Topology optimization of the manifold microchannels with triple-objective functions

2021 ◽  
pp. 1-26
Author(s):  
Xun Liu ◽  
Li Chen ◽  
Ming Peng ◽  
Wen-Tao Ji ◽  
Wen-Quan Tao
Keyword(s):  
Topology Optimization ◽  
Objective Functions

Design of Compliant Structural Mechanisms Using B-Spline Elements

2011 ◽  
Author(s):  
Ashok V. Kumar ◽  
Anand Parthasarathy
Keyword(s):  
Inverse Problem ◽  
Topology Optimization ◽  
Compliant Mechanisms ◽  
Spline Approximation ◽  
Structural Response ◽  
Field Application ◽  
Optimization Approach ◽  
Objective Functions ◽  
B Spline ◽  
Spline Basis

Structural design is an inverse problem where the geometry that fits a specific design objective is found iteratively through repeated analysis or forward problem solving. In the case of compliant structures, the goal is to design the structure for a particular desired structural response that mimics traditional mechanisms and linkages. It is possible to state the inverse problem in many different ways depending on the choice of objective functions used and the method used to represent the shape. In this paper, some of the objective functions that have been used in the past, for the topology optimization approach to designing compliant mechanisms are compared and discussed. Topology optimization using traditional finite elements often do not yield well-defined smooth boundaries. The computed optimal material distributions have shape irregularities unless special techniques are used to suppress them. In this paper, shape is represented as the contours or level sets of a characteristic function that is defined using B-spline approximation to ensure that the contours, which represent the boundaries, are smooth. The analysis is also performed using B-spline elements which use B-spline basis functions to represent the displacement field. Application of this approach to design a few simple mechanisms is presented.

Damage Identification Using Static and Dynamic Responses Based on Topology Optimization and Lasso Regularization

2020 ◽  
Author(s):  
Ryo Sugai ◽  
Akira Saito ◽  
Hidetaka Saomoto
Keyword(s):  
Topology Optimization ◽  
Numerical Experiments ◽  
Damage Identification ◽  
Dynamic Responses ◽  
High Fidelity ◽  
Dynamic Problems ◽  
Objective Functions ◽  
Identification Method ◽  
Design Variables ◽  
Active Design

Abstract This paper presents a damage identification method based on topology optimization and Lasso regularization. The method uses static displacements or dynamic responses to identify damages of structures. The method has the potential to identify damages with high fidelity, in comparison with ordinary damage identification method based on optimization with parameterized geometry of the damages. However, it is difficult to precisely detect damage using topology optimization due mostly to the large number of design variables. Therefore, supposing that the damage is sufficiently small, we propose a method adding Lasso regularization to the objective functions to suppress active design variables during topology optimization process. To verify the effectiveness of the proposed method, we conducted a set of numerical experiments for static and dynamic problems. We have succeeded in suppressing active design variables and delete artificially generated damages and the location and shape of damage have been precisely identified.

Topology Optimization of Passive Constrained Layer Damping on Plates with Respect to Noise Control

2013 ◽  
Vol 774-776 ◽  
pp. 3-6
Author(s):  
Ying Feng Lei ◽  
Wei Guang Zheng ◽  
Qi Bai Huang ◽  
Chuan Bing Li
Keyword(s):  
Topology Optimization ◽  
Numerical Study ◽  
Harmonic Excitation ◽  
Surface Velocity ◽  
Viscoelastic Layer ◽  
Constrained Layer Damping ◽  
Objective Functions ◽  
Normal Surface ◽  
Simple Interface ◽  
Passive Constrained Layer Damping

The square of normal surface velocity of a thin plate with a harmonic excitation is minimized by optimizing the topologies of attached passive constrained layer damping (PCLD) treatments. An extended solid isotropic material with penalization model for topology optimization is introduced based on a simple interface finite element modeling for viscoelastic layer of PCLD patch. For the purpose of illustrating the proposed method, a clamped square plate is used in the numerical study. Significant reductions of the objective functions are achieved by the optimal distributions.

Topology Optimization for Work Flat of Tower-Belt under Multi-Loading Cases

2012 ◽  
Vol 197 ◽  
pp. 614-618
Author(s):  
Yi Xian Du ◽  
Jin Run Hu ◽  
Zi Fan Fang ◽  
Qi Hua Tian
Keyword(s):  
Topology Optimization ◽  
Static Analysis ◽  
Geometric Model ◽  
Mathematical Optimization ◽  
Structural Models ◽  
Optimal Topology ◽  
Multiple Objective ◽  
Objective Functions ◽  
Minimum Compliance ◽  
Mathematical Optimization Model

Taking minimum compliance of the whole structure as the objective, the mathematical optimization model of multi-loading cases topology optimization is constructed by using the weight compromise programming method to coordinate the multiple objective functions. The optimal topology of the work flat is obtained using Hyperworks/Optistruct software and geometric model is reconstructed. The static analysis of original and reconstructed structural models of the work flat show that the optimized structure can not only decrease the weight, but also improve the stiffness and reduce the stress. The work flat will be more safe and reliable than before.

scholarly journals A Comparative Study of the Application of Different Commercial Software for Topology Optimization

2022 ◽  
Vol 12 (2) ◽  
pp. 611
Author(s):  
Evangelos Tyflopoulos ◽  
Martin Steinert
Keyword(s):  
Topology Optimization ◽  
Comparative Study ◽  
Design Method ◽  
Design Domain ◽  
Online Database ◽  
Objective Functions ◽  
Commercial Software ◽  
Optimization Software ◽  
Software Platforms ◽  
The Given

