scholarly journals Shape-Adaptive Metastructures with Variable Bandgap Regions by 4D Printing

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 519 ◽  
Author(s):  
Reza Noroozi ◽  
Mahdi Bodaghi ◽  
Hamid Jafari ◽  
Ali Zolfagharian ◽  
Mohammad Fotouhi
Keyword(s):  
Structural Engineering ◽  
Shape Recovery ◽  
Fused Deposition Modeling ◽  
Functionally Graded ◽  
Temperature Sensitive ◽  
Frequency Range ◽  
4D Printing ◽  
Fe Method ◽  
Fused Deposition ◽  
Material Tailoring

This article shows how four-dimensional (4D) printing technology can engineer adaptive metastructures that exploit resonating self-bending elements to filter vibrational and acoustic noises and change filtering ranges. Fused deposition modeling (FDM) is implemented to fabricate temperature-responsive shape-memory polymer (SMP) elements with self-bending features. Experiments are conducted to reveal how the speed of the 4D printer head can affect functionally graded prestrain regime, shape recovery and self-bending characteristics of the active elements. A 3D constitutive model, along with an in-house finite element (FE) method, is developed to replicate the shape recovery and self-bending of SMP beams 4D-printed at different speeds. Furthermore, a simple approach of prestrain modeling is introduced into the commercial FE software package to simulate material tailoring and self-bending mechanism. The accuracy of the straightforward FE approach is validated against experimental observations and computational results from the in-house FE MATLAB-based code. Two periodic architected temperature-sensitive metastructures with adaptive dynamical characteristics are proposed to use bandgap engineering to forbid specific frequencies from propagating through the material. The developed computational tool is finally implemented to numerically examine how bandgap size and frequency range can be controlled and broadened. It is found out that the size and frequency range of the bandgaps are linked to changes in the geometry of self-bending elements printed at different speeds. This research is likely to advance the state-of-the-art 4D printing and unlock potentials in the design of functional metastructures for a broad range of applications in acoustic and structural engineering, including sound wave filters and waveguides.

scholarly journals 4D Printing Self-Morphing Structures

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1353 ◽  
Author(s):  
Mahdi Bodaghi ◽  
Reza Noroozi ◽  
Ali Zolfagharian ◽  
Mohamad Fotouhi ◽  
Saeed Norouzi
Keyword(s):  
Composite Structures ◽  
Fused Deposition Modeling ◽  
Functionally Graded ◽  
Complex Structures ◽  
Mechanical Behaviors ◽  
4D Printing ◽  
Digital Tool ◽  
Fused Deposition ◽  
Straightforward Method ◽  
Deposition Modeling

The main objective of this paper is to introduce complex structures with self-bending/morphing/rolling features fabricated by 4D printing technology, and replicate their thermo-mechanical behaviors using a simple computational tool. Fused deposition modeling (FDM) is implemented to fabricate adaptive composite structures with performance-driven functionality built directly into materials. Structural primitives with self-bending 1D-to-2D features are first developed by functionally graded 4D printing. They are then employed as actuation elements to design complex structures that show 2D-to-3D shape-shifting by self-bending/morphing. The effects of printing speed on the self-bending/morphing characteristics are investigated in detail. Thermo-mechanical behaviors of the 4D-printed structures are simulated by introducing a straightforward method into the commercial finite element (FE) software package of Abaqus that is much simpler than writing a user-defined material subroutine or an in-house FE code. The high accuracy of the proposed method is verified by a comparison study with experiments and numerical results obtained from an in-house FE solution. Finally, the developed digital tool is implemented to engineer several practical self-morphing/rolling structures.

scholarly journals 4D printing of reconfigurable metamaterials and devices

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Teunis van Manen ◽  
Shahram Janbaz ◽  
Kaspar M. B. Jansen ◽  
Amir A. Zadpoor
Keyword(s):  
Fused Deposition Modeling ◽  
Production Method ◽  
Single Step ◽  
Layer By Layer ◽  
Design Strategies ◽  
4D Printing ◽  
Large Shift ◽  
Simple Modification ◽  
3D Shape ◽  
Fused Deposition

