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During a fire load, a charred layer forms on the timber elements, which is a natural protection against fire, so that a certain level of fire resistance could be achieved by using elements with a larger cross-section. However, this modus of fire protection is not always suitable. One of the most commonly used fire protection systems are fire protection boards. In this work, a large-scale fire test was carried out on a protected load-bearing wall made of hollow elements under the effect of sustained mechanical loads and fire exposure. Different stages of charring were observed. The test was aborted at the 91st minute due to a decrease in the load-bearing capacity and integrity criteria. The allowable average temperature rise on the non-exposed side of the specimen (140 K) was not exceeded until the 91st minute of the test, and the allowable maximum temperature rise on the non-exposed side of the specimen (180 K) was not exceeded until the 90th minute of the test. The loss of specimen integrity occurred at the 90th minute of the test. For surfaces protected by fire-resistant panels, it should be considered that the onset of charring is delayed until a certain time. According to EN 1995-1-2, charring can start before the fire protection is removed, but at a lower charring rate than the rates up to the time of failure of the fire protection. The expression proposed in EN 1995-1-2 shows relatively accurate results for certain systems and thicknesses of fire protection linings. However, it does not consider the presence of more than one lining layer or the full range of lining thicknesses themselves. For the wall described in this paper, the predicted failure time of the fire boards would therefore be 41.5 min, which is not consistent with the results of the experiment (51 min). The results of the calculation model according to EN 1995-1-2 did not fully agree with the results of the fire test on the protected load-bearing wall. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HAP) displays a high degree of similarity to the inorganic components that make up roughly 70% of human hard tissue, and it possesses exceptional biological activity and biocompatibility. It is currently internationally recognized as the most biologically active hard tissue implant material. However, its substandard mechanical properties have significantly limited the application of HAP in areas requiring load bearing or in the repair of large bone defects. In this study, HAP/45S5 bioglass laminated ceramic composites were consolidated using the spark plasma sintering (SPS) technique. The grain growth and phase transformation of HAP and 45S5 bioglass were examined at various sintering temperatures. The mechanical properties of the laminated composites were investigated. At 950 °C, the flexural strength and fracture work of the sintered body were (153.22 ± 7.7) MPa and (2049 ± 34) J·m−2, respectively. These results corresponded to the load–displacement curves and showed that the composites met the mechanical performance requirements of the support material. [ABSTRACT FROM AUTHOR]

Sealing materials have a wide range of applications in the fields of mechanical power and petrochemicals, they are important basic components for preventing leaks and maintaining the normal operation of equipment. Graphene micronano sheets have become one of the key sealing materials due to their excellent thermal conductivity, corrosion resistance, and mechanical properties. This article mainly uses graphene micro-nano sheets as the main filler, phenolic resin (PF) and polyvinyl butyral (PVB) as binders, combined with tape casting and hot pressing technology, to study the effects of graphene micro-nano sheets content, binder ratio, and hot pressing pressure on the tensile strength, compression rate, and rebound rate of composite sealing gaskets, and explore the hot pressing and laminated object manufacturing process of graphene micro-nano sheets composite sealing gaskets. The results show that when the content of graphene micro-nano sheets is 55%, the PF/PVB mass ratio is 8:15, the molding pressure is 15 MPa, the molding temperature is 120 °C, and the insulation time is 30 min, the graphene micro-nano sheets composite sealing gasket has the best molding processability and property, which can be prepared to meet the quality requirements of graphene micro-nano sheets composite sealing gaskets. [ABSTRACT FROM AUTHOR]

The bamboo structure has received more and more attention as a green, renewable construction with an increasing focus on environmental issues. Cracking at joints or openings and brittle fracture of bamboo are urgent problems in bamboo structures, leading to reduced rigidity, decreased load capacity, and even endangering structural safety. This research aims to explore the mechanism of self-tapping screw reinforcement in improving the brittle fracture characteristic of bamboo laminate. To achieve an optimal effect of reinforcement, fracture tests of bamboo laminated with different numbers of self-tapping screws and screw positions were conducted to study their impact on fracture behaviors. Through the analysis of the ultimate load, the deformation capacity, the initial energy release rate, and the energy release rate caused by the self-tapping screws reinforcement, a model for calculating the energy release rate of bamboo laminate with self-tapping screws is established. Based on the model, the load-bearing capacity of steel-bamboo connections with self-tapping screws can be reasonably estimated.

