scholarly journals Exploration of the design freedom of 3D printed continuous fibre-reinforced polymers in open-hole tensile strength tests

2019 ◽  
Vol 171 ◽  
pp. 135-151 ◽  
Author(s):  
Lincy Pyl ◽  
Kalliopi-Artemi Kalteremidou ◽  
Danny Van Hemelrijck
Keyword(s):  
Tensile Strength ◽  
Reinforced Polymers ◽  
Continuous Fibre ◽  
Strength Tests ◽  
Open Hole ◽  
3D Printed ◽  
Design Freedom

scholarly journals Embedding Ultra-High-Molecular-Weight Polyethylene Fibers in 3D-Printed Polylactic Acid (PLA) Parts

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1825 ◽  
Author(s):  
Amza ◽  
Zapciu ◽  
Eyþórsdóttir ◽  
Björnsdóttir ◽  
Borg
Keyword(s):  
Molecular Weight ◽  
Tensile Strength ◽  
3D Printing ◽  
High Molecular Weight ◽  
Polylactic Acid ◽  
Strength Tests ◽  
Raster Angle ◽  
Uhmwpe Fibers ◽  
3D Printed ◽  
Ultra High Molecular Weight

This study aims to assess whether ultra-high-molecular-weight polyethylene (UHMWPE) fibers can be successfully embedded in a polylactic acid (PLA) matrix in a material extrusion 3D printing (ME3DP) process, despite the apparent thermal incompatibility between the two materials. The work started with assessing the maximum PLA extrusion temperatures at which UHMWPE fibers withstand the 3D printing process without melting or severe degradation. After testing various fiber orientations and extrusion temperatures, it has been found that the maximum extrusion temperature depends on fiber orientation relative to extrusion pathing and varies between 175 °C and 185 °C at an ambient temperature of 25 °C. Multiple specimens with embedded strands of UHMWPE fibers have been 3D printed and following tensile strength tests on the fabricated specimens, it has been found that adding even a small number of fiber strands laid in the same direction as the load increased tensile strength by 12% to 23% depending on the raster angle, even when taking into account the decrease in tensile strength due to reduced performance of the PLA substrate caused by lower extrusion temperatures.

Open hole tensile testing of 3D printed parts using in-house fabricated PLA filament

2020 ◽  
Vol 26 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Harshit K. Dave ◽  
Ashish R. Prajapati ◽  
Shilpesh R. Rajpurohit ◽  
Naushil H. Patadiya ◽  
Harit K. Raval
Keyword(s):  
Tensile Strength ◽  
Layer Thickness ◽  
Process Parameters ◽  
Geometrical Shape ◽  
Content Type ◽  
Fused Deposition ◽  
Open Hole ◽  
Raster Angle ◽  
3D Printed ◽  
The Impact

Purpose Fused deposition modeling (FDM) is being increasingly used in automotive and aerospace industries because of its ability to produce specimens having difficult geometrical shape. However, owing to lack of critical information regarding the reliability and mechanical properties of FDM-printed parts at various designs, the use of 3D printed parts in these industries is limited. Therefore, the purpose of this paper is to investigate the impact of process parameters of FDM on the tensile strength of open-hole specimen printed using in-house-fabricated polylactic acid (PLA). Design/methodology/approach In the present study, three process parameters, namely, raster angle, layer thickness and raster width, are selected for investigation of tensile strength. To produce the tensile specimens in the FDM machine, the PLA filament is used which is fabricated from PLA granules using a single-screw extruder. Further, the experimental values are measured and critically analysed. Failure modes under tests are studied using scanning electron microscopy (SEM). Findings Results indicate that the raster angle has a significant effect on the tensile strength of open-hole tensile specimen. Specimens built with 0° raster angle, 200-µm layer thickness and 500-µm raster width obtained maximum tensile strength. Originality/value In this work, a new concept of testing a plate that has a rectangular shape and a circular hole at the centre is tested. Open-hole tensile test standard ASTM D5766 has been implemented for the first time for the FDM process.

Study of Bismuth Telluride Crystal Strength

2019 ◽  
pp. 1-8
Author(s):  
A. A. Gorbatovskiy
Keyword(s):  
Tensile Strength ◽  
Bismuth Telluride ◽  
Elasticity Modulus ◽  
Testing Machine ◽  
Bend Testing ◽  
Instron Testing Machine ◽  
Measurement Results ◽  
Strength Tests ◽  
Semiconductor Properties

The article presents results of strength tests of bismuth telluride prismatic samples obtained by growing crystals. These crystals have semiconductor properties and are used in the heat machines, the run-ability of which largely depends on the strength of crystals. Data available in the literature are significantly different from each other. It has been shown that, the most consistent strength tests results are obtained in case of bend testing. The measurement results of the elasticity modulus and tensile strength are given. For tests, an INSTRON testing machine with maximum direct stress of the 1000 H was used.

