scholarly journals On understanding of design problem formulation for compliant mechanisms through topology optimization

2013 ◽  
Vol 4 (2) ◽  
pp. 357-369 ◽  
Author(s):  
L. Cao ◽  
A. Dolovich ◽  
W. J. Zhang
Keyword(s):  
Topology Optimization ◽  
Compliant Mechanisms ◽  
Optimization Technique ◽  
Problem Formulation ◽  
Functional Requirements ◽  
Motion Generation ◽  
Design Problems ◽  
Standard Design ◽  
Quantitative Design ◽  
Future Work

Abstract. General problems associated with the design of compliant mechanisms through the topology optimization technique are defined in this paper due to the lack of comprehensive definitions for these problems in the literature. Standard design problems associated with rigid body mechanisms, i.e. function generation, path generation and motion generation, are extended to compliant mechanisms. Functional requirements and the associated 25 formulations in the literature are comprehensively reviewed along with their limitations. Based on whether the output is controlled quantitatively or not, these formulations are categorized into two types: (1) formulations for quantitative design; and (2) formulations for qualitative design. In addition, formulations that aim to solve the point flexure problem are also discussed. Future work is identified based on the discussion of each topic.

Design of Grip-and-Move Manipulators Using Symmetric Path Generating Compliant Mechanisms

2008 ◽  
Vol 130 (11) ◽  
Author(s):  
N. F. Wang ◽  
K. Tai
Keyword(s):  
Topology Optimization ◽  
Compliant Mechanisms ◽  
Optimization Procedure ◽  
Problem Formulation ◽  
Optimization Approach ◽  
Structural Topology ◽  
Graph Theoretic ◽  
Mutation Operators ◽  
Future Work ◽  
Crossover And Mutation

This paper presents the problem formulation and design of compliant grip-and-move manipulators. Each manipulator is composed of two identical path generating compliant mechanisms such that it can grip an object and convey it from one point to another. The integration of both gripping and moving behaviors within a simple mechanism is accomplished by the use of compliant mechanisms, which generate paths that are symmetric. The automated synthesis of these symmetric path generating mechanisms is by a structural topology optimization approach. The problem of topology optimization of continuum structures is solved using a multiobjective genetic algorithm coupled with a morphological representation of geometry that efficiently defines the variable structural geometry upon a finite element grid. A graph-theoretic chromosome encoding together with compatible crossover and mutation operators are then applied to form an effective evolutionary optimization procedure. Two designs have been created and are presented in this paper, and some concluding remarks and future work are put forward.

Adapting Ant Colony for Topology Optimization of Compliant Mechanisms With Variable Material Density

2017 ◽  
Author(s):  
Nadim Diab
Keyword(s):  
Topology Optimization ◽  
Ant Colony Optimization ◽  
High Performance ◽  
Compliant Mechanisms ◽  
Optimization Technique ◽  
Optimization Techniques ◽  
Ant Colony ◽  
Intensity Level ◽  
Material Density ◽  
Swarm Intelligence Optimization

Swarm intelligence optimization techniques are widely used in topology optimization of compliant mechanisms. The Ant Colony Optimization has been implemented in various forms to account for material density distribution inside a design domain. In this paper, the Ant Colony Optimization technique is applied in a unique manner to make it feasible to optimize for the beam elements’ cross-section and material density simultaneously. The optimum material distribution algorithm is governed by two various techniques. The first technique treats the material density as an independent design variable while the second technique correlates the material density with the pheromone intensity level. Both algorithms are tested for a micro displacement amplifier and the resulting optimized topologies are benchmarked against reported literature. The proposed techniques culminated in high performance and effective designs that surpass those presented in previous work.

Integrated Design of Compliant Mechanisms and Embedded Rotary Actuators and Bending Actuators for Motion Generation

2016 ◽  
Author(s):  
Lin Cao ◽  
Wenjun (Chris) Zhang
Keyword(s):  
Compliant Mechanisms ◽  
Optimization Technique ◽  
Integrated Design ◽  
Simultaneous Optimization ◽  
Motion Generation ◽  
Element Analysis ◽  
Integrated Design Approach ◽  
3D Printed ◽  
Checking Scheme ◽  
Actuator Placement

This paper presents an integrated design approach, a new topology optimization technique, to simultaneously synthesizing the optimal structural topologies of compliant mechanisms (CMs) and actuator placement — bending actuators and rotary actuators — for motion generation. The approach has the following salient features: (1) the use of bending actuators and rotary actuators as the actuation of CMs, (2) the simultaneous optimization of the CM and the location and orientation of the actuator that is embedded in the CM, (3) the guiding of a flexible link from an initial configuration to a series of desired configurations (including precision positions, orientations, and shapes), and (4) a new connectivity checking scheme to check whether the regions of interest in a design candidate are well connected. A program was employed for the geometrically nonlinear finite element analysis of large-displacement CMs driven by either bending actuators or rotary actuators. Two design examples were presented to demonstrate the proposed approach. The design results were 3D printed, and they all achieved desired shape changes when actuated.

