Layout Optimization Of Structures Research Articles

Multiobjective Structural Layout Optimization of Tall Buildings Subjected to Dynamic Wind Loads

Multiobjective Structural Layout Optimization of Tall Buildings Subjected to Dynamic Wind Loads

Efficient Sizing and Layout Optimization of Truss Benchmark Structures Using ISRES Algorithm

This paper presents a comprehensive investigation into the application of the Improved Stochastic Ranking Evolution Strategy (ISRES) algorithm for the sizing and layout optimization of truss benchmark structures. Truss structures play a crucial role in engineering and architecture, and optimizing their designs can lead to more efficient and cost-effective solutions. The ISRES algorithm, known for its effectiveness in multi-objective optimization, is adapted for the single-objective optimization of truss designs with multiple design constraints. This study encompasses a wide range of truss benchmark structures, including 10-bar, 15-bar, 18-bar, 25-bar, and 72-bar configurations, each subjected to distinct loading conditions and stress constraints. The objective is to minimize the truss weight while ensuring stress and displacement limits are met. Through extensive experimentation, the ISRES algorithm demonstrates its ability to efficiently explore the solution space and converge to optimal solutions for each truss benchmark structure. The algorithm effectively handles the complexity of the problems, which involve numerous design variables, stress constraints, and nodal displacement limits. A comparative analysis is conducted to assess the performance of the ISRES algorithm against other state-of-the-art optimization methods reported in the literature. The comparison evaluates the quality of the solutions and the computational efficiency of each method. Furthermore, the optimized truss designs are subjected to finite element analysis to validate their structural integrity and stability. The verification process confirms that the designs adhere to the imposed constraints, ensuring the safety and reliability of the final truss configurations. The results of this study demonstrate the efficacy of the ISRES algorithm in providing practical and reliable solutions for the sizing and layout optimization of truss benchmark structures. The algorithm’s competitive performance and robustness make it a valuable tool for structural engineers and designers, offering a versatile and powerful approach for complex engineering optimization tasks. Overall, the findings contribute to the advancement of optimization techniques in structural engineering, promoting the development of more efficient and cost-effective truss designs for a wide range of engineering and architectural applications. The study’s insights empower practitioners to make informed decisions in selecting appropriate optimization strategies for complex truss-design scenarios, fostering advancements in structural engineering and sustainable design practices.

Development of a non-uniform cellular automata framework for sizing, topology and layout optimization of truss structures

This article presents a bi-level non-uniform cellular automata (CA) algorithm for the solution of sizing, topology and layout optimization of truss structures. The non-uniform CA was successfully used in a previous study to solve the weight optimization problem of truss structures for topology and sizing (El Bouzouiki, Sedaghati, and Stiharu 2021. Computers & Structures 242: 106394). In this article, an extended version of the non-uniform CA algorithm is proposed, based on the fully stressed design approach and the distribution of strain energy within the structure, to find the optimal position of the cell’s (joint’s) coordinates. The proposed non-uniform CA algorithm can solve the minimum weight optimization problem of truss structures subjected to both stress and displacement constraints. Several benchmark problems are presented to demonstrate the efficiency and accuracy of the proposed methodology.

Layout and cross-sectional size optimization of truss structures with mixed design variables based on gradient method

The object of the study was truss-type rod structures, which were investigated for the purpose of finding the optimal design solution in a mixed (continuous and discrete) space of variables. The parameters of the geometric scheme of the truss, as well as the dimensions of the cross-sections of its elements, were considered as design variables. The stated optimization problem is represented as a nonlinear programming task, in which the objective function and nonlinear constraints of the mathematical model are continuously differentiable functions of the design variables. The system of constraints includes strength and stability inequalities, formulated for the design cross-sections of the rod elements of the structure, which is subject to the effect of the design load combinations of the ultimate limit states. As a part of the system of constraints, the displacement constraints formulated for the specified structural nodes, which is subject to the action of design load combinations of the serviceability limit states, are considered. To solve the stated optimization problem, a method of the objective function gradient on the surface of active constraints was used, with the simultaneous elimination of residuals in the violated restrictions. For design variables, the variation of which must be performed according to a given set of possible discrete values, a discretization procedure for the optimal solution obtained in the continuous space of design variables is proposed. A comparison of the proposed optimization methodology with alternative metaheuristic methods and algorithms reported in the literature was performed. On the considered problem of parametric optimization of a 47-span tower structure, a design solution with a weight of 835,403 kg was obtained, which is 1.53...4.6 % better than the optimal solutions obtained by other authors

