scholarly journals Topology optimized thermoelectric generator: a parametric study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
John Mativo ◽  
Kevin Hallinan ◽  
Uduak George ◽  
Greg Reich ◽  
Robin Steininger
Keyword(s):  
Topology Optimization ◽  
Thermoelectric Generator ◽  
Volume Fraction ◽  
Power Conversion ◽  
Power Production ◽  
Power Reduction ◽  
Void Volume Fraction ◽  
Thermoelectric Generators ◽  
Maximal Power ◽  
Design Yield

Abstract Typical thermoelectric generator legs are brittle which limits their application in vibratory and shear environments. Research is conducted to develop compliant thermoelectric generators (TEGs) capable of converting thermal loads to power, while also supporting shear and vibratory loads. Mathematical structural, thermal, and power conversion models are developed. Topology optimization is employed to tailor the TEG design yield maximal power production while sustaining the applied shear and vibratory loads. As a specific example, results are presented for optimized TEG legs with a void volume fraction of 0.2 that achieve compliance shear displacement of 0.0636 (from a range of 0.0504 to 0.6079). In order to achieve the necessary compliance to support the load, the power reduction is reduced by 20% relative to similarly sized void free TEG legs.

scholarly journals A Sequential Approach for Aerodynamic Shape Optimization with Topology Optimization of Airfoils

2021 ◽  
Vol 26 (2) ◽  
pp. 34
Author(s):  
Isaac Gibert Martínez ◽  
Frederico Afonso ◽  
Simão Rodrigues ◽  
Fernando Lau
Keyword(s):  
Topology Optimization ◽  
Shape Optimization ◽  
Volume Fraction ◽  
Optimization Techniques ◽  
Free Form ◽  
Aerodynamic Shape Optimization ◽  
Sequential Approach ◽  
Airfoil Surface ◽  
Aerodynamic Shape ◽  
Design Variables

The objective of this work is to study the coupling of two efficient optimization techniques, Aerodynamic Shape Optimization (ASO) and Topology Optimization (TO), in 2D airfoils. To achieve such goal two open-source codes, SU2 and Calculix, are employed for ASO and TO, respectively, using the Sequential Least SQuares Programming (SLSQP) and the Bi-directional Evolutionary Structural Optimization (BESO) algorithms; the latter is well-known for allowing the addition of material in the TO which constitutes, as far as our knowledge, a novelty for this kind of application. These codes are linked by means of a script capable of reading the geometry and pressure distribution obtained from the ASO and defining the boundary conditions to be applied in the TO. The Free-Form Deformation technique is chosen for the definition of the design variables to be used in the ASO, while the densities of the inner elements are defined as design variables of the TO. As a test case, a widely used benchmark transonic airfoil, the RAE2822, is chosen here with an internal geometric constraint to simulate the wing-box of a transonic wing. First, the two optimization procedures are tested separately to gain insight and then are run in a sequential way for two test cases with available experimental data: (i) Mach 0.729 at α=2.31°; and (ii) Mach 0.730 at α=2.79°. In the ASO problem, the lift is fixed and the drag is minimized; while in the TO problem, compliance minimization is set as the objective for a prescribed volume fraction. Improvements in both aerodynamic and structural performance are found, as expected: the ASO reduced the total pressure on the airfoil surface in order to minimize drag, which resulted in lower stress values experienced by the structure.

scholarly journals Forming Limit Stress Diagram Prediction of Pure Titanium Sheet Based on GTN Model

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1783 ◽  
Author(s):  
Tao Huang ◽  
Mei Zhan ◽  
Kun Wang ◽  
Fuxiao Chen ◽  
Junqing Guo ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Pure Titanium ◽  
Void Volume Fraction ◽  
Void Volume ◽  
Forming Limit ◽  
Stress And Strain ◽  
Gtn Model ◽  
Stress Diagram ◽  
Limit Stress ◽  
Hemispherical Punch

In this paper, the initial values of damage parameters in the Gurson–Tvergaard–Needleman (GTN) model are determined by a microscopic test combined with empirical formulas, and the final accurate values are determined by finite element reverse calibration. The original void volume fraction (f0), the volume fraction of potential nucleated voids (fN), the critical void volume fraction (fc), the void volume fraction at the final failure (fF) of material are assigned as 0.006, 0.001, 0.03, 0.06 according to the simulation results, respectively. The hemispherical punch stretching test of commercially pure titanium (TA1) sheet is simulated by a plastic constitutive formula derived from the GTN model. The stress and strain are obtained at the last loading step before crack. The forming limit diagram (FLD) and the forming limit stress diagram (FLSD) of the TA1 sheet under plastic forming conditions are plotted, which are in good agreement with the FLD obtained by the hemispherical punch stretching test and the FLSD obtained by the conversion between stress and strain during the sheet forming process. The results show that the GTN model determined by the finite element reverse calibration method can be used to predict the forming limit of the TA1 sheet metal.

