scholarly journals Computational Synthesis of Large Deformation Compliant Mechanisms Undergoing Self and Mutual Contact

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Prabhat Kumar ◽  
Anupam Saxena ◽  
Roger A. Sauer
Keyword(s):  
Large Deformation ◽  
Compliant Mechanisms ◽  
Mean Value ◽  
Active Set ◽  
Mutual Contact ◽  
Mean Value Coordinates ◽  
Computational Synthesis ◽  
Augmented Lagrange Multiplier ◽  
Rigid Contact ◽  
Boundary Smoothing

Topologies of large deformation contact-aided compliant mechanisms (CCMs), with self and mutual contact, exemplified via path generation applications, are designed using the continuum synthesis approach. Design domain is parameterized using honeycomb tessellation. Assignment of material to each cell, and generation of rigid contact surfaces, are accomplished via suitably sizing and positioning negative circular masks using the stochastic hill-climber search. To facilitate contact analysis, boundary smoothing is implemented. Mean value coordinates are employed to compute shape functions, as many regular hexagonal cells get degenerated into irregular, concave polygons as a consequence of boundary smoothing. Both geometric and material nonlinearities are considered. The augmented Lagrange multiplier method with a formulated active set strategy is employed to incorporate both self and mutual contact. Synthesized contact-aided compliant continua trace paths with single, and importantly, multiple kinks and experience multiple contact interactions pertaining to both self and mutual contact modes.

Synthesis of C0 Path-Generating Contact-Aided Compliant Mechanisms Using the Material Mask Overlay Method

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Prabhat Kumar ◽  
Roger A. Sauer ◽  
Anupam Saxena
Keyword(s):  
Compliant Mechanisms ◽  
Synthesis Method ◽  
Mean Value ◽  
Contact Boundary ◽  
Element Formulation ◽  
Active Set ◽  
Set Constraints ◽  
Mean Value Coordinates ◽  
Augmented Lagrange Multiplier ◽  
The Continuum

Contact-aided compliant mechanisms (CCMs) are synthesized via the material mask overlay strategy (MMOS) to trace desired nonsmooth paths. MMOS employs hexagonal cells to discretize the design region and engages negative circular masks to designate material states. To synthesize CCMs, the modified MMOS presented herein involves systematic mutation of five mask parameters through a hill climber search to evolve not only the continuum topology but also to position the rigid, interacting surfaces within some masks. To facilitate analysis with contact, boundary smoothing is performed by shifting boundary nodes of the evolving continuum. Various geometric singularities are subdued via hexagonal cells, and the V-notches at the continuum boundaries are alleviated. Numerous hexagonal cells get morphed into concave subregions as a consequence. Large deformation finite-element formulation with mean-value coordinates based shape functions is used to cater to the generic hexagonal shapes. Contact analysis is accomplished via the Newton–Raphson (NR) iteration with load incrementing in conjunction with the augmented Lagrange multiplier method and active set constraints. An objective function based on Fourier shape descriptors (FSDs) is minimized subject to suitable design constraints. Two examples of path-generating CCMs are presented, their performance compared with a commercial software and fabricated to establish the efficacy of the proposed synthesis method.

On Synthesis of Contact Aided Compliant Mechanisms Using the Material Mask Overlay Method

2015 ◽  
Author(s):  
Prabhat Kumar ◽  
Roger A. Sauer ◽  
Anupam Saxena
Keyword(s):  
Compliant Mechanisms ◽  
Synthesis Method ◽  
Mean Value ◽  
Contact Analysis ◽  
Element Formulation ◽  
Active Set ◽  
Set Constraints ◽  
Mean Value Coordinates ◽  
Smooth Path ◽  
The Continuum

Contact Aided Compliant Mechanisms (CCMs) are synthesized via the Material Mask Overlay Strategy (MMOS) to trace a desired non-smooth path. MMOS employs hexagonal cells to discretize the design region and engages negative circular masks to designate material states. To synthesize CCMs, the modified MMOS presented herein involves systematic mutation of five mask parameters through a hill climber search to evolve not only the continuum topology (slave surfaces), but also, to introduce the desired rigid, interacting surfaces within some masks. Various geometric singularities are subdued via hexagonal cells though numerous V-notches get retained at the continuum boundaries. To facilitate contact analysis, boundary smoothing is performed by shifting boundary nodes of the evolving continuum systematically. Numerous hexagonal cells get morphed into concave sub-regions as a consequence. Large deformation finite element formulation with Mean Value Coordinates (MVC) based shape functions is used to cater to the generic hexagonal shapes. Contact analysis is accomplished via the Newton-Raphson iterations with load increment in conjunction with the penalty method and active set constraints. An objective function based on Fourier Shape Descriptors is minimized subject to suitable design constraints. An example of a path generating CCM is included to establish the efficacy of the proposed synthesis method.

