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Carbon fiber-reinforced composites are widely used in the aerospace industry due to their exceptional mechanical properties. However, the dome region of composite pressure vessels is prone to stress concentrations under internal pressure, often resulting in premature failure and reduced burst strength. This study developed a finite element model of a reinforced dome structure, which showed excellent agreement with hydrostatic test results, with less than 5.9% deviation in strain measurements. To optimize key reinforcement parameters, a high-accuracy surrogate model based on a backpropagation neural network was integrated with a multi-objective genetic algorithm. The results indicate that compared to the unreinforced dome, the optimized structure reduced the maximum fiber-aligned stress in the dome region by 6.8%; moreover, it achieved a 9.3% reduction in overall mass compared to the unoptimized reinforced configuration. These findings contribute to the structural optimization of composite pressure vessel domes.

Shape sensing as a crucial component of structural health monitoring plays a vital role in real-time actuation and control of smart structures, and monitoring of structural integrity. As a model-based method, the inverse finite element method (iFEM) has been proved to be a valuable shape sensing tool that is suitable for complex structures. In this paper, we propose a novel approach for the shape sensing of thin shell structures with iFEM. Considering the structural form and stress characteristics of thin-walled structure, the error function consists of membrane and bending section strains only which is consistent with the Kirchhoff–Love shell theory. For numerical implementation, a new four-node quadrilateral inverse-shell element, iDKQ4, is developed by utilizing the kinematics of the classical shell theory. This new element includes hierarchical drilling rotation degrees-of-freedom (DOF) which enhance applicability to complex structures. Firstly, the reconstruction performance is examined numerically using a cantilever plate model. Following the validation cases, the applicability of the iDKQ4 element to more complex structures is demonstrated by the analysis of a thin wallpanel. Finally, the deformation of a typical aerospace thin-wall structure (the composite tank) is reconstructed with sparse strain data with the help of iDKQ4 element.

Reinforced concrete shell structures produced using an inflated form are widely used in large‐span thin‐shell spatial structures. Unlike the construction technology of traditional concrete building structures, this method involves prefabricating the membrane material into a designed shape as the construction framework. After inflation, a polyurethane layer is sprayed, steel bars are placed, and concrete is sprayed inside the inflatable membrane. This innovative construction method effectively addresses the issues of complex framework procedures, high costs, and difficulty in concrete pouring in traditional thin concrete shell construction, offering significant advantages. However, despite its wide application in the industrial sector and the gradual maturation of related construction techniques, the structure still faces many technical challenges that need to be addressed. Existing research remains insufficient in areas such as standardization processes, material performance optimization, and long‐term durability, which limit the further development and application of this technology. Although there have been some related reviews, most of them have not comprehensively covered all the key technologies in this field. This article provides the first systematic review, filling the research gap in the existing literature. By reviewing the relevant background, structural forms, engineering applications, and key technologies of reinforced concrete shell structures produced using an inflated form, this article proposes several improvements for these technical challenges and discusses future research directions, particularly in the areas of standardization processes, material performance optimization, and long‐term durability.

This work seeks to define original ways of creating architectonic forms using kinesiology studies. A series of methodologies are devised to record subjects in motion, with analogue and digital modelling techniques rigorously used independently and in combination to transpose these into sculptural figures with differing levels of formal fidelity and dimensional precision. Surface structures, and in particular thin shells, are found to have great potential for moving from abstract figures to structural forms. Such structures are traditionally problematic in terms of ‘constructional energy’, which has limited their usefulness and application. In response, the ‘hanging cloth reversed’ modelling technique devised by Heinz Isler is investigated to capitalise on the ambiguity between large-scale models and small structures. A construction method is devised that accords with the principles of structural art which, significantly, suggests that (small-span) shell structures could be liberated from the strictures of formwork to create economic, efficient and elegant minimal structures.

Green indium phosphide (InP)-based quantum dot light-emitting diodes (QD-LEDs) still suffer from low efficiency and short operational lifetime, posing a critical challenge to fully cadmium-free QD-LED displays and lighting 1 – 3 . Unfortunately, the factors that underlie these limitations remain unclear and, therefore, no clear device-engineering guidelines are available. Here, by using electrically excited transient absorption spectroscopy, we find that the low efficiency of state-of-the-art green cadmium-free QD-LEDs (which ubiquitously adopt the InP–ZnSeS–ZnS core–shell–shell structure) originates from the ZnSeS interlayer because it imposes a high injection barrier that limits the electron concentration and trap saturation. We demonstrate, both experimentally and theoretically, that replacing the currently widely used ZnSeS interlayer with a thickened ZnSe interlayer enables improved electron injection and depressed leakage simultaneously, allowing to achieve a peak external quantum efficiency of 26.68% and T 95 lifetime (time for the luminance to drop to 95% of the initial value) of 1,241 h at an initial brightness of 1,000 cd m –2 in green InP-based QD-LEDs emitting at 543 nm—exceeding the previous best values by a factor of 1.6 and 165, respectively 3 , 4 . Replacing ZnSeS with a thickened ZnSe layer in green InP-based QD-LEDs improves the efficiency and lifetime, boosting electron injection and reducing leakage, enabling 26.68% external quantum efficiency and 1,241 h T 95 lifetime.

