scholarly journals SHAPE OPTIMIZATION OF COMPLIANT MECHANISMS FOR SEISMIC ISOLATOR MODEL

2010 ◽  
Vol 75 (647) ◽  
pp. 113-119 ◽  
Author(s):  
Takuya KINOSHITA ◽  
Makoto OHSAKI
Keyword(s):  
Shape Optimization ◽  
Compliant Mechanisms ◽  
Seismic Isolator

Large Deformation Behavior of Compliant Mechanisms

2001 ◽  
Author(s):  
Jinyong Joo ◽  
Sridhar Kota ◽  
Noboru Kikuchi
Keyword(s):  
Shape Optimization ◽  
Large Deformation ◽  
Deformation Behavior ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Linear Formulation ◽  
Scaling Effect ◽  
Beam Elements ◽  
Linear And Nonlinear ◽  
Amplification Mechanism

Abstract This paper presents a non-linear formulation for size and shape optimization of compliant mechanisms using tapered beam elements. Designs based on linear and nonlinear formulations are compared using a stroke amplification mechanism example. Also, the scaling effect of the compliant mechanism is investigated.

An Energy Formulation for Parametric Size and Shape Optimization of Compliant Mechanisms

1999 ◽  
Vol 121 (2) ◽  
pp. 229-234 ◽  
Author(s):  
J. A. Hetrick ◽  
S. Kota
Keyword(s):  
Shape Optimization ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Optimization Procedure ◽  
Stress Constraints ◽  
Optimization Techniques ◽  
Mechanical Transmission ◽  
Dimensional Synthesis ◽  
Size And Shape ◽  
Mechanical Devices

Compliant mechanisms are jointless mechanical devices that take advantage of elastic deformation to achieve a force or motion transformation. An important step toward automated design of compliant mechanisms has been the development of topology optimization techniques. The next logical step is to incorporate size and shape optimization to perform dimensional synthesis of the mechanism while simultaneously considering practical design specifications such as kinematic and stress constraints. An improved objective formulation based on maximizing the energy throughput of a linear static compliant mechanism is developed considering specific force and displacement operational requirements. Parametric finite element beam models are used to perform the size and shape optimization. This technique allows stress constraints to limit the maximum stress in the mechanism. In addition, constraints which restrict the kinematics of the mechanism are successfully applied to the optimization problem. Resulting optimized mechanisms exhibit efficient mechanical transmission and meet kinematic and stress requirements. Several examples are given to demonstrate the effectiveness of the optimization procedure.

Size and Shape Optimization of Compliant Mechanisms: An Efficiency Formulation

1998 ◽  
Author(s):  
Joel A. Hetrick ◽  
Sridhar Kota
Keyword(s):  
Shape Optimization ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Optimization Procedure ◽  
Stress Constraints ◽  
Mechanical Efficiency ◽  
Optimization Techniques ◽  
Mechanical Transmission ◽  
Dimensional Synthesis ◽  
Size And Shape

Abstract Compliant mechanisms are jointless mechanical devices that take advantage of elastic deformation to achieve a force or motion transformation. A milestone toward systematic design of compliant mechanisms has been the development of topology optimization techniques. The next logical step is to incorporate size and shape optimization to identify the exact dimensional form of the mechanism. A new objective formulation based on maximizing the mechanical efficiency of a compliant mechanism is developed in order to perform the size and shape optimization. An advantage of this formulation is that precise control over the mechanism’s mechanical or geometric advantage can be enforced during optimization. Finite element beam models are used to perform dimensional synthesis of planar compliant mechanisms. This technique allows stress constraints to limit the maximum stress in the mechanism which improves the mechanism’s durability and flexibility. Resulting optimized mechanisms exhibit efficient mechanical transmission and meet kinematic and stress requirements. Several examples are given to demonstrate the effectiveness of the optimization procedure.

A Two-Stage Design Method for Compliant Mechanisms Having Specified Non-Linear Output Paths

2006 ◽  
Author(s):  
Masakazu Kobayashi ◽  
Hiroshi Yamakawa ◽  
Shinji Nishiwaki ◽  
Kazuhiro Izui ◽  
Masataka Yoshimura
Keyword(s):  
Topology Optimization ◽  
Shape Optimization ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Design Method ◽  
Two Stage ◽  
Traditional Methods ◽  
Stage Design ◽  
Second Stage ◽  
Additional Constraints

Compliant mechanisms generated by traditional topology optimization methods have linear output response, and it is difficult for traditional methods to implement mechanisms having non-linear output responses, such as nonlinear deformation or path. To design a compliant mechanism having a specified nonlinear output path, a two-stage design method based on topology and shape optimization is constructed here. In the first stage, topology optimization generates an initial and conceptual compliant mechanism based on ordinary design conditions, with “additional” constraints that are used to control the output path at the second stage. In the second stage, an initial model for the shape optimization is created, based on the result of the topology optimization, and the additional constraints are replaced by spring elements. The shape optimization is then executed, to generate a detailed shape of the compliant mechanism having the desired output path. In this stage, parameters that represent the outer shape of the compliant mechanism and the properties of spring elements are used as design variables in the shape optimization. In addition to configuration of the specified output path, executing the shape optimization after the topology optimization also makes it possible to consider the stress concentration and large displacement effects. This is an advantage offered by the proposed method, since it is difficult for traditional methods to consider these aspects, due to inherent limitations of topology optimization.