Topology optimization (TO) has been a popular design method among CAD designers in the last decades. This method optimizes the given design domain by minimizing/maximizing one or more objective functions, such as the structure’s stiffness, and at the same time, respecting the given constraints like the volume or the weight reduction. For this reason, the companies providing the commercial CAD/FEM platforms have taken this design trend into account and, thus, have included TO in their products over the last years. However, it is not clear which features, algorithms, or, in other words, possibilities the CAD designers do have using these software platforms. A comparative study among the most applied topology optimization software was conducted for this research paper. First, the authors developed an online database of the identified TO software in the form of a table. Interested CAD designers can access and edit its content, contributing in this way to the creation of an updated library of the available TO software. In addition, a deeper comparison among three commercial software platforms—SolidWorks, ANSYS Mechanical, and ABAQUS—was implemented using three common case studies—(1) a bell crank lever, (2) a pillow bracket, and (3) a small bridge. These models were designed, optimized, and validated numerically, as well as compared for their strength. Finally, the above software was evaluated with respect to optimization time, optimized designs, and TO possibilities and features.

Fluid-thermal topology optimization of gas turbine blade internal cooling ducts

2021 ◽  
pp. 1-85
Author(s):  
Shinjan Ghosh ◽  
Erik Fernandez ◽  
Jayanta Kapat
Keyword(s):  
Topology Optimization ◽  
Aspect Ratio ◽  
Gas Turbine ◽  
Thermal Performance ◽  
High Aspect Ratio ◽  
Turbine Blades ◽  
Internal Cooling ◽  
Objective Functions ◽  
Serpentine Channel ◽  
Cooling Ducts

Abstract Topology optimization uses a variable permeability approach to manipulate flow geometries. Such a method has been employed in the current work to modify the geometric configuration of internal cooling ducts by manipulating the distribution of material blockage. A modified version of the OpenFOAM solver AdjointshapeoptimizationFOAM has been used to optimize the flow path of a serpentine channel and high aspect ratio rectangular ducts, with increase in heat transfer and reduction in pressure drop as the objective functions. These duct shapes are typically used as internal cooling channels in gas turbine blades for sustaining the blade material at high inlet temperatures. The serpentine channel shape was initially topologically optimized, the fluid path from which was post-processed and re-simulated in STAR-CCM+. The end result had an improvement in thermal performance efficiency by 24%. Separation regions were found to be reduced when compared to the original baseline. The second test geometry was a high aspect ratio rectangular duct. Weight factors were assigned to the objective functions in this multi-objective approach, which were varied to obtain a unique shape for each such combination. The addition of mass penalization to the existing objective function resulted in a complex lattice like structure, which was a different outcome in geometry and shape when compared to the case without any additional penalization. The thermal performance efficiency of this shape was found to be higher by at-least 18% when compared to the CFD results of a few other turbulator shapes from literature.

Topology Optimization With Locally Evaluable Complement Space Connectivity

2021 ◽  
Author(s):  
Clinton B. Morris ◽  
Amir M. Mirzendehdel ◽  
Morad Behandish
Keyword(s):  
Topology Optimization ◽  
Primary Objective ◽  
Objective Functions ◽  
Post Processing ◽  
Local Decision ◽  
Global Nature ◽  
Compliance Problem ◽  
Local Decision Making ◽  
Update Rules ◽  
Structural Compliance

Abstract Enforcing connectivity of parts or their complement space during automated design is essential for various manufacturing and functional considerations such as removing powder, wiring internal components, and flowing internal coolant. The global nature of connectivity makes it difficult to incorporate into generative design methods that rely on local decision making, e.g., topology optimization (TO) algorithms whose update rules depend on the sensitivity of objective functions or constraints to locally change the design. Connectivity is commonly corrected for in a post-processing step, which may result in suboptimal designs. We propose a recasting of the connectivity constraint as a locally differentiable violation measure, defined as a “virtual” compliance, modeled after physical (e.g., thermal or structural) compliance. Such measures can be used within TO alongside other objective functions and constraints, using a weighted penalty scheme to navigate tradeoffs. By carefully specifying the boundary conditions of the virtual compliance problem, the designer can enforce connectivity between arbitrary regions of the part’s complement space while satisfying a primary objective function in the TO loop. We demonstrate the effectiveness of our approach using both 2D and 3D examples, show its flexibility to consider multiple virtual domains, and confirm the benefits of considering connectivity in the design loop rather than enforcing it through post-processing.

Conceptual Design of Structures Using an Upper Bound of von Mises Stress

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Ashok V. Kumar
Keyword(s):  
Topology Optimization ◽  
Stress Concentration ◽  
Upper Bound ◽  
Von Mises Stress ◽  
Optimization Approach ◽  
Objective Functions ◽  
Stress Concentrations ◽  
Handling Stress ◽  
Design Concepts ◽  
Von Mises

Optimal layouts for structural design have been generated using topology optimization approach with a wide variety of objectives and constraints. Minimization of compliance is the most common objective but the resultant structures often have stress concentrations. Two new objective functions, constructed using an upper bound of von Mises stress, are presented here for computing design concepts that avoid stress concentration. The first objective function can be used to minimize mass while ensuring that the design is conservative and avoids stress concentrations. The second objective can be used to tradeoff between maximizing stiffness versus minimizing the maximum stress to avoid stress concentration. The use of the upper bound of von Mises stress is shown to avoid singularity problems associated with stress-based topology optimization. A penalty approach is used for eliminating stress concentration and stress limit violations which ensures conservative designs while avoiding the need for special algorithms for handling stress localization. In this work, shape and topology are represented using a density function with the density interpolated piecewise over the elements to obtain a continuous density field. A few widely used examples are utilized to study these objective functions.

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