Guided by the uncertainty theory, this paper considers the complex and variable working conditions of tents and expounds the feasibility of finite element analysis under the condition of uncertainty ...of both material and working conditions. It then proposes the topology optimization based on reliability. The scheme takes the reliability index as the constraint condition and transforms uncertain parameters into deterministic parameters, and then the variable density algorithm topology optimization is performed. Taking two typical structure frames of military and civil tents as examples, respectively, the stress of the frame under wind load is considered, and the feasibility of the design scheme and algorithm logic is verified. The results of the mechanical simulations show that the scheme not only obtains the ideal results, but also avoids repeated iterative scheme trial calculations, thus significantly reducing the time costs and workload of the R＆D process, thus promising optimal promotion value and applicabi
Topology optimization design provides innovative structures with excellent thermal, mechanical and acoustic performance for modern engineering. Moving Morphable Component (MMC), as an emerging ...explicit topology optimization method, can effectively avoid many optimization problems such as the checkerboard phenomenon, however, its optimization iteration process still consumes considerable time, which makes real-time structural topology optimization impossible. Therefore, a lightweight and high-efficiency convolutional neural network, the improved convolutional block attention U-Net (Cba-U-Net) model, is proposed for topology-optimized configuration prediction, which avoids its own tedious iterative computation process and acquires the topology configuration in real-time. It is demonstrated that the proposed network not only obtains accurate topology-optimized configurations in negligible time but also has an accuracy rate of 91.42% compared to other deep learning models. The improved Cba-U-Net model is suitable not only for Moving Morphable Components but also for other optimization algorithms, such as Solid Isotropic Material with Penalization (SIMP) and Evolutionary Structural Optimization Method (ESO). By combining deep learning with topological optimization algorithms, this form of optimization is highly generalizable for practical large-scale projects.
In recent years, new methods have been developed to synthesize complex porous and micro-structured geometry in a variety of ways. In this work, we take these approaches one step further and present ...these methods as an efficacious design paradigm. Specifically, complex micro-structure geometry can be synthesized while optimizing certain properties such as maximal heat exchange in heat exchangers, or minimal weight under stress specifications.
By being able to adjust the geometry, the topology and/or the material properties of individual tiles in the micro-structure, possibly in a gradual way, a porous object can be synthesized that is optimal with respect to the design specifications. As part of this work, we exemplify this paradigm on a variety of diverse applications.
•Support for microstructures design with graded heterogeneous materials.•A framework for editing microstructures, affecting individual tiles’ geometry, topology, and material.•Direct support for (isogeometric) analysis of microstructures.
In additive manufacturing process, support structures are often required to ensure the quality of the final built part. In this article, we present mathematical models and their numerical ...implementations in an optimization loop, which allow us to design optimal support structures. Our models are derived with the requirement that they should be as simple as possible, computationally cheap, and, yet, based on a realistic physical modelling. Supports are optimized with respect to two different physical properties. First, they must support overhanging regions of the structure for improving the stiffness of the supported structure during the building process. Second, supports can help in channeling the heat flux produced by the source term (typically a laser beam) and thus improving the cooling down of the structure during the fabrication process. Of course, more involved constraints or manufacturability conditions could be taken into account, most notably removal of supports. Our work is just a first step, proposing a general framework for support optimization. Our optimization algorithm is based on the level set method and on the computation of shape derivatives by the Hadamard method. In a first approach, only the shape and topology of the supports are optimized, for a given and fixed structure. In a second and more elaborated strategy, both the supports and the structure are optimized, which amounts to a specific multiphase optimization problem. Numerical examples are given in 2D and 3D.
•The mechanics of the vein domains are revealed to be correlated with morphology.•The layout of wing veins is explained by multi-objective optimization.•Structural biology is evolved based on the ...gradient optimization.
The intricate network of veins on dragonfly wings has captured the attention of many researchers due to its fascinating configuration and excellent mechanical properties. In this paper, based on the observation of the layout of the vein domains on the hind wing of dragonfly, the types of domains were characterized from the aspects of area and shape. The numerical analysis revealed that different shaped domains enhance either stiffness or vibration stability of the wing. According to this feature, a multi-objective gradient optimization algorithm based on stiffness, mass transport efficiency and first order frequency was proposed. Associated by the size constraints, the optimal layout of the venation was obtained and subsequently used to generate the Voronoi patterns, whose positions and shapes could be further optimized by an evolutionary algorithm to match the mechanical analysis results. The effectiveness of this multi-cellular configuration was verified by testing the bending and vibration stability of the additive manufactured model. The aerodynamic simulation analysis of this flapping wing structure was also investigated. This study has important implications for understanding the evolutionary mechanisms of venation on biological wings and designing reinforcement for sheets.
