Theoretical prediction of mechanical properties of 3D printed Kagome honeycombs and its experimental evaluation

2019 ◽  
Vol 233 (18) ◽  
pp. 6559-6576 ◽  
Author(s):  
Xuefeng Zhu ◽  
Longkun Xu ◽  
Xiaochen Liu ◽  
Jinting Xu ◽  
Ping Hu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Modulus ◽  
Tensile Testing ◽  
Elastic Moduli ◽  
Uniaxial Tensile ◽  
Anisotropy Ratio ◽  
Young’S Moduli ◽  
Analytical Formulas ◽  
3D Printed ◽  
Printed Materials

Kagome honeycomb structure is proved to incorporate excellent mechanical and actuation performances due to its special configuration. However, until now, the mechanical properties of 3D printed Kagome honeycomb have not been investigated. Hence, the objective of this work is to explore some mechanical properties of 3D-printed Kagome honeycomb structures such as elastic properties, buckling, and so on. In this paper, the analytical formulas of some mechanical properties of Kagome honeycombs made of 3D-printed materials are given. Effective elastic moduli such as Young's modulus, shear modulus, and Poisson's ratio of orthotropic Kagome honeycombs under in-plane compression and shear are derived in analytical forms. By these formulas, we investigate the relationship of the elastic moduli, the relative density, and the shape anisotropy–ratio of 3D-printed Kagome honeycomb. By the uniaxial tensile testing, the effective Young's moduli of 3D printed materials in the lateral and longitudinal directions are obtained. Then, by the analytical formulas and the experimental results, we can predict the maximum Young's moduli and the maximum shear modulus of 3D-printed Kagome honeycombs. The isotropic behavior of 3D-printed Kagome honeycombs is investigated. We also derived the equations of the initial yield strength surfaces and the buckling surfaces. We found that the sizes of the buckling surfaces of 3D printed material are smaller than that of isotropic material. The efficiency of the presented analytical formulas is verified through the tensile testing of 3D printed Kagome honeycomb specimens.

Mechanical Characterization of Polymer Nanowires Using MEMS

2006 ◽  
Author(s):  
B. A. Samuel ◽  
Bo Yi ◽  
R. Rajagopalan ◽  
H. C. Foley ◽  
M. A. Haque
Keyword(s):  
Mechanical Properties ◽  
Tensile Testing ◽  
Furfuryl Alcohol ◽  
Mechanical Characterization ◽  
Uniaxial Tensile ◽  
Testing Device ◽  
Uniaxial Tensile Testing ◽  
Polymer Nanowires

We present results on the mechanical properties of single freestanding poly-furfuryl alcohol (PFA) nanowires (aspect ratio > 50, diameters 100–300 nm) from experiments conducted using a MEMS-based uniaxial tensile testing device in-situ inside the SEM. The specimens tested were pyrolyzed PFA nanowires (pyrolyzed at 800° C).

scholarly journals Influence of Topography on 3D printed Titanium Foot and Ankle Implants

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0001
Author(s):  
Bijan Abar ◽  
Cambre N. Kelly ◽  
Nicholas B. Allen ◽  
Helena Barber ◽  
Alexander P. Kelly ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Testing ◽  
Cellular Proliferation ◽  
Quantitative Polymerase Chain Reaction ◽  
Biological Properties ◽  
Titanium Implants ◽  
Foot And Ankle ◽  
Cell Viability Assay ◽  
Osseous Integration ◽  
3D Printed

Category: Basic Sciences/Biologics; Ankle; Trauma Introduction/Purpose Foot and ankle etiologies such as traumatic fractures, Charcot Arthropathy, nonunion after high risk arthrodesis and infectious debridement can result in critical sized bone defect (CSD). CSD is defined as bone loss greater than 1-2 cm in length or greater than 50% loss in circumference of bone. CSD remain a significant challenge in Orthopaedics. Custom 3D printed porous Titanium implants are currently being implemented when allograft is not an option. However, in a subset of cases, Titanium implants need to be removed due to infection or poor osseous integration where surrounding bone does not grow onto or through the scaffold. There is no one clear reason for poor osseous integration. This study explores effects of 3D printed topography on mechanical and biological properties. Methods: Titanium dog bones and discs were printed via laser powder bed fusion. Roughness groups were polished, blasted, as built, sprouts and rough sprouts. Roughness was measured with line measurement using a confocal microscope. To assess mechanical properties, tensile testing of samples from each roughness group produced stress strain curves. MC3T3 preosteoblast were seeded on discs. Samples were analyzed at 0, 2, and 4 weeks. A cell viability assay and confocal florescent microscopy assessed cell growth. Alkaline Phosphatase (ALP) assay and Quantitative Polymerase Chain Reaction (qPCR) examined cell differentiation. Extracellular matrix (ECM) was stained for collagen and calcium. Scanning Electron Microcopy (SEM) was done on sputter coated discs. Results: Rz, maximum peak to valley distance of the sample profile, for the polished, blasted, as built, sprouts and rough sprouts were 2.6, 22.6, 33.0, 41.4 and 65.1 µm respectively. The addition of printed roughness in the sprouts and rough sprouts group significantly diminished ductility resulting in early strain to failure during tensile testing. Cells adhered and proliferated on discs regardless of roughness group. There was no statically difference in ALP activity, but qPCR showed that rough groups (sprouts and rough sprouts) had diminished Osteocalcin gene expression at week 2 and 4. The ECM observed with SEM in the rough groups was more resistant to repeated washes and was more extensive compared to the less rough groups. Conclusion: The addition of 3D printed artificial roughness leads to inferior mechanical properties and confers no clear benefit regarding cellular proliferation. Printed topography increases the initiation of fractures resulting in diminished tensile strength and ductility. Concurrently, the resolution of LBF is not fine enough at this time to create surface features that enhance cell behavior. Therefore, data in this study suggest that artificially printing roughness is not an effective strategy to enhance osseous integration into Titanium implants for critical sized defects.