Fatigue constrained topology optimization for the jacket support structure of offshore wind turbine under the dynamic load

This paper proposes a topology optimization method considering fatigue constraints for the jacket support structure of offshore wind turbine. Jacket support structure is an important component and supports the whole wind turbine weight under the dynamic environmental loads, which would induce serious fatigue problems. To obtain the optimal structural layout, the topology optimization method considering fatigue constrained is introduced for the jacket support structure under the dynamic load. The fatigue lifetime is constrained base on the Miner's cumulative damage rule. The design sensitivity of the objective and constraint functions are evaluated analytically, while the equivalent static load approach is applied. Some typical topology optimization problems are introduced to verify the effectiveness of the proposed method, and this method can obtain the appropriate layouts with stable convergence. A case study on the OC4 reference jacket indicates that the method can achieve a reasonable layout structure under the dynamic load, which meets the fatigue constraint. And the final design is reconstructed based on the topology optimization layout. Finally, a lighter jacket structure has good performance on the ultimate bearing capacity, eigenfrequency, and buckling, which is suited for long operation life.

Topology optimization considering self‐weight

AbstractIn civil engineering self‐weight loading usually represents the preponderant load case and shall therefore be considered in structural optimization. The present study investigates numerical topology optimization of structural stiffness with a bound on disposable amount of material. A customized topology optimization routine based on Sequential Quadratic Programming was built and is examined by means of known benchmark problems complemented by consideration of self‐weight. This study aims to highlight the relevance of consideration of self‐weight in resource efficient structural design by demonstrating its impact on the optimal structural layout.

Triangular Position Multi-Bolt Layout Structure Optimization

Stress concentration often occurs around bolt holes in load-bearing joint structures of large complex equipment, ships, aerospace and other complex machinery fields, which is an important mechanical factor leading to the failure of joint structures. It is of great engineering significance to study the phenomenon of stress concentration on connected structures for the safety of large and complex equipment; meanwhile, the layout of bolts seriously affects the stress around holes. Many scholars have studied the layout optimization of multi-bolted structures through experiments and simulations, but few algorithms have been applied to the layout optimization of bolted structures. And most of the studied types of multi-bolt structures are symmetrical. Therefore, in this paper, the gray wolf algorithm is used to optimize the layout of nickel steel plate connectors with a bolt layout in triangular position, and the optimal objective function is found based on the hole circumferential stress of the nickel steel plate, maximum shear stress of the bolt and bending stress of the nickel steel plate. Comparing the optimal values obtained by the fruit fly optimization algorithm, particle swarm optimization algorithm, gray wolf optimization algorithm, multiverse optimization algorithm and wind driven optimization algorithm, the accuracy of selecting the gray wolf algorithm for optimization is verified. A multi-bolt connection structure model was established in ABAQUS, and the surface stress before and after optimization was compared to verify the correctness of the gray wolf algorithm applied to the structure layout optimization of the nickel steel flat bolt connection. The results show that under the force of 15 KN, compared with the original bolt structure layout, the optimized upper side nickel steel plate bore peripheral stress is reduced by 73.1 MPa, and the optimization rate is 24%; bolt stress is reduced by 47.7 MPa, and the optimization rate is 12.5%; when the load is less than 18 KN, the optimization effect of both the upper nickel steel plate and bolt group is more than 10%. When the load is greater than 18 KN, the optimization effect is reduced, and when the load is greater than 21 KN, the nickel steel plate has exceeded the yield limit. Due to the existence of fixed constraints, the optimization of the lower nickel steel plate is not obvious. The results of this study can provide data and theoretical support for the layout optimization of the nickel steel flat bolt connection structure, and help to improve reliability analysis and health monitoring in complex assembly fields such as large complex equipment and aerospace.