Hybrid Compliant Mechanism Design Using a Mixed Mesh of Flexure Hinge Elements and Beam Elements Through Topology Optimization

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Lin Cao ◽  
Allan T. Dolovich ◽  
Wenjun (Chris) Zhang
Keyword(s):  
Topology Optimization ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Optimization Technique ◽  
Flexure Hinge ◽  
Beam Elements ◽  
Flexure Hinges ◽  
New Type ◽  
Meshing Scheme ◽  
Compliant Mechanism Design

This paper proposes a topology optimization framework to design compliant mechanisms with a mixed mesh of both beams and flexure hinges for the design domain. Further, a new type of finite element, i.e., super flexure hinge element, was developed to model flexure hinges. Then, an investigation into the effects of the location and size of a flexure hinge in a compliant lever explains why the point-flexure problem often occurs in the resulting design via topology optimization. Two design examples were presented to verify the proposed technique. The effects of link widths and hinge radii were also investigated. The results demonstrated that the proposed meshing scheme and topology optimization technique facilitate the rational decision on the locations and sizes of beams and flexure hinges in compliant mechanisms.

Optimal Synthesis of Compliant Mechanisms to Satisfy Kinematic and Structural Requirements: Preliminary Results

1996 ◽  
Author(s):  
Mary I. Frecker ◽  
Noboru Kikuchi ◽  
Sridhar Kota
Keyword(s):  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Synthesis Method ◽  
Design Procedure ◽  
Problem Formulation ◽  
Mechanism Synthesis ◽  
Ground Structure ◽  
Design Problems ◽  
Structural Requirements ◽  
External Loads

Abstract Compliant mechanism synthesis is an automated design procedure which allows the designer to systematically generate the optimal structural form for a particular set of loading and motion requirements. The synthesis method presented here solves a particular class of design problems, where the compliant mechanism is required to be both flexible to meet motion requirements, and stiff to withstand external loads. A two-part problem formulation is proposed using mutual and strain energies, whereby the conflicting design objectives of required flexibility and stiffness are handled via multi-criteria optimization. The resulting compliant mechanism topologies satisfy both kinematic and structural requirements. The problem formulation is implemented using a truss ground structure and SLP algorithm. Several design examples are presented to illustrate this method.

Genetic Algorithm-Based Structural Topology Design With Compliance and Topology Simplification Considerations

1996 ◽  
Vol 118 (1) ◽  
pp. 89-98 ◽  
Author(s):  
C. D. Chapman ◽  
M. J. Jakiela
Keyword(s):  
Genetic Algorithm ◽  
Topology Optimization ◽  
Optimization Technique ◽  
Topology Design ◽  
Structural Topology Optimization ◽  
Structural Topology ◽  
Design Representation ◽  
Homogenization Methods ◽  
Future Work ◽  
Structural Topology Design

The genetic algorithm (GA), an optimization technique based on the theory of natural selection, is applied to structural topology design problems. After reviewing the genetic algorithm and previous research in structural topology optimization, we detail the chromosome-to-design representation which enables the genetic algorithm to perform structural topology optimization. Extending our prior investigations, this article first compares our genetic-algorithm-based technique with homogenization methods in the minimization of a structure’s compliance subject to a maximum volume constraint. We then use our technique to generate topologies combining high structural performance with a variety of material connectivity characteristics which arise directly from our discretized design representation. After discussing our findings, we describe potential future work.

Multidomain Topology Optimization for Structural and Material Designs

2005 ◽  
Vol 73 (4) ◽  
pp. 565-573 ◽  
Author(s):  
Zheng-Dong Ma ◽  
Noboru Kikuchi ◽  
Christophe Pierre ◽  
Basavaraju Raju
Keyword(s):  
Topology Optimization ◽  
Engineering Design ◽  
Optimization Technique ◽  
Functionally Graded ◽  
Material Distribution ◽  
Design Problems ◽  
Linearization Methods ◽  
Engineering Design Problems ◽  
Wide Range ◽  
Multiple Materials

A multidomain topology optimization technique (MDTO) is developed, which extends the standard topology optimization method to the realm of more realistic engineering design problems. The new technique enables the effective design of a complex engineering structure by allowing the designer to control the material distribution among the subdomains during the optimal design process, to use multiple materials or composite materials in the various subdomains of the structure, and to follow a desired pattern or tendency for the material distribution. A new algorithm of Sequential Approximate Optimization (SAO) is proposed for the multidomain topology optimization, which is an enhancement and a generalization of previous SAO algorithms (including Optimality Criteria and Convex Linearization methods, etc.). An advanced substructuring method using quasi-static modes is also introduced to condense the nodal variables associated with the multidomain topology optimization problem, especially for the nondesign subdomains. The effectiveness of the new MDTO approach is demonstrated for various design problems, including one of “structure-fixture simultaneous design,” one of “functionally graded material design,” and one of “crush energy management.” These case studies demonstrate the potential significance of the new capability developed for a wide range of engineering design problems.