Mean value coordinates for closed triangular meshes

2005 ◽  
Vol 24 (3) ◽  
pp. 561-566 ◽  
Author(s):  
Tao Ju ◽  
Scott Schaefer ◽  
Joe Warren
Keyword(s):  
Mean Value ◽  
Triangular Meshes ◽  
Mean Value Coordinates

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.

scholarly journals Design of compliant mechanism-based variable camber morphing wing with nonlinear large deformation

2019 ◽  
Vol 16 (6) ◽  
pp. 172988141988674 ◽  
Author(s):  
Yaqing Zhang ◽  
Wenjie Ge ◽  
Ziang Zhang ◽  
Xiaojuan Mo ◽  
Yonghong Zhang
Keyword(s):  
Large Deformation ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Flight Performance ◽  
Morphing Wing ◽  
Structure Topology ◽  
Trailing Edges ◽  
Morphing Wings

The morphing wing with large deformation can benefit its flight performance a lot in different conditions. In this study, a variable camber morphing wing with compliant leading and trailing edges is designed by large-displacement compliant mechanisms. The compliant mechanisms are carried out by a hyperelastic structure topology optimization, based on a nonlinear meshless method. A laminated leading-edge skin is designed to fit the curvature changing phenomenon of the leading edge during deformation. A morphing wing demonstrator was manufactured to testify its deformation capability. Comparing to other variable camber morphing wings, the proposal can realize larger deflection of leading and trailing edges. The designed morphing wing shows great improvement in aerodynamic performance and enough strength to resist aerodynamic and structural loadings.

A Mesh Deformation Method with Multiple Editing Granularities

2012 ◽  
Vol 263-266 ◽  
pp. 1822-1829
Author(s):  
Zheng Jie Deng ◽  
Feng Wei Wang ◽  
Guo Yuan Chen ◽  
Chun Shi ◽  
Shu Qian He ◽  
...  
Keyword(s):  
Mean Value ◽  
Original Model ◽  
Mesh Deformation ◽  
Accuracy Control ◽  
Deformation Method ◽  
Mean Value Coordinates ◽  
Control Mesh

This paper proposes a mesh deformation method being able to quickly exchange between different editing granularities. The method firstly simplifies the original model mesh to obtain an accuracy-specified control mesh while preserving user’s pre-configured control handle vertices, and then computes the original mesh vertices’ mean value coordinates on the control mesh. Next, uses the Laplacian deformation to deform the control mesh with user’s editing, and then computes the deforming result based on the new control mesh and the previous mean value coordinates. Users can quickly generate a different accuracy control mesh of the new mesh again for deforming with a different granularity. Users only need edit some control vertices, which contains user’s specified handles, so the manipulation is convenient. Experiments show that users can deform models with this method, while changing the granularity fluently and preserving mesh’s features.

Large Deformation Analysis and Experiments With Double Parallelogram Compliant Mechanisms

2018 ◽  
Author(s):  
Abhijit A. Tanksale ◽  
Prasanna S. Gandhi
Keyword(s):  
Large Deformation ◽  
High Precision ◽  
Large Deformations ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Vertical Plane ◽  
Coupled Analysis ◽  
Deformation Analysis ◽  
Flexible Beams ◽  
Straight Line

Compliant mechanisms are highly preferred in applications demanding motion with high precision. These mechanisms provide friction-less, backlash-free precise motion obtained through deformation of flexible members. The double parallelogram compliant mechanism (DPCM) is one the most important compliant mechanisms to obtain highly precise straight-line motion. DPCM when operated in horizontal plane yield high precision straight-line motion (even with large deformations) useful in several engineering applications. However, constraints such as space, dead loads, etc. may demand DPCMs to be used in the vertical plane. For DPCMs operating in a vertical plane, the axial load due to gravity causes tension and compression in flexible beams which get coupled to bending under large deformations. This ultimately affects the parasitic error of straight-line motion. This paper presents a coupled analysis, along with experimental validation, of DPCM operating in vertical plane considering gravity effects with large deformation.

scholarly journals Fit Evaluation during Repetition Interaction in Garment Pattern Design

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Yuxiang Zhu ◽  
Yanjun Peng
Keyword(s):  
Design Procedure ◽  
Mean Value ◽  
Interpolation Algorithm ◽  
Triangle Mesh ◽  
Pattern Design ◽  
Mean Value Coordinates ◽  
Speed Up ◽  
Evaluation Outcome ◽  
Garment Design ◽  
Mesh Update

We present a novel virtual try-on solution for fitting evaluation and pattern modification to design various types of garment and speed up the garment design process. In the phase of fit evaluation, we propose a method for producing two-dimensional (2D) color maps by comparing a 2D triangle mesh panel garment and a 3D triangle mesh garment, which can display the fit evaluation outcome in real time. In the phase of pattern modification, a novel prior condition based on maximum entropy coordinates and a more comprehensive mean value coordinates interpolation algorithm are proposed. By a combination of the two deformation methods, the positions of the internal vertices are updated smoothly. Applying the proposed method to the repetition of the garment design procedure, the experimental results show that it can easily pinpoint the location where it needs to be modified and can achieve arbitrary pattern modification with a smooth mesh update.

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