Numerical Analysis of 3D CSP MEMS Under Thermal Cycle-Impact Coupled Multiphysics Loads

In this paper, reliability analysis of 3D CSP MEMS and IC under thermal cycle-impact coupled multi-physics loads was investigated. COMSOL Multiphysics, a finite element software, was used to analyze our device’s mechanical behavior under a -55°C/125 °C thermal cycling and 1500G@1ms with half-sine pulse impact coupled load. In details, MEMS chip was bonded on a silicon interposer by solder balls and an application specific integrated circuit (ASIC). Thermal stress of single solder joint, whole device, and the simulation of device reliability under different magnitudes and forms of mechanical shock were carried out, respectively. Combining the effects of impact and thermal stress loads, we hope to find out the failure modes of interconnect structures for future design including solder joints and whole device. The stress distribution and deformation of the overall device will be carried out for layout optimization of interconnect structures.

Compound Optimization of Territorial Spatial Structure and Layout at the City Scale from "Production-Living-Ecological" Perspectives.

Land-use optimization, as an important resource-allocation method, can be defined as the process of allocating various activities to different geographic units. How to manage and control land expansion has become an urgent issue, leading a series of problems such as environmental damage and a sharp decrease in cultivated land, leading to unfavorable phenomena such as excessive urban expansion, occupation of cultivated land and important ecological spaces, and overheating of real estate development. Based on the land-use data of Wuhan city in 2020, a coupling MOP (Multi-Objective Programming) and FLUS (Future Land-Use Simulation) model was used to examine the national spatial structure and the optimization of the spatial layout. Our results showed that (1) in terms of quantitative optimal allocation, the ecological space and urban space increased, while the agricultural space greatly decreased under the three development scenarios. (2) In the simulation of spatial layout, the urban space mainly expanded vertically in the north-south direction. In the ecological space scenario, the ecological space occupied part of the cultivated land in the northeast of the city, resulting in a high degree of landscape fragmentation, which is not conducive to large-scale agricultural management. However, under optimal comprehensive benefit, part of the fragmented ecological space in the western part of Wuhan was transformed into an agricultural space. (3) A combination of the MOP and FLUS models could effectively determine land-use structure and address spatial layout optimization problems and can project space in the future urban resource configuration mode. This finding can provide a reference for the optimization of the spatial structure and layout of similar cities.

Planting Structure Adjustment and Layout Optimization of Feed Grain and Food Grain in China Based on Productive Potentials

Increasing feed grain supply, particularly domestic supply, is intended to guarantee feed grain security and, as a result, food security. Based on the Global Agro-Ecological Zones (GAEZ) model, the potential yield and actual yield of feed and food grain in China were estimated. According to the theory of factor endowment, the yield potential development coefficient and the yield efficiency advantage index were then constructed to determine whether the current spatial layout of feed grain is reasonable and how it could be adjusted. The results showed that: (1) There was an imbalance in feed crops production: yield loss in high-potential regions and excessive development in low-potential regions. The imbalances lead to a mismatch between feed production and resource endowment which causes productivity losses and ecological risks. (2) There was considerable potential for increasing the feed grain yield on the Northeast China Plain, the Loess Plateau and in the northern arid and semiarid region. The soybean yield can be increased by about 25%, and the maize yield can be increased by even more. (3) The feed grain should be planted in regions with sufficient potential yield but insufficient actual yield; 26.42% of China’s soybeans and 34.74% of its maize were planted in these regions. (4) Some 16.69% and 15.65% of wheat and rice planting areas could be adjusted to soybeans, respectively; 20.76% and 21.04% of wheat and rice planting areas could be adjusted to maize, respectively. Through agricultural technology research and development, infrastructure support, comprehensive planning design and policy design, the yield potentials of feed grain can be realized. This will redress the imbalance wherein a food grain surplus and a feed grain shortage coexist.

Explicit layout optimization of complex rib-reinforced thin-walled structures via computational conformal mapping (CCM)

Rib-reinforced thin-walled structures are commonly used in various important industrial fields. In this paper, an explicit layout optimization method is developed to design rib-reinforced thin-walled structures with complex geometries. The proposed method includes the following two key steps: (1) parameterizing the complex surfaces with the use of the Computational Conformal Mapping (CCM) technique, and (2) carrying out explicit layout optimization under the Moving Morphable Component (MMC)-based solution framework integrating with the surface cutting operation and the multi-patch stitching scheme on the parametric space. In addition, both the base panel and the reinforced ribs are modeled by 3D shell elements, which have the advantage of providing accurate mechanical analysis results for thin-walled structures with less computational effort. The proposed method can provide clear rib-reinforced layouts of thin-walled structures with complex geometries and the optimized results can be directly imported into CAD/CAE systems without any post-processing. Several representative numerical examples, including a rib-reinforced blunt shell, a rib-reinforced torus-shaped shell, a rib-reinforced flower-shaped shell and a rib-reinforced tee-branch pipe, are presented to validate the effectiveness of the proposed method.