Topology Optimization of Blank Geometry for the Sheet Forming Process

2012 ◽  
Author(s):  
Saber DorMohammadi ◽  
Mohammad Rouhi ◽  
Masoud Rais-Rohani
Keyword(s):  
Topology Optimization ◽  
Volume Fraction ◽  
Structural Response ◽  
Sheet Forming ◽  
Forming Process ◽  
Exchange Method ◽  
Forming Simulation ◽  
Blank Shape Optimization ◽  
Blank Shape ◽  
Consistent Subset

The newly developed element exchange method (EEM) for topology optimization is applied to the problem of blank shape optimization for the sheet-forming process. EEM uses a series of stochastic operations guided by the structural response of the model to switch solid and void elements in a given domain to minimize the objective function while maintaining the specified volume fraction. In application of EEM to blank optimization, a sheet forming simulation model is developed using Abaqus/Explicit. With the goal of minimizing the variability in wall thickness of the formed component, a subset of solid (i.e., high density) elements with the highest increase in thickness is exchanged with a consistent subset of void (i.e., low density) elements having the highest decrease in thickness so that the volume fraction remains constant. The EEM operations coupled with finite element simulations are repeated until the optimum blank geometry (i.e., boundary and initial thickness) is found. The developed numerical framework is applied to blank optimization of a benchmark problem. The results show that EEM is successful in generating the optimum blank geometry efficiently and accurately.

Age- and Activity-Related Differences in the Mechanisms Underlying Maximal Power Production in Young and Older Adults

2014 ◽  
Vol 30 (1) ◽  
pp. 12-20 ◽  
Author(s):  
Thomas Korff ◽  
Ann H. Newstead ◽  
Renate van Zandwijk ◽  
Jody L. Jensen
Keyword(s):  
Older Adults ◽  
Knee Flexion ◽  
Power Production ◽  
Activity Level ◽  
Maximum Power ◽  
Maximal Power ◽  
Joint Power ◽  
Age Related ◽  
Peak Knee ◽  
Active Adults

The purpose of this study was to examine the interactions between aging, activity levels and maximal power production during cycling. Participants were divided into younger adults (YA), older active adults (OA,) and older sedentary adults (OS). Absolute maximum power was significantly greater in YA compared with OS and OA; no differences were found between OA and OS. The age-related difference in maximum power was accompanied by greater absolute peak knee extension and knee flexion powers. Relative joint power contributions revealed both age- and activity-related differences. YA produced less relative hip extension power than older adults, regardless of activity level. The OS participants produced less relative knee flexion power than active adults, regardless of age. The results show the age-related decline in muscular power production is joint specific and that activity level can be a modifier of intersegmental coordination, which has implications for designing interventions for the aging population.

scholarly journals Numerical Study of Hydrodynamic Impact on Bubbly Water

2015 ◽  
Author(s):  
Mehdi Elhimer ◽  
Aboulghit El Malki Alaoui ◽  
Kilian Croci ◽  
Céline Gabillet ◽  
Nicolas Jacques
Keyword(s):  
Volume Fraction ◽  
Numerical Study ◽  
Numerical Data ◽  
Void Volume Fraction ◽  
Bubbly Liquid ◽  
Impact Loads ◽  
Hydrodynamic Impact ◽  
Physical Mechanisms ◽  
The Impact ◽  
The Relationship

The phenomenon of slamming on a bubbly liquid has many occurrences in marine and costal engineering. However, experimental or numerical data on the effect of the presence of gas bubbles within the liquid on the impact loads are scarce and the related physical mechanisms are poorly understood. The aim of the present paper is to study numerically the relationship between the void volume fraction and the impact loads. For that purpose, numerical simulations of the impact of a cone on bubbly water have been performed using the finite element code ABAQUS/Explicit. The present results show the diminution of the impact loads with the increase of the void fraction. This effect appears to be related to the high compressibility of the liquid-gas mixture.