To industrialize printed full-color displays based on quantum-dot light-emitting diodes, one must explore the degradation mechanism and improve the operational stability of blue electroluminescence. Here, we report that although state-of-the-art blue quantum dots, with monotonically-graded core/shell/shell structures, feature near-unity photoluminescence quantum efficiency and efficient charge injection, the significant surface-bulk coupling at the quantum-dot level, revealed by the abnormal dipolar excited state, magnifies the impact of surface localized charges and limits operational lifetimes. Inspired by this, we propose blue quantum dots with a large core and an intermediate shell featuring nonmonotonically-graded energy levels. This strategy significantly reduces surface-bulk coupling and tunes emission wavelength without compromising charge injection. Using these quantum dots, we fabricate bottom-emitting devices with emission colors varying from near-Rec.2020-standard blue to sky blue. At an initial luminance of 1000 cd m −2 , these devices exhibit T 95 operational lifetimes ranging from 75 to 227 h, significantly surpassing the existing records. The surface localized charges in colloidal quantum dots induce a degradation that limits the electroluminescence performance. Here, Chen et al. propose quantum dots with monmonotonically-graded core/shell/shell structures to boost the device’s performance by reducing the surface-bulk coupling.

Thin-walled shell structures are widely used in aeronautical and aerospace engineering. This paper develops an effective B-spline parameterization method for stiffener layout optimization of shell structures. Height variables are defined by B-spline control parameters to characterize the stiffener layout reinforcing the shell structure. A continuous height field is subsequently generated via B-spline and basis functions. In view of possible curvatures of shell structures, the height field is projected from parametric space onto the shell structure by means of the parametric mapping. In this work, the finite element method is adopted with the solid-shell coupling method used for structural analysis. Pseudo-densities associated with solid elements are determined based on the B-spline parameterization and Heaviside function. Several numerical examples are dealt with to demonstrate the proposed method. Compared with the standard density-based method, the proposed method produces checkerboard-free design results with a clear layout and naturally avoids overhang stiffeners.

A conical shell is one of the typical structural forms of underwater navigation. This paper explores the free vibration properties of finite-length cones, analyses the modular frequency and modular vibration type properties in vacuum and underwater cones, and conducts a comparative analysis. The numerical calculations show: The use of hydrogen in conjunction with the hydrophobic structure of the cone will lead to a significant decrease in the modular frequency of the shell, with a maximum decrease of 40% for the first 10 modules of this model; Modal vibration patterns are similar in air and underwater, but the order of the modal vibrations may vary, indicating that the frequency reduction of different modal frequencies caused by the water medium is different. The conclusions of this article can be used as a reference for the design, optimization, and application of conical shells in engineering.

Photon upconversion in lanthanide-doped upconversion nanoparticles offers a wide variety of applications including deep-tissue biophotonics. However, the upconversion luminescence and efficiency, especially involving multiple photons, is still limited by the concentration quenching effect. Here, we demonstrate a multilayered core-shell-shell structure for lanthanide doped NaYF 4 , where Er 3+ activators and Yb 3+ sensitizers are spatially separated, which can enhance the multiphoton emission from Er 3+ by 100-fold compared with the multiphoton emission from canonical core-shell nanocrystals. This difference is due to the excitation energy transfer at the interface between activator core and sensitizer shell being unexpectedly efficient, as revealed by the structural and temperature dependence of the multiphoton upconversion luminescence. Therefore, the concentration quenching is suppressed via alleviation of cross-relaxation between the activator and the sensitizer, resulting in a high quantum yield of up to 6.34% for this layered structure. These findings will enable versatile design of multiphoton upconverting nanoparticles overcoming the conventional limitation. Photon upconversion in nanoparticles is often limited by concentration quenching. The authors present a multi-layered particle approach that enables increased upconversion efficiency by reducing cross-relaxation, through spatial separation of activator and sensitizer.

Molluscan shells, mainly composed of calcium carbonate, also contain organic components such as proteins and polysaccharides. Shell organic matrices construct frameworks of shell structures and regulate crystallization processes during shell formation. To date, a number of shell matrix proteins (SMPs) have been identified, and their functions in shell formation have been studied. However, previous studies focused only on SMPs extracted from adult shells, secreted after metamorphosis. Using proteomic analyses combined with genomic and transcriptomic analyses, we have identified 31 SMPs from larval shells of the pearl oyster, Pinctada fucata, and 111 from the Pacific oyster, Crassostrea gigas. Larval SMPs are almost entirely different from those of adults in both species. RNA-seq data also confirm that gene expression profiles for larval and adult shell formation are nearly completely different. Therefore, bivalves have two repertoires of SMP genes to construct larval and adult shells. Despite considerable differences in larval and adult SMPs, some functional domains are shared by both SMP repertoires. Conserved domains include von Willebrand factor type A (VWA), chitin-binding (CB), carbonic anhydrase (CA), and acidic domains. These conserved domains are thought to play crucial roles in shell formation. Furthermore, a comprehensive survey of animal genomes revealed that the CA and VWA–CB domain-containing protein families expanded in molluscs after their separation from other Lophotrochozoan linages such as the Brachiopoda. After gene expansion, some family members were co-opted for molluscan SMPs that may have triggered to develop mineralized shells from ancestral, nonmineralized chitinous exoskeletons.