scholarly journals Evaluating FDM Process Parameter Sensitive Mechanical Performance of Elastomers at Various Strain Rates of Loading

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3202 ◽  
Author(s):  
Muhammad Salman Chaudhry ◽  
Aleksander Czekanski
Keyword(s):  
Tensile Strength ◽  
High Strain Rate ◽  
Strain Rate ◽  
Process Parameters ◽  
Mechanical Performance ◽  
High Strain ◽  
Influence Of Process Parameters ◽  
Layer Height ◽  
Fused Deposition ◽  
Rate Of Loading

To optimize the mechanical performance of fused deposition modelling (FDM) fabricated parts, it is necessary to evaluate the influence of process parameters on the resulting mechanical performance. The main focus of the study was to characterize the influence of the initial process parameters on the mechanical performance of thermoplastic polyurethane under a quasi-static and high strain rate (~2500 s−1). The effects of infill percentage, layer height, and raster orientation on the mechanical properties of an FDM-fabricated part were evaluated. At a quasi-static rate of loading, layer height was found to be the most significant factor (36.5% enhancement in tensile strength). As the layer height of the sample increased from 0.1 to 0.4 mm, the resulting tensile strength sample was decreased by 36.5%. At a high-strain rate of loading, infill percentage was found to be the most critical factor influencing the mechanical strength of the sample (12.4% enhancement of compressive strength at 100% as compared to 80% infill). Furthermore, statistical analysis revealed the presence of significant interactions between the input parameters. Finally, using an artificial neural networking approach, we evaluated a regression model that related the process parameters (input factors) to the resulting strength of the samples.

scholarly journals An Image-Based Impact Test for the High Strain Rate Tensile Properties of Brittle Materials

2018 ◽  
Vol 183 ◽  
pp. 02042
Author(s):  
Lloyd Fletcher ◽  
Fabrice Pierron
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
High Strain Rate ◽  
Strain Rate ◽  
Stress Wave ◽  
High Strain ◽  
Brittle Materials ◽  
Test Method ◽  
Strain Rates ◽  
High Strain Rates

Testing ceramics at high strain rates presents many experimental diffsiculties due to the brittle nature of the material being tested. When using a split Hopkinson pressure bar (SHPB) for high strain rate testing, adequate time is required for stress wave effects to dampen out. For brittle materials, with small strains to failure, it is difficult to satisfy this constraint. Because of this limitation, there are minimal data (if any) available on the stiffness and tensile strength of ceramics at high strain rates. Recently, a new image-based inertial impact (IBII) test method has shown promise for analysing the high strain rate behaviour of brittle materials. This test method uses a reflected compressive stress wave to generate tensile stress and failure in an impacted specimen. Throughout the propagation of the stress wave, full-field displacement measurements are taken, from which strain and acceleration fields are derived. The acceleration fields are then used to reconstruct stress information and identify the material properties. The aim of this study is to apply the IBII test methodology to analyse the stiffness and strength of ceramics at high strain rates. The results show that it is possible to identify the elastic modulus and tensile strength of tungsten carbide at strain rates on the order of 1000 s-1. For a tungsten carbide with 13% cobalt binder the elastic modulus was identified as 516 GPa and the strength was 1400 MPa. Future applications concern boron carbide and sapphire, for which limited data exist in high rate tension.

Tensile strength of aluminum-epoxy resin composite structure under high strain rate conditions

2012 ◽  
Author(s):  
Damien Laporte ◽  
Frederic Malaise ◽  
Michel Boustie ◽  
Jean-Marc Chevalier ◽  
Eric Buzaud
Keyword(s):  
Tensile Strength ◽  
High Strain Rate ◽  
Strain Rate ◽  
Epoxy Resin ◽  
Composite Structure ◽  
High Strain ◽  
Resin Composite ◽  
Epoxy Resin Composite

scholarly journals High Strain Rate Tensile Properties of Annealed 2 1/4 Cr-1 Mo Steel

1976 ◽  
Vol 98 (4) ◽  
pp. 361-368 ◽  
Author(s):  
R. L. Klueh ◽  
R. E. Oakes
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
High Strain Rate ◽  
Strain Rate ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
High Strain ◽  
Total Elongation ◽  
Major Effect ◽  
Dynamic Strain

The high strain rate tensile properties of annealed 2 1/4 Cr-1 Mo steel were determined and the tensile behavior from 25 to 566°C and strain rates of 2.67 × 10−6 to 144/s were described. Above 0.1/s at 25°C, both the yield stress and the ultimate tensile strength increased rapidly with increasing strain rate. As the temperature was increased, a dynamic strain aging peak appeared in the ultimate tensile strength-temperature curves. The peak height was a maximum at about 350°C and 2.67 × 10−6/s. With increasing strain rate, a peak of decreased height occurred at progressively higher temperatures. The major effect of strain rate on ductility occurred at elevated temperatures, where a decrease in strain rate caused an increase in total elongation and reduction in area.