AbstractShape-shifting materials are a powerful tool for the fabrication of reconfigurable materials. Upon activation, not only a change in their shape but also a large shift in their material properties can be realized. As compared with the 4D printing of 2D-to-3D shape-shifting materials, the 4D printing of reconfigurable (i.e., 3D-to-3D shape-shifting) materials remains challenging. That is caused by the intrinsically 2D nature of the layer-by-layer manner of fabrication, which limits the possible shape-shifting modes of 4D printed reconfigurable materials. Here, we present a single-step production method for the fabrication and programming of 3D-to-3D shape-changing materials, which requires nothing more than a simple modification of widely available fused deposition modeling (FDM) printers. This simple modification allows the printer to print on curved surfaces. We demonstrate how this modified printer can be combined with various design strategies to achieve high levels of complexity and versatility in the 3D-to-3D shape-shifting behavior of our reconfigurable materials and devices. We showcase the potential of the proposed approach for the fabrication of deployable medical devices including deployable bifurcation stents that are otherwise extremely challenging to create.

scholarly journals Implementation of Fused Filament Fabrication in Dentistry

2021 ◽  
Vol 11 (14) ◽  
pp. 6444
Author(s):  
Jörg Lüchtenborg ◽  
Felix Burkhardt ◽  
Julian Nold ◽  
Severin Rothlauf ◽  
Christian Wesemann ◽  
...  
Keyword(s):  
Fused Deposition Modeling ◽  
Present Report ◽  
Cost Effective ◽  
Great Promise ◽  
Temperature Sensitive ◽  
Fused Filament Fabrication ◽  
Digital Light Processing ◽  
Fused Deposition ◽  
Surgical Guides ◽  
Novel Approach

Additive manufacturing is becoming an increasingly important technique for the production of dental restorations and assistive devices. The most commonly used systems are based on vat polymerization, e.g., stereolithography (SLA) and digital light processing (DLP). In contrast, fused filament fabrication (FFF), also known under the brand name fused deposition modeling (FDM), is rarely applied in the dental field. This might be due to the reduced accuracy and resolution of FFF compared to vat polymerization. However, the use of FFF in the dental sector seems very promising for in-house production since it presents a cost-effective and straight forward method. The manufacturing of nearly ready-to-use parts with only minimal post-processing can be considered highly advantageous. Therefore, the objective was to implement FFF in a digital dental workflow. The present report demonstrates the production of surgical guides for implant insertion by FFF. Furthermore, a novel approach using a temperature-sensitive filament for bite registration plates holds great promise for a simplified workflow. In combination with a medical-grade filament, a multi-material impression tray was printed for optimized impression taking of edentulous patients. Compared to the conventional way, the printed thermoplastic material is pleasant to model and can allow clean and fast work on the patient.

scholarly journals Compressive Properties of Additively Manufactured Functionally Graded Kagome Lattice Structure

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 517 ◽  
Author(s):  
Rinoj Gautam ◽  
Sridhar Idapalapati
Keyword(s):  
Energy Absorption ◽  
Fused Deposition Modeling ◽  
Mechanical Performance ◽  
Lattice Structure ◽  
Peak Load ◽  
Functionally Graded ◽  
Uniform Density ◽  
Compressive Properties ◽  
Fused Deposition ◽  
Number Of Layers

Cellular lattice structures have important applications in aerospace, automobile and defense industries due to their high specific strength, modulus and energy absorption. Additive manufacturing provides the design freedom to fabricate complex cellular structures. This study investigates the compressive properties and deformation behavior of a Ti-6Al-4V unit Kagome structure fabricated by selective laser melting. Further, the mechanical performance of multi-unit and multi-layer Kagome structure of acrylonitrile butadiene styrene (ABS) ABS-M30™ manufactured by fused deposition modeling is explored. The effect of a number of layers of Kagome structure on the compressive properties is investigated. This paper also explores the mechanical properties of functionally graded and uniform density Kagome structure. The stiffness of the structure decreased with the increase in the number of layers whereas no change in peak load was observed. The functionally graded Kagome structure provided 35% more energy absorption than the uniform density structure.

