•New Movement Strategy of Cuckoo Search (NMS-CS) for solving optimization problems.•3 proposed functions are used to establish new strategy movement of Cuckoo birds.•Large scale function (CEC2005) ...and engineering design problems are verified.•The NMS-CS algorithm has proven highly reliable in solving optimization problems.•NMS-CS is considered to be a more complete version than original CS algorithm.
In this paper, a Cuckoo search algorithm, namely the New Movement Strategy of Cuckoo Search (NMS-CS), is proposed. The novelty is in a random walk with step lengths calculated by Lévy distribution. The step lengths in the original Cuckoo search (CS) are significant terms in simulating the Cuckoo bird's movement and are registered as a scalar vector. In NMS-CS, step lengths are modified from the scalar vector to the scalar number called orientation parameter. This parameter is controlled by using a function established from the random selection of one of three proposed novel functions. These functions have diverse characteristics such as; convex, concave, and linear, to establish a new strategy movement of Cuckoo birds in NMS-CS. As a result, the movement of NMS-CS is more flexible than a random walk in the original CS. By using the proposed functions, NMS-CS achieves the distance of movement long enough at the first iterations and short enough at the last iterations. It leads to the proposed algorithm achieving a better convergence rate and accuracy level in comparison with CS. The first 23 classical benchmark functions are selected to illustrate the convergence rate and level of accuracy of NMS-CS in detail compared with the original CS. Then, the other Algorithms such as Particle Swarm Optimization (PSO), Gravitational Search Algorithm (GSA), and Grey Wolf Optimizer (GWO) are employed to compare with NMS-CS in a ranking of the best accuracy. In the end, three engineering design problems (tension/compression spring design, pressure vessel design and welded beam design) are employed to demonstrate the effect of NMS-CS for solving various real-world problems. The statistical results show the potential performance of NMS-CS in a widespread class of optimization problems and its excellent application for optimization problems having many constraints.
Source codes of NMS-CS is publicly available at http://goldensolutionrs.com/codes.html.
A simple, yet powerful, new technique based on Artificial Neural Network (ANN) combined with Particle Swarm Optimization (PSO) for damage quantification in laminated composite plates using Cornwell ...indicator (CI) is proposed. The analysis is performed in two stages. In the first stage, IsoGeometric Analysis (IGA) is formulated for square laminated composite plates having three layers0°/90°/0°. In the second stage, IGA model is coupled with PSO for damage quantification using an inverse problem approach and CI as an objective function to minimize the difference between calculated and measured values. This paper aims to assess the application of ANN-PSO for damage quantification in composite structures in order to achieve efficient computational time. IGA is used as modelling technique, CI is used as input data, whereas damage locations and severities are used as output data. The result indicates that high accuracy of damage quantification is achieved using ANN-PSO-IGA-CI. Furthermore, it is demonstrated that huge saving in computational time is achieved when using ANN-PSO-IGA-CI compared with PSO-IGA-CI.
In this article, we present for the first time a research analysis for the size-dependent effects on thermal buckling and post-buckling behaviors of functionally graded material micro-plates with ...porosities (imperfect FGM) using isogeometric analysis. A seventh-order shear deformation plate theory associated with the modified couple stress theory (MCST) is particularly imposed to capture the size-dependent phenomenon within imperfect FGM micro-plates. The material properties of imperfect FGM micro-plates with three different distributions of porosities including even, uneven and logarithmic-uneven varying across the plate thickness are derived from the modified rule-of-mixture assumption. The nonlinear governing equation for size-dependent imperfect FGM micro-plate under uniform, linear and nonlinear temperature rise is derived using the Von-Kármán assumption and Hamilton’s principle. Through numerical example, the effect of temperature rise, boundary conditions, power index, porosity volume fraction, porosity distribution pattern and material length scale parameter on thermal buckling and post-buckling behaviors of FGP micro-plates are investigated.
This paper presents size-dependency effects on nonlinear transient dynamic response of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) nanoplates under a transverse uniform load ...in thermal environments. To consider the length scale and size-dependency effect of nanostructures, a nonlocal continuum theory of Eringen is adopted. The nonlocal governing equations for nanoplate theory are derived from the Hamilton’s principle and approximated by using isogeometric analysis associated with the higher-order shear deformation theory. A numerical model based on the von Kármán strains and Newmark time integration scheme is employed to solve geometrically nonlinear transient problems. The material properties of the FG-CNTRC nanoplate are assumed to be graded and temperature-dependent in the thickness direction, which are expressed through a micromechanical model. Effects of nonlocal parameter, carbon nanotube volume fraction, length-to-thickness ratio, distributions of carbon nanotubes and temperatures through thickness are investigated in detail. Several numerical results show the reliability of the present method.