scholarly journals Influence of Process Parameters on Tensile Strength of Additive Manufactured PLA Parts using Taguchi Method

2019 ◽  
Vol 8 (3) ◽  
pp. 7635-7639
Keyword(s):  
Tensile Strength ◽  
Layer Thickness ◽  
Fused Deposition Modeling ◽  
Optimal Parameter ◽  
Fused Filament Fabrication ◽  
Influence Of Process Parameters ◽  
Layer Height ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Nozzle Temperature

Influence of layer thickness nozzle temperature and angle on tensile strength of PLA fabricated with FDM (FFF) was experimentally investigated. Polylactic Acid (PLA) is a semi-crystalline and bio-friendly thermoplastic polymer has identified as important material in different applications due to its mechanical characteristics. Fused Deposition Modeling (FDM) is a one of the proved technology in Fused Filament Fabrication (FFF) technique in additive manufacturing process. In present investigation different specimens were fabricated using FDM technique with different layer height and different layer angles for finding influence of these manufacturing parameters on tensile strength of the specimen. Specimens were fabricated and tested as per ASTM D638 standard. It is clearly observed that tensile strength is more for +450 /-450 layer angle than the +00 /-0 0 layer angle for a given layer height(h=0.10 mm, h=0.15mm and h=0.20mm).The TAGUCHI analysis is carried with nozzle temperature, layer thickness and angle finding optimal values. It has been observed that, the optimal parameter is angle, which is equal to 30 0 .the ANOVA variation of angle layer with tensile strength has been observed that 18.10-31.90.

scholarly journals Mechanical characterization of 3D printed concrete subjected to dynamic loading

2021 ◽  
Vol 250 ◽  
pp. 01009
Author(s):  
Rosanna Napolitano ◽  
Costantino Menna ◽  
Daniele Forni ◽  
Domenico Asprone ◽  
Ezio Cadoni
Keyword(s):  
Tensile Strength ◽  
High Strain Rate ◽  
Strain Rate ◽  
Waiting Time ◽  
High Strain ◽  
Waiting Times ◽  
Digital Fabrication ◽  
Tensile Tests ◽  
Experimental Program ◽  
3D Printed

In concrete structures realized by digital fabrication techniques, such as 3D concrete printing, under severe dynamic loadings (e.g. earthquakes and impact loads), the strength at the bond interfaces between layers is weak. Since these contact zones, also referred as cold joint, could potentially compromise the structural stability and also the durability of printed elements, their behaviour under high dynamic loads is fundamental to investigate. An experimental program on 3D printed concrete elements varying the waiting time, through medium and high strain-rate tensile tests is running, with a Hydro-Pneumatic Machine and a modified Hopkinson tensile bar respectively. The results of dynamic tensile tests at three different strain rates (10-5, 50 and 200 s-1) on 3D printed cementitious elements for waiting times of 0min, 10min and 30 min have been presented, in terms of Dynamic increase factors DIF versus strain rate, showing a behaviour highly strain-rate sensitive, recording an increase in tensile strength DIF up to 7.6 in the case of high strain-rate and waiting time of 30 min. The results exhibited a decrease in the dynamic interface tensile strength with the waiting time up to over 90% for a medium strain-rate and over 20% for a high strain-rate.

Dynamic Characterization of Additively Manufactured Polylactide (PLA)

2021 ◽  
pp. 146442072110651
Author(s):  
GTL Priyanka ◽  
Ch. Saideep ◽  
T. Tadepalli
Keyword(s):  
Compressive Strength ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Fused Deposition Modelling ◽  
Strain Rates ◽  
Simple Modification ◽  
Fused Deposition ◽  
Softening Behavior ◽  
3D Printed

Additively manufactured materials have excellent properties with wide applications in many industries. For designing components exposed to extreme loading situations, it is essential to characterize the high strain rate response of 3D printed (fused deposition modelling) materials. In this study, uniaxial quasi-static and dynamic compressive tests were carried out at various strain rates (10−2 s−1 and 200 s−1 to 1800 s−1) for 3D printed PLA. Strain rate dependent compressive response of Polylactide acid (PLA) disk specimens 3D printed at 0°, 45° and 90° orientations was obtained using the Split Hopkinson bar technique. The results show that the compressive strength increases with corresponding strain rates for 0° and 45° print orientations. PLA printed at 0° has higher compressive strength compared to 45° and 90° orientations under quasi-static as well as high strain rate loading. Toughness was observed to increase with strain rate in all three orientations. A simple modification to the Johnson-Cook model is proposed, which accounts for the effects of print orientation, porosity and strain softening behavior.

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