Factors in maximal power production and in exercise endurance relative to maximal power

1990 ◽  
Vol 60 (3) ◽  
pp. 222-227 ◽  
Author(s):  
J. F. Patton ◽  
W. J. Kraemer ◽  
H. G. Knuttgen ◽  
E. A. Harman
Keyword(s):  
Power Production ◽  
Maximal Power ◽  
Exercise Endurance

Experimental Study of Thermoelectric Generators

2014 ◽  
Vol 663 ◽  
pp. 299-303 ◽  
Author(s):  
Ubaidillah ◽  
Suyitno ◽  
Imam Ali ◽  
Eko Prasetya Budiana ◽  
Wibawa Endra Juwana
Keyword(s):  
Output Voltage ◽  
Thermoelectric Generator ◽  
Electrical Energy ◽  
Thermoelectric Generators ◽  
Data Logger ◽  
Computer Data ◽  
Standard Module ◽  
Self Powered ◽  
Resistive Loads ◽  
The Relationship

Thermoelectric generator is solid-state device which convert temperature difference, ∆T into electrical energy based on Seebeck effect phenomenon. The device has been widely used in self-powered system applications. This paper focuses on presentation of methodology for characterizing thermoelectric generators. The measurement of its behavior is performed by varying load resistances. A standard module of thermoelectric generator (TEC1-12710) is used in examination and an instrument setup consists of controllable heat source, controllable cooler, personal computer, data logger MCC DAQ USB-1208LS equipped with two sets of K-type thermocouples. The experiment is performed by measuring output voltage and output current in 4 values of temperature gradient by applying 10 values of resistive loads connected to the thermoelectric output wires. The common parameters studied in this research are output voltage, current and power. Generally, the relationship between parameters agrees with the basic theory and the procedure can be adopted for characterizing other type of thermoelectric generator.

Large-scale three-dimensional anisotropic topology optimization of variable-axial lightweight composite structures

2021 ◽  
pp. 1-15
Author(s):  
Yuqing Zhou ◽  
Tsuyoshi Nomura ◽  
Enpei Zhao ◽  
Kazuhiro Saitou
Keyword(s):  
Topology Optimization ◽  
Composite Structures ◽  
Large Scale ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Optimization Method ◽  
Optimized Design ◽  
Adaptive Meshing ◽  
Design Synthesis ◽  
Fiber Placement

Abstract Variable-axial fiber-reinforced composites allow for local customization of fiber orientation and thicknesses. Despite their significant potential for performance improvement over the conventional multiaxial composites and metals, they pose challenges in design optimization due to the vastly increased design freedom in material orientations. This paper presents an anisotropic topology optimization method for designing large-scale, 3D variable-axial lightweight composite structures subject to multiple load cases. The computational challenges associated with large-scale 3D anisotropic topology optimization with extremely low volume fraction are addressed by a tensor-based representation of 3D orientation that would avoid the 2π periodicity of angular representations such as Euler angles, and an adaptive meshing scheme, which, in conjunction with PDE regularization of the density variables, refines the mesh where structural members appear and coarsens where there is void. The proposed method is applied to designing a heavy-duty drone frame subject to complex multi-loading conditions. Finally, the manufacturability gaps between the optimized design and the fabrication-ready design for Tailored Fiber Placement (TFP) is discussed, which motivates future work toward a fully-automated design synthesis.

Flexible film-based thermoelectric generators

MRS Advances ◽  
2019 ◽  
Vol 4 (30) ◽  
pp. 1691-1697
Author(s):  
Shuping Lin ◽  
Wei Zeng ◽  
Lisha Zhang ◽  
Xiaoming Tao
Keyword(s):  
Seebeck Coefficient ◽  
Thermoelectric Generator ◽  
Low Cost ◽  
Thermoelectric Generators ◽  
Polystyrene Sulfonate ◽  
Paper Substrate ◽  
Thermoelectric Element ◽  
Flexible Film ◽  
P Type ◽  
Flexible Thermoelectric

ABSTRACT:The present work highlights the progress in the field of flexible thermoelectric generator (f-TEGs) fabricated by 3-D printing strategy on the typing paper substrate. In this study, printable thermoelectric paste was developed. The dimension of each planer thermoelectric element is 30mm*4mm with a thickness of 50 μm for P-type Bismuth Tellurium (Bi2Te3)-based/ poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) leg. A single thermoleg with this dimension can generate a voltage of 5.38 mV at a temperature difference of 70 K. The calculated Seebeck Coefficient of a single thermoleg is 76.86 μV/K. This work demonstrates that low-cost printing technology is promising for the fabrication of f-TEGs.

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