Design of 2D and 3D Non-linear Compliant Mechanisms using Hybrid Cellular Automata (original) (raw)

On Design Methods for Compliant Mechanisms

2010

This paper gives a brief overview and comparison of the methods applied in the design of compliant mechanisms. Since the first research works on the subject appeared in the 1980s, several methods have being conceived to analyze and design these mechanisms that gain part of their motion from the deflection of flexible members rather than from movable joints only. The scope and limitations of the most widely used design tools in the field; pseudo-rigid model based methods, optimization based methods), and a novel inverse design method are investigated and discussed. Mecánica Computacional Vol XXIX, págs. 59-72 (artículo completo) Eduardo Dvorkin, Marcela Goldschmit, Mario Storti (Eds.) Buenos Aires, Argentina, 15-18 Noviembre 2010 Copyright © 2010 Asociación Argentina de Mecánica Computacional http://www.amcaonline.org.ar

Methodology of Compliant Mechanisms and its Current Developments in Applications: A Review

2007

Traditional rigid-body mechanisms consist of a number of components to implement their functions. Therefore they face problems such as backlash, wear, increase in part-count, weight, assembly cost and time, regular maintenance. Reducing these problems will help in increasing mechanism performance and cost reduction. Recently, there are several examples of compliant mechanisms that have been designed and widely used in various fields such as for adaptive structures, biomedical, hand-held tools, components in transportations, MEMS and robotics. However, the largest challenge was relative difficulty in analyzing and designing compliant mechanisms. Two approaches known in the literature for the systematic synthesis of compliant mechanisms are the kinematics-based approach and the structural optimisation based approach.

A Review on Design Methods for Compliant Mechanisms

Mecánica Computacional, 2010

This paper gives a brief overview and comparison of the methods applied in the design of compliant mechanisms. Since the first research works on the subject appeared in the 1980s, several methods have being conceived to analyze and design these mechanisms that gain part of their motion from the deflection of flexible members rather than from movable joints only. The scope and limitations of the most widely used design tools in the field; pseudo-rigid model based methods, optimization based methods), and a novel inverse design method are investigated and discussed.

Analysis of large-displacement compliant mechanisms using an incremental linearization approach

Mechanism and Machine Theory, 2008

Compliant mechanisms transmit motion and force by deflection of their flexible members. They are usually made of a monolithic piece of material and thus involve no wear, backlash, noise, and lubrication. To predict more accurately their deflected shape in larger working range, the analysis of compliant mechanisms has usually based on nonlinear numerical techniques such as the finite element method. However, the problems of nonlinear analyses are their numerical instability and extensive computation time. These have limited further applications of compliant mechanisms. In this paper, the global coordinate model (GCM) with an incremental linearization approach is presented to turn the nonlinear problem into a sequence of linear problems. Both geometric and material nonlinearities are considered. As a result, numerous linear analysis techniques can be applied to facilitate design and prototyping of compliant mechanisms. Systematic procedures are developed to analyze generic compliant mechanisms that may include non-uniform or initially curved segments. Illustrations are shown with results validated experimentally and by comparing with the nonlinear finite element method. It is expected that the proposed approach can serve as a basis for broader applications of compliant mechanisms.

Stress-based topology optimization of compliant mechanisms using nonlinear mechanics

Mechanics & Industry

The present work demonstrates how a light structure can be easily designed through Topology Optimization even including complex analysis and sizing criteria such as hyperelastic Neo-Hookean materials for nonlinear analysis and aggregated stress constraints. The SIMP approach was adopted and two different strategies were analysed using an in house versatile MATLAB code. MMA was used as reference optimizer (in structural optimization) whereas a unified aggregation and relaxation method was adopted to deal with stress constraints. Feasibility was analyzed from the viewpoint of allowable stress verification. Two test cases are then studied: a morphing airfoil (for aeronautical applications) and a geometric inverter (for mechanics and bio-medical applications). For both, a hyperelastic Neo-Hookean material was chosen. Finally a complementary study on the effects of constraints and the input force intensity is also presented.