Stitched filaments are known to modify the mechanical properties of glass-fiber-reinforced polymers 2D (GFRPs 2D), so studying the effect on mechanical properties is underway to determine the critical variables involved. This research focuses on the study of the tensile strength effect of stitched low-density Barkley FBA BGQS15-15 nylon monofilament on biaxial E-Glass Saertex 830 g/m2 (+/−45°) cured with Polyester Sypol Resin 8086 CCP using a vacuum infusion process. Four specimens were made with longitudinal distances between the stitched reinforcements of 0.5, 1.0, 1.5, and 2.0 cm, respectively. Tensile strength tests based on standard ASTM D3039 were performed to study how stitching can affect toughness, Young's modulus, deformation, ultimate strength, and yield strength. The results indicated that the stitching increases Young's modulus up to 99.2%, UTS is increased by up to +3.14%, deformation decreases by up to −41.66%, and toughness decreases by up to −36.89%. Although the stitching's main function is to increase interlaminar resistance, it also induces the formation of stress concentrations by the new threads, and premature failure in the matrix was shown. [ABSTRACT FROM AUTHOR]

Bamboo is suitable to be a material for the production of new products that can be used indoors and outdoors. Five-, seven- and nine-ply laminated woven bamboo mat boards from semantan bamboo, Gigantochloa scortechinii, were fabricated in this study. G. scortechinii has been used commercially in a structural application and is easily available in Malaysia. The present work investigated the physico-mechanical properties and flammability of the laminated bamboo mat boards as a function of the number of ply. Phenol-formaldehyde resin was used as a binder. The panels' density, physical, mechanical properties, formaldehyde emission and flammability were evaluated. As the number of ply increased, the density of the laminated boards decreased. Similarly, the highest modulus of elasticity was found in 5-ply laminated boards. However, the lowest modulus of rupture was also measured in 5-ply laminated boards. Regarding shear strength, 5-ply and 7-ply laminated boards outperformed 9-ply laminated boards. Meanwhile, 7-ply laminated boards exhibited the highest dimensional stability, as evidenced by the lowest water absorption and thickness swelling. In terms of flammability, all composites are classified as V-0 because the burning stops within 10 s and no flaming drips are observed. [ABSTRACT FROM AUTHOR]

This study aims to analyze the performance of laminated glass against ballistic loading and investigates its residual load-bearing capacity. Two groups of specimens were used in quasi-static four-point bending experiments, first without prior ballistic damage and then with it. The main objective was to compare the load-bearing capacity of these two groups to see the effect of ballistic damage. Three different layer compositions were used. The ballistic loading was conducted using an in-service 9 mm bullet fired from a semiautomatic carbine with the glass specimens hanging on steel ropes in a free boundary setup. Numerical simulation and analytical methods were used and validated against the measured response of the undamaged specimens. The simulations were in good agreement with the experimental results. All of the glass specimens were able to withstand the ballistic loading, and the subsequent performance during the quasi-static bending loading was similar to that of the undamaged specimens. The quality of the glass edges seemed to be more important than ballistic damage. The front-plate damage played a negligible role, and the back-plate damage needed to be extensive to influence subsequent performance. Provided that ballistic damage is mainly localized only to the centers of the plates, it did not affect the post-impact loading capacity. [ABSTRACT FROM AUTHOR]

Process robustness of ferroelectric HfO2 films formed by dopant-laminated structure is investigated. Ferroelectric hysteresis obtained by the sub-monolayer Y2O3 laminated structure confirms that entire doping to the HfO2 films is not indispensable to stabilizing the ferroelectric phase. The Y-laminated HfO2 capacitors show robustness against the oxygen plasma exposure time, in contrast to the positive hysteresis shift for uniformly doped HfO2 ones. The number of switching cycles was increased, presumably owing to the reduction of oxygen vacancies associated with the incorporated dopants. Moreover, the leakage current showed a reduction with a higher breakdown voltage. [ABSTRACT FROM AUTHOR]

Stitched filaments are known to modify the mechanical properties of glass-fiber-reinforced polymers 2D (GFRPs 2D), so studying the effect on mechanical properties is underway to determine the critical variables involved. This research focuses on the study of the tensile strength effect of stitched low-density Barkley FBA BGQS15-15 nylon monofilament on biaxial E-Glass Saertex 830 g/m2 (+/−45°) cured with Polyester Sypol Resin 8086 CCP using a vacuum infusion process. Four specimens were made with longitudinal distances between the stitched reinforcements of 0.5, 1.0, 1.5, and 2.0 cm, respectively. Tensile strength tests based on standard ASTM D3039 were performed to study how stitching can affect toughness, Young’s modulus, deformation, ultimate strength, and yield strength. The results indicated that the stitching increases Young’s modulus up to 99.2%, UTS is increased by up to +3.14%, deformation decreases by up to −41.66%, and toughness decreases by up to −36.89%. Although the stitching’s main function is to increase interlaminar resistance, it also induces the formation of stress concentrations by the new threads, and premature failure in the matrix was shown.