scholarly journals Proper Blends of Biodegradable Polycaprolactone and Natural Rubber for 3D Printing

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2416
Author(s):  
Thossapit Wissamitanan ◽  
Charoenyutr Dechwayukul ◽  
Ekwipoo Kalkornsurapranee ◽  
Wiriya Thongruang
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Natural Rubber ◽  
Shape Recovery ◽  
Fused Deposition Modeling ◽  
Melt Flow ◽  
Melt Flow Rate ◽  
Fused Deposition ◽  
Compression Set ◽  
Deposition Modeling

Flexible thermoplastic elastomers (TPE) were prepared for fused deposition modeling (FDM) or 3D printing. These materials can be used for medical purposes such as disposable soft splints and other flexible devices. Blends of 50% epoxidized natural rubber (ENR-50) and block rubber (Standard Thai Rubber 5L (STR5L)) with polycaprolactone (PCL) were produced and compared. The purpose of this study was to investigate the properties of natural rubber (NR) and PCL in simple blends with PCL contents of 40%, 50%, and 60% by weight (except at 75% for morphology study) in the base mixture (NR/PCL). The significant flow factors for FDM materials, such as melting temperature (Tm) and melt flow rate (MFR), were observed by differential scanning calorimetry (DSC) and via the melt flow index (MFI). In addition, the following mechanical properties were also determined: tensile strength, compression set, and hardness. The results from DSC showed that the melting temperature changed slightly (1–2 °C) with amount of PCL used, and there was a suspicious point in the 50/50 blends with both types of rubber. The lowest melting enthalpy of both blends was found at the 50/50 blended composition. The MFI results showed that PCL significantly affected the melt flow rate of both blends. The ENR-50/PCL blend flowed better than the STR5L/PCL blend. The conclusion was that this was due to the morphology of its phase structure having better uniformity than that of the STR5L/PCL blend. In compression set testing or measuring shape recovery, rubber directly influenced the recovery in all blends. The ENR-50/PCL blend had less recovery than the STR5L/PCL blend, probably due to the functional effects of epoxide groups and polarity mismatch. The hard phase PCL significantly affected the hardness of samples but improved shape recovery of the material. The ENR-50/PCL blend had better tensile properties than the STR5L/PCL blend. The elongation at break of both blends improved with a high rubber content. Hence, the ENR-50/PCL blend was superior to STR5L/PCL for printing purposes due to its better miscibility, uniformity, and flow, which are the keys to success for optimizing the fused deposition modeling conditions as well as the overall mechanical properties of products. Most blends in this study were only slightly different, but the 50/50 blend of ENR-50/PCL seemed to be near optimal for 3D printing.

Additive manufacturing of shape memory polymers: effects of print orientation and infill percentage on shape memory recovery properties

2020 ◽  
Vol 26 (9) ◽  
pp. 1593-1602
Author(s):  
Jorge Villacres ◽  
David Nobes ◽  
Cagri Ayranci
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory ◽  
Shape Recovery ◽  
Fused Deposition Modeling ◽  
Large Strain ◽  
Shape Memory Polymers ◽  
Polymeric Materials ◽  
Content Type ◽  
Fused Deposition ◽  
Memory Recovery

Purpose The purpose of this paper is to study the shape memory properties of SMP samples produced through a MEAM process. Fused deposition modeling or, as it will be referred to in this paper, material extrusion additive manufacturing (MEAM) is a technique in which polymeric materials are extruded though a nozzle creating parts via accumulation and joining of different layers. These layers are fused together to build three-dimensional objects. Shape memory polymers (SMP) are stimulus responsive materials, which have the ability to recover their pre-programmed form after being exposed to a large strain. To induce its shape memory recovery movement, an external stimulus such as heat needs to be applied. Design/methodology/approach This project investigates and characterizes the influence of print orientation and infill percentage on shape recovery properties. The analyzed shape recovery properties are shape recovery force, shape recovery speed and time elapsed before activation. To determine whether the analyzed factors produce a significant variation on shape recovery properties, t-tests were performed with a 95% confidence factor between each analyzed level. Findings Results proved that print angle and infill percentage do have a significant impact on recovery properties of the manufactured specimens. Originality/value The manufacturing of SMP objects through a MEAM process has a vast potential for different applications; however, the shape recovery properties of these objects need to be analyzed before any practical use can be developed. These have not been studied as a function of print parameters, which is the focus of this study.

