scholarly journals Polymer 4D printing: Advanced shape‐change and beyond

2021 ◽  
Author(s):  
Patrick Imrie ◽  
Jianyong Jin
Keyword(s):  
Shape Change ◽  
4D Printing

Reversible shape change structures by grayscale pattern 4D printing

2018 ◽  
Vol 1 (1) ◽  
pp. 015002 ◽  
Author(s):  
Jiangtao Wu ◽  
Zeang Zhao ◽  
Xiao Kuang ◽  
Craig M Hamel ◽  
Daining Fang ◽  
...  
Keyword(s):  
Shape Change ◽  
4D Printing

4D Printing: Multi-Material Shape Change

2014 ◽  
Vol 84 (1) ◽  
pp. 116-121 ◽  
Author(s):  
Skylar Tibbits
Keyword(s):  
Shape Change ◽  
4D Printing

4D Printing of Complex Ceramic Structures via Controlling Zirconia Contents and Patterns

2021 ◽  
Author(s):  
Zhicheng Rong ◽  
Chang Liu ◽  
Yingbin Hu
Keyword(s):  
3D Printing ◽  
Shape Memory ◽  
Shape Change ◽  
Three Dimensional ◽  
Ceramic Materials ◽  
Full Potential ◽  
Sintering Process ◽  
4D Printing ◽  
3D Printed ◽  
Dynamic Components

Abstract In recent years, more and more attentions have been attracted on integrating three-dimensional (3D) printing with fields (such as magnetic field) or innovating new methods to reap the full potential of 3D printing in manufacturing high-quality parts and processing nano-scaled composites. Among all of newly innovated methods, four-dimensional (4D) printing has been proved to be an effective way of creating dynamic components from simple structures. Common feeding materials in 4D printing include shape memory hydrogels, shape memory polymers, and shape memory alloys. However, few attempts have been made on 4D printing of ceramic materials to shape ceramics into intricate structures, owing to ceramics’ inherent brittleness nature. Facing this problem, this investigation aims at filling the gap between 4D printing and fabrication of complex ceramic structures. Inspired by swelling-and-shrinking-induced self-folding, a 4D printing method is innovated to add an additional shape change of ceramic structures by controlling ZrO2 contents and patterns. Experimental results evidenced that by deliberately controlling ZrO2 contents and patterns, 3D-printed ceramic parts would undergo bending and twisting during the sintering process. To demonstrate the capabilities of this method, more complex structures (such as a flower-like structure) were fabricated. In addition, functional parts with magnetic behaviors were 4D-printed by incorporating iron into the PDMS-ZrO2 ink.

Shape Adaptive Structures by 4D Printing

2017 ◽  
Author(s):  
G. F. Hu ◽  
A. R. Damanpack ◽  
M. Bodaghi ◽  
W. H. Liao
Keyword(s):  
Fused Deposition Modeling ◽  
Shape Change ◽  
Material Model ◽  
Element Formulation ◽  
4D Printing ◽  
Plate Structures ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Programming Mechanism ◽  
Polymeric Structures

This paper introduces a 4D printing method to program shape memory polymers (SMPs) during fabrication process. Fused deposition modeling is employed to program SMPs during depositing the material. This approach is implemented to fabricate complicated polymeric structures by self-bending features without need of any post-programming. Experiments are conducted to demonstrate feasibility of one-dimensional (1D)-to 2D and 2D-to-3D self-bending. It is shown that 4D printed plate structures can transform into 3D curved shell structures by simply heating. A 3D macroscopic constitutive model is developed to predict thermo-mechanical behaviors of the printed SMPs. Governing equations are also established to simulate programming mechanism during printing process and shape change of self-bending structures. In this respect, a finite element formulation is developed considering von-Kármán geometric non-linearity and solved by implementing iterative Newton-Raphson scheme. The accuracy of the computational approach is checked with experimental results. It is shown that the structural-material model is capable of replicating the main features observed in the experiments.

scholarly journals GDFE: Geometry-Driven Finite Element for Four-Dimensional Printing

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Tsz-Ho Kwok ◽  
Yong Chen
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Shape Change ◽  
Material Structure ◽  
Structure Property ◽  
4D Printing ◽  
Shape Transformation ◽  
Physical Experiments ◽  
Primary Focus ◽  
The Relationship

Four-dimensional (4D) printing is a new category of printing that expands the fabrication process to include time as the fourth dimension, and its simulation and planning need to take time into consideration as well. The common tool for estimating the behavior of a deformable object is the finite element method (FEM). However, there are various sources of deformation in 4D printing, e.g., hardware and material settings. To model the behavior by FEM, a complete understanding of the process is needed and a mathematical model should be established for the structure–property–process relationship. However, the relationship is usually complicated, which requires different kinds of testing to formulate such models due to the process complexity. With the insight that the characteristic of shape change is the primary focus in 4D printing, this paper introduces geometry-driven finite element (GDFE) to simplify the modeling process by inducing deformation behavior from a few physical experiments. The principle of GDFE is based on the relationship between material structure and shape transformation. Accordingly, a deformation simulation can be developed for 4D printing by applying the principles to the GDFEs. The GDFE framework provides an intuitive and effective way to enable simulation and planning for 4D printing even when a complete mathematical model of new material is not available yet. The use of the GDFE framework for some applications is also presented in this paper.

scholarly journals 4D Textiles Made by Additive Manufacturing on Pre-Stressed Textiles—An Overview

Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 31
Author(s):  
Hannah Carlotta Koch ◽  
David Schmelzeisen ◽  
Thomas Gries
Keyword(s):  
Additive Manufacturing ◽  
Web Of Science ◽  
Shape Change ◽  
Material Behavior ◽  
Future Research ◽  
Material Structure ◽  
4D Printing ◽  
Research Directions ◽  
Production Technologies ◽  
Future Research Directions

Four-dimensional textiles are textiles that can change shape or function over time by the influence of a stimulus, mainly force and heat. In this review, the focus is on 4D textiles made by additive manufacturing which is built on the concept of 4D printing. A literature survey in Web of Science and Scopus was carried out, which resulted in 29 contributions on additive manufacturing on pre-stressed textiles. In this paper, an overview of materials, production technologies and testing methods is given. The concepts of form giving and shape change transferred to 4D textiles are classified. The influencing factors on the properties of the material structure are presented. The main focus of the literature lies in defining process and material properties for improving the adhesion. Only limited research has been conducted on simulating the material behavior. Ideas for applications exist but no research has been conducted on real applications. Therefore, the challenges are identified, and future research directions are derived.

Role of spectrin in membrane fusion and in shape change of human erythrocyte ghost

1978 ◽  
Vol 36 (2) ◽  
pp. 328-329
Author(s):  
Hideo Hayashi ◽  
Yoshikazu Hirai ◽  
John T. Penniston
Keyword(s):  
Conformational Changes ◽  
Human Erythrocyte ◽  
Shape Change ◽  
Membrane Surface ◽  
Slight Modification ◽  
Active Role ◽  
Main Role ◽  
Bank Blood ◽  
Human Erythrocyte Ghost

Spectrin is a membrane associated protein most of which properties have been tentatively elucidated. A main role of the protein has been assumed to give a supporting structure to inside of the membrane. As reported previously, however, the isolated spectrin molecule underwent self assemble to form such as fibrous, meshwork, dispersed or aggregated arrangements depending upon the buffer suspended and was suggested to play an active role in the membrane conformational changes. In this study, the role of spectrin and actin was examined in terms of the molecular arrangements on the erythrocyte membrane surface with correlation to the functional states of the ghosts.Human erythrocyte ghosts were prepared from either freshly drawn or stocked bank blood by the method of Dodge et al with a slight modification as described before. Anti-spectrin antibody was raised against rabbit by injection of purified spectrin and partially purified.

Microstructural characterization of laser-melted/roller-quenched dicalcium silicate

1988 ◽  
Vol 46 ◽  
pp. 582-583
Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Shape Change ◽  
Microstructural Characterization ◽  
Particle Size Effect ◽  
Dicalcium Silicate ◽  
Laser Melting ◽  
Uniform Size ◽  
Cell Shape Change ◽  
Wide Range

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.

Conditions Affecting the Responses of Human Platelets to Epinephrine

1988 ◽  
Vol 60 (02) ◽  
pp. 209-216 ◽  
Author(s):  
Chantal Lalau Keraly ◽  
Raelene L Kinlough-Rathbone ◽  
Marian A Packham ◽  
Hidenori Suzuki ◽  
J Fraser Mustard
Keyword(s):  
Platelet Rich Plasma ◽  
Shape Change ◽  
Human Platelets ◽  
Dense Granule ◽  
Primary Phase ◽  
Lag Phase ◽  
Acid Citrate Dextrose ◽  
Two Phases ◽  
Citrate Dextrose ◽  
Thromboxane Formation

SummaryConditions affecting the responses of human platelets to epinephrine were examined. In platelet-rich plasma prepared from blood anticoagulated with hirudin or PPACK (D-pheny- lalanyl-L-prolyl-L-arginine chloromethyl ketone), epinephrine did not cause shape change or aggregation. In a Tyrode-albumin- apyrase solution containing a concentration of Ca2+ in the physiological range, and fibrinogen, epinephrine in concentrations as high as 40 μM did not induce platelet shape change, caused either no primary aggregation or very slight primary aggregation, and did not induce thromboxane formation, release of dense granule contents, or secondary aggregation. In contrast, in citrated platelet-rich plasma, epinephrine induced two phases of aggregation. This is not attributable to the generation of traces of thrombin since the same effects were evident when blood was taken into a combined citrate-hirudin anticoagulant or a combined citrate-PPACK anticoagulant. In a modified Tyrode-albu- min-apyrase solution containing approximately 20 μM Ca2+, 1 mM Mg2+, and fibrinogen, epinephrine induced extensive aggregation after a lag phase, but no primary phase was evident; thromboxane formation and release of dense granule contents accompanied the aggregation response. These responses were also observed when PPACK was included with the acid-citrate- dextrose anticoagulant, and in the washing and resuspending fluids. In the presence of aspirin or the thromboxane receptor blocker BM 13.177 a few small aggregates were detected by particle counting and by scanning electron microscopy; with the latter inhibitor, the platelets in the aggregates retained their disc shape; secondary aggregation and the responses associated with it did not occur. Thus thromboxane A2 formation is not necessary for the formation of these small aggregates, but is required for extensive aggregation and release. As with other weak agonists, the close platelet-to-platelet contact in the low Ca2+ medium appears to be necessary for full secondary aggregation. Omission of fibrinogen from the low Ca2+ medium prevented both primary and secondary aggregation in response to epinephrine. An antibody (10E5) to the glycoprotein Ilb/IIIa complex was completely inhibitory in the presence of fibrinogen. Thus the response of human platelets to epinephrine is influenced by the concentration of Ca2+ and the presence of fibrinogen in the medium in which they are suspended.

Sign in / Sign up

Export Citation Format

Share Document