scholarly journals GEOMETRY AND MECHANICAL PROPERTIES OF A 3D-PRINTED TITANIUM MICROSTRUCTURE

2018 ◽  
Vol 15 ◽  
pp. 104-108
Author(s):  
Luboš Řehounek ◽  
Petra Hájková ◽  
Petr Vakrčka ◽  
Aleš Jíra
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Uniaxial Compression ◽  
Elastic Moduli ◽  
Weight Ratio ◽  
Porous Structures ◽  
Compression Tests ◽  
Local Material ◽  
3D Printed ◽  
Titanium Microstructure

Construction applications sometimes require use of a material other than construction steel or concrete – mainly in cases, where strength to weight ratio needs to be considered. A suitable solution to this problem are structures manufactured using the 3D printing process, as they have a very good strength to weight ratio (i.e.: Ti-6Al-4V – σ<sub>ult</sub> = 900 MPa and ρ = 4500 kg/m<sup>3</sup>). Trabecular structures are porous structures with local material characteristics identical to their commonly manufactured counterparts, but due to their geometry, they have different global mechanical properties and are suited for special applications. We designed and manufactured six variants of these structures and subjected them to uniaxial compression tests, nanoindentation tests and subsequently evaluated their differences and elastic moduli. The values of global moduli E are in the range of 2.55 GPa – 3.55 GPa for all specimens.

scholarly journals Polyjet 3D printing of tissue-mimicking materials: how well can 3D printed synthetic myocardium replicate mechanical properties of organic myocardium?

2019 ◽  
Author(s):  
Leah Severseike ◽  
Vania Lee ◽  
Taycia Brandon ◽  
Chris Bakken ◽  
Varun Bhatia
Keyword(s):  
Mechanical Properties ◽  
Biological Tissue ◽  
Mechanical Response ◽  
Axial Loading ◽  
Stress Concentrations ◽  
Friction Forces ◽  
Compliance Testing ◽  
3D Printed ◽  
Printed Materials ◽  
Digital Anatomy

AbstractAnatomical 3-D printing has potential for many uses in education, research and development, implant training, and procedure planning. Conventionally, the material properties of 3D printed anatomical models have often been similar only in form and not in mechanical response compared to biological tissue. The new Digital Anatomy material from Stratasys utilizes composite printed materials to more closely mimic the mechanical properties of tissue. Work was done to evaluate Digital Anatomy myocardium under axial loading for comparison with porcine myocardium regarding puncture, compliance, suturing, and cutting performance.In general, the Digital Anatomy myocardium showed promising comparisons to porcine myocardium. For compliance testing, the Digital Anatomy was either within the same range as the porcine myocardium or stiffer. Specifically, for use conditions involving higher stress concentrations or smaller displacements, Digital Anatomy was stiffer. Digital Anatomy did not perform as strongly as porcine myocardium when evaluating suture and cutting properties. The suture tore through the printed material more easily and had higher friction forces both during needle insertion and cutting. Despite these differences, the new Digital Anatomy myocardium material was much closer to the compliance of real tissue than other 3D printed materials. Furthermore, unlike biological tissue, Digital Anatomy provided repeatability of results. For tests such as cyclic compression, the material showed less than two percent variation in results between trials and between parts, resulting in lower variability than tissue. Despite some limitations, the myocardium Digital Anatomy material can be used to configure structures with similar mechanical properties to porcine myocardium in a repeatable manner, making this a valuable research tool.

scholarly journals Inverse Identification Of Elastic Moduli For 3D Printed PLA, Using Impulse Excitation Technique (IET)

2021 ◽  
Author(s):  
Afridi Mohsin
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Bulk Material ◽  
Dynamic Properties ◽  
Test Results ◽  
Young’S Moduli ◽  
Vibration Experiment ◽  
3D Printed ◽  
Printed Materials

