scholarly journals Analysis of Notch Effect in 3D-Printed ABS Fracture Specimens Containing U-Notches

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4716
Author(s):  
Sergio Cicero ◽  
Victor Martínez-Mata ◽  
Alejandro Alonso-Estebanez ◽  
Laura Castanon-Jano ◽  
Borja Arroyo
Keyword(s):  
Acrylonitrile Butadiene Styrene ◽  
Experimental Tests ◽  
Tensile Tests ◽  
Fracture Mechanisms ◽  
Notch Effect ◽  
Fracture Assessment ◽  
3D Printed ◽  
Fracture Tests ◽  
Cracked Specimens ◽  
Fracture Specimens

In this paper a fracture assessment in additive manufactured acrylonitrile butadiene styrene (ABS) fracture specimens containing U-notches is performed. We performed 33 fracture tests and 9 tensile tests, combining five different notch radii (0 mm, 0.25 mm, 0.50 mm, 1 mm and 2 mm) and three different raster orientations: 0/90, 30/−60 and 45/−45. The theory of critical distances (TCD) was then used in the analysis of fracture test results, obtaining additional validation of this theoretical framework. Different versions of TCD provided suitable results contrasting with the experimental tests performed. Moreover, the fracture mechanisms were evaluated using scanning electron microscopy in order to establish relationships with the behaviour observed. It was demonstrated that 3D-printed ABS material presents a clear notch effect, and also that the TCD, through both the point method and the line method, captured the physics of the notch effect in 3D-printed ABS. Finally, it was observed that the change in the fracture mechanisms when introducing a finite notch radius was limited to a narrow band behind the original defect, which appeared in cracked specimens but not in notched specimens.

scholarly journals On the Post-Processing of 3D-Printed ABS Parts

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1559
Author(s):  
Mohammad Reza Khosravani ◽  
Jonas Schüürmann ◽  
Filippo Berto ◽  
Tamara Reinicke
Keyword(s):  
Surface Treatment ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Acrylonitrile Butadiene Styrene ◽  
Experimental Tests ◽  
Fracture Load ◽  
Post Processing ◽  
Fused Deposition ◽  
Dog Bone ◽  
3D Printed

Application of Additive Manufacturing (AM) has significantly increased in the past few years. AM also known as three-dimensional (3D) printing has been currently used in fabrication of prototypes and end-use products. Considering the new applications of additively manufactured components, it is necessary to study structural details of these parts. In the current study, influence of a post-processing on the mechanical properties of 3D-printed parts has been investigated. To this aim, Acrylonitrile Butadiene Styrene (ABS) material was used to produce test coupons based on the Fused Deposition Modeling (FDM) process. More in deep, a device was designed and fabricated to fix imperfection and provide smooth surfaces on the 3D-printed ABS specimens. Later, original and treated specimens were subjected to a series of tensile loads, three-point bending tests, and water absorption tests. The experimental tests indicated fracture load in untreated dog-bone shaped specimen was 2026.1 N which was decreased to 1951.7 N after surface treatment. Moreover, the performed surface treatment was lead and decrease in tensile strength from 29.37 MPa to 26.25 MPa. Comparison of the results confirmed effects of the surface modification on the fracture toughness of the examined semi-circular bending components. Moreover, a 3D laser microscope was used for visual investigation of the specimens. The documented results are beneficial for next designs and optimization of finishing processes.

scholarly journals Experimental, Computational, and Dimensional Analysis of the Mechanical Performance of Fused Filament Fabrication Parts

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1766
Author(s):  
Iván Rivet ◽  
Narges Dialami ◽  
Miguel Cervera ◽  
Michele Chiumenti ◽  
Guillermo Reyes ◽  
...  
Keyword(s):  
Dimensional Analysis ◽  
Mechanical Performance ◽  
Cost Savings ◽  
Acrylonitrile Butadiene Styrene ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Zone Model ◽  
Key Factors ◽  
Fused Filament Fabrication ◽  
3D Printed