1 Spring-lever Model of a Compliant Mechanism and a Feasibil

2015

We present a distributed compliant mechanism, which acts like a transmission between a flapping wing of a micro air vehicle and a laminated piezoelectric actuator. The piezoelectric bimorph actuator is connected in the cantilever configuration with the compliant mechanism at its free tip. The mechanism takes translational deflection at its input from the piezoelectric actuator to provide angular displacement at its output, which causes flapping. We used topology optimization to obtain the design concept. The design of the mechanism is finalised using nonlinear elastic analysis. The final mechanism is a planar structure of 1 mm thickness and 40 mm × 24 mm in-plane footprint. The compliant mechanism exhibits 711 N/m input stiffness and 0.014 Nm/rad output torsional stiffness. The mechanism produces around 7 angular displacement per 1 mm input stroke, and around 8 angular displacement per 1 N force at its input. The mechanism has a fundamental frequency of 391 Hz, which is almost eight...

IJERT-Design of Constant Force Compliant Mechanisms

International Journal of Engineering Research and Technology (IJERT), 2014

https://www.ijert.org/design-of-constant-force-compliant-mechanisms https://www.ijert.org/research/design-of-constant-force-compliant-mechanisms-IJERTV3IS070028.pdf Compliant mechanisms realize mechanism functions by utilizing the elastic deformations of flexible components rather than the relative motions of rigid joints. The advantages of compliant mechanisms stem from the removal or replacement of rigid joints, which include the elimination of backlash, friction, wear and lubrication, the reduction of vibration and noise, the decreased manufacturing and assembly cost, and the increased precision. Because of the integrated motion and force behavior and the nonlinearities of large deformations, designing compliant mechanisms is much more challenging than rigid mechanisms. Constant force compliant mechanisms produce an output force that does not change for a large range of input motion and have many different applications. A method is introduced in this paper for designing constant force compliant mechanisms. A designed constant force compliant mechanism is modelled as a network of variable width spline curves which are defined by their interpolation circles. The design of constant force compliant mechanisms is systematized as optimizing the independent parameters of the variable width spline curves. The presented method is demonstrated by the design of a constant force compliant mechanism in the paper.

New Software for Synthesis of Compliant Mechanisms

A compliant mechanism is defined generally as a single piece structure that accomplishes its functions — transferring of motion or force through elastic deformation. The synthesis of this kind of mechanisms represents a challenging task, especially because flexible segments of compliant mechanism usually must undergo large, nonlinear deflections which include difficult nonlinear analysis. In this paper the new software for synthesis of compliant mechanisms is developed. Software uses topology optimization technique that is especially useful when the designer does not have a particular compliant mechanism already in mind. The capability and methodology that software uses will be shown on the example of synthesis of complaint gripper and displacement inverter.

Dynamic analysis of flexible mechanisms by finite element method

2010

I also would like to thank faculties who tought me engineering courses in both under graduate and graduate levels. I am delighted to announce that my family has already been with me. I appreciate them for their support during the entire period of my study.

Dynamic Model of Mechanisms With Highly Compliant Members

Dynamic Systems and Control, Parts A and B, 2005

The dynamic model for links in most mechanisms has often based on small deflection theory without considering geometrical nonlinearity. For applications like light-weight links or high-precision elements, it is necessary to capture the large deflection caused by bending forces. A complete dynamic model is presented here to characterize the motion of a compliant mechanism capable of large deflection with shear and axial deformation. We derive the governing equations from Hamilton’s principle along with the essential geometric constraints that relate deformation and coordinate variables, and solve them using a semi-discrete method based on the Newmark scheme and shooting method. The dynamic model has been validated experimentally. We also extend the model for analyzing compliant mechanisms. It is expected that the dynamic model will serve as a basis for analyzing a wide spectrum of compliant multi-link mechanisms.