Fire safety greatly contributes to feeling safe, and it is a key parameter for the selection of building materials. The combustibility of timber is one of the main reasons to have the strict restriction on timber for use as a building material, especially for multistory buildings. Therefore, the main prerequisite for the use of timber in buildings is to ensure adequate fire resistance, using passive and active fire protection measures. This article contains the results of mechanical and fire experimental tests of both normal and innovative hollow glued laminated timber beams. A total of 10 timber beams were tested at ambient temperature, and 3 timber beams in fire conditions, which differed in cross-section type but also in the applied fire protection. The first beam was a normal GL beam without fire protection, the second a hollow beam covered by intumescent paint, while the third was also hollow, additionally protected by mineral wool infill inside the holes. The load-carrying capacity of the hollow beam in ambient conditions was estimated at 65% of the load-carrying capacity of a normal GL beam. Fire tests indicated that hollow timber beams with both intumescent paint and mineral wool infill failed at a similar time as a normal GL beam without fire protection. One-dimensional β0 and notional charring rates βn were obtained. Time to the protective material failure was 17 min. The main cause of failure of hollow beams was the appearance of delamination due to the reduction of the lamella bonding surface. [ABSTRACT FROM AUTHOR]

In this research article, thermal and hygrothermal stress analysis of composite layered and sandwich plate having one dimension infinitely long and simply supported on the edges is presented using a new fifth-order theory. The proposed theory considers, the effect of thickness stretching. The present theory uses a polynomial shape function to account for transverse shear deformation using the expansion of thickness up to the fifth-order while to consider the effect of thickness stretching the derivative of shape function is used in the transverse displacement. In this theory, the shear strain variation is assumed to be parabolic across the thickness. The present displacement field satisfies zero shear stress condition both at the top and bottom surfaces and avoids the use of a shear correction factor. The governing equations are derived using the virtual work principle. For solution of problem, Navier’s solution technique is used. The results generated using the present theory are compared with the existing elasticity solution wherever it is available. However, many results for the cylindrical flexural analysis of laminated and sandwich plates subjected to environmental loading are presented for the first time in this paper.

Mermi gibi hızlı parçacıkların, karşısında ki bir yapıyı delip geçmesini önlemeye yönelik çalışmalar, ilk çağlardan beri insanlık için süregelen uğraşı olmuştur. Mermi ve delici parçalara karşı zırh tasarımı çalışmaları ilgi odağı olmaya devam etmektedir. Bu amaçla yüzlerce çalışmada onlarca malzeme denenmiştir. Çeşitli yapılar, birçok geometrik varyasyonlar ve formlarda tasarlanmakta, test ortamlarında balistik davranışları ölçülmektedir. Levhalı tasarımlar ağırlıklı olarak alüminyum, seramik ve zırh çeliği levhalarla oluşturulmuşlardır. Ön ve arka destek katmanları olarak bu malzemeler kullanılmıştır. Bazı çalışmalarda, polietilen, fiber, kevlar kumaş gibi malzemelerle bileşik ve kompozit yapılar meydana getirilmiştir. Kompozit yapıların bazılarında, mermi ve delici parçacık yönünü değiştirebilecek farklı geometrik yapılar tasarlanmıştır. Bu sert metal malzemeli yapı, kumaş içine alınarak kolay hareket ve taşınabilirlik ihtiyacı karşılanmaya çalışılmıştır. Bazı çalışmalarda seçilen metal levha malzeme, çeşitli kalınlık ve sıralamalarla test edilmiş, balistik performansları ve darbe etkisine karşı dayanım özellikleri tespit edilmiştir. Bu derleme çalışmasında son yıllarda yapılan çalışmaların bir kısmının özetleri sunulmakta, gelecekte yapılabilecek çalışmalara bir hedef ve perspektif oluşturulmak istenmektedir.

The Messeturm in Frankfurt/Main is currently adjusted to the requirements of a modern office building. The lobby area has been enlarged by a highly transparent facade consisting of oversized insulating glass (IG) units. The IG units are curved and have a size of up to 17 m x 2.8 m. The IG units are supported by tapered stainless steel fins. Inclined steel beams connect the top of the facade fins with the tower structure creating a rounded roof. The facade with its glass roof allows maximum transparency for people inside the lobby as well as for people passing by. [ABSTRACT FROM AUTHOR]

Bamboo is suitable to be a material for the production of new products that can be used indoors and outdoors. Five-, seven- and nine-ply laminated woven bamboo mat boards from semantan bamboo, Gigantochloa scortechinii, were fabricated in this study. G. scortechinii has been used commercially in a structural application and is easily available in Malaysia. The present work investigated the physico-mechanical properties and flammability of the laminated bamboo mat boards as a function of the number of ply. Phenol-formaldehyde resin was used as a binder. The panels’ density, physical, mechanical properties, formaldehyde emission and flammability were evaluated. As the number of ply increased, the density of the laminated boards decreased. Similarly, the highest modulus of elasticity was found in 5-ply laminated boards. However, the lowest modulus of rupture was also measured in 5-ply laminated boards. Regarding shear strength, 5-ply and 7-ply laminated boards outperformed 9-ply laminated boards. Meanwhile, 7-ply laminated boards exhibited the highest dimensional stability, as evidenced by the lowest water absorption and thickness swelling. In terms of flammability, all composites are classified as V-0 because the burning stops within 10 s and no flaming drips are observed.

