Investigation of the Static Behavior and Failure Mechanisms of a 3D Printed Bio-Based Sandwich with Auxetic Core

2020 ◽  
Vol 12 (05) ◽  
pp. 2050051
Author(s):  
Khawla Essassi ◽  
Jean-Luc Rebiere ◽  
Abderrahim El Mahi ◽  
Mohamed Amine Ben Souf ◽  
Anas Bouguecha ◽  
...  
Keyword(s):  
Failure Mechanisms ◽  
Three Dimensional ◽  
Acoustic Emissions ◽  
Shear Stiffness ◽  
Tensile Tests ◽  
Sandwich Composite ◽  
Static Behavior ◽  
Flax Fibers ◽  
Data Points ◽  
3D Printed

In this research contribution, the static behavior and failure mechanisms are developed for a three-dimensional (3D) printed dogbone, auxetic structure and sandwich composite using acoustic emissions (AEs). The skins, core and whole sandwich are manufactured using the same bio-based material which is polylactic acid reinforced with micro-flax fibers. Tensile tests are conducted on the skins and the core while bending tests are conducted on the sandwich composite. Those tests are carried out on four different auxetic densities in order to investigate their effect on the mechanical and damage properties of the materials. To monitor the invisible damage and damage propagation, a highly sensitive AE testing method is used. It is found that the sandwich with high core density displays advanced mechanical properties in terms of bending stiffness, shear stiffness, facing bending stress and core shear stress. In addition, the AE data points during testing present an amplitude range of 40–85[Formula: see text]dB that characterizes visible and invisible damage up to failure.

scholarly journals On the Influence of Inhomogeneous Interphase Layers on Instabilities in Hyperelastic Composites

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 763 ◽  
Author(s):  
Nitesh Arora ◽  
Adi Batan ◽  
Jian Li ◽  
Viacheslav Slesarenko ◽  
Stephan Rudykh
Keyword(s):  
Three Dimensional ◽  
Shear Stiffness ◽  
Polymerization Process ◽  
Layer By Layer ◽  
Layered Composites ◽  
Buckling Mode ◽  
Buckling Behavior ◽  
Critical Wavelength ◽  
Different Types ◽  
3D Printed

Polymer-based three-dimensional (3D) printing—such as the UV-assisted layer-by-layer polymerization technique—enables fabrication of deformable microstructured materials with pre-designed properties. However, the properties of such materials require careful characterization. Thus, for example, in the polymerization process, a new interphase zone is formed at the boundary between two constituents. This article presents a study of the interphasial transition zone effect on the elastic instability phenomenon in hyperelastic layered composites. In this study, three different types of the shear modulus distribution through the thickness of the interphasial layer were considered. Numerical Bloch-Floquet analysis was employed, superimposed on finite deformations to detect the onset of instabilities and the associated critical wavelength. Significant changes in the buckling behavior of the composites were observed because of the existence of the interphasial inhomogeneous layers. Interphase properties influence the onset of instabilities and the buckling patterns. Numerical simulations showed that interlayer inhomogeneity may result in higher stability of composites with respect to classical layup constructions of identical shear stiffness. Moreover, we found that the critical wavelength of the buckling mode can be regulated by the inhomogeneous interphase properties. Finally, a qualitative illustration of the effect is presented for 3D-printed deformable composites with varying thickness of the stiff phase.

scholarly journals Silicate-Based Electro-Conductive Inks for Printing Soft Electronics and Tissue Engineering

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 240
Author(s):  
Sadaf Samimi Gharaie ◽  
Amir Seyfoori ◽  
Bardia Khun Jush ◽  
Xiong Zhou ◽  
Erik Pagan ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Flexible Electronics ◽  
Mechanical Performance ◽  
Wearable Sensors ◽  
Three Dimensional ◽  
Tensile Tests ◽  
Rheological Characterization ◽  
Mechanical And Electrical Properties ◽  
3D Printed ◽  
Extrusion Printing