Coastal erosion describes the displacement of sand caused by the movement induced by tides, waves or currents. Some of its wave phenomena are modelled by Helmholtz-type equations. Our purposes, in ...this paper are, first, to study optimal shapes obstacles to mitigate sand transport under the constraint of the Helmholtz equation. And the second side of this work is related to Dirichlet and Neumann spectral problems. We show the existence of optimal shapes in a general admissible set of quasi open sets. And necessary optimality conditions of first order are given in a regular framework using both shape and topological optimization. Some numerical simulations are given to represent optimal domains.
Nanoantennas capable of large fluorescence enhancement with minimal absorption are crucial for future optical technologies from single-photon sources to biosensing. Efficient dielectric nanoantennas ...have been designed, however, evaluating their performance at the individual emitter level is challenging due to the complexity of combining high-resolution nanofabrication, spectroscopy and nanoscale positioning of the emitter. Here, we study the fluorescence enhancement in infinity-shaped gallium phosphide (GaP) nanoantennas based on a topologically optimized design. Using fluorescence correlation spectroscopy (FCS), we probe the nanoantennas enhancement factor and observe an average of 63-fold fluorescence brightness enhancement with a maximum of 93-fold for dye molecules in nanogaps between 20 and 50 nm. The experimentally determined fluorescence enhancement of the nanoantennas is confirmed by numerical simulations of the local density of optical states (LDOS). Furthermore, we show that beyond design optimization of dielectric nanoantennas, increased performances can be achieved via tailoring of nanoantenna fabrication.
A multifunctional stealth technology compatible with infrared and radar is one of the most feasible ways to improve the survival of military equipment under high-temperature conditions. However, it ...is difficult to effectively integrate multiple functions into one material owing to the contradictory stealth mechanisms of infrared and radar. Herein, the near-room-temperature integrated preparation of a hierarchical metastructure with high-temperature resistance, broadband microwave absorption, and infrared stealth is realized by combining topological optimization of metastructure and a papermaking method. The tailored metastructure exhibits an effective bandwidth and absorption peak of 3.1 GHz and −25.9 dB at 1,000°C. The excellent thermal insulation allows the metastructure to achieve infrared stealth, which can reduce the radiation temperature of an object from 1,200°C to 340°C. The new technology paves the way for the design and preparation of a radar-infrared bi-stealth metastructure applied to high temperature.
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•Multidimensional topological optimization design•Preparation of high-temperature-resistant ceramic fiber paper•Radar-infrared multispectrum stealth performance of metastructure•Near-room-temperature integration molding
In the development of aerospace technology, a multifunctional stealth technology compatible with infrared and radar is one of the most feasible ways to improve the survival of military equipment under high-temperature conditions. However, it is difficult to effectively integrate multiple functions into one material owing to the contradictory stealth mechanisms of infrared and radar. Herein, the near-room-temperature integrated preparation of a hierarchical metastructure with high-temperature resistance, broadband microwave absorption, and infrared stealth is realized by combining topological optimization of metastructure and a papermaking method. It integrates an impedance-matching layer, pattern-resistant film, and thermal insulation, which realizes a high-temperature multispectrum stealth control. This study provides new inspiration and insights into the preparation of multifunctional stealth structures.
Infrared- and radar-compatible multifunction stealth technology is one of the most feasible ways to improve the survival of military equipment under high-temperature conditions. A hierarchical metastructure with high-temperature resistance, broadband microwave absorption, and infrared stealth was synthesized by combining topological optimization and a papermaking method at near room temperature. This study provides new enlightenment and insight into the preparation of a multifunctional stealth structure and lays a foundation for the design and preparation of high-temperature radar-infrared dual stealth element structures.
In order to improve the structural performance of the aero-engine gearbox housing and reduce the adverse effects of the engine bad working conditions on the supporting components， the topology ...optimization theory based on variable density method is adopted， and the minimum flexibility index and weighted average transverse eigenvalue are taken as the target number， and the coupling of thermal-elastohydrodynamic-lubrication effects of the supporting components are considered. Taking the maximum deformation less than 0.15 mm and the equivalent stress less than the material stress as the constraint conditions， the topology optimization design of the aero-engine gearbox housing is carried out. According to the topology optimization results， the geometric reconstruction of the housing structure is carried out， and the strength， stiffness and mass of the shell structure before and after optimization are compared and analyzed. The results show that， after optimization， the housing mass is reduced from 5.53 kg to 5.10
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