Multi-Domain Topology Optimization for Vehicle Substructure Design

2002 ◽  
Author(s):  
Zheng-Dong Ma ◽  
Noboru Kikuchi ◽  
Christophe Pierre ◽  
Basavaraju Raju
Keyword(s):  
Topology Optimization ◽  
Design Problem ◽  
Degrees Of Freedom ◽  
Optimization Technique ◽  
Synthesis Method ◽  
Material Design ◽  
Functionally Graded ◽  
Structural Domain ◽  
Management Problem ◽  
Design Problems

Topology optimization of a structure is generally considered as a problem of optimum material distribution (OMD) within a given structural domain, subject to a given amount of material and to boundary conditions and loading conditions applied to the structure. The effective design of a complex engineering structure, however, may require controllability over how the material should be distributed among the various subdomains of the structure, as well as even the use of different materials for the different subdomains. A multi-domain topology optimization technique is therefore proposed in this paper, which is based upon the homogenization method, and which employs a generalized Sequential Approximation Optimization (GSAO) algorithm. This algorithm enhances the capabilities of current topology optimization methods by using advanced updating rules and providing additional flexibility in the optimization process, thus resulting in improved convergence and higher computational efficiency. A Component Mode Synthesis method is also employed, which can significantly reduce the number of degrees of freedom associated with the subdomains whose designs are fixed at the current stage. Several example design problems are considered, including a “structure-fixture simultaneous design” problem, a “functionally graded material design” problem, a “crush energy management” problem, and a “truck frame design” problem that illustrates how the technique developed can be applied to real vehicle substructure design problems.

Topology optimization for infill in MEx

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Matt Schmitt ◽  
Il Yong Kim
Keyword(s):  
Topology Optimization ◽  
Numerical Optimization ◽  
Optimization Technique ◽  
Problem Formulation ◽  
Optimization Techniques ◽  
Manufacturing Constraints ◽  
Support Material ◽  
Element Mesh ◽  
Content Type ◽  
Manufacturing Method

Purpose In furthering numerical optimization techniques for the light-weighting of components, it is paramount to produce algorithms that closely mimic the physical behavior of the specific manufacturing method under which they are created. The continual development in topology optimization (TO) has reduced the difference in the optimized geometry from what can be physically realized. As the reinterpretation stage inevitably deviates from the optimal geometry, each progression in the optimization code that renders the final solution more realistic is beneficial. Despite the efficacy of material extrusion (MEx) in producing complex geometries, select manufacturing constraints are still required. Thus, the purpose of this paper is to develop a TO code which demonstrates the incorporation of MEx specific manufacturing constraints into a numerical optimization algorithm. Design/methodology/approach A support index is derived for each element of the finite element mesh that is used to penalize elements, which are insufficiently supported, discouraging their existence. The support index captures the self-supporting angle and maximum allowable bridging distance for a given MEx component. The incorporation of the support index into a TO code is used to demonstrate the efficacy of the method on multiple academic examples. Findings The case studies presented demonstrate the methodology is successful in generating a resulting topology that is self-supporting given the manufacturing parameters specified in the code. Comparative to a general TO problem formulation, the optimal material distribution results in a minimally penalized design on a compliance normalization metric while fully adhering to the MEx specific parameters. The methodology, thus, proves useful in generating an infill geometry is fully enclosed regions, where support material extraction is not a possibility. Originality/value The work presented is the first paper to produce a novel methodology that incorporates the manufacturing-specific constraint of bridging distance for MEx into TO code. The results generated allow for the creation of printed components with hollow inclusions that do not require any additional support material beyond the intended structure. Given the advancement, the numerical optimization technique has progressed to a more realistic representation of the physical manufacturing method.

scholarly journals Genetic Algorithms as an Approach to Configuration and Topology Design

1994 ◽  
Vol 116 (4) ◽  
pp. 1005-1012 ◽  
Author(s):  
C. D. Chapman ◽  
K. Saitou ◽  
M. J. Jakiela
Keyword(s):  
Genetic Algorithm ◽  
Topology Optimization ◽  
Optimization Technique ◽  
Topology Design ◽  
Structural Topology Optimization ◽  
Structural Topology ◽  
Design Representation ◽  
Future Work ◽  
Structural Topology Design ◽  
Algorithm Search

The genetic algorithm, a search and optimization technique based on the theory of natural selection, is applied to problems of structural topology design. An overview of the genetic algorithm will first describe the genetics-based representations and operators used in a typical genetic algorithm search. Then, a review of previous research in structural optimization is provided. A discretized design representation, and methods for mapping genetic algorithm “chromosomes” into this representation, is then detailed. Several examples of genetic algorithm-based structural topology optimization are provided: we address the optimization of cantilevered plate topologies, and we investigate methods for optimizing finely-discretized design domains. The genetic algorithm’s ability to find families of highly-fit designs is also examined. Finally, a description of potential future work in genetic algorithm-based structural topology optimization is offered.

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