Hydrogel-based bio-inks have been extensively used for developing three-dimensional (3D) printed biomaterials for biomedical applications. However, poor mechanical performance and the inability to conduct electricity limit their application as wearable sensors. In this work, we formulate a novel, 3D printable electro-conductive hydrogel consisting of silicate nanosheets (Laponite), graphene oxide, and alginate. The result generated a stretchable, soft, but durable electro-conductive material suitable for utilization as a novel electro-conductive bio-ink for the extrusion printing of different biomedical platforms, including flexible electronics, tissue engineering, and drug delivery. A series of tensile tests were performed on the material, indicating excellent stability under significant stretching and bending without any conductive or mechanical failures. Rheological characterization revealed that the addition of Laponite enhanced the hydrogel’s mechanical properties, including stiffness, shear-thinning, and stretchability. We also illustrate the reproducibility and flexibility of our fabrication process by extrusion printing various patterns with different fiber diameters. Developing an electro-conductive bio-ink with favorable mechanical and electrical properties offers a new platform for advanced tissue engineering.

scholarly journals Evaluation of Tensile Properties and Damage of Continuous Fibre Reinforced 3D-Printed Parts

2018 ◽  
Vol 774 ◽  
pp. 161-166 ◽  
Author(s):  
Octavio Andrés González-Estrada ◽  
Alberto Pertuz ◽  
Jabid E. Quiroga Mendez
Keyword(s):  
3D Printing ◽  
Tensile Properties ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Tensile Tests ◽  
Fused Deposition Modelling ◽  
Printing Process ◽  
Fused Deposition ◽  
3D Printed

Three-dimensional (3D) printing technology has been traditionally used for the production of prototypes. Recently, developments in 3D printing using Fused Deposition Modelling (FDM) and reinforcement with continuous fibres (fiberglass and carbon fibre), have allowed the manufacture of functional prototypes, considerably improving the mechanical performance of the composite parts. In this work, we characterise the elastic tensile properties of fibre reinforced specimens, considering the variation of several parameters available during the printing process: fibre orientation, volume fraction, fill pattern, reinforcement distribution. Tensile tests were performed according to ASTM D638 to obtain Young’s modulus and ultimate strength for different material configurations available during the printing process. We also perform a fractographic analysis using Scanning Electron Microscopy (SEM) to give an insight of the failure mechanisms present in the specimens.

scholarly journals Mechanical and Dimensional Investigation of Additive Manufactured Multimaterial Parts

2021 ◽  
Vol 9 ◽  
Author(s):  
Markus Königshofer ◽  
Martin Stoiber ◽  
Ewald Unger ◽  
Christian Grasl ◽  
Francesco Moscato
Keyword(s):  
Three Dimensional ◽  
Dimensional Accuracy ◽  
Tensile Tests ◽  
Biological Tissues ◽  
Test Methods ◽  
Medical Models ◽  
3D Printed ◽  
Eden Prairie ◽  
Design And Manufacture

Additive manufacturing machines, based on the multimaterial jetting technology, are widely used for three-dimensional (3D) printing of sophisticated medical models, which are aimed to be used for preoperative planning and surgical training. Gaining knowledge of process-related influences on mechanical and dimensional properties of 3D-printed parts makes up an essential basis for the design and manufacture of medical models. There are few studies on characterization of multimaterial parts, and those are limited to tests that are not based on standardized methods. Within the scope of this work, mechanical and dimensional investigations were performed on multimaterial parts that were printed using an Objet500–Connex3 3D printer (Stratasys Ltd., Minnesota, Eden Prairie, MN, USA). Among test methods listed in DIN EN ISO 17296-3, tensile tests were chosen for mechanical characterization. In the tensile tests, combinations of four different materials (Tango+, VeroClear, VeroPureWhite, MED610) were tested in three build orientations (XY, YX, ZX). To investigate the orientation-dependent printing accuracy, the tensile specimens were further checked for their dimensional accuracy. Statistically significant variations in the mechanical properties were found between different orientation levels. In general, specimens printed in XY orientation show higher tensile strength than YX- and ZX-oriented specimens. The tensile moduli determined are in the range from 0.2 to 2,500 MPa and compare well with the tensile moduli found in soft biological tissues. Dimensional deviations were found highest for the length of ZX-oriented tensile specimens. For this orientation level, it could be observed that multimaterial specimens, which contain higher percentage of the soft material Tango+, are characterized by higher shrinkage. For tensile specimens printed from the pure photopolymer Tango+, a shrinkage of 4.6% in length was determined. In summary, it was found that with multimaterial jetting technology, the increased shrinkage and lower mechanical strength in the ZX direction must be considered in the design process.

