Design Patterns of Soft Products Using Surface Flattening

2018 ◽  
Vol 18 (2) ◽  
Author(s):  
Dongliang Zhang ◽  
Jituo Li ◽  
Jin Wang
Keyword(s):  
Design Patterns ◽  
Three Dimensional ◽  
Optimization Method ◽  
Surface Flattening ◽  
Manufactured Products ◽  
Mass Spring Model ◽  
Boundary Optimization ◽  
Pattern Development ◽  
Mass Spring ◽  
Flattening Process

In this paper, we present a pattern development method for soft product design. We utilize a surface fattening method based on a mass-spring model to create 2D patterns unfolding from a three-dimensional (3D) model. Multilevel meshes are proposed to expedite the flattening process, and a boundary optimization method is employed to guarantee 2D patterns can be sewn well. We apply the proposed method to the design of real soft products. Experimental results show that it can deal with complex surfaces efficiently and robustly, and manufactured products are satisfactory.

A Three-Dimensional Lumped Parameter Model of Nanoscale Phononic Crystals

2009 ◽  
Author(s):  
Bruce L. Davis ◽  
Mahmoud I. Hussein
Keyword(s):  
Equations Of Motion ◽  
Three Dimensional ◽  
Phononic Crystals ◽  
Lumped Parameter Model ◽  
Lagrangian Equations ◽  
Area Of Interest ◽  
Simple Cubic ◽  
Lumped Parameter ◽  
Mass Spring Model ◽  
Mass Spring

This work focuses on modeling nanoscale phononic crystals by setting up the appropriate Lagrangian equations of motion. The atomic structure and force constants are accounted for by means of a lumped parameter mass-spring model. In particular we focus on a simple cubic lattice with one mass per primitive unit cell. We use the model to predict the wave propagation frequency spectrum. We then use the model to conduct a series of studies on the influence of defects intentionally introduced to the lattice at a supercell level. One area of interest is the effect of such alterations on the size and location of band gaps.

Tuning of Bandgap Structures in Three-Dimensional Kagome-Sphere Lattice

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Ying Liu ◽  
Xiu-zhan Sun ◽  
Wen-zheng Jiang ◽  
Yu Gu
Keyword(s):  
Phononic Crystal ◽  
Three Dimensional ◽  
Structure Design ◽  
Geometrical Parameters ◽  
Geometrical Condition ◽  
Mass Spring Model ◽  
Sphere Radius ◽  
Equivalent Mass ◽  
Kagome Truss ◽  
Mass Spring

In this manuscript, acoustic wave propagation in a novel three-dimensional porous phononic crystal-Kagome lattice, is studied by using finite element method. Firstly, a Kagome-sphere structure is established based on Kagome truss. For lattice with fixed rods (sphere radius varied) or fixed spheres (rod radius varied), the band structures are calculated in order to clarify the influence of geometrical parameters (sphere and rod sizes) on the bandgap characteristics in Kagome-sphere lattice. The vibration modes at the band edges of the lowest bandgaps are investigated with the aim to understand the mechanism of the bandgap generation. It is found that the emergence of the bandgap is due to the local resonant vibration of the unit cell at the adjacent bands. The width and position of this bandgap can be tuned by adjusting the geometrical parameters. An equivalent mass-spring model is proposed and the equivalent system resonance frequency can be evaluated which predicts well the upper and lower edges of the complete bandgaps. Moreover, the critical geometrical parameter is formulated which gives the critical geometrical condition for the opening of the complete bandgaps. The results in this paper are relevant to the bandgap structure design of three-dimensional porous phononic crystals (PPCs).

Modeling of Underwater Flexible Structures and Its Application to the Fishing Gear System Simulation

2004 ◽  
Author(s):  
Chun-Woo Lee ◽  
Ju-Hee Lee ◽  
Bong-Jin Cha ◽  
Hyun-Young Kim ◽  
Ji-Hoon Lee
Keyword(s):  
Flexible Structures ◽  
Three Dimensional ◽  
Stable Solution ◽  
Commercial Fishing ◽  
Flexible Systems ◽  
Physically Based Model ◽  
Mass Spring Model ◽  
Physically Based ◽  
External Forces ◽  
Mass Spring

This paper describes a physically based model for underwater flexible systems and presents its simulation results. In this study, a flexible structure is divided into a finite number of elements and those elements are connected with flexible lines. The elements of a structure can be modeled using the mass-spring model. The model is described as a nonlinear and stiff equation by considering the elasticity of the lines and external forces. The Newmark β method is used for the numerical integration of the system. It is found that this method offers low computational times and a stable solution. Also introduced is an algorithm to design various flexible systems using computer graphics, an automatic model creating system from the designed plan and a three-dimensional graphics tool that can show the calculated results. Application examples in design and simulation for the commercial fishing gears are presented.