Based on the finite element model, laminated graphene ceramic tool materials were designed, and the effects of the number of layers and thickness ratio on the residual stress were investigated. According to the simulation design results, laminated Al 2 O 3 –TiB 2 –graphene/Al 2 O 3 –TiN (ATBGN) ceramic tool materials with various structures were prepared using the spark plasma sintering process, and their mechanical properties and microstructures were studied and analyzed. The fracture toughness and flexural strength of ATBGN were 8.65 ± 0.18 MPa m1/2 and 755 ± 25 MPa, respectively, which increased by 66.7% and 21.6%, respectively, compared to those of monolithic Al 2 O 3 –TiB 2 ceramic. Under the synergistic action of graphene and residual compressive stress, the multiscale deflection of cracks and the change in fracture mode occurred, which made the substantial contribution to the improvement in mechanical properties. [ABSTRACT FROM AUTHOR]

Der Messeturm in Frankfurt war zur Zeit seiner Errichtung 1991 das höchste Gebäude Europas. Fast 30 Jahre später findet seine Revitalisierung durch JAHN mit Werner Sobek als Tragwerks‐ und Fassadenplaner und mit seele als Fassadenbauer statt. Die vier großen Eingangsfassaden und die Innenverglasung der Kernwände verwandeln den vergrößerten Lobbybereich in ein modernes Bürogebäude. Jede der vier Fassaden besteht aus neun Isolierglas‐Einheiten mit einer Größe von bis zu 17 m × 2,8 m. Um eine perfekt gebogene Fassade zu erhalten, kommen Isoliergläser mit laminationsgebogenen Verbundgläsern zum Einsatz. Der bestehende, bislang achteckige Aufzugskern des Messeturms wird nun kreisförmig ausgebildet. Eine gebogene transluzente Verglasung auf einer Stahlunterkonstruktion bildet diese neue Form. Dieser mittig platzierte Glaszylinder wird hinterleuchtet und verleiht der neuen Lobby ein sehr elegantes Erscheinungsbild. Maximum Transparency – Messeturm Frankfurt. The Messeturm ("Trade Fair Tower") in Frankfurt/Main was adjusted to the requirements of a modern office building. The lobby area has been enlarged by a highly transparent facade consisting of oversized insulating glass (IG) units. The IG units are curved and have a size of up to 17 m × 2.8 m. To obtain a perfectly curved facade, the IG units were fabricated with laminated cold‐bended glass panes. Horizontally the IG units are supported by tapered stainless steel fins. The vertical facade with its glass roof allows for maximum transparency. In the context of the ongoing refurbishment the old octagon shaped elevator core of the Messeturm has been transformed into a circular shape. Curved translucent, laminated glass units with point fixings on a steel substructure make up this shape. This centrally located glass cylinder is illuminated from behind, giving the lobby a very elegant appearance. [ABSTRACT FROM AUTHOR]

Laminated ZrB 2 –SiC ceramics with graphite and BN as the interface layers were fabricated by tape casting and consequent hot pressing. The influences of interface materials on the thermal shock resistance of the laminated ceramics were studied by both experimental and theoretical analyses. Experimental results show that the critical temperature differences of G/LZS (laminated ZrB 2 –SiC/G) and BN/LZS (laminated ZrB 2 –SiC/BN) were 237 and 99 °C, respectively. The stress gradients of G/LZS and BN/LZS calculated via finite element analysis were 709 and 809 MPa/mm, respectively. Thus, the thermal shock resistance of G/LZS was higher than that of BN/LZS. Such merits of G/LZS can be explained by the following two reasons: one is the thermal conductivity of the graphite interface layer was higher than that of the BN interface layer; the other is the difference of the thermal expansion coefficient for the graphite interface layer and the matrix layer was lower than that for the BN interface layer and the matrix layer. [ABSTRACT FROM AUTHOR]

To overcome the severe problems arising from the insufficient light absorption of ultrathin self-assembly active layers and the high cost use of atomic force deposition (ALD)-grown low-leakage-current transport layers, we successfully developed a low-cost, simple and facile strategy of floating-film transfer and multilayer lamination (FFTML) for constructing highly-efficient ALD-free broadband polarization-sensitive organic photodetectors (OPDs) with the two commonly used structures of donor/acceptor planar heterojunction (PHJ) and donor:acceptor multilayer bulk heterojunction (BHJ). It was found that the PHJ-based polarization-sensitive OPD by FFTML possesses a low dark current due to the high carrier injection barrier, indicating it is more suitable to be applied in low polarized light detection scenarios. In contrast, the BHJ-based device by FFTML has a higher spectral responsivity in the whole wavelength due to more photo-excitons transferred to the donor:acceptor interface and dissociated into photoexcited carrirers. Furthermore, the film thickness, which is tuned by increasing lamination number of BHJ layers, has a big effect on the polarization-sensitive photodetection performance. The polarization-sensitive 4-BHJ OPD by FFTML finally achieved a high specific detectivity of 8.33 × 10 10 Jones, which was much higher than 2.72 × 10 10 Jones for the 2-BHJ device at 0 V. This work demonstrates that layer-by-layer lamination of self-assembly films can effectively improve the polarized-light detection performance, contributing significantly to the rapid development of the field., (© 2024 IOP Publishing Ltd.)