scholarly journals Attempts to Diminish the Drawbacks of Polylactic Acid Designed for 3D/4D Printing Technology-Fused Deposition Modeling

2021 ◽  
Vol 58 (1) ◽  
pp. 142-153
Author(s):  
Doina Dimonie ◽  
Nicoleta Dragomir ◽  
Rusandica Stoica
Keyword(s):  
3D Printing ◽  
Polylactic Acid ◽  
Fused Deposition Modeling ◽  
New Materials ◽  
4D Printing ◽  
Printing Technology ◽  
Fused Deposition ◽  
New Material ◽  
Deposition Modeling ◽  
Laboratory Line

In order to improve thermal behavior and dimensional strability of polylactic acid (PLA) designed both for 3D and 4D printing technology-fused deposition modeling (FDM) using a scalable procedure, the polymer was melt compounded with additives which control the morphology by crystallization and/or reinforcing. Using the formulations which provide polylactic acid (PLA) improved thermo-mechanical properties and desired dimensional stability, the new materials were shaped, on a laboratory line, as filaments for printing technology. The selected compounds were than scaled up on a 50 kg/h compounding line into granules which prove to have good shapability as filaments for printing technology (1.85 +/- 0.05 mm diameter, required ovality, good appearance and smooth surface) and performed properly at 3D printing. The obtained results proved that functional properties of PLA can be improved by various methods so that, depending on the reached performances, the new material can be converted through printing technology into items for performance applications. The novelty of the article is related to the fact that it identifies a modifying solution for controlling the morphology of a type of PLA designed for 3D printing that already has an advanced crystallinity.

Multimaterial printing and characterization for mechanical and surface properties of functionally graded prototype

2019 ◽  
Vol 233 (19-20) ◽  
pp. 6741-6753 ◽  
Author(s):  
Sudhir Kumar ◽  
Rupinder Singh ◽  
TP Singh ◽  
Ajay Batish
Keyword(s):  
Polylactic Acid ◽  
Surface Properties ◽  
Fused Deposition Modeling ◽  
Mechanical Performance ◽  
Three Dimensional ◽  
Surface Hardness ◽  
Functionally Graded ◽  
Three Dimensional Printing ◽  
Fused Deposition ◽  
Dimensional Printing

In this work, an effort has been made for multimaterial three-dimensional printing of functionally graded prototypes of polylactic acid matrix (tensile specimens as per ASTM D638 type IV) followed by characterization of mechanical and surface properties. The work is an extension of previous reported studies on twin-screw extrusion process for the preparation of multimaterial wires as feedstock filaments in possible three-dimensional printing applications. The results of the study suggest that the highest peak strength (46.28 MPa) and break strength (41.65 MPa) was obtained for multimaterial three-dimensional printed samples at infill density 100%, infill angle 45°, and infill speed of 90 mm/s on commercial open source fused deposition modeling setup. Further surface hardness measurements performed on two extreme surfaces (top surface comprising magnetite (Fe3O4)-reinforced polylactic acid and bottom with polylactic acid without any reinforcement) revealed that the hardness for the bottom layer was more than the hardness for the top layer. From fractured surface analysis (using photomicrographs), it has been observed that the three-dimensional printed samples with low infill density resulted into more void formation due to which the performance while mechanical testing was poor in comparison to samples printed with higher infill density. The results are also supported by rendered images of photomicrographs, which revealed that high roughness value of samples printed with low infill density was also one of the reasons for poor mechanical performance of multimaterial three-dimensional printed functionally graded prototypes.

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