Mean Value-Based Parallel Collaborative Optimization Method for Modular Aircraft Structural Layout

The conventional structural layout optimization method is usually used to solve the layout optimization problem of a single structure, but it is difficult to apply to the layout optimization problem of the modular aircraft structure containing multiple substructures. Therefore, this paper proposes the mean value-based parallel collaborative optimization method (MVPM) for modular aircraft structural layout. This method is a two-stage optimization method based on decomposition. The basic idea of the MVPM is decomposing the layout optimization problem of the modular aircraft structure into a system coordination problem and several independent subsystem optimization problems by introducing coordination variables. The subsystem optimizes each aircraft structure. Under the constraints of the structure itself, the performance of each structure is better, and the shared variables are as close to the coordination variables as possible. The system coordination adjusts the coordination variables according to the optimization results of each subsystem. With constant iteration between the system and subsystems, the shared variables of each subsystem eventually agree with the coordination variables. The numerical test results show that the MVPM has high optimization efficiency and stability.

Spatial Differentiation and Influencing Factors of Water Pollution-Intensive Industries in the Yellow River Basin, China.

The structure adjustment and layout optimization of water pollution-intensive industries (WPIIs) are crucial to the health and sustainable development of the watershed life community. Based on micro-detailed data of Chinese industrial enterprises from 2003 to 2013, we analyzed and revealed the spatial differentiation characteristics and influencing factors of WPIIs in the Yellow River Basin (YRB) from 2003 to 2013 by constructing a water pollution-intensive index and integrating kernel density estimation and geographically weighted regression models from a watershed perspective. The results show that: (1) the scale of WPIIs in the YRB showed a growth trend from 2003 to 2013, and the output value increased from 442.5 billion yuan in 2003 to 6192.4 billion yuan in 2013, an increase of 13 times. (2) WPIIs are generally distributed in an east-west direction, and their spatial distribution is river-side, with intensive distribution in the downstream areas and important tributaries such as Fen River and Wei River. (3) WPIIs are generally clustered in high density downstream, but the spatial clustering characteristics of different industries varied significantly. The chemical industries, paper industries, etc. were mainly concentrated in downstream areas. Processing of food from agricultural products was distributed in the upper, middle and downstream areas. Resource-intensive industries such as coal and oil were concentrated in energy-rich midstream areas. (4) Natural resource endowment was the main factor affecting the distribution of WPIIs in the midstream and upstream areas of the basin, and technological innovation played a significant role in the distribution of downstream industries. The level of economic development and industrial historical foundation promoted the geographical concentration of industries. The scale of wastewater discharge and the proximity of rivers influenced the concentration of industries in the midstream and downstream.

A practical shear wall layout optimization framework for the design of high-rise buildings

In the design of high-rise buildings, the lateral structural system that resists seismic and wind actions often dominates the overall design, and as a result, the optimum design of the lateral structural system is important for material efficiency. This paper aims to present a new design methodology that relies on an extended Evolutionary Structural Optimization (ESO) method to optimize the shear wall layout for the design of high-rise buildings. By discretizing all the shear walls of the ground structure into wall elements, different shear wall layouts were described by a binary matrix where ‘0′ and ‘1′ indicate the absence or presence of a wall element respectively. The proposed framework borrowed the intuitive concept of the ESO method, where the less stressed wall elements in the structure were gradually removed but the highly stressed wall elements were reserved. The conceptual design method was combined with the optimization algorithm to control the optimization process and to reduce structural eccentricity considering architecture, strength and serviceability constraints. Then, the structural weight could be automatically minimized under multiple loading cases and design constraints. By integrating the commercially available ETABS, a dedicated optimization software with an independent interface was developed and details were also presented in this paper for practical software development. The proposed framework was used to optimize the layouts of different shear wall structures, and case studies showed that the proposed framework could optimize shear wall structures with a material saving of up to 14% compared to the conventional design, which proved the feasibility and effectiveness of the framework. The paper can therefore be referenced by other researchers and software engineers to further explore the layout optimization of shear wall structures and to reduce material usage for a more sustainable design.

