scholarly journals Phononic Bandgap Optimization in Sandwich Panels Using Cellular Truss Cores

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5236
Author(s):  
Leonel Quinteros ◽  
Viviana Meruane ◽  
Eduardo Lenz Cardoso ◽  
Rafael O. Ruiz
Keyword(s):  
Sandwich Panels ◽  
Topological Optimization ◽  
Cellular Structures ◽  
Optimization Approach ◽  
Geometrical Properties ◽  
Vibration Absorption ◽  
Mechanical Waves ◽  
Potential Applications ◽  
Convergent Method ◽  
Optimization Methodology

The development of custom cellular materials has been driven by recent advances in additive manufacturing and structural topological optimization. These contemporary materials with complex topologies have better structural efficiency than traditional materials. Particularly, truss-like cellular structures exhibit considerable potential for application in lightweight structures owing to their excellent strength-to-mass ratio. Along with being light, these materials can exhibit unprecedented vibration properties, such as the phononic bandgap, which prohibits the propagation of mechanical waves over certain frequency ranges. Consequently, they have been extensively investigated over the last few years, being the cores for sandwich panels among the most important potential applications of lattice-based cellular structures. This study aims to develop a methodology for optimizing the topology of sandwich panels using cellular truss cores for bandgap maximization. In particular, a methodology is developed for designing lightweight composite panels with vibration absorption properties, which would bring significant benefits in applications such as satellites, spacecraft, aircraft, ships, automobiles, etc. The phononic bandgap of a periodic sandwich structure with a square core topology is maximized by varying the material and the geometrical properties of the core under different configurations. The proposed optimization methodology considers smooth approximations of the objective function to avoid non-differentiability problems and implements an optimization approach based on the globally convergent method of moving asymptotes. The results show that it is feasible to design a sandwich panel using a cellular core with large phononic bandgaps.

scholarly journals Development and Testing of Woven FRP Flexure Hinges for Pressure-Actuated Cellular Structures with Regard to Morphing Wing Applications

Aerospace ◽  
2019 ◽  
Vol 6 (11) ◽  
pp. 116
Author(s):  
Patrick Meyer ◽  
Johannes Boblenz ◽  
Cornelia Sennewald ◽  
Michael Vorhof ◽  
Christian Hühne ◽  
...  
Keyword(s):  
Operating Conditions ◽  
Cellular Structures ◽  
High Lift ◽  
Reinforced Plastics ◽  
Flexure Hinges ◽  
Key Factor ◽  
Potential Applications ◽  
Fiber Reinforced Plastics ◽  
The One ◽  
External Forces

Shape-variable structures can change their geometry in a targeted way and thus adapt their outer shape to different operating conditions. The potential applications in aviation are manifold and far-reaching. The substitution of conventional flaps in high-lift systems or even the deformation of entire wing profiles is conceivable. All morphing approaches have to deal with the same challenge: A conflict between minimizing actuating forces on the one hand, and maximizing structural deflections and resistance to external forces on the other. A promising concept of shape variability to face this challenging conflict is found in biology. Pressure-actuated cellular structures (PACS) are based on the movement of nastic plants. Firstly, a brief review of the holistic design approach of PACS is presented. The aim of the following study is to investigate manufacturing possibilities for woven flexure hinges in closed cellular structures. Weaving trials are first performed on the material level and finally on a five-cell PACS cantilever. The overall feasibility of woven fiber reinforced plastics (FRP)-PACS is proven. However, the results show that the materials selection in the weaving process substantially influences the mechanical behavior of flexure hinges. Thus, the optimization of manufacturing parameters is a key factor for the realization of woven FRP-PACS.

WINDOPT: An Optimization Tool for Floating Support Structures for Deep Water Wind Turbines

2011 ◽  
Author(s):  
Ivar Fylling ◽  
Petter Andreas Berthelsen
Keyword(s):  
Optimization Problems ◽  
Integrated Design ◽  
Design Tool ◽  
Mooring Line ◽  
Curvature Radius ◽  
Optimization Approach ◽  
Mooring System ◽  
Simple Relationship ◽  
Line Load ◽  
Geometrical Properties

An integrated design tool for optimization of a floating wind turbine support structure of the spar buoy type, including mooring system and power takeoff cable, is described in this paper. The program utilizes efficient design tools for analysis of mooring system forces and vessel motions, and combines this with a gradient method for solution of non-linear optimization problems with arbitrary constraints. The objective function to be minimized is the spar buoy cost, and the mooring line and cable costs. Typical design requirements that may be included as constraints are: mooring line load limitations and minimum fatigue life, cable curvature radius, cable tension, tower top acceleration, and vessel motion and inclination. The spar buoy is modelled as composed of a set of cylindrical sections with different mass, buoyancy and cost properties, where each section is assumed to have a uniform mass distribution. It is assumed that a representative initial cost figure is available, and that it can be scaled in proportion with material mass. A simple relationship between mass and geometrical properties is proposed for both massive and thin walled tubular sections. Examples are included to demonstrate the various aspects of the optimization approach, including different parameterizations of the spar buoy.

scholarly journals Benefits of 3D printing technologies for aerospace lattice structures