The Messeturm (“Trade Fair Tower”) in Frankfurt/Main is currently adjusted to the requirements of a modern office building. The lobby area has been enlarged by a highly transparent façade consisting of oversized insulating glass (IG) units. The IG units are curved and have a size of up to 17 m x 2.8 m. To obtain a perfectly curved façade, the IG units were fabricated with laminated cold-bended glass panes. Horizontally the IG units are supported by tapered stainless steel fins. Inclined steel beams connect the top of the façade fins with the tower structure creating a rounded roof. The vertical façade with its glass roof allows maximum transparency for people inside the lobby as well as for people passing by outside to the nearby trade fair grounds. The glass was fabricated by sedak. The façade was installed by seele on behalf of the owner OFFICEFIRST, the asset-management of Blackstone.

The current work presents a hygrothermal analysis of laminated composite rhombic hyperbolic paraboloids. The cubic variation in displacement field together with cross curvature effects of the shell were used to solve the hygrothermal problem. Because of the parabolic variation of the transverse shear deformation, the shear correction factor was not necessary in this paper. In the mathematical model, the zero conditions of the transverse shear stress at the bottom and top of the shell were applied. The nine-noded curved isoparametric element with seven unknowns in each node was used to implement the present realistic mathematical model. The implementation of the finite element C0 (FE) of the present mathematical model was coded and performed in FORTRAN. The skew hyperbolic paraboloid on which the hygrothermal analysis was conducted had various temperatures, ply orientation, curvatures, moisture concentration, boundary conditions and thickness ratio. The paper shows that with the increase of the skew angle, the non-dimensional deflection decreases, and with the increase of moisture concentration, hygrothermal load and curvature ratio, the deflection increases. The results of the model presented in the paper were compared with other results published in the literature and were found to be consistent with them.

In this study, effects of gelcoat thickness on the mechanical properties and interfacial bonding of woven glass/polyester laminated composite are investigated by using three point flexural test and tensile test. The composites had been applied at variance thickness of gelcoat layers (0.25, 0.3, 0.35, 0.4, 0.45, and 0.5mm) using hand lay-up method. Samples were measured in two techniques for the flexural test, i.e., coated surface facing the loads (concave) and bare surface facing the loads (convex). Since the coated surface was concavely bent, greatest increase of flexural strength that acquired 5- fold of increase was shown by composite with 0.3 mm of gelcoat thickness for both measurements. The increasing of thickness to 0.35 mm and above deflated the rising percentage in flexural strength. This event was happened because of the gelcoat thickness ratio was greater than the matrix/reinforcement ratio. For tensile test, composite applied with gelcoat of 0.4 mm thickness exhibited the highest increase in strength. An increase of almost 38 % in tensile strength was recorded compared to the uncoated composite. Similarly, the increase in tensile strength reduced slightly when the gelcoat thickness was increased above 0.4 mm. The results demonstrate that the mechanical properties of the composite improve as the gelcoat thickness increases. However, the mechanical properties show no further improvement as the thickness is further increased above the optimum thickness.

The main objective of this study is to perform the free and forced vibration analysis of transversely isotropic and laminated composite parabolic arches with a continuous cross-section variation. The anisotropy of the material of the arch, effects of the rotary inertia, and shear deformations are considered. An efficient unified numerical procedure of the Complementary Functions Method and Laplace transform is applied to solve the strong form of the differential equations that govern the dynamic response of the above structures. The validity and the accuracy of the presented scheme are tested by means of several comparisons with available literature and results of ANSYS. The presented approach has proven to be an accurate and stable numerical method. It is believed that derived results can be used as benchmark solutions for validation of related works in the future. [ABSTRACT FROM AUTHOR]

In the present study, thermoelastic analysis of laminated composite and sandwich shells (cylindrical/spherical) is presented using fifth-order shear and normal deformation theory. The significant characteristic of the present theory is that it includes the effects of both transverse shear and normal deformations. The mathematical formulation uses the principle of virtual work to derive the variationally consistent governing equations and traction free boundary conditions. To obtain the static solution, these governing equations are solved by employing Navier's solution technique. The shell is subjected to a mechanical/thermal load sinusoidally distributed over the top surface of the shell. The thermal load linearly varies across the thickness of the shell. The present results are compared with other higher-order models and 3D elasticity solution wherever possible. Thermal stresses presented in this study will act as a benchmark for the future work. [ABSTRACT FROM AUTHOR]

