scholarly journals 3D Printing of Thermoplastic Elastomers: Role of the Chemical Composition and Printing Parameters in the Production of Parts with Controlled Energy Absorption and Damping Capacity

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3551
Author(s):  
Marina León-Calero ◽  
Sara Catherine Reyburn Valés ◽  
Ángel Marcos-Fernández ◽  
Juan Rodríguez-Hernandez
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
3D Printing ◽  
Energy Absorption ◽  
Thermoplastic Elastomers ◽  
Damping Capacity ◽  
Compression Tests ◽  
Wide Range ◽  
Printing Parameters

Additive manufacturing (AM) is a disruptive technology that enables one to manufacture complex structures reducing both time and manufacturing cost. Among the materials commonly used for AM, thermoplastic elastomers (TPE) are of high interest due to their energy absorption capacity, energy efficiency, cushion factor or damping capacity. Previous investigations have exclusively focused on the optimization of the printing parameters of commercial TPE filaments and the structures to analyse the mechanical properties of the 3D printed parts. In the present paper, the chemical, thermal and mechanical properties for a wide range of commercial thermoplastic polyurethanes (TPU) filaments were investigated. For this purpose, TGA, DSC, 1H-NMR and filament tensile strength experiments were carried out in order to determine the materials characteristics. In addition, compression tests have been carried out to tailor the mechanical properties depending on the 3D printing parameters such as: infill density (10, 20, 50, 80 and 100%) and infill pattern (gyroid, honeycomb and grid). The compression tests were also employed to calculate the specific energy absorption (SEA) and specific damping capacity (SDC) of the materials in order to establish the role of the chemical composition and the geometrical characteristics (infill density and type of infill pattern) on the final properties of the printed part. As a result, optimal SEA and SDC performances were obtained for a honeycomb pattern at a 50% of infill density.

scholarly journals An Overview on the Rheology, Mechanical Properties, Durability, 3D Printing, and Microstructural Performance of Nanomaterials in Cementitious Composites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2950
Author(s):  
Hongwei Song ◽  
Xinle Li
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Three Dimensional ◽  
Cementitious Materials ◽  
Research Area ◽  
Cementitious Composites ◽  
Split Tensile Strength ◽  
Contour Crafting ◽  
Wide Range ◽  
Active Research

The most active research area is nanotechnology in cementitious composites, which has a wide range of applications and has achieved popularity over the last three decades. Nanoparticles (NPs) have emerged as possible materials to be used in the field of civil engineering. Previous research has concentrated on evaluating the effect of different NPs in cementitious materials to alter material characteristics. In order to provide a broad understanding of how nanomaterials (NMs) can be used, this paper critically evaluates previous research on the influence of rheology, mechanical properties, durability, 3D printing, and microstructural performance on cementitious materials. The flow properties of fresh cementitious composites can be measured using rheology and slump. Mechanical properties such as compressive, flexural, and split tensile strength reveal hardened properties. The necessary tests for determining a NM’s durability in concrete are shrinkage, pore structure and porosity, and permeability. The advent of modern 3D printing technologies is suitable for structural printing, such as contour crafting and binder jetting. Three-dimensional (3D) printing has opened up new avenues for the building and construction industry to become more digital. Regardless of the material science, a range of problems must be tackled, including developing smart cementitious composites suitable for 3D structural printing. According to the scanning electron microscopy results, the addition of NMs to cementitious materials results in a denser and improved microstructure with more hydration products. This paper provides valuable information and details about the rheology, mechanical properties, durability, 3D printing, and microstructural performance of cementitious materials with NMs and encourages further research.

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 The Flame Retardancy of Polyethylene Composites: From Fundamental Concepts to Nanocomposites

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5157
Author(s):  
Erfan Rezvani Ghomi ◽  
Fatemeh Khosravi ◽  
Zahra Mossayebi ◽  
Ali Saedi Ardahaei ◽  
Fatemeh Morshedi Dehaghi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flame Retardancy ◽  
Cost Efficiency ◽  
Research Papers ◽  
The Past ◽  
Wide Range ◽  
Fire Retardance ◽  
Low Toxicity ◽  
Implementing Strategies

Polyethylene (PE) is one the most used plastics worldwide for a wide range of applications due to its good mechanical and chemical resistance, low density, cost efficiency, ease of processability, non-reactivity, low toxicity, good electric insulation, and good functionality. However, its high flammability and rapid flame spread pose dangers for certain applications. Therefore, different flame-retardant (FR) additives are incorporated into PE to increase its flame retardancy. In this review article, research papers from the past 10 years on the flame retardancy of PE systems are comprehensively reviewed and classified based on the additive sources. The FR additives are classified in well-known FR families, including phosphorous, melamine, nitrogen, inorganic hydroxides, boron, and silicon. The mechanism of fire retardance in each family is pinpointed. In addition to the efficiency of each FR in increasing the flame retardancy, its impact on the mechanical properties of the PE system is also discussed. Most of the FRs can decrease the heat release rate (HRR) of the PE products and simultaneously maintains the mechanical properties in appropriate ratios. Based on the literature, inorganic hydroxide seems to be used more in PE systems compared to other families. Finally, the role of nanotechnology for more efficient FR-PE systems is discussed and recommendations are given on implementing strategies that could help incorporate flame retardancy in the circular economy model.

