One primary problem in Shape Optimization of structures is making a robust link between design model (geometric description) and analysis model. This paper investigates the potential of Isogeometric Analysis (IGA) for solving this problem. The generic framework of Shape Optimization of structures is presented based on Isogeometric analysis. By discretization of domain via NURBS functions, the analysis model will precisely demonstrate the geometry of structure. In this study Particle Swarm Optimization (PSO) is used for Isogeometric Shape Optimization. The option of selecting the position and weight of control points as design variables, needless to sensitivity analysis relationships, is the superiority of the proposed method over gradient-based methods. The other advantages of this method are its straightforward implementation and acceptable accuracy. The numerical examples verify the authenticity of this method.

The main aim of the present study is to propose a modified harmony search (MHS) algorithm for size and Shape Optimization of structures. The standard harmony search (HS) algorithm is conceptualized using the musical process of searching for a perfect state of the harmony. It uses a stochastic random search instead of a gradient search. The proposed MHS algorithm is designed based on elitism. In fact the MHS is a multi-staged version of the HS and in each stage a new harmony memory is created using the information of the previous stages. Numerical results reveal that the proposed algorithm is a powerful Optimization technique with improved exploitation characteristics compared with the standard HS.

The most promising method for micro scale energy scavenging is via vibration energy harvesting which convertsmechanical energy to electrical energy. Using piezoelectric cantilevers is the most common method for vibrationenergy harvesting. Changing the Shape of the cantilevers can lead to changing the generated output voltage and power. In this work vibration energy harvesting via piezoelectric resonant unimorph cantilevers is studied and new design forobtaining more efficient piezoelectric energy harvester is suggested. This study provides comprehensive analysis ofthe output voltage relationships and deducing a considerable precise rule of thumb for calculating resonance frequencyin cantilever-type unimorph piezoelectric energy harvesters using Rayleigh method. The analytical formula, is thenanalyzed and verified by FEM simulation in ABAQUS. The analytical data was found to be very close to simulationdata. A key finding is that among all the unimorph trapezoidal V-Shaped cantilever beams with uniform thickness, thetriangular tapered cantilever, can lead to highest resonance frequency and by increasing the ratio of the trapezoidalbases, the resonance frequency decreases. These new findings provide guidelines on system parameters that can bemanipulated for more efficient performance in different ambient source conditions.

In this paper Shape and size Optimization of truss structures subjected to frequency constraints is addressed utilizing a newly developed multi-agent meta-heuristic algorithm called Tug of War Optimization (TWO). The algorithm considers each candidate solution as a team participating in a series of rope pulling competitions. Frequency constraint structural Optimization corresponds to highly non-linear, discontinuous, and non-convex search spaces including several local optima. Such problems call for properly balanced competent Optimization algorithms. Here, viability of TWO is demonstrated using four numerical examples.

This research was conducted to find a reliable technique to Shape an abrupt contraction for minimizing the energy loss. The method may find broader applications in design of variety of transitional cross-sections in hydraulic structures. The streamlines in a 2-D contraction were calculated through solving the potential flow equations in rectangular and curvilinear coordinates. The natural cubic spline equations were applied to approximate the Shape of streamlines. The streamlines close to the solid boundary, usually those that represent 5 and 95 percent of the discharge, were repeatedly mapped onto the solid boundary in a trial and error procedure until a negligible difference between two consecutive Shapes was achieved. This procedure was applied through a code developed in C++, namely Streamlining Program Code or SPC. The initial and final Shapes were used to validate SPC by the help of a robust CFD software, OpenFOAM. In a 2-D contraction with contraction ratio of 5, entrance velocity of 1 m/s and outlet pressure of atmosphere (P=0 pa), the maximum spatial difference between the stream lines found by the code and OpenFOAM was limited to 2.74% that occurred in the entrance of the contraction. Finally, according to the validation, the streamlining technique and the code could successfully applied to Shape Optimization of hydraulic structures.

A high performance numerical technique in the study of aorto-coronaric bypass anastomoses configurations using steady Stokes equations is presented. The problem is first expressed as an optimal control problem. Then, by using an embedding method, the class of admissible Shapes is replaced by a class of positive Borel measures. The Optimization problem in measure space is then approximated by a linear programming problem. The optimal measure representing optimal Shape is approximated by solving this finite-dimensional linear programming problem. An illustrative example demonstrates the effectiveness of the method.

This paper describes a methodology to develop the interface between a finite element software and Optimization algorithm for Optimization of concrete high arch dams. The objective function is the volume of the dam. The numbers of design variables are 31 including the thickness and upstream profile of crown cantilever, left and right abutment thickness, radius of curvature of water and air face left and right by use of polynomial curve fitting and cubic spline function. The constraint conditions are the geometric Shape, stress and the stability against sliding. Initially, a program is developed in MATLAB in order to generate the coordinate of nodes, then finite element software ANSYS is taken for modeling the geometry of dam. Finally, the Optimization technique is performed by Simultaneous Perturbation Stochastic Approximation algorithm. To include dead weight of dam body, stage construction is considered. The proposed method is applied successfully to an arch dam and good results are achieved. The results indicate that the concrete volume of the dam optimized is reduced by an average 21%. Compared with the initial Shape, the time of convergence of this method is very short and the method is fairly effective. It can be applied to practical engineering design.