Tensile strength of 3D printed materials: Review and reassessment of test parameters

2018 ◽  
Vol 60 (7-8) ◽  
pp. 679-686 ◽  
Author(s):  
Jim Floor ◽  
Bas van Deursen ◽  
Erik Tempelman
Keyword(s):  
Tensile Strength ◽  
Test Parameters ◽  
3D Printed ◽  
Printed Materials

scholarly journals The Direct 3D Printing of Functional PEEK/Hydroxyapatite Composites via a Fused Filament Fabrication Approach

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 545
Author(s):  
Krzysztof Rodzeń ◽  
Preetam K. Sharma ◽  
Alistair McIlhagger ◽  
Mozaffar Mokhtari ◽  
Foram Dave ◽  
...  
Keyword(s):  
Tensile Strength ◽  
3D Printing ◽  
Selective Laser Sintering ◽  
Fused Filament Fabrication ◽  
Bone Apposition ◽  
Innovative Solutions ◽  
3D Printed ◽  
Work Samples ◽  
Viable Approach ◽  
Crystalline Domains

The manufacture of polyetheretherketone/hydroxyapatite (PEEK/HA) composites is seen as a viable approach to help enhance direct bone apposition in orthopaedic implants. A range of methods have been used to produce composites, including Selective Laser Sintering and injection moulding. Such techniques have drawbacks and lack flexibility to manufacture complex, custom-designed implants. 3D printing gets around many of the restraints and provides new opportunities for innovative solutions that are structurally suited to meet the needs of the patient. This work reports the direct 3D printing of extruded PEEK/HA composite filaments via a Fused Filament Fabrication (FFF) approach. In this work samples are 3D printed by a custom modified commercial printer Ultimaker 2+ (UM2+). SEM-EDX and µCT analyses show that HA particles are evenly distributed throughout the bulk and across the surface of the native 3D printed samples, with XRD highlighting up to 50% crystallinity and crystalline domains clearly observed in SEM and HR-TEM analyses. This highlights the favourable temperature conditions during 3D printing. The yield stress and ultimate tensile strength obtained for all the samples are comparable to human femoral cortical bone. The results show how FFF 3D printing of PEEK/HA composites up to 30 wt% HA can be achieved.

scholarly journals The effect of liquid nitrogen cooling on coal cracking and mechanical properties

2018 ◽  
Vol 36 (6) ◽  
pp. 1609-1628 ◽  
Author(s):  
Chengzheng Cai ◽  
Feng Gao ◽  
Yugui Yang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Acoustic Emission ◽  
Liquid Nitrogen ◽  
Wave Velocity ◽  
Count Rate ◽  
Initial State ◽  
Nitrogen Injection ◽  
Strength Tests ◽  
Liquid Nitrogen Cooling

Liquid nitrogen is a type of super-cryogenic fluid, which can cause the reservoir temperature to decrease significantly and thereby induce formation rock damage and cracking when it is injected into the wellbore as fracturing fluid. An experimental set-up was designed to monitor the acoustic emission signals of coal during its contact with cryogenic liquid nitrogen. Ultrasonic and tensile strength tests were then performed to investigate the effect of liquid nitrogen cooling on coal cracking and the changes in mechanical properties thereof. The results showed that acoustic emission phenomena occurred immediately as the coal sample came into contact with liquid nitrogen. This indicated that evident damage and cracking were induced by liquid nitrogen cooling. During liquid nitrogen injection, the ring-down count rate was high, and the cumulative ring-down counts also increased rapidly. Both the ring-down count rate and the cumulative ring-down counts during liquid nitrogen injection were much greater than those in the post-injection period. Liquid nitrogen cooling caused the micro-fissures inside the coal to expand, leading to a decrease in wave velocity and the deterioration in mechanical strength. The wave velocity, which was measured as soon as the sample was removed from the liquid nitrogen (i.e. the wave velocity was recorded in the cooling state), decreased by 14.46% on average. As the cryogenic samples recovered to room temperature, this value increased to 18.69%. In tensile strength tests, the tensile strengths of samples in cooling and cool-treated states were (on average) 17.39 and 31.43% less than those in initial state. These indicated that both during the cooling and heating processes, damage and cracking were generated within these coal samples, resulting in the acoustic emission phenomenon as well as the decrease in wave velocity and tensile strength.

Research in Recycling Technology of Fiber Reinforced Polymers for Reduction of Environmental Load: Optimum Decomposition Conditions of Carbon Fiber Reinforced Polymers in the Purpose of Fiber Reuse

2011 ◽  
Vol 343-344 ◽  
pp. 142-149 ◽  
Author(s):  
Jian Shi ◽  
Kiyoshi Kemmochi ◽  
Li Min Bao
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Superheated Steam ◽  
Fiber Reinforced Polymers ◽  
Environmental Load ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Carbon Fiber Reinforced ◽  
Recycled Fibers

The objective of the present study is to investigate the effect of pyrolysis time and temperature on the mechanical properties of recycled carbon fiber, based on tensile strength measurements, determining the optimum decomposition conditions for carbon fiber-reinforced polymers (CFRPs) by superheated steam. In this research, CFRPs were efficiently depolymerized and reinforced fibers were separated from resin by superheated steam. Tensile strength of fibrous recyclates was measured and compared to that of virgin fiber. Although tensile strength of recycled fibers were litter lower than that of virgin fiber, under some conditions tensile strength of recycled fibers were close to that of virgin fiber. With pyrolysis, some char residue from the polymer remains on the fibers and degrees of char on the recycled fibers were closely examined by scanning electron microscopy.

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