Controlling of Distribution of Mechanical Properties in Functionally-Graded Syntactic Foams for Impact Energy Absorption

2012 ◽  
Vol 706-709 ◽  
pp. 729-734 ◽  
Author(s):  
Masahiro Higuchi ◽  
Tadaharu Adachi ◽  
Yuto Yokochi ◽  
Kenta Fujimoto
Keyword(s):  
Mechanical Properties ◽  
Density Distribution ◽  
Energy Absorption ◽  
Impact Energy ◽  
Volume Fraction ◽  
Functionally Graded ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Density Distributions ◽  
Control Distribution

In the study, novel fabrication processes of functionally-graded (FG) syntactic foams were developed to control distribution of the mechanical properties in the FG foams for highly impact energy absorption. In order to control mechanical properties, the density distributions in FG foams were graded by floating phenomenon of the light-weight micro-balloons in matrix resin during curing process. The density distribution in the foam could be controlled by adjusting the average volume fraction and the turning procedure of the mold before grading the micro-balloons in the foam. The compression tests of the fabricated FG foams suggested that the foams had high absorption of impact energy since the foams collapsed progressively due to the grading of the density distribution.

Microstructure and Mechanical Properties of Rapidly Solidified Al-Fe-Ni-Mg Alloys

2011 ◽  
Vol 674 ◽  
pp. 165-170 ◽  
Author(s):  
Anna Kula ◽  
Ludwik Blaz ◽  
Makoto Sugamata
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Rapid Solidification ◽  
Spray Deposition ◽  
Research Work ◽  
Mg Alloys ◽  
Solid Solution Hardening ◽  
Compression Tests ◽  
Microstructure And Mechanical Properties ◽  
Wide Range

Rapid solidification (RS) combined with following mechanical consolidation of RS powders is considered as a valuable commercial method for the production of a wide range of metallic materials having fine-grained structures. Reported research results for various alloys demonstrate better compositional homogeneity, smaller grain size and relatively fine precipitates distributed homogenously in RS alloys than that for the materials produced by conventional metallurgical processing. The effect of rapid solidification on the microstructure and mechanical properties of selected Al-Fe-Ni-Mg alloys have been investigated. The basic item of the research work was obtaining aluminum PM materials strengthened by highly-dispersed transition metal compounds and aluminum-magnesium solid solution. Rapid solidification (RS) of Al-4Fe-4Ni and Al-4Fe-4Ni-5Mg alloys was performed by means of gas atomizing of the molten alloy and the spray deposition on the rotating water-cooled copper roll. Using typical powder metallurgy (PM) methods, i.e. cold pressing, vacuum degassing and hot extrusion, the RS-flakes were consolidated to the bulk PMmaterials. For comparison purposes, the conventionally cast and hot extruded Al-4Fe-4Ni and Al-4Fe-4Ni-5Mg alloys were studied as well. Mechanical properties of as-extruded materials were examined by compression tests performed at 293 K – 873 K. It was found that relatively high strength of as-extruded PM materials was accompanied by high ductility of samples deformed by hot compression test. Structural observations confirmed beneficial influence of rapid solidification on effective refining of intermetallic compounds, although some inhomogeneity of fine precipitates distribution was observed. Nevertheless, it was considered that an effective increase of the microhardness and strength of tested RS materials mostly result from achieved dispersion of structural components and can be intensified by solid solution hardening due to Mg-addition.

scholarly journals Rice Husk Shredding as a Means of Increasing the Long-Term Mechanical Properties of Earthen Mixtures for 3D Printing

2022 ◽  
Author(s):  
Elena Ferretti ◽  
Massimo Moretti ◽  
Alberto Chiusoli ◽  
Lapo Naldoni ◽  
Francesco De Fabritiis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Uniaxial Compression ◽  
Rice Husk ◽  
Brittle Material ◽  
Strict Sense ◽  
Compression Tests ◽  
Vegetable Fiber ◽  
Natural Way