Process parameters in Additive Manufacturing (AM) are key factors in the mechanical performance of 3D-printed parts. In order to study their effect, a three-zone model based on the printing pattern was developed. This modelization distinguished three different zones of the 3D-printed part, namely cover, contour, and inner; each zone was treated as a different material. The cover and contour zones were characterized via uniaxial tensile tests and the inner zones via computational homogenization. The model was then validated by means of bending tests and their corresponding computational simulations. To reduce the number of required characterization experiments, a relationship between the raw and 3D-printed material was established by dimensional analysis. This allowed describing the mechanical properties of the printed part with a reduced set of the most influential non-dimensional relationships. The influence on the performance of the parts of inter-layer adhesion was also addressed in this work via the characterization of samples made of Polycarbonate Acrylonitrile Butadiene Styrene (ABS/PC), a polymeric material well known for its poor adhesion strength. It was concluded that by using this approach, the number of required testing configurations could be reduced by two thirds, which implies considerable cost savings.

Fracture tests under mixed mode I + III loading: An assessment based on the local energy

2016 ◽  
Vol 26 (6) ◽  
pp. 881-894 ◽  
Author(s):  
Filippo Berto ◽  
MR Ayatollahi ◽  
A Campagnolo
Keyword(s):  
Polymethyl Methacrylate ◽  
Mixed Mode ◽  
Local Strain ◽  
Mode I ◽  
Local Energy ◽  
Large Bulk ◽  
Fracture Assessment ◽  
Fracture Tests ◽  
Cracked Specimens ◽  
Good Agreement

In this paper, some recent data exploring mixed mode I + III fracture of cracked polymethyl methacrylate specimens are re-analysed in terms of the local energy. The data have been obtained by using a new loading fixture proposed for exploring mixed mode I + III fracture experimentally. While a large bulk of experimental results from cracked specimens of polymethyl methacrylate under pure modes of loading, in particular under mode I loading, can be found in the literature, only very few tests have been carried out considering multiaxial static loadings, and for this reason, only limited studies have been performed on possible criteria for the fracture assessment under mixed mode I + III conditions. By taking advantage of the recent set of data on polymethyl methacrylate tested at different values of the mode mixity ratio, a criterion based on the local strain energy density previously applied by the same authors only to pure modes of loading is successfully extended here to the case of tension and torsion loadings applied in combination. Good agreement is shown to exist between the theoretical estimates and the experimental data.

scholarly journals 3D Printed Hierarchical Honeycombs with Carbon Fiber and Carbon Nanotube Reinforced Acrylonitrile Butadiene Styrene

2021 ◽  
Vol 5 (2) ◽  
pp. 62
Author(s):  
Michel Theodor Mansour ◽  
Konstantinos Tsongas ◽  
Dimitrios Tzetzis
Keyword(s):  
Carbon Fibers ◽  
Mechanical Performance ◽  
Acrylonitrile Butadiene Styrene ◽  
Experimental Tests ◽  
Fused Filament Fabrication ◽  
Element Analysis ◽  
Compression Performance ◽  
Honeycomb Structures ◽  
3D Printed ◽  
Butadiene Styrene

The mechanical properties of Fused Filament Fabrication (FFF) 3D printed specimens of acrylonitrile butadiene styrene (ABS), ABS reinforced with carbon fibers (ABS/CFs) and ABS reinforced with carbon nanotubes (ABS/CNTs) are investigated in this paper using various experimental tests. In particular, the mechanical performance of the fabricated specimens was determined by conducting compression and cyclic compression testing, as well as nanoindentation tests. In addition, the design and the manufacturing of hierarchical honeycomb structures are presented using the materials under study. The 3D printed honeycomb structures were examined by uniaxial compressive tests to review the mechanical behavior of such cellular structures. The compressive performance of the hierarchical honeycomb structures was also evaluated with finite element analysis (FEA) in order to extract the stress-strain response of these structures. The results revealed that the 2nd order hierarchy displayed increased stiