Computational Design of Active Lattice Structures for 4D Printed Pneumatic Shape Morphing

2019 ◽  
Author(s):  
Cosima du Pasquier ◽  
Pascal Koller ◽  
Tino Stankovic ◽  
Kristina Shea
Keyword(s):  
Complex Shape ◽  
Lattice Structure ◽  
Design Method ◽  
Shape Change ◽  
Computational Design ◽  
Digital Fabrication ◽  
Computational Effort ◽  
Shape Morphing ◽  
Actuator Placement ◽  
Shape Changes

Abstract With advances in 3D printing and digital fabrication an opportunity is presented to realize highly customized designs whose shape can change and adapt to facilitate their functionality. A computational design method to determine the configuration of 2D pneumatic shape morphing lattices using a direct search method is implemented and assessed. The method is tested using a Kagome unit cell lattice structure, which is particularly well suited for shape morphing. To achieve shape change, beams are replaced by linear actuators such as those found in pneumatic 4D printing, whose number and placement are optimized to replicate a given target shape. The actuator placement and deformation accuracy are given for four main curvature changes: linear, convex, concave and the transition from one to the other. The results are assessed in terms accuracy of deformation and computational effort. It is shown that the method proposed produces structures that can replicate complex shape changes within 1% of the desired shape. Reducing the number of actuators for robustness purposes is shown to affect the results minimally.

Constraint-Based Synthesis of Shape-Morphing Structures in Virtual Reality

2010 ◽  
Author(s):  
Judy M. Vance ◽  
Denis Dorozhkin
Keyword(s):  
Virtual Reality ◽  
Rigid Body ◽  
Method Development ◽  
Compliant Mechanisms ◽  
Design Method ◽  
Shape Change ◽  
The Body ◽  
Motion Path ◽  
Primary Methods ◽  
Shape Morphing

This manuscript outlines a novel approach to the design of compliant shape-morphing structures using constraint-based design method. Development of robust methods for designing shape-morphing structures is the focus of multiple current research projects, since the ability to modify geometric shapes of the individual system components, such as aircraft wings and antenna reflectors, provides the means to affect the performance of the corresponding mechanical systems. Of particular interest is the utilization of compliant mechanisms to achieve the desired adaptive shape change characteristics. Compliant mechanisms, as opposed to the traditional rigid link mechanisms, achieve motion guidance via the compliance and deformation of the mechanism’s members. The goal is to design a single-piece flexible structure capable of morphing a given curve or profile into a target curve or profile while utilizing the minimum number of actuators. The two primary methods prevalent in the design community at this time are the pseudo-rigid body method (PRBM) and the topological synthesis. Unfortunately these methods either tend to suffer from a poor ability to generate potential solutions (being more suitable for the analysis of existing structures) or are susceptible to overly-complex solutions. By utilizing the constraint-based design method (CBDM) we aim to address those shortcomings. The concept of CBDM has generally been confined to the Precision Engineering community and is based on the fundamental premise that all motions of a rigid body are determined by the position and orientation of the constraints (constraint topology) which are placed upon the body. Any mechanism motion path may then be defined by the proper combination of constraints. In order to apply the CBDM concepts to the design and analysis of shape-morphing compliant structures we propose a tiered design method that relies on kinematics, finite element analysis, and optimization. By discretizing the flexible element that comprises the active shape surface at multiple points in both the initial and the target configurations and treating the resulting individual elements as rigid bodies that undergo a planar or general spatial displacement we are able to apply the traditional kinematics theory to rapidly generate sets of potential solutions. The final design is then established via an FEA-augmented optimization sequence. Coupled with a virtual reality interface and a force-feedback device this approach provides the ability to quickly specify and evaluate multiple design problems in order to arrive at the desired solution.

A design framework for absorption and diffusion panels with sustainable materials

2021 ◽  
Vol 263 (4) ◽  
pp. 2207-2218
Author(s):  
Jonathan Dessi-Olive ◽  
Timothy Hsu
Keyword(s):  
Material Selection ◽  
Design Method ◽  
Computational Design ◽  
Digital Fabrication ◽  
Design Methods ◽  
Acoustic Properties ◽  
Visual Appearance ◽  
Sustainable Material ◽  
Architectural Acoustics ◽  
Wide Range

Architectural acoustics has not traditionally had unified design methods that specify acoustical performance, visual appearance, and sustainable material selection, leading to underperforming products that contribute to a waste stream of petro-chemical foam and fiberglass materials. The evolution of design, materials, and manufacturing techniques in recent years has created new opportunities to reimagine acoustic diffusers and absorbers. Previous work by the authors have demonstrated a unifying framework for design and collaboration in architectural acoustics. The framework uses visually-driven computational design method inspired by shape grammars that generate a wide range of acoustic phase grating diffuser arrays that display unique visual and performative qualities. Simulation and evaluation metrics to assess the complexity of each design are rated in terms of their diffusion and absorption coefficients and a visual aesthetic coefficient. This paper extends the framework to include digital fabrication protocols and sustainable material specifications - including the use of fungi-based materials. Built prototypes demonstrate an expanded acoustic design space that gives acousticians the potential to create custom diffuser shapes with precise acoustical response. The innovative combination of computational design methods and sustainable fabrication protocols will be discussed, and the acoustic properties of arrays will be evaluated and compared to simulations of corresponding designs.

scholarly journals Surrogate-Based Optimization of Horizontal Axis Hydrokinetic Turbine Rotor Blades

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4045
Author(s):  
David Menéndez Arán ◽  
Ángel Menéndez
Keyword(s):  
Turbine Blade ◽  
Design Method ◽  
Optimization Method ◽  
Turbine Rotor ◽  
Computational Effort ◽  
Rotor Blades ◽  
Linear Functions ◽  
Cavitation Inception ◽  
Hydrokinetic Turbine ◽  
Blade Geometry

A design method was developed for automated, systematic design of hydrokinetic turbine rotor blades. The method coupled a Computational Fluid Dynamics (CFD) solver to estimate the power output of a given turbine with a surrogate-based constrained optimization method. This allowed the characterization of the design space while minimizing the number of analyzed blade geometries and the associated computational effort. An initial blade geometry developed using a lifting line optimization method was selected as the base geometry to generate a turbine blade family by multiplying a series of geometric parameters with corresponding linear functions. A performance database was constructed for the turbine blade family with the CFD solver and used to build the surrogate function. The linear functions were then incorporated into a constrained nonlinear optimization algorithm to solve for the blade geometry with the highest efficiency. A constraint on the minimum pressure on the blade could be set to prevent cavitation inception.

Autonomy and non-autonomy in Drosophila mesoderm determination and morphogenesis

Development ◽  
1994 ◽  
Vol 120 (4) ◽  
pp. 853-859 ◽  
Author(s):  
M. Leptin ◽  
S. Roth
Keyword(s):  
Cell Shape ◽  
Shape Change ◽  
Developmental Program ◽  
Cell Shape Change ◽  
Ventral Furrow ◽  
Large Numbers ◽  
The Individual ◽  
Mutant Cells ◽  
Transplantation Experiments ◽  
Shape Changes

The mesoderm in Drosophila invaginates by a series of characteristic cell shape changes. Mosaics of wild-type cells in an environment of mutant cells incapable of making mesodermal invaginations show that this morphogenetic behaviour does not require interactions between large numbers of cells but that small patches of cells can invaginate independent of their neighbours' behaviour. While the initiation of cell shape change is locally autonomous, the shapes the cells assume are partly determined by the individual cell's environment. Cytoplasmic transplantation experiments show that areas of cells expressing mesodermal genes ectopically at any position in the egg form an invagination. We propose that ventral furrow formation is the consequence of all prospective mesodermal cells independently following their developmental program. Gene expression at the border of the mesoderm is induced by the apposition of mesodermal and non-mesodermal cells.

A Framework for Component Layout and Geometry Design of Mechanical Systems: Configuration Network and its Viewing Control

1995 ◽  
Author(s):  
Kikuo Fujita ◽  
Shinsuke Akagi
Keyword(s):  
Design Method ◽  
Mechanical Systems ◽  
Optimization Procedure ◽  
Computational Design ◽  
Object Oriented Programming ◽  
Design System ◽  
Air Conditioner ◽  
Programming Technique ◽  
Geometry Design ◽  
Component Layout

Abstract A Framework of computational design method and model is proposed for layout and geometry design of complicated mechanical systems, which is named “configuration network and its viewing control”. In the method, a design object is represented with a set of declarative relationships among various elements of a system, that is, configurations, which is gradually extended from schematic structure to exact layout and geometry through design process. Since a whole of such configurations forms a too complicated network to compute all together, how to view subparts is controlled based on levels of granularity and width of scope range. Such a configuration network is made to grow and refined through embodying geometry and layout corresponding to a focused subpart with a numerical optimization procedure. The framework has also an ability to flexibly integrate with engineering analysis. Moreover, a design system is implemented with an object-oriented programming technique, and it is applied to a design problem of air conditioner units in order to show the validity and effectiveness of the framework.

Computational Design for Digitally Fabricated 3D Inductive Power Transfer Coils

2022 ◽  
pp. 1-28
Author(s):  
Jun Xu ◽  
Eugeni L. Doubrovski ◽  
Jo Geraedts ◽  
Yu Song
Keyword(s):  
Design Method ◽  
Computational Design ◽  
Future Research ◽  
Receiver Coil ◽  
Power Transfer ◽  
Coil Design ◽  
Optimal Position ◽  
Inductive Power Transfer ◽  
Transmitter Coil ◽  
Inductive Power

Abstract The geometric shapes and the relative position of coils influence the performance of a three-dimensional (3D) inductive power transfer system. In this paper, we propose a coil design method for specifying the positions and the shapes of a pair of coils to transmit the desired power in 3D. Given region of interests (ROIs) for designing the transmitter and the receiver coils on two surfaces, the transmitter coil is generated around the center of its ROI first. The center of the receiver coil is estimated as a random seed position in the corresponding 3D surface. At this position, we use the heatmap method with electromagnetic constraints to iteratively extend the coil until the desired power can be transferred via the set of coils. In each step, the shape of the extension, i.e. a new turn of the receiver coil, is found as a spiral curve based on the convex hulls of adjacent turns in the 2D projection plane along their normal direction. Then, the optimal position of the receiver coil is found by maximizing the efficiency of the system. In the next step, the position and the shape of the transmitter coil are optimized based on the fixed receiver coil using the same method. This zig-zag optimization process iterates until an optimum is reached. Simulations and experiments with digitally fabricated prototypes were conducted and the effectiveness of the proposed 3D coil design method was verified. Possible future research directions are highlighted well.

scholarly journals An Experimental Study on the Shape Changes of TiO2Nanocrystals Synthesized by Microemulsion-Solvothermal Method

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Wei Kong ◽  
Bo Liu ◽  
Bo Ye ◽  
Zhongping Yu ◽  
Hua Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Stainless Steel ◽  
Oleic Acid ◽  
Solvothermal Method ◽  
Shape Change ◽  
Tetrabutyl Titanate ◽  
Microemulsion System ◽  
Solvothermal Process ◽  
Shape Changes ◽  
Shape And Size

Titanium dioxide (TiO2) nanocrystals of different shape were successfully synthesized in a new microemulsion system through a solvothermal process. The TiO2nanocrystals were prepared from the reaction of tetrabutyl titanate (TBT),H2O, and oleic acid (OA), which were used as solvent and surfactant at 300∘Cand 240∘Cin a stainless steel autoclave. The sphere, polygon, and rhombus-shaped nanocrystals have been prepared at 300∘Cand the dot- and- rod shaped nanocrystals have been synthesized at 240∘C. The effect of the reaction time on the shape and size of TiO2nanocrystals in this method was studied in the present paper. The size distribution of TiO2nanocrystals prepared at 300∘Cfor different hours is also studied. In addition, an attempt to describe the mechanism of shape change of TiO2nanocrystals was presented in this paper.

Compaction-related deformation in Cambrian olenelloid trilobites and its implications for fossil morphometry

1999 ◽  
Vol 73 (2) ◽  
pp. 355-371 ◽  
Author(s):  
Mark Webster ◽  
Nigel C. Hughes
Keyword(s):  
Lower Cambrian ◽  
Shape Change ◽  
Anterior Lobe ◽  
Interspecific Differences ◽  
Fracture Patterns ◽  
Morphometric Analyses ◽  
Ontogenetic Trajectories ◽  
Metric Distances ◽  
Relative Convexity ◽  
Shape Changes

Morphometric analyses of silicified and nonsilicified (preserved in shale) specimens of the olenelloid trilobites Olenellus (Olenellus) gilberti Meek (in White, 1874) and Nephrolenellus geniculatus Palmer, 1998, from the Lower Cambrian C-Shale Member of the Pioche Formation show that even well-preserved specimens in shales have undergone significant changes in lateral as well as vertical dimensions as a result of compaction. Analyses of cephalic landmarks show that in both species compaction causes posteriordirected collapse of the anterior lobe of the glabella, adaxial deformation of the ocular lobes, and abaxial and anterior splaying of genal regions. These shape changes are explicable in terms of observed exoskeletal fracture patterns. Landmarks show an increase in scatter around their ontogenetic trajectories that is generally proportional to the degree of lateral shift each landmark has undergone. Interspecific differences in compactional response may depend on the relative convexity of the cephalon. Olenellus (Olenellus) gilberti is a low-convexity species and shows marked lateral shape change, particularly in the genal region. Nephrolenellus geniculatus is more convex and shows less severe lateral shape change. Landmarks of both species exhibit an average trebling of the degree of scatter around their average ontogenetic trajectories in compacted samples. Because even well-preserved specimens in shales differ in shape from their precompactional appearance, results of morphometric studies utilizing metric distances between landmarks in trilobites where compaction can be detected must be interpreted with caution.

PUSHOVER ANALYSIS BY ONE ELEMENT PER MEMBER FOR PERFORMANCE-BASED SEISMIC DESIGN

2010 ◽  
Vol 10 (01) ◽  
pp. 111-126 ◽  
Author(s):  
S. W. LIU ◽  
Y. P. LIU ◽  
S. L. CHAN
Keyword(s):  
Seismic Design ◽  
Design Method ◽  
Pushover Analysis ◽  
Nonlinear Behavior ◽  
Computational Effort ◽  
Effective Length ◽  
Single Element ◽  
Individual Element ◽  
Economical Design ◽  
Performance Based Seismic Design

Nonlinear static (pushover) analysis is an effective and simple tool for evaluating the seismic response of structures and offers an attractive choice for the performance-based design. As such, it has generally been used in modern design due to its practicality. However, the nonlinear plastic design method consumes extensive computational effort for practical structures under numerous load cases. Thus, an efficient element capturing the nonlinear behavior of a beam-column will be useful. In this paper, the authors propose a practical pushover analysis procedure using a single element per member for seismic design. As an improvement to previous research works, both P – Δ and P – δ effects as well as initial imperfections in global and member levels are considered. Therefore, the section capacity check without the assumption of effective length is adequate for present design and the conventional individual element design is avoided. The uncertainty of the buckling effects and effective length method can be eliminated and so a more economical design can be achieved. Two benchmark steel frames of three-storey and nine-storey in FEMA 440 were analyzed to illustrate the validity of the proposed method.

scholarly journals Adaptive Strategies for Mud Shell Robotic Fabrication

2018 ◽  
Vol 3 (2) ◽  
pp. 64
Author(s):  
Chaltiel Stephanie ◽  
Bravo Maite ◽  
Ibrahim Abdullah
Keyword(s):  
Spray Deposition ◽  
Sustainable Use ◽  
Adaptive Strategies ◽  
Computational Design ◽  
Digital Fabrication ◽  
Construction Methods ◽  
Robotic Fabrication ◽  
Material Deposition ◽  
Physical Tests ◽  
Full Scale Tests

The digital fabrication of monolithic shell structures is presenting some challenges related to the interface between computational design, materialist, and fabrication techniques. This research proposes a singular method for the sequential robotic spray deposition in layers of diverse clay mixes over a temporary fabric form-work pulled in between peripheral and cross section arches. This process relies mainly on the continuity of the construction phases for stability and durability but has encountered some challenges in physical tests related to sagging, displacement, and deformations during the robotic deposition of the material. Adaptive strategies during the digital fabrication stages are proposed for a sequential exploration of the geometry, structural analysis, and construction techniques. Alternative adjustments of protocols for the robotic material deposition include both predictable and unsuspected behaviors preventing the structure to reach non-viable geometric thresholds. Two case studies of physical tests describe, analyze, and simulate some of these strategies and identify specific parameters inquiring the sequential adjustments of the robotic material deposition. These strategies will drive future full-scale tests within a sustainable use of materials and adaptive construction methods, seeking an optimized structural performance that could open a new chapter for the digital fabrication of earthen shells.

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