In flexible electronics, a highly electroconductive, flexible, and durable material is important for various applications. This study describes the property changes in graphene nanosheets (GNSs) doped into a conductive silver (Ag) paste that is used to form a grid-style pattern on a polyurethane hot melt film (PU HMF) for electromagnetic wave shielding. Electrical conductivity, thermal conductivity, and bending tests were performed for materials fabricated by an electronic printing method. The results showed that the conductive paste with a loading of 0.3 wt% GNSs (3SC) had good electromagnetic shielding effectiveness (EMSE, 49.9 dB at 1800 MHz), much better electrical conductivity (4.63*104 S/cm) than the pure silver paste (1.38*104 S/cm), and an improved bending ability. The coefficient of variation of GNS loading (3.01% to 3.80%) under 1000 cyclic bending tests was better than that of the pure silver paste (6.94%) at 2.4% strain, but the results under 500 cyclic elongation tests at 10.0% strain did not exhibit the same pattern. The coefficients of variation (CVs) of all samples in the GNS group (8.3–13.3%) were worse than those of the pure silver group (6.3%) after the elongation test. The reason for the differences in the electrical conductivity and flexibility was explained by the SEM results, which indicated notable damage after the bending and elongation tests. Woven fabrics laminated with a PU/Ag/GNS conductive film that were doped with different amounts of fillers were successfully manufactured by electronic printing and can be used for Electromagnetic Interference (EMI) shielding materials, electrodes for sensor components, wearable elements, smart home textiles, and conductive materials, for example. [ABSTRACT FROM AUTHOR]

The lifetime of ceramic tool is decreased because of the extension of cracks, and it will be prolonged if the cracks can be self healed. The healing ability of laminated Al 2 O 3 cutting tool composites (Al 2 O 3 -(WC-Co)-MgO/Al 2 O 3 –TiC–MgO) were assessed. For determining which laminated structure and the healing condition was the best for the composite, the flexural strength and recovery rates were measured and different healing condition were used. XRD, EDS and SEM technology were carried out to identify their compositions and microstructures after the healing. The number of cracks filled with TiO 2 , crack size and the oxide content effect were utilized to explain why the flexural strength and recovery rates of laminated Al 2 O 3 cutting tool composite after the healing were different. A single particle model was utilized to identify the relation between the threshold time, grain size and the self healing temperature of the composites. [ABSTRACT FROM AUTHOR]

The laminated Al 2 O 3 –ZrB 2 –MgO/Al 2 O 3 –TiN–MgO (AZTM) ceramic composites were fabricated by hot-press sintering technology. The mechanical properties, microstructures and fracture behaviors of the laminated AZTM ceramic composites, were investigated comprehensively from the micro and macro scale perspectives. The residual stresses, R -curve behaviors and displacement in the laminated AZTM ceramic composites were calculated and analyzed. Compared to the monolithic Al 2 O 3 –TiN ceramic composite, the remarkable improvement in the fracture toughness of the laminated AZTM ceramic composite was obtained. Micro and macro crack deflection, crack bifurcation, bridging toughening and serrated propagation were helpful to the enhancement of the fracture toughness. An intracrystalline/intergranular mixed microstructure, as well as the combination of intergranular failure and transgranular failure contributed to the improvement of the flexural strength for the laminated AZTM ceramic composite. [ABSTRACT FROM AUTHOR]

The current work presents a hygrothermal analysis of laminated composite rhombic hyperbolic paraboloids. The cubic variation in displacement field together with cross curvature effects of the shell were used to solve the hygrothermal problem. Because of the parabolic variation of the transverse shear deformation, the shear correction factor was not necessary in this paper. In the mathematical model, the zero conditions of the transverse shear stress at the bottom and top of the shell were applied. The nine-noded curved isoparametric element with seven unknowns in each node was used to implement the present realistic mathematical model. The implementation of the finite element C0 (FE) of the present mathematical model was coded and performed in FORTRAN. The skew hyperbolic paraboloid on which the hygrothermal analysis was conducted had various temperatures, ply orientation, curvatures, moisture concentration, boundary conditions and thickness ratio. The paper shows that with the increase of the skew angle, the non-dimensional deflection decreases, and with the increase of moisture concentration, hygrothermal load and curvature ratio, the deflection increases. The results of the model presented in the paper were compared with other results published in the literature and were found to be consistent with them. [ABSTRACT FROM AUTHOR]

The purpose of this work is to analyze the bending behavior of laminated composite plates using the refined four-variable theory and the finite element method approach using an ANSYS 12 computational code. The analytical model is based on the multilayer plate theory of shear deformation of the nth-order proposed by Xiang et al 2011 using the theory principle developed by Shimpi and Patel 2006. Unlike other theories, the number of unknown functions in the present theory is only four, while five or more in the case of other theories of shear deformation. The formulation of the present theory is based on the principle of virtual works, it has a strong similarity with the classical theory of plates in many aspects, it does not require shear correction factor and gives a parabolic description of the shear stress across the thickness while filling the condition of zero shear stress on the free edges. The analysis is validated by comparing results with those in the literature. [ABSTRACT FROM AUTHOR]