On a cellular developmental method for layout optimization via the two-point topological derivative

This paper introduces a two-point topological derivative for elasticity and a cellular developmental method for layout optimization of structures. The two-point derivative measures the change on a functional due to the addition of a thin ligament between parts of the domain. It contrasts with the existing single-point topological derivatives that measure the change of a functional due to the subtraction of material. Based on the two-point topological derivative, a cellular developmental method is presented, which builds the layout of a structure in a sequence of cellular divisions and cellular dynamics developmental cycles. The methodology introduced in this work can easily account for member sizes and angle constraints among members of the frame, and the optimization can be performed in the free space or in a bounded domain. Benchmark problems are solved to demonstrate the capability of the cellular developmental method to solve optimization problems in structural mechanics.

Stiffener layout optimization of shell structures with B-spline parameterization method

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.

Sizing and layout optimization of truss structures with artificial bee colony algorithm

In this paper, a swarm intelligence-based optimization technique called Artificial Bee Colony algorithm (ABC) is employed in combined optimization of truss structures. The objective is to optimize the layout and members size of truss structures with displacement, stress and buckling constraints. The ABC is based on simulating the intelligent foraging behavior of honey bees. The nodal coordinates of the joints and the cross-sectional areas of the members for the truss structure system are the design variables of shape and size optimization, respectively. Allowable stress, Euler buckling stress, and displacement are considered as the problem constraints. The efficiency of the ABC is tested in four benchmark structural optimization problems. The results clearly reveal the superiority of ABC over other algorithms in terms of optimized weight, standard deviation and number of structural analyses. The ABC demonstrates a robust performance with a 100% success rate.

Industrial Structure Transformation and Layout Optimization of Beijing-Tianjin-Hebei Region under Carbon Emission Constraints

To address the issue of global warming, there is a trend towards low-carbon economies in world economic development. China’s rapid economic growth and high carbon energy structure contribute to its large carbon emissions. To achieve sustainable development, China must transform its industrial structure to conserve energy, reduce emissions, and adapt to climate change. This study measured the carbon entropy and carbon emission efficiency of 25 industries in the Beijing-Tianjin-Hebei region from 2000 to 2015 by building carbon entropy models and total factor industrial carbon emission efficiency evaluation models. The study showed that: (a) Priority development industries in the Beijing-Tianjin-Hebei region were expanding, the regional competitiveness of the moderate development industry was improving, and the proportion of restricted development industries had dropped significantly; (b) the spatial distribution of the three types of industries presented a pattern of concentric rings, with priority industries at the core, surrounded by moderate, then by restricted development industries; (c) the status of medium- and high-efficiency industries had improved, while the status of low-efficiency industries had decreased. Spatially, high- and low-efficiency industries were becoming concentrated, and medium-efficiency industries were becoming dispersed; (d) considering carbon entropy and carbon emission efficiency, the path of industrial structure transformation and upgrading and layout optimization in Beijing-Tianjin-Hebei region was proposed.

Принципы и современные методы оптимального проектирования крупногабаритных судовых перекрытий

Based on the previously developed approach to structural ship design, the authors optimize a large-span deck grillage taking into account several design loading scenarios. Topological optimization made it possible to find an optimal structural layout of the grillage, and parametric optimization yielded the scantlings of beams and simultaneously reduced grillage weight. Additional gain in structural weight was achieved by means of the openings in beam webs.

Size, Layout, and Topology Optimization of Skeletal Structures Using Plasma Generation Optimization

In this paper, plasma generation optimization (PGO) as a newly developed physics-based metaheuristic algorithm is applied to perform the size, layout, and topology optimization problems of skeletal structures. PGO is a population-based optimizer inspired by the process of plasma generation. In this optimization method, each agent is modeled as an electron. The movement of electrons and changing their energy level are performed based on simulating the process of excitation, de-excitation, and ionization. These processes occur iteratively through the plasma generation. Evaluating the robustness and performance of the PGO is illustrated through six design examples for different types of structural optimization. The results reveal that the PGO algorithm outperforms other state-of-the-art optimization techniques considered from the literature.