2021 ◽  
Vol XXIV (1) ◽  
pp. 8-16
Author(s):  
VOICU Andrei - Daniel
Keyword(s):  
3D Printing ◽  
Cell Structure ◽  
Weight Ratio ◽  
High Strength ◽  
Cellular Structures ◽  
Lattice Structures ◽  
Mass Reduction ◽  
Aerospace Sector ◽  
Potential Applications ◽  
Remote Operations

The article makes a brief presentation of the latest 3D printing methods that are used for manufacturing aerospace lattice structures. Most 3D printing technologies are not fully deployed on the industrial scale of aerospace sector, but are rather used for rapid prototyping of components. One of the main potential applications is for them to offer a rapid solution for remote operations, where it is difficult to supply parts. Additive manufactured lattice structures are cellular structures based on biomimicry (inspired from nature lattice structures such as bones, metal crystallography, etc.), that possess many superior properties compared to solid materials and are ideal for fabricating aerospace structures mainly due to the mass reduction they introduce and the high strength-to-weight ratio. Their mechanical properties are defined by the infill percentage, the geometry of the cell structure and the material used in the manufacturing process.

scholarly journals Optimization of a ducted fan propulsion system for a single engine aircraft

2021 ◽  
Author(s):  
Adam Jasudavisius
Keyword(s):  
Line Search ◽  
Design Space ◽  
Propulsion System ◽  
Optimization Approach ◽  
Control Points ◽  
Ducted Fan ◽  
Optimization Methodology ◽  
High Degree ◽  
Cruise Flight ◽  
Initial Geometry

The objective of this study was to perform a 3D aerodynamic shape optimization on a ducted fan propulsion system configured for cruise flight on an aircraft. The initial shapes of the duct and hub were determined using a basic grid searching optimization approach. An efficient optimization algorithm was created that utilized the BFGS searching technique with a QuasiNewton line search to refine the initial geometry. The ducted fan was chosen to be controlled by 13 control points connected using a combination of splines, ellipses and conics. The optimum design resulted in a 33.54% and 36.45% reduction in drag for the duct and hub respectively. The propeller thrust was also increased by 141.49%. The optimization methodology used throughout this study proved to be an efficient technique in finding the optimal design to within a high degree of resolution based on the entire design space considered.

Multi-Disciplinary Conceptual Modeling and Optimization With Uncertainty Effects Consideration

2006 ◽  
Author(s):  
Nan Liu ◽  
Souran Manoochehri ◽  
Chan Yu
Keyword(s):  
Design Optimization ◽  
Conceptual Modeling ◽  
Design System ◽  
Optimization Approach ◽  
Performance Achievement ◽  
Uncertainty Factors ◽  
Target Values ◽  
Optimization Formulation ◽  
Optimization Methodology ◽  
And Performance

A multi-disciplinary modeling and design optimization formulation for uncertainty effects consideration is presented in this paper. The optimization approach considers minimization of uncertainty factors related to the overall system performance while satisfying target requirements specified in the form of constraints. The design problem is decomposed into two analysis systems; performance design and uncertainty effects analysis. Each design system can be partitioned into several subsystems according to the different functions they perform. Performance evaluation is considered by minimizing the variations between specified expected values of performance functions and their target values. Uncertainty effects analysis is defined by minimizing the ratio of the maximum variations caused by uncertainty factors over the expected function values. The entire problem has been treated as a multi-disciplinary design optimization (MDO) for maximum robustness and performance achievement. An electromechanical system is used as an example to demonstrate this optimization methodology.

scholarly journals Enforcing a Force–Displacement Curve of a Nonlinear Structure Using Topology Optimization with Slope Constraints

2020 ◽  
Vol 10 (8) ◽  
pp. 2676 ◽  
Author(s):  
Jongsuh Lee ◽  
Thibaut Detroux ◽  
Gaëtan Kerschen
Keyword(s):  
Topology Optimization ◽  
Structural Features ◽  
Optimization Process ◽  
Displacement Curve ◽  
Optimization Approach ◽  
Nonlinear Structure ◽  
The Difference ◽  
Optimization Methodology ◽  
Force Displacement ◽  
Slope Constraints

The objective of this study is to develop an optimization methodology to find a layout that traces a prescribed force–displacement curve through a topology optimization approach. To this end, we propose an objective function to minimize the difference between a prescribed force–displacement curve and the curve calculated at each iteration of the optimization process. Slope constraints are introduced to solve issues encountered when using a small number of target points. In addition, a projection filter is employed to suppress the gray region observed between the solid and void regions, which generally occurs when using a density-based filter. A recently proposed energy interpolation scheme is implemented to stabilize the instability in the nonlinear analysis, which generally results from excessive distortion in the void region when the structure is modeled on a fixed mesh in the topology optimization process. To validate the outlined methodology, several case studies with different types of nonlinearity and structural features of the obtained layouts are investigated.

scholarly journals A Three-Dimensional and Bi-objective Topological Optimization Approach Based on Piezoelectric Energy Harvester