scholarly journals Effects of Raster Orientation, Infill Rate and Infill Pattern on the Mechanical Properties of 3D Printed Materials

2017 ◽  
Vol 69 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Cristian Dudescu ◽  
Laszlo Racz
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Tensile Tests ◽  
Technological Parameters ◽  
Three Dimensional Printing ◽  
3D Printed ◽  
Printed Materials ◽  
Aided Design ◽  
Design And Manufacture

AbstractThree-dimensional printing is an additive manufacturing process that allows rapid design and manufacture of complex component based on computer-aided design models. Compared with some conventional manufacturing processes, additive manufacturing part properties can depend on structural and process parameters rather than purely on material properties. The objectives of the paper are to evaluate the tensile properties of 3D printed components produced using a commercial 3D printer by performing standard tensile tests and to assess the influence of the technological parameters upon mechanical proprieties of printed specimens, considering different printing directions, infill rates and infill patterns. The influence of raster angles is tested through the designed specimens with different transverse plane, they are printed by placing in different angle, including 0°, 30°, 45° and 90°. Specimens with an infill rate varying from 20% to 100% and six different infill patterns has been tested.

scholarly journals Fabrication of Biocompatible Polycaprolactone–Hydroxyapatite Composite Filaments for the FDM 3D Printing of Bone Scaffolds

2021 ◽  
Vol 11 (14) ◽  
pp. 6351
Author(s):  
Chang Geun Kim ◽  
Kyung Seok Han ◽  
Sol Lee ◽  
Min Cheol Kim ◽  
Soo Young Kim ◽  
...  
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Bone Structure ◽  
Three Dimensional ◽  
Tensile Tests ◽  
Raw Material ◽  
Fused Deposition ◽  
Bone Scaffolds ◽  
3D Printed ◽  
Mechanical Tensile

Recently, three-dimensional printing (3DP) technology has been widely adopted in biology and biomedical applications, thanks to its capacity to readily construct complex 3D features. Using hot-melt extrusion 3DP, scaffolds for bone tissue engineering were fabricated using a composite of biodegradable polycaprolactone (PCL) and hydroxyapatite (HA). However, there are hardly any published reports on the application of the fused deposition modeling (FDM) method using feed filaments, which is the most common 3D printing method. In this study, we report on the fabrication and characterization of biocompatible filaments made of polycaprolactone (PCL)/hydroxyapatite (HA), a raw material mainly used for bone scaffolds, using FDM 3D printing. A series of filaments with varying HA content, from 5 to 25 wt.%, were fabricated. The mechanical and electrical properties of the various structures, printed using a commercially available 3D printer, were examined. Specifically, mechanical tensile tests were performed on the 3D-printed filaments and specimens. In addition, the electrical dielectric properties of the 3D-printed structures were investigated. Our method facilitates the fabrication of biocompatible structures using FDM-type 3DP, creating not only bone scaffolds but also testbeds for mimicking bone structure that may be useful in various fields of study.