This paper is part of a study of earthen mixtures for 3D printing of buildings. To meet the ever-growing environmental needs, the focus of the paper is on a particular type of biocomposite for the stabilization of earthen mixtures&mdash;the rice husk-lime biocomposite&mdash;and on how to enhance its effect on the long-term mechanical properties of the hardened product. Having assumed that the shredding of the vegetable fiber is precisely one of the possible ways to improve the mechanical properties, we compared the results of uniaxial compression tests performed on cubic specimens made with both shredded and unaltered vegetable fiber, for three curing periods. The results showed that the hardened earthen mixture is not a brittle material in the strict sense, because it exhibits some peculiar behaviors, anomalous for a brittle material. However, being a &ldquo;designable&rdquo; material, its properties can be varied with a certain flexibility to get as close as possible to the desired ones. One of the peculiar properties of the hardened earthen mixture deserves further investigation, rather than corrections. This is the vulcanization that occurs (in a completely natural way) in the long term, thanks to the mineralization of the vegetable fiber by carbonation of the lime.

scholarly journals Factors That Affect the Mechanical Strength of Archaeological Wood—A Case Study of 18th-Century Wooden Water Pipes from Bóżnicza Street in Poznań, Poland

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7632
Author(s):  
Magdalena Broda ◽  
Carmen-Mihaela Popescu ◽  
Daniel Ilie Timpu ◽  
Dawid Rowiński ◽  
Edward Roszyk
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Mechanical Strength ◽  
Wood Density ◽  
Mechanical Performance ◽  
Cellulose Crystallinity ◽  
Compression Tests ◽  
Substantial Impact ◽  
Archaeological Wood

Large amounts of archaeological wood are often excavated during groundworks in cities and towns. Part of the unearthed artefacts is usually saved, conserved and then presented in museums. However, if the finding contains several similar objects, some of them could potentially be further employed for some other practical purposes. The research aimed to determine the mechanical performance of the remains of wooden water mains excavated at Bóżnicza street in Poznań, Poland and evaluate its potential usefulness for any practical purposes. First, wood density was determined along with its mechanical strength in compression. The density of archaeological wood identified as Scots pine was lower than contemporary pinewood (383 kg × m−3 vs. 572 kg × m−3); therefore, its mechanical properties in compression tests were also lower, as expected, making the wood unsuitable for any practical applications. However, the differences in modulus of elasticity and compressive strength were not justified by the differences in wood density. Further infrared spectroscopy and X-ray diffraction analyses revealed additional differences in chemical composition and cellulose crystallinity between archaeological and contemporary wood. The results indicated the decrease in carbohydrate content and cellulose crystallinity in degraded wood, which, in addition to wood density, apparently contribute to the deterioration in mechanical strength of archaeological wood. The case study of the excavated archaeological wooden pipes shows that they have historical value but are not useful for practical purposes. It also revealed that not only wood density but also its chemical composition and cellulose crystallinity level has a substantial impact on the wood mechanical properties, particularly in compression.

3D Printing and Stretching Effects on Alignment Microstructure in PDMS/CNT Nanocomposites

2019 ◽  
Author(s):  
Blake Herren ◽  
Tingting Gu ◽  
Qinggong Tang ◽  
Mrinal Saha ◽  
Yingtao Liu
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
3D Printing ◽  
Pdms Substrate ◽  
Polymeric Matrices ◽  
Direct Ink Writing ◽  
Unique Approach ◽  
Writing Technology ◽  
Reinforcing Particle ◽  
Printing Parameters

Abstract The alignment of high aspect ratio reinforcing nanoparticles within a polymer matrix can have significant effects on the mechanical, electrical, and thermal properties of the nanocomposite. Therefore, in order to tailor the properties of the composite, it is imperative to develop novel methods to control the alignment of these filler particles in various polymeric matrices. This paper reports a unique approach to alter the alignment of carbon nanotubes (CNT) within polydimethylsiloxane (PDMS) nanocomposites using 3D printing technology. A line of the reinforced PDMS resin is printed on a PDMS substrate using direct ink writing technology, which can produce alignment in the print direction depending on printing parameters, the loading of the reinforcing particle, and the rheology of the ink. Then, the substrate is stretched and placed in an oven to cure the printed nanocomposites line with increased alignment in the stretch direction. These two techniques have the advantage of simplicity over other techniques and can efficiently manufacture nanocomposites with the alignment of nanoparticles. Optical microscopy will be used to quantify the alignment within the printed line. Electrical and mechanical properties will be tested to determine the effects of the different alignments within the elastomer. The ability to control the alignment of elastomeric CNT composites is advantageous for the growing field of polymer-based electronics.

Sign in / Sign up

Export Citation Format

Share Document