Multiobjective Topology Extraction of the Compliant Mechanisms

2014 ◽  
Vol 971-973 ◽  
pp. 1941-1948
Author(s):  
Zhao Kun Li ◽  
Hua Mei Bian ◽  
Li Juan Shi ◽  
Xiao Tie Niu
Keyword(s):  
Topology Optimization ◽  
Shape Optimization ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Threshold Value ◽  
Jump Discontinuity ◽  
Engineering Practice ◽  
Distribution Method ◽  
Black And White ◽  
Design Variables

Homogenization or material distribution method based topology optimization will create final topologies in grey level image and saw tooth jump discontinuity boundaries that are not suitable for direct engineering practice, so it is necessary to extract the topological diagram. And a new topology extraction method for compliant mechanisms is presented. In the fist stage, the grey image is transferred into the black-and white finite element topology optimization results. The threshold value meeting to objective function is obtained so that each element is either empty or solid; in the second stage, the density contour approach is used by redistributing nodal densities to generate the smooth boundaries; in the third stage, Smooth boundaries are represented by parameterized B-spline curves whose control points selected from the viewpoint of stiffness and flexibility constitute the parameters ready to undergo shape optimization; Then shape optimization is executed to improve stress-based local performance, The parameters that present the outer shape of the compliant mechanism are used as design variables; In the final stage, simulations of numerical examples are presented to show the validity of the proposed method.

Freeform Skeletal Shape Optimization of Compliant Mechanisms

2003 ◽  
Vol 125 (2) ◽  
pp. 253-261 ◽  
Author(s):  
Dong Xu ◽  
G. K. Ananthasuresh
Keyword(s):  
Shape Optimization ◽  
Compliant Mechanisms ◽  
Optimization Methods ◽  
Optimization Method ◽  
Analytical Sensitivity ◽  
Adaptive Finite Element ◽  
Bezier Curves ◽  
Bézier Curves ◽  
Element Discretization ◽  
Analytical Sensitivity Analysis

Compliant mechanisms are elastic continua used to transmit or transform force and motion mechanically. The topology optimization methods developed for compliant mechanisms also give the shape for a chosen parameterization of the design domain with a fixed mesh. However, in these methods, the shapes of the flexible segments in the resulting optimal solutions are restricted either by the type or the resolution of the design parameterization. This limitation is overcome in this paper by focusing on optimizing the skeletal shape of the compliant segments in a given topology. It is accomplished by identifying such segments in the topology and representing them using Bezier curves. The vertices of the Bezier control polygon are used to parameterize the shape-design space. Uniform parameter steps of the Bezier curves naturally enable adaptive finite element discretization of the segments as their shapes change. Practical constraints such as avoiding intersections with other segments, self-intersections, and restrictions on the available space and material, are incorporated into the formulation. A multi-criteria function from our prior work is used as the objective. Analytical sensitivity analysis for the objective and constraints is presented and is used in the numerical optimization. Examples are included to illustrate the shape optimization method.

Topology and Size–Shape Optimization of an Adaptive Compliant Gripper with High Mechanical Advantage for Grasping Irregular Objects

Robotica ◽  
2019 ◽  
Vol 37 (08) ◽  
pp. 1383-1400 ◽  
Author(s):  
Chih-Hsing Liu ◽  
Chen-Hua Chiu ◽  
Mao-Cheng Hsu ◽  
Yang Chen ◽  
Yen-Pin Chiang
Keyword(s):  
Topology Optimization ◽  
Optimal Design ◽  
Shape Optimization ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Experimental Studies ◽  
Design Procedure ◽  
Optimization Methods ◽  
Optimization Method ◽  
Mechanical Advantage

SummaryThis study presents an optimal design procedure including topology optimization and size–shape optimization methods to maximize mechanical advantage (which is defined as the ratio of output force to input force) of the synthesized compliant mechanism. The formulation of the topology optimization method to design compliant mechanisms with multiple output ports is presented. The topology-optimized result is used as the initial design domain for subsequent size–shape optimization process. The proposed optimal design procedure is used to synthesize an adaptive compliant gripper with high mechanical advantage. The proposed gripper is a monolithic two-finger design and is prototyped using silicon rubber. Experimental studies including mechanical advantage test, object grasping test, and payload test are carried out to evaluate the design. The results show that the proposed adaptive complaint gripper assembly can effectively grasp irregular objects up to 2.7 kg.

Sign in / Sign up

Export Citation Format

Share Document