Use of Three-dimensional Printing in the Development of Optimal Cardiac CT Scanning Protocols

2020 ◽  
Vol 16 (8) ◽  
pp. 967-977
Author(s):  
Zhonghua Sun
Keyword(s):  
Cardiovascular Disease ◽  
Cardiac Computed Tomography ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Aortic Diseases ◽  
Clinical Value ◽  
Three Dimensional Printing ◽  
Doctor Patient Communication ◽  
Medical Education And Training ◽  
3D Printed

Three-dimensional (3D) printing is increasingly used in medical applications with most of the studies focusing on its applications in medical education and training, pre-surgical planning and simulation, and doctor-patient communication. An emerging area of utilising 3D printed models lies in the development of cardiac computed tomography (CT) protocols for visualisation and detection of cardiovascular disease. Specifically, 3D printed heart and cardiovascular models have shown potential value in the evaluation of coronary plaques and coronary stents, aortic diseases and detection of pulmonary embolism. This review article provides an overview of the clinical value of 3D printed models in these areas with regard to the development of optimal CT scanning protocols for both diagnostic evaluation of cardiovascular disease and reduction of radiation dose. The expected outcomes are to encourage further research towards this direction.

scholarly journals 3D Printed Clamps for In Vitro Tensile Tests of Human Gracilis and the Superficial Third of Quadriceps Tendons

2021 ◽  
Vol 11 (6) ◽  
pp. 2563
Author(s):  
Ivan Grgić ◽  
Vjekoslav Wertheimer ◽  
Mirko Karakašić ◽  
Željko Ivandić
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Tensile Tests ◽  
Biomechanical Properties ◽  
Testing Procedure ◽  
Laboratory Equipment ◽  
Fused Deposition ◽  
Custom Made ◽  
3D Printed

Recent soft tissue studies have reported issues that occur during experimentation, such as the tissue slipping and rupturing during tensile loads, the lack of standard testing procedure and equipment, the necessity for existing laboratory equipment adaptation, etc. To overcome such issues and fulfil the need for the determination of the biomechanical properties of the human gracilis and the superficial third of the quadriceps tendons, 3D printed clamps with metric thread profile-based geometry were developed. The clamps’ geometry consists of a truncated pyramid pattern, which prevents the tendons from slipping and rupturing. The use of the thread application in the design of the clamp could be used in standard clamping development procedures, unlike in previously custom-made clamps. Fused deposition modeling (FDM) was used as a 3D printing technique, together with polylactic acid (PLA), which was used as a material for clamp printing. The design was confirmed and the experiments were conducted by using porcine and human tendons. The findings justify the usage of 3D printing technology for parts manufacturing in the case of tissue testing and establish independence from the existing machine clamp system, since it was possible to print clamps for each prepared specimen and thus reduce the time for experiment setup.

scholarly journals Midface Reconstruction: Planning and Outcome

2020 ◽  
Vol 53 (03) ◽  
pp. 324-334
Author(s):  
Gautam Biswas
Keyword(s):  
Digital Imaging ◽  
3D Structure ◽  
Three Dimensional ◽  
The Past ◽  
Complex Anatomy ◽  
Osseointegrated Implants ◽  
Low Profile ◽  
3D Printed ◽  
Midface Reconstruction ◽  
Reconstruction Planning

Abstract Reconstruction of the complex anatomy and aesthetics of the midface is often a challenge. A careful understanding of this three-dimensional (3D) structure is necessary. Anticipating the extent of excision and its planning following oncological resections is critical.In the past over two decades, with the advances in microsurgical procedures, contributions toward the reconstruction of this area have generated interest. Planning using digital imaging, 3D printed models, osseointegrated implants, and low-profile plates, has favorably impacted the outcome. However, there are still controversies in the management: to use single composite tissues versus multiple tissues; implants versus autografts; vascularized versus nonvascularized bone; prosthesis versus reconstruction.This article explores the present available options in maxillary reconstruction and outlines the approach in the management garnered from past publications and experiences.

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