Three-dimensional asymmetric maximum weight lifting prediction considering dynamic joint strength

2021 ◽  
pp. 095441192098703
Author(s):  
Rahid Zaman ◽  
Yujiang Xiang ◽  
Jazmin Cruz ◽  
James Yang
Keyword(s):  
Experimental Data ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Three Dimensional ◽  
Optimization Method ◽  
Weight Lifting ◽  
Joint Torque ◽  
Maximum Weight ◽  
Angular Velocities ◽  
Asymmetric Lifting

In this study, the three-dimensional (3D) asymmetric maximum weight lifting is predicted using an inverse-dynamics-based optimization method considering dynamic joint torque limits. The dynamic joint torque limits are functions of joint angles and angular velocities, and imposed on the hip, knee, ankle, wrist, elbow, shoulder, and lumbar spine joints. The 3D model has 40 degrees of freedom (DOFs) including 34 physical revolute joints and 6 global joints. A multi-objective optimization (MOO) problem is solved by simultaneously maximizing box weight and minimizing the sum of joint torque squares. A total of 12 male subjects were recruited to conduct maximum weight box lifting using squat-lifting strategy. Finally, the predicted lifting motion, ground reaction forces, and maximum lifting weight are validated with the experimental data. The prediction results agree well with the experimental data and the model’s predictive capability is demonstrated. This is the first study that uses MOO to predict maximum lifting weight and 3D asymmetric lifting motion while considering dynamic joint torque limits. The proposed method has the potential to prevent individuals’ risk of injury for lifting.

scholarly journals Review on the 3-D simulation for weft knitted fabric

2021 ◽  
Vol 16 ◽  
pp. 155892502110125
Author(s):  
Sha Sha ◽  
Anqi Geng ◽  
Yuqin Gao ◽  
Bin Li ◽  
Xuewei Jiang ◽  
...  
Keyword(s):  
Physical Models ◽  
Spring Model ◽  
Finite Element Analyses ◽  
Knitted Fabrics ◽  
Piecewise Function ◽  
Fabric Structure ◽  
Weft Knitted Fabric ◽  
Mass Spring Model ◽  
Virtual Display ◽  
Mass Spring

There are different kinds of geometrical models and physical models used to simulate weft knitted fabrics nowadays, such as loop models based on Pierce, piecewise function, spline curve, mass-spring model, and finite element analyses (FEA). Weft knitting simulation technology, including modeling and yarn reality, has been widely adopted in fabric structure designing for the manufacturer. The technology has great potentials in both industries and dynamic virtual display. The present article is aimed to review the current development of 3-D simulation technique for weft knitted fabrics.

scholarly journals Optimization of Polymer Extrusion Die Based on Response Surface Method

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1043 ◽  
Author(s):  
Amin Razeghiyadaki ◽  
Dichuan Zhang ◽  
Dongming Wei ◽  
Asma Perveen
Keyword(s):  
Three Dimensional ◽  
Theoretical Work ◽  
Optimization Method ◽  
Extrusion Die ◽  
Surface Method ◽  
Spline Fitting ◽  
Die Profile ◽  
Response Optimization ◽  
Geometric Variables ◽  
Volume Method

A coupled surface response optimization method with a three-dimensional finite volume method is adopted in this study to identify five independent geometric variables of the die interior that provides a design with the lowest velocity variance at the exit of the coat-hanger extrusion die. Two of these five geometric variables represent the manifold dimension while the other three variables represent the die profile. In this method, B-spline fitting with four points was used to represent the die profile. A comparison of the optimized die obtained in our study and the die with a geometry derived by a previous theoretical work shows a 20.07% improvement in the velocity distribution at the exit of the die.