Abstract In this article, higher-order closed-form solutions are obtained for static bending and free vibration analysis of laminated composite and sandwich spherical shells using a generalized higher-order shell theory. A theory is independent of the choice of shearing stress function (polynomial/non-polynomial) which eventually results in a theoretical unification of most of the classical and higher-order shear deformation theories. The present theory yields an accurate distribution of transverse shear stresses through the shell thickness; therefore, it does not require problem dependent shear correction factor. Governing equations and associated boundary conditions of the theory are derived by employing Hamilton's principle. Navier type higher-order closed-form solutions are obtained for simply supported boundary conditions. Displacements, stresses and natural frequencies are presented for laminated composite and sandwich plates as well as shallow and deep spherical shells. The results of parabolic, trigonometric, hyperbolic, and exponential models are compared with each other and previously published results to verify the accuracy and efficiency of the present generalized shell theory. [ABSTRACT FROM AUTHOR]

The comprehensive effect of the mechanical properties, laminated structure and healing conditions on the self-healing behaviors of laminated Al 2 O 3 -MgO ceramic composites was researched. The flexural strengths before and after healing at the temperatures of 715, 815 and 915 °C for 30 min, 60 min and 90 min were measured. According to recovering rate the best healing condition was 900 °C for 60 min. The crack-healing ability of the laminated Al 2 O 3 -MgO ceramic composites was improved due to the enhancement of the original flexural residual effect and the oxide content effect by the elimination of pores and the filling of cracks. In addition, the factors influencing the original flexural residual effect and the oxide content effect were analyzed. Meanwhile, the effects of the particle size and the healing temperature on the healing ability were analyzed qualitatively based on the healing of a single particle model. [ABSTRACT FROM AUTHOR]

In the present study, a new computational model which incorporates the effect of transverse shear and normal deformation is presented for the thermal analysis of laminated composite and sandwich plates. The present theory involves nine unknowns and uses a polynomial function in terms of thickness coordinates which is expanded up to fifth-order. In the present fifth-order shear and normal deformation theory (FOSNDT), the governing equations are variationally consistent and obtained by using the principle of virtual work. Plates are analyzed for simply supported boundary conditions using Navier's solution technique. Numerical results obtained by using the present theory are compared with three-dimensional elasticity solution and other higher-order theories available in the literature. It is found that the present theory is accurately predicting the thermal response of laminated composite and sandwich plates compared to any other theory available in the literature. [ABSTRACT FROM AUTHOR]

Abstract Laminated structure is an effective design to improve the fracture and ablation behaviors of ceramics in the high temperature fields. To investigate the effect of interface layer on the fracture manner of laminated ceramics, two laminated ZrB 2 -SiC/SiC w (LZS w) and ZrB 2 -SiC/SiC p (LZS p) ceramics were prepared by hot pressing with SiC whiskers and SiC powders as strong interface layers, respectively. The flexural strength and fracture toughness of LZS w ceramic reached 471 MPa and 15.9 MPa m1/2, respectively. This improved fracture toughness of the LZS w ceramic was mainly attributed to the introduction of SiC whiskers as the strong interface layer, which significantly prompted crack deflection and branching, increased crack propagation path and consumed more fracture energy during fracture process. [ABSTRACT FROM AUTHOR]

The owner of a 1970s, 24-story commercial office tower in Ottawa, Canada sought to rejuvenate their main lobby with a new glass entry wall. The wall’s purpose is to provide a notable, grand entryway for the re-development of a commercial podium on a main thoroughfare. The final design featured a 12 m tall by 35 m long curving glass fin wall. The height of the wall is broken up into two sections. The first is a 9 m tall section between the ground floor and a third-floor terrace that provides the main building with a new front entrance, including a double-height space. The second is a cantilevered 3 m tall balustrade that creates a new third floor terrace. The glass fins between the ground floor and third floor terrace are continuous, triple-laminated panels free of splices. The curved panels have a 30 m curvature radius and feature a ceramic frit to prevent bird strikes and promote environmental sensitivity. In addition, the panels are insulated glass units (IGUs) with a low-emissivity coating (low-e) to meet the City of Ottawa’s energy standards and the expected interior comfort of top tier retail and office space within the city. Furthermore, the glass panels are supported at discrete points, so the team used a composite resin as the laminate for the interior and exterior lites to maintain the cold bent curvature radius.

The aim of this paper is to explain how the design intent of a bespoke glazed façade develops from the point of view of the façade consultant BIFF SA. The explanation of this concept development is not only interesting because of the different phases of the process, but also because of the unusual specifications and demands established by the architects and the Client, and for the project evolution trough several technical solutions up to final project state. During the concept development materials like stone, steel, aluminum or fabric are normally combined with glass. This challenging glazed façade has been developed for a luxury villa in Switzerland where a triple laminated glass cladding has been selected as the final most suitable solution for creating a building envelope with glass panes of 3000mm W x 7000mm H bonded to a back frame with structural silicone. These units have obviously aesthetic requirements and also different functional applications and the solution should fulfill all demands and do not the technical aspects of building up a façade with such a big glass units.