2020 ◽  
Vol 10 (19) ◽  
pp. 6772 ◽  
Author(s):  
Yizhi Liu ◽  
Ziyu Huang ◽  
Yufei Gao
Keyword(s):  
Piezoelectric Transducer ◽  
Energy Harvester ◽  
Piezoelectric Materials ◽  
Three Dimensional ◽  
Iteration Process ◽  
Optimality Criteria ◽  
Topological Optimization ◽  
Optimization Approach ◽  
Piezoelectric Energy ◽  
First Time

Topological optimization can realize the optimization of the mass distribution in the whole objective domain. Compared with morphology and size optimization, it has a higher degree of freedom. In this work, the three-dimensional topological optimization based on piezoelectric materials was discussed. Using the Optimality Criteria, topology optimization was applied to the cantilever piezoelectric transducer. The structure optimization was realized with the voltage and stiffness as the multi-objective function. The corresponding codes are given to show the process of optimization. With 70% of the origin volume, the bi-objective optimization increases the global stiffness by 50.9% and the voltage by 30%. As the iteration process shows, the results of bi-objective optimization prove the value of additive mass at the bottom of the cantilever. This lays the foundation for future piezoelectric transducer structural optimization. Using only stiffness as the objective, the final objective increases inconspicuously. Bi-objective optimization shows its superiority. There are quite a few papers that research the combination of stiffness and voltage, and research which studies three-dimensionality is a point of innovation. Furthermore, this is also the first time a piezoelectric topology code has been shared.

System Hierarchy Optimization Method for MEMS Applications

2005 ◽  
Author(s):  
Nan Liu ◽  
Souran Manoochehri
Keyword(s):  
Design Optimization ◽  
Design Problem ◽  
Optimization Method ◽  
Optimization Approach ◽  
Micro Electro Mechanical Systems ◽  
Performance Achievement ◽  
Optimization Methodology ◽  
And Performance ◽  
Analysis System ◽  
Micro Accelerometer

A new design optimization methodology for Micro-Electro-Mechanical Systems (MEMS) application is presented. The optimization approach considers minimization of several uncertainty factors on the overall system performance while satisfying target requirements specified in the form of constraints on micro-fabrication processes and materials system. The design process is modeled as a multi-level hierarchical optimal design problem. The design problem is decomposed into two analysis systems; uncertainty effects analysis and performance sensitivity analysis. Each analysis system can be partitioned into several subsystems according to the different functions they perform. The entire problem has been treated as a multi-disciplinary design optimization (MDO) for maximum robustness and performance achievement. In this study, the analysis results are provided as optimized device geometry parameters for the example of the selected micro accelerometer device.

Application of Optimization Methodology on Vehicular Crash Reconstruction

2009 ◽  
Author(s):  
Fengjiao Guan ◽  
Aditya Belwadi ◽  
Xu Han ◽  
King H. Yang
Keyword(s):  
Quadratic Programming ◽  
Sequential Quadratic Programming ◽  
Fe Simulation ◽  
Principal Direction ◽  
Accurate Determination ◽  
Kriging Model ◽  
Optimization Approach ◽  
Fe Model ◽  
Assessment Index ◽  
Optimization Methodology

In vehicular crash reconstruction, software packages such as PC-Crash, SMAC (Simulation Model of Automobile Collisions), WinSmash and HVE (Human Vehicle Environment) use physical evidences such as tire marks along with measurements of the deformed vehicles and photographs of the accident scene to determine the crash energy, impact velocity, and Principal Direction Of Force (PDOF). However, accurate determination of these parameters requires more sophisticated numerical methods, such as Finite Element (FE) modeling. At present, multiple runs of FE models need to be performed on a trial-and-error basis before the model predicted results are consistent with the actual ones. An optimization method to quickly and accurately determine key sensitive parameters in vehicular accident reconstruction is desired. We propose the use of Kriging model and sequential quadratic programming in conjunction with Latin Hypercube Sampling (LHS) to minimize the time needed for reconstruction and minimize the disparity between the actual and FE model predicted vehicular deformations. A selected number of modeling parameters, namely the velocity of impact, PDOF and initial impact position, are varied using this optimization approach until the deformation of six points measured on the impacted vehicle closely matches those measured in real world case. The optimization is performed in two stages. In the first stage, an approximated model was created by simplifying detailed FE models of the vehicles involved to reduce the simulation time without sacrificing accuracy. In the second stage, an assessment index ‘E’, the objective function, is maximized. To improve computational efficiency, the Kriging model is employed. The sampling points are distributed uniformly over the entire design space using the LHS. For evaluating the approximated model’s performance, the regression parameter is used as the error indicator. The objective functions based on approximated models are optimized using a sequential quadratic programming which has a higher efficiency and better convergence. Results show that through the application of this method, the deformations of the key points are in accord to the measured deformation within a small window of variability. The average difference between the deformation measured from the actual crash and that calculated from FE simulation using the optimum parameters as inputs is around 31 mm. The difference in the assessment index calculated from FE simulation with optimal assessment parameters and that from the Kriging model is only 1%. The proposed optimization methodology is a good tool to promptly reveal key parameters in a crash while simultaneously providing scientific basis for crash reconstruction.

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