The use of modified couple stress theory to simulate the size-dependent phenomenon of composite laminate microplate is commonly limited to simple boundary conditions and mechanical bending load. The ...small-scale effects on bending and buckling on composite laminate microplate under complex boundary conditions in thermal environment have not been understood fully in the literature. Hence, this research develops, for the first time, a model to overcome the above limitation through the combination of a new modified couple stress theory and isogeometric analysis (IGA). By solving the governing equation using IGA, the thermal displacement, stress and thermal buckling load for various material length scale parameters are obtained. To satisfy the continuous shear stress condition at the layer interfaces, the equilibrium equations as integrated in-plane stress derivatives over the thickness are imposed. In addition, the non-uniform rational B-splines (NURBS) satisfy the higher-order derivative of shape function using the equilibrium equation. Furthermore, to show the effectiveness of presented model for capturing the size effect on thermal bending and thermal buckling of multi-ply laminate microplate, the influences of fiber orientation, thickness ratio, boundary condition and the variation in material length scale parameter are investigated.
In this study, a meta-heuristic algorithm, named The Planet Optimization Algorithm (POA), inspired by Newton's gravitational law is proposed. POA simulates the motion of planets in the solar system. ...The Sun plays the key role in the algorithm as at the heart of search space. Two main phases, local and global search, are adopted for increasing accuracy and expanding searching space simultaneously. A Gauss distribution function is employed as a technique to enhance the accuracy of this algorithm. POA is evaluated using 23 well-known test functions, 38 IEEE CEC benchmark test functions (CEC 2017, CEC 2019) and three real engineering problems. The statistical results of the benchmark functions show that POA can provide very competitive and promising results. Not only does POA require a relatively short computational time for solving problems, but also it shows superior accuracy in terms of exploiting the optimum.
In this paper, we present for the first time a size-dependent model based on the modified couple stress theory (MCST) and isogeometric analysis (IGA) for the static and free vibration behaviors of ...functionally graded carbon nanotube reinforced composite (FG-CNTRC) nanoplates. By using higher order shear deformation theory for displacement fields, the shear correction factor is omitted when determining the stiffness matrix. Based on the rule of mixture, the effective Young’s and shear moduli of carbon nanotube (CNT) are established. For verifying the accuracy and trustworthiness of the proposed method, the present results are compared with those of analytical solutions, and excellent agreement is obtained. The proposed model can capture the small scale effect for FG-CNTRC nanoplates. The effect of length scale on stresses and natural frequencies of FG-CNTRC nanoplates is discussed in details.
The static bending behavior of porous functionally graded (PFG) micro-plate under the geometrically nonlinear analysis is studied in this article. A small-scale nonlinear solution is established ...using the Von-Kármán hypothesis and the modified couple stress theory (MCST). To obtain the deflection of the plate, the Reddy higher-order plate theory coupled with isogeometric analysis (IGA) is utilized. The distribution of porosities is assumed to be even and uneven across the plate’s thickness and the effective material properties of porous functionally graded micro-plate are calculated using the refined rule-of-mixture hypothesis. The influence of power index, porosity parameter and material length scale parameter on the nonlinear behaviors of static bending of porous FGM micro-plates are also investigated using several numerical examples.
This paper presents the application of a new Shrimp and Goby Association Search algorithm (SGA) to solve large-scale global optimization problems. The performance of SGA is assessed using 13 ...benchmark high-dimensional functions, 10 classical benchmark functions, and several real-world engineering applications. For the first time, an efficient optimization approach for structural health monitoring (SHM) in truss-like structures is presented. The proposed approach is applied for damage identification of complex structures. A real structure, namely Canton Tower in Guangzhou, China, is served as an example for damage detection. Interestingly, this tower was the tallest structure in the world in 2009 with a height of 610 m. The great merit of this example is that it provides a real complex structure with a high-dimensional problem to assess the performance of SGA in the real world. The results show that SGA can deal with this problem effectively, at the same time, it operates better to escape from local optima with faster convergence rate than population-based algorithms.
In this article, a refined modified couple stress theory based on isogeomeric analysis to capture the small-scale effect on laminated composite micro-plates is developed for the first time. Based on ...Hamilton's principle, the weak form for composite plate is established by using the Reddy's third order shear deformation theory without shear correction factor and the refined modified couple stress theory. Unlike the modified couple stress theory, which contains only one material length scale parameter, the proposed theory contains three material length scale parameters. To confirm the accuracy of the proposed method, several examples are presented, discussed and compared to references' solutions. In addition, cut-out complicated shapes are analyzed to show the influences of the small-scale effect on free vibration behaviors of laminated micro-plates. An increase in the material length scale parameter leads to decrease in the deflection, stresses and increase in frequencies and critical buckling load factor. The presented numerical results show the great efficiency of the NURBS-based isogeometric analysis for capturing the small-scale effect of the composite laminated micro-plates.
•Small-scale effect on laminated composite micro-plates.•A refined modified couple stress theory based on isogeomeric analysis.•The proposed theory contain three material length scale parameters.•Effect of material length scale parameter on mechanical behaviour of composite micro-plates.
PDF