Due to the recent terrorist attacks, the market demand for security glazing has rapidly grown and turned from a “bank counters” market to a facade market. In this context, it appears to be legitimate to ask the question of the applicability of current standards to this changing environment: Are they still adapted to fulfil the security requirements of the market ? If not, which adaptations could be performed ? In the present talk, the current European standards dedicated to the security glazing resistance against explosion pressure - EN 13541 - is reviewed and compared to its ISO standard pendant - ISO 16934 - and alternative - ISO 16933 -. Moreover, based on numerical simulations, the current extension rules applicable to the specific case of the explosion resistance of insulating glazing units - EN 1279-5 - are discussed as well.

Laminated ZrC-SiC ceramic was prepared through tape casting and hot pressing. The green tapes of ZrC and SiC were prepared at room temperature. In order to improve the density of composite, the binder of green tapes were removed at 550 °C for 1 h. The laminated structure and the cracks propagation path, which is not a straight line, are observed by optical metalloscope. The compact laminated ZrC-SiC composite sintered by vacuum hot-pressing at 1650 °C for 90 min under pressure of 20 MPa was researched by X-ray diffraction and scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis. The results showed that interlayer bonding is tight, and no disordered phase has formed in the interlayers of ZrC or SiC, and the combination mode is physical mechanism.

Abstract This article reports the fabrication of fiber cloth-reinforced mullite composite via an optimized layer-by-layer (LbL) assembly method involving the infiltration and pyrolysis of fiber cloth with mullite precursor (PIP) followed by brushing matrix onto the treated fiber cloth and hot pressing. The influence of fiber content on the microstructure and mechanical properties of composite are investigated and the crack propagation is discussed to explain the toughening mechanisms. The composite with 30 vol% fiber content exhibited a high density 2.89 g/cm3, flexural strength 135.5 MPa and fracture toughness 4.13 MPa m1/2. After PIP pretreatment, the gaps existed in the fiber bundle are filled with mullite matrix which transform from mullite precursor, improving the density from 2.89 g/cm3 to 2.94 g/cm3, flexural strength from 135.5 MPa to 163.2 MPa and fracture toughness from 4.13 MPa m1/2 to 4.55 MPa m1/2. The optimized LbL assembly method realizes the creation of fiber cloth-reinforced mullite composites with high density and excellent mechanical properties. [ABSTRACT FROM AUTHOR]

The laminated silicon carbide/boron nitride (SiC/BN) ceramics with different structural designs were fabricated by pressureless sintering at 1900 °C for 1 h in argon flow. The alumina (Al 2 O 3 )-and yttrium(III) oxide (Y 2 O 3 )-doped SiC ceramic exhibited a significant intergranular fracture behavior, which could be attributed to the yttrium aluminum garnet (YAG) phase located at the grains boundaries. The bending strength and fracture toughness were used to characterize the crack propagation including the delamination cracking, crack kinking, and crack deflection. The energy absorption in the process of crack propagation was characterized by the work of fracture (WOF) and damping capacity. The mode of crack propagation changed with the change in the structure and variation of BN content in the BN layer. The delamination cracks occurred inside the BN layer or at the interface between SiC and BN layers. The sample with a gradient structure exhibited the combination of delamination cracks occurring at the interface and inside the BN layer, which showed the maximum WOF of 2.43 KJ m −2 , bending strength of 300 MPa, and fracture toughness of 8.5 MPa m 1/2 . The damping capacity varied with the change of the structure and the amplitude. The sample with a gradient structure exhibited the damping capacity of 0.088 and the maximum loss modulus of 9.758 GPa. [ABSTRACT FROM AUTHOR]

In the present paper, a new fifth-order shear and normal deformation theory (FOSNDT) is developed for the bi-directional bending analysis of laminated composite and sandwich plates subjected to transverse loads. This theory considered the effects of both transverse shear and normal deformations. In-plane displacements use a polynomial shape function expanded up to fifth-order in terms of the thickness coordinate to properly account the effect of transverse shear deformation. Transverse displacement is the function of x, y and z-coordinates to account the effect of transverse normal deformations i.e. thickness stretching. Hence, the present theory involves nine unknowns in the displacement field. The present theory does not require a problem dependent shear correction factor as it satisfies traction free boundary conditions at top and bottom surfaces of the plate. The governing differential equations and associated boundary conditions are obtained using the principle of virtual work. The plate is analysed for simply supported boundary conditions using Navier's solution technique. To prove the efficiency of the present theory, the nondimensional displacements and stresses obtained for laminated composite and sandwich plates are compared with existing exact elasticity solutions and other theories. It is observed from the comparision that the displacements and stresses obtained by the present theory are in excellent agreement with the results obtained by exact elasticity solutions compared to other higher-order plate theories available in the literature. [ABSTRACT FROM AUTHOR]