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Structural health monitoring obtains data reflecting the service status of grid structures through sensors. One of the issues to consider in optimal sensor placement is how to obtain as much information as possible with a limited number of sensors. In this paper, a sensor placement method is proposed based on damage sensitivity and correlation analysis, which is based on strain energy calculation and is suitable for grid structures. Specifically, with the sensor locations as optimization variables, a mathematical optimization model is established by considering the damage sensitivity and redundancy of the monitoring scheme, and a genetic algorithm is employed for computation. Two examples, including a lattice shell and a flat grid, are provided to illustrate the method, followed by a discussion of the sensitivity of parameters such as stiffness reduction degree and load form. The results indicate that the redundancy of the optimized schemes for the two examples decreased by approximately 80% and 30%, respectively. The proposed method ensures a certain degree of damage sensitivity while significantly reducing redundancy, demonstrating its applicability and robustness in sensor placement for grid structures. [ABSTRACT FROM AUTHOR]

Space grid structures are widely used in the field of structural engineering due to their good mechanical properties and simple construction procedures. This paper reviews the development of space grid structures and mainly introduces the development of space grid structures in China in recent years. Some typical applications of space grid structures are introduced and the technical developments are summarized. It shows that China not only has a large number of engineering applications of space grid structures, but also a rapid development of related technologies. Finally, some prospects for space grid structures are discussed. [ABSTRACT FROM AUTHOR]

Flexible zinc‐air batteries have received widespread attention due to their high specific energy and eco‐friendly environment. However, the water in the hydrogel is easily lost to the external environment because of the semi‐open structure zinc‐air batteries, leading to performance degradation of the batteries. Here a saline gel of NaCl‐KOH‐PAA (sodium chloride‐potassium hydroxide‐polyacrylic acid) without soaking in the alkaline solution before use is designed, refining the grid structure of the hydrogel and reducing water loss through NaCl doping. Meanwhile, the gel exhibits no significant decrease in ion conductivity before and after NaCl doping and can maintain stability of around 170 and 150 mS cm−1 at room temperature and −20 °C, respectively. The results demonstrate that the lifetime of flexible zinc‐air batteries with NaCl‐doped hydrogel can be extended by nearly 50%. The NaCl doping gel also displays superior flexibility under extreme physical deformation conditions. Moreover, the phenomenon of hydrogel delamination with NaCl doping is observed and the mechanism of gel water retention is uncovered. These findings will pave the way for developing flexible zinc‐air battery. [ABSTRACT FROM AUTHOR]

The article is devoted to numerical methods for solving the problem of diffraction of electromagnetic waves by conducting bodies. Two approaches to solving the problem are considered. The first one is based on the use of the thin-wire integral representation of the electromagnetic field (TP-method) for a grid model of the body surface. The second approach is associated with the use of the basis functions of RaoWiltonGlisson when solving a vector integral equation formulated with respect to the electric current density on the body surface (RWG-method). The diffraction of a plane linearly polarized electromagnetic wave by a sphere is considered as a test problem. The results of calculations of the normalized diagrams of the scattered field are presented. It is shown that there are practically no visual differences for the results obtained using both approaches. At the same time, it should be noted that the TP method is much simpler in numerical implementation than the RWG method.

Nowadays grid structures are considered as one of the most useful composites because of their various applications. Since grid structures are vulnerable to impact loads, they should be investigated under such loadings. The present paper studies the low-velocity impact loading of sandwich panels with grid-stiffened cores using both experimental and numerical simulations. In addition to the impact behaviour and the resultant damage of the sandwich panels, the behaviour of these structures under three-point bending was studied before and after the impact loading. The results were provided for impact and bending loadings separately. Then the effect of impact loadings on bending strength was investigated and it was found that the impact loading decreases the bending strength. A consistency between numerical and experimental results was also observed, which confirms the applicability of the Finite Element Method (FEM) in simulating the behaviour of such structures under impact and bending loads, while saving lots of time, efforts and costs.

• The recent achievement of a pivotal component in modern aeronautical and aerospace architectures, i. e. advanced lightweight composite shells, is reviewed. • The development of three key component technologies, including manufacturing, mechanical characterization and optimum design methods, are analyzed. • A comprehensive review of their applications and potentials in aeronautical and aerospace systems is presented. The development of modern aeronautical and aerospace industries has greatly been accelerated by the upgradation of advanced lightweight architecture materials. As a recognized and promising kind, lightweight composite structures amalgamate the benefits of advanced fiber-reinforced composite materials and innovative design concepts for weight reduction and thus have attracted substantial attention from structural engineers and scholars over the past few decades. The primary objective of the present article is to provide an extensive review and analysis of the recent achievement of a pivotal component in modern aeronautical and aerospace architectures: lightweight composite shells. This review delves into various composite grid, grid-stiffened, and sandwich shells with diverse constructions, elucidating their structural design concepts and applicable conditions. The academic discourse focuses on the three relevant key component technologies for developing lightweight composite shells, including manufacturing techniques, mechanical characterization and optimum design methods. Additionally, this article presents a comprehensive review of their applications and potentials in aeronautical and aerospace systems. The existing research gap and contemplates on future directions are discussed. The encountered challenges and possible opportunities for lightweight composite shells are also illuminated. [ABSTRACT FROM AUTHOR]