3D Printing has recently undergone extensive development due to its lower cost and flexibility. A number of studies have been carried out to determine 3D printed material properties. This study focuses on the determination of the dynamic properties for PLA. The PLA material is processed through the popular FDM method with three different build orientations. A vibration experiment is conducted to evaluate the first modal frequency and Young’s modulus. The results are then compared to the FEM modal analysis and finally the traditional tensile testing results. The anisotropy of the 3D printed components, mainly due to the density changes caused by voids and filament alignment, result in the variation of the Young’s modulus which is different than the homogenous bulk material. The calculated Young’s moduli values are very slightly higher than the tensile test results which is in conformance with the trend documented by earlier studies on similar printed materials using the same techniques

Effect of the Stretch Rate During Uniaxial Testing on the Mechanical Properties of Prolene®

2012 ◽  
Author(s):  
T. M. Bazi ◽  
A. H. Ammouri ◽  
R. F. Hamade
Keyword(s):  
Mechanical Properties ◽  
Tensile Testing ◽  
Relative Elongation ◽  
Testing Machine ◽  
Peak Load ◽  
Displacement Rate ◽  
Uniaxial Tensile ◽  
P Value ◽  
Stretch Rate ◽  
Uniaxial Tensile Testing

We assess the effects of stretch rate on the mechanical properties of Prolene® (Ethicon, Gynecare, Somerville, NJ, USA), a knitted polypropylene mesh. Prolene®, consisting of macroporous knitted polypropylene, is considered here as a suitable proxy to midurethral tape (MUT) as well as to many other prosthesis products used in surgery applications. Such products are utilized to treat urine incontinence, pelvic organ prolapse, as well as hernia in humans. Of the mechanical properties of special significance are the following three properties: peak load (N), extension (%) at peak load, and linear stiffness (N/mm). Uniaxial tensile testing was performed on mesh samples on a universal testing machine and involved loading different samples at 5 cross-head speeds of: 1, 10, 50, 100, and 500 mm/min. The corresponding properties were measured under these 5 conditions. In order to minimize damage to the specimens at the jaws, special dual action pneumatically operated grips with rubber faced jaws were used to hold the samples in place. The effectiveness of these grips was illustrated by the fact that none of the failed samples broke at grips. Statistically significant findings suggest an increasing trend for Prolene® stiffness vs. stretch rate (R2 = 0.9679; two-tailed p value = 0.0025) where the stiffness increases 26.2% when increasing the displacement rate from 1 to 500 mm/min. For extension (%) at peak load, a decreasing trend was found vs. stretch rate (R2 = 0.81; two-tailed p value = 0.037) where increasing the displacement rate from 1 mm/min to 500 mm/min corresponds to a 22% decrease in the relative elongation of the mesh. No statistically significant dependence of peak load on stretch rate was found. These findings may help workers in the biomedical field develop suitable uniaxial tensile testing protocols of such materials.

Forming Limit Diagram of the AMS 5599 Sheet Metal

2013 ◽  
Vol 58 (4) ◽  
pp. 1213-1217
Author(s):  
W. Fracz ◽  
F. Stachowicz ◽  
T. Trzepieciński ◽  
T. Pieją
Keyword(s):  
Mechanical Properties ◽  
Sheet Metal ◽  
Plastic Anisotropy ◽  
Experimental Studies ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Strain Hardening Exponent ◽  
Uniaxial Tensile Test ◽  
Anisotropy Ratio

Abstract Formability of sheet metal is dependent on the mechanical properties. Some materials form better than others - moreover, a material that has the best formability for one stamping may behave very poorly in a stamping of another configuration. For these reasons, extensive test programs are often carried out in an attempt to correlate material formability with value of some mechanical properties. The formability of sheet metal has frequently been expressed by the value of strain hardening exponent and plastic anisotropy ratio. The stress-strain and hardening behaviour of a material is very important in determining its resistance to plastic instability. However experimental studies of formability of various materials have revealed basic differences in behaviour, such as the ”brass-type” and the ”steel-type”, exhibiting respectively, zero and positive dependence of forming limit on the strain ratio. In this study mechanical properties and the Forming Limit Diagram of the AMS 5599 sheet metal were determined using uniaxial tensile test and Marciniak’s flat bottomed punch test respectively. Different methods were used for the FLD calculation - results of these calculations were compared with experimental results

Design Paradigm Utilizing Reversible Diels–Alder Reactions to Enhance the Mechanical Properties of 3D Printed Materials

2016 ◽  
Vol 8 (26) ◽  
pp. 16961-16966 ◽  
Author(s):  
Joshua R. Davidson ◽  
Gayan A. Appuhamillage ◽  
Christina M. Thompson ◽  
Walter Voit ◽  
Ronald A. Smaldone
Keyword(s):  
Mechanical Properties ◽  
Diels Alder ◽  
Design Paradigm ◽  
3D Printed ◽  
Printed Materials
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