The results show that a foamed ceramic board with a density of 410 kg/m³ is suitable for a panel of composite wallboard; when the age of the foam concrete increases from 3 to 7 days, and the interface bond strength of the composite wallboard increases, then the bonding strength of the composite wallboard gradually decreases with the increase in age; with the increase in freeze–thaw cycles, the interface bond strength of the composite wallboard decreases gradually. The interface agent was pre-painted on the foamed ceramic board, which can improve the interface bonding strength of the composite wallboard. The drying, shrinkage, and freezing and thawing cycles of the foam concrete have a great influence on the interface bond strength of the composite wallboard. The perforated long hole and rubber sleeve can be used to improve the safety of the composite wallboard. Full article

Strippable film is effective for removing radioactive contamination. However, it still has some limitations, such as the long curing time (about 30 min~24 h) and the requirement of organic solvents. To address these issues, we report a simple protocol to prepare strippable decontamination films using liquid polybutadiene (LPB) and tert-butyl acrylate (TBA) as the raw materials without solvent and using camphorquinone/ethyl 4-dimethylaminobenzoate (CQ/EDB) as a photoinitiator, where the film was formed under household LED panel light or daylight irradiation for about 540 s. After a thorough study of viscosity, real-time Fourier transform infrared (RT-FTIR spectra), gel and volatile organic compound (VOC) contents, mechanical properties and decontamination efficiency, the optimum composition and curing conditions were determined for the decontamination strippable film. VOC content is as low as 12.7 ± 0.7% and the resultant strippable film exhibits good mechanical performances with a tensile strength of up to 5.4 ± 0.4 MPa and elongation of up to 66.6 ± 13%. Most important, the decontamination efficiencies of this strippable film for ¹³³CsCl on glass, ceramic and metal surfaces reach up to 98.1%, 94.3% and 97.6%, respectively. Full article

Exploring new armor-piercing materials is crucial for improving the penetrative ability of projectiles. Based on the process of in situ solidification injection molding through ceramic dispersant hydrolytic degradation, a ZrO₂ ceramic material suitable for use as the tip of a 12.7 mm kinetic energy (KE) projectile was prepared. The ZrO₂ ceramic tip can be matched with the metal core of a conventional projectile to form a ceramic composite projectile, increasing the damage to the Al₂O₃ ceramic composite armor. Specifically, the ZrO₂ ceramic tip can increase the impact load on the Al₂O₃ ceramic panel, prolonging the pre-damage phase and reducing the stable penetration phase, shortening the mass erosion time of the metal core compared with a 12.7 mm metal KE projectile tip. The ceramic composite projectile with the ZrO₂ ceramic tip has a lower critical penetration velocity than a 12.7 mm metal KE projectile for Al₂O₃ ceramic composite armor. Furthermore, the residual velocity, residual length, and residual mass of the metal core of the ceramic composite projectile that penetrated the Al₂O₃ ceramic composite armor are greater than those of a 12.7 mm metal KE projectile. Full article

During the microwave sintering of a polymer-ceramic composite plasma discharge is experienced. The discharge could occur failure of the power source. The solution proposed by the paper is original, no similar solutions being presented by the literature. It consists of using a polymer-ceramic composite protective panel, to stop the plasma discharge to the entrance of the guiding tunnel. Six composites resulted by combining three polymers, Polytetrafluoroethylene (PTFE), STRATITEX composite and Polyvinylchloride (PVC) with two natural ceramics containing calcium carbonate: Rapana Thomasiana (RT) sea-shells and beach sand were used to build the protective panel.Theoretical balance of the power to the panel was analysed and the thermal field was determined. It was applied heating using 0.6-1.2-1.8-2.4-3.0 kW microwave beam power. The panels were subjected to heating with and without material to be sintered. It was analyzed: RT chemical (CaCO₃ as Calcite and Aragonite), burned area (range: 200–4000 mm²) and penetration (range: 1.6–5.5 mm), and thermal analysis of the burned areas comparing to the original data. PTFE-RT composite proved the lowest penetration to 0.6 and 1.2 kW. Other 1.2 kW all composites experienced vital failures. Transformation of the polymer matrix of composite consisted of slightly decreasing of the phase shifting temperature and of slightly increasing of the melting start and liquidus temperature. Full article

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. Full article

Within EU project LightCoce (Building an Ecosystem for the upscaling of lightweight multi-functional concrete and ceramic materials and structures), RISE will be running a Pilot Line to allow the design and development of materials, elements of Cellular Lightweight Concrete (CLC) and/or lightweight composite elements with improved functionalities. One of these functionalities is self-sensing (damage and stress detection), achieved by reducing the natural concrete’s resistance with incorporation of the multi-walled carbon nanotubes (MWCNTs). By applying a small electric current in the outer electrodes attached to the concrete and measuring voltage on the inner electrodes the resistivity of the material can be easily calculated. The resistivity changes may indicate cracking and changing stress levels. In our study concrete was enhanced with various amounts of MWCNTs and tested in cyclic compression. The change of stress levels was clearly visible on the resistivity changes. After that, ultrahigh-performance concrete (UHPC) panels with two types of textile reinforcement (GFRP and CFRP) were tested in cyclic 4-point bending to investigate concretes sensitivity for multiple cracking. The resistivity measurement was able to capture multiple discrete cracks and the material degradation at micro-level due to fatigue. Full article

In order to expand the range of pot materials for induction cookers, a kind of sandwich structural composite ceramic panel that consists of an Al₂O₃ ceramic substrate, magnetic heating interlayer, and ZrO₂ ceramic substrate was developed by combining the tape casting process and the screen printing process. In this research, the slurry composition of the functional phase, glass powder, and organic carrier was optimized for preparing the heating interlayer with excellent electromagnetic properties. The influences of the glass powder content and the magnetic layer structure on the thermal shock resistance of the composite ceramic panel were studied. The finite element model of the composite ceramic panel under thermal load was established through ANSYS software. In the range of 0.1–0.3 mm thickness of a magnetic heating interlayer, the temperature field and the macroscopic stress field of the composite ceramic panel were simulated, and the influence of the magnetic layer structure on the thermal stress distribution of the composite ceramic panel was analyzed. The experimental results showed that the magnetic layer had the best quality when the amount of glass powder added was 9 wt%. The ANSYS simulation revealed that the gradient structure of the magnetic layer could reduce the stress between the alumina layer and the magnetic layer from 308 to 192 MPa, which significantly improved the thermal shock resistance of the composite ceramic panel. Therefore, the gradient structure of the magnetic layer could ensure the stability of the composite ceramic panel after five cycles of electromagnetic heating. Full article