This paper presents the evolution of and influence that the use of a triangular grid has had on the transformation of layered grid structures during the last two centuries. Historical facts, technological advances, economic and social crises among other factors influence the process of change and evolution of the grid systems in architecture to make construction processes more efficient by reducing the consumption of materials and qualified labor. Geometry and structure innovate styles and processes that are perfected over the years, achieving lighter and more stable structures. For the purpose of this paper historical data will be collected that allows the development of a theory that shows the influence of various periods based on technological advances. This research shows four historical periods in the evolution of layered grid structures. Being the triangular grid a widely used methodology in the construction of a diversity of geometric proposals and innovative construction systems for the solution of a diversity of buildings from the first domes built in the early 19th century to the free-form structures built from the late 20th century to the present day.

Nowadays grid structures are considered as one of the most useful composites because of their various applications. Since grid structures are vulnerable to impact loads, they should be investigated under such loadings. The present paper studies the low-velocity impact loading of sandwich panels with gridstiffened cores using both experimental and numerical simulations. In addition to the impact behaviour and the resultant damage of the sandwich panels, the behaviour of these structures under three-point bending was studied before and after the impact loading. The results were provided for impact and bending loadings separately. Then the effect of impact loadings on bending strength was investigated and it was found that the impact loading decreases the bending strength. A consistency between numerical and experimental results was also observed, which confirms the applicability of the Finite Element Method (FEM) in simulating the behaviour of such structures under impact and bending loads, while saving lots of time, efforts and costs. [ABSTRACT FROM AUTHOR]

It is shown that the solvothermal synthesis of mixed vanadium – molybdenum oxide 0.5V2O5 : 0.5MoO3 in the presence of surfactants permits one to exert an effective control over the phase formation and to obtain needle-like crystals exhibiting high aspect ratio. The synthesis in the presence of polyethylene-glycol (non-ionogenic surfactant) ensures blocking of the terminal OH-groups at the surface of mixed oxide thus preventing the agglomeration of arising grid structures with high surface-to-volume ratio showing much promise as the heterogeneous catalysts.

In this paper, we present an analytical method based on equivalent continuum homogenization for the global buckling analysis of the general grid lattice cylindrical structures. In the proposed scheme, grid structures with arbitrary cell geometries can be analyzed by obtaining their effective cell stiffness based on force and moment analysis of the struts. The grid structures are assumed to be composed of curvilinear axial, circumferential, and oblique unidirectional composite ribs. To evaluate the results of the presented analytical method, a parametric finite element code is derived to generate the desired geometry of the grid structures and their buckling loads are obtained and compared with the analytical method. The effects of various parameters, including the number of ribs, their thickness and elastic properties, and helical angle of the oblique ribs are studied for hexagonal, triangular, and mixed grid shells. The results are compared with the available data published in the literature with a good agreement. [ABSTRACT FROM AUTHOR]

Measuring a large grid structure is always based on the traditional total station, which requires a significant workforce. Aiming at the ring structure's characteristics, this paper fully uses multi-sensor advantages and proposes an automatic identification method of grid structure nodes. This method combines deep learning, panoramic camera, and laser scanning and improves the existing method of measuring the lifting process of the grid structure. The main contributions of this paper are as follows: (1) Aiming at the issue with existing measurement methods relying on complex multi-camera systems, a method based on a single panoramic camera and deep learning is proposed to quickly complete the full-field image target points detection, which provides a basis for the identification of target areas in the point clouds; (2) For the challenge posed by a large number of point clouds models and complex processing, a method of automatically capturing point clouds nodes by integrating panoramic camera and laser scanning was proposed. The projection points of the interest region of the image corresponding to the target region in the point clouds and precise identification of nodes were completed; (3) A node classification method and optimization method based on density peak clustering was proposed to solve the problem of node aliasing and processing node center in some areas of interest, for the classification and displacement calculation of grid structure nodes. The proposed method is validated on the scale frame model of a gymnasium, demonstrating the practicability of the proposed approach. • Aiming at the issue with existing measurement methods relying on complex multi-camera systems, a method based on a single panoramic camera and deep learning is proposed to complete image target detection, which provides a basis for the identification of target areas in the points cloud; • Aiming at the challenge posed by a large number of point clouds models and complex processing, a method of automatically capturing point clouds nodes by integrating panoramic camera and lidar was proposed. • A node classification method and optimization method based on density peak clustering was proposed to solve the problem of node aliasing and processing node center in some areas of interest, for the classification and displacement calculation of cable network structure nodes. [ABSTRACT FROM AUTHOR]