Packing Optimization by Enhanced Rubber Band Analogy

2005 ◽  
Author(s):  
Hong Dong ◽  
Georges M. Fadel ◽  
Vincent Y. Blouin
Keyword(s):  
Three Dimensional ◽  
Optimization Method ◽  
Rubber Band ◽  
Volume Relaxation ◽  
New Developments ◽  
Packing Problems ◽  
Rubber Balloon ◽  
Elastic Forces ◽  
Reaction Forces ◽  
Packing Optimization

In this paper, some new developments to the packing optimization method based on the rubber band analogy are presented. This method solves packing problems by simulating the physical movements of a set of objects wrapped by a rubber band in the case of two-dimensional problems or by a rubber balloon in the case of three-dimensional problems. The objects are subjected to elastic forces applied by the rubber band to their vertices as well as reaction forces when contacts between objects occur. Based on these forces, objects translate or rotate until maximum compactness is reached. To improve the compactness further, the method is enhanced by adding two new operators: volume relaxation and temporary retraction. These two operators allow temporary volume (elastic energy) increase to get potentially better packing results. The method is implemented and applied for three-dimensional arbitrary shape objects.

scholarly journals Computational Approach to Seasonal Changes of Living Leaves

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Ying Tang ◽  
Dong-Yan Wu ◽  
Jing Fan
Keyword(s):  
Seasonal Changes ◽  
Markov Chain Model ◽  
Geometric Model ◽  
Environmental Parameters ◽  
Computational Approach ◽  
Chain Model ◽  
Color Changes ◽  
Mass Spring Model ◽  
Scanned Image ◽  
Mass Spring

This paper proposes a computational approach to seasonal changes of living leaves by combining the geometric deformations and textural color changes. The geometric model of a leaf is generated by triangulating the scanned image of a leaf using an optimized mesh. The triangular mesh of the leaf is deformed by the improved mass-spring model, while the deformation is controlled by setting different mass values for the vertices on the leaf model. In order to adaptively control the deformation of different regions in the leaf, the mass values of vertices are set to be in proportion to the pixels' intensities of the corresponding user-specified grayscale mask map. The geometric deformations as well as the textural color changes of a leaf are used to simulate the seasonal changing process of leaves based on Markov chain model with different environmental parameters including temperature, humidness, and time. Experimental results show that the method successfully simulates the seasonal changes of leaves.

scholarly journals The Coplane Analysis Technique for Three-Dimensional Wind Retrieval Using the HIWRAP Airborne Doppler Radar

2015 ◽  
Vol 54 (3) ◽  
pp. 605-623 ◽  
Author(s):  
Anthony C. Didlake ◽  
Gerald M. Heymsfield ◽  
Lin Tian ◽  
Stephen R. Guimond
Keyword(s):  
Global Optimization ◽  
Doppler Radar ◽  
Three Dimensional ◽  
Optimization Method ◽  
Vertical Wind ◽  
Wind Component ◽  
Global Optimization Method ◽  
Analysis Technique ◽  
Radar Measurements ◽  
Cross Track

AbstractThe coplane analysis technique for mapping the three-dimensional wind field of precipitating systems is applied to the NASA High-Altitude Wind and Rain Airborne Profiler (HIWRAP). HIWRAP is a dual-frequency Doppler radar system with two downward-pointing and conically scanning beams. The coplane technique interpolates radar measurements onto a natural coordinate frame, directly solves for two wind components, and integrates the mass continuity equation to retrieve the unobserved third wind component. This technique is tested using a model simulation of a hurricane and compared with a global optimization retrieval. The coplane method produced lower errors for the cross-track and vertical wind components, while the global optimization method produced lower errors for the along-track wind component. Cross-track and vertical wind errors were dependent upon the accuracy of the estimated boundary condition winds near the surface and at nadir, which were derived by making certain assumptions about the vertical velocity field. The coplane technique was then applied successfully to HIWRAP observations of Hurricane Ingrid (2013). Unlike the global optimization method, the coplane analysis allows for a transparent connection between the radar observations and specific analysis results. With this ability, small-scale features can be analyzed more adequately and erroneous radar measurements can be identified more easily.

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