Grid stiffened panels promise increased damage tolerance with reduced weight. Recent progress in automated manufacturing of composites has made it possible to produce such panels at low cost and thus has made them a competitive alternative to traditional skin-stiffened or sandwich panels. Fuselage skin panels typical of a 150 passenger aircraft were designed using an iterative process combining finite element models and local special purpose analysis methods. 40 cm by 30 cm panels, representing the final design, were fabricated using vacuum assisted resin transfer moulding. Pristine and impact damaged panels were tested in compression to failure. A progressive failure model was used to predict the extent and type of damage during impact. It was then combined with the global finite element model to obtain residual strength predictions. Analytical predictions were very close to test results. The fabrication method showed good quality and consistency and, when automated, can be used for production. [ABSTRACT FROM AUTHOR]

China's power sector has experienced rapid development over the past decade. With the clean energy targets and carbon mitigation objectives proposed by the government as well as rapid development of power transmission infrastructure, future potential pathways for the expansion of China's power sector are worth assessing. In this paper, a mathematical model, named the Long-term Multi-region Load-dispatch Grid-structure-based (LoMLoG) has been developed and a “most-likely” scenario has been created that delivers insights into optimal regional power generation, transmission and emissions profiles. The results confirm the importance of clean energy targets in driving deployment of renewable energy and maximizing its contribution to carbon mitigation of China’s power sector. In addition, the development of power transmission infrastructure will significantly influence regional power generation and transmission profiles. Last but not least, carbon mitigation approaches in the long term are discussed, and rational methods of allocating future carbon caps are presented. [ABSTRACT FROM AUTHOR]

The minimum mass designs of state of the art helical circumferential grids are compared to axial helical grids. Analytical models based on the classical laminate theory deliver optimization results in less than one second. Using finite element models the obtained results are validated and adjusted in a second optimization step. Studies on the influence of rib heights and Young’s modulus show potential to create lighter grids in axial helical design than in helical circumferential design. This is shown for medium length cylinders from relatively low up to very high load levels. [ABSTRACT FROM AUTHOR]

The main focus of this paper is the study of grid stiffened plates. The plates are modeled using the finite element approach. A 2D 8-node plate element is proposed. The advantage of the proposed element is that it can model plates with stiffeners within the element. This can yield models with many fewer elements for grid structures. A parametric study is presented to study the effect of the stiffener angle on the element stiffness in an attempt to optimize the stiffener configuration. For validation purposes, three cases are considered; plain plate, plate with straight stiffeners, and plate with isogrid stiffeners. The modal frequencies and modes of the plates are calculated using the proposed model and compared with the predictions of the commercial finite element package ANSYS® as well as experimental measurements taken on three plates manufactured by stereo lithography technique. The comparisons demonstrate the validity of the proposed model and the effectiveness of the isogrid stiffeners compared to straight stiffeners of the same mass in significantly increasing the fundamental frequency. The obtained results emphasize the potential of employing isogrid stiffeners in numerous vibration and noise control applications. [ABSTRACT FROM AUTHOR]

Meteorological research involves the analysis of multi-field, multi-scale, and multi-source data sets. In order to better understand these data sets, models and measurements at different resolutions must be analyzed. Unfortunately, traditional atmospheric visualization systems only provide tools to view a limited number of variables and small segments of the data. These tools are often restricted to two-dimensional contour or vector plots or three-dimensional isosurfaces. The meteorologist must mentally synthesize the data from multiple plots to glean the information needed to produce a coherent picture of the weather phenomenon of interest. In order to provide better tools to meteorologists and reduce system limitations, we have designed an integrated atmospheric visual analysis and exploration system for interactive analysis of weather data sets. Our system allows for the integrated visualization of 1 D, 2D, and 3D atmospheric data sets in common meteorological grid structures and utilizes a variety of rendering techniques. These tools provide meteorologists with new abilities to analyze their data and answer questions on regions of interest, ranging from physics-based atmospheric rendering to illustrative rendering containing particles and glyphs. In this paper, we will discuss the use and performance of our visual analysis for two important meteorological applications. The first application is warm rain formation in small cumulus clouds. Here, our three-dimensional, interactive visualization of modeled drop trajectories within spatially correlated fields from a cloud simulation has provided researchers with new insight. Our second application is improving and validating severe storm models, specifically the Weather Research and Forecasting (WRF) model. This is done through correlative visualization of WRF model and experimental Doppler storm data. [ABSTRACT FROM AUTHOR]

In this article, the spectral element method combined with Bloch theorem is applied to calculate complete vibration band gap characteristics of two-dimensional periodic grid structures, which is verified by structural vibration transmission results based on spectral element method and finite element method. According to the differential equation of motion, complete spectral stiffness matrix of beam element is established at first, then stiffness matrix of grid structure can be obtained by coordinate transformation and assembly method, so as to form governing equation of motion based on Bloch boundary conditions. The band gap characteristics of periodic structures can be calculated by solving motion equation. Through band gap distribution analysis of two-dimensional periodic grid structures, the dispersion relations of different unit arrangements and effects of material and structural parameters on band gap characteristics are obtained which can be applied to acoustic design or vibration and noise reduction areas. [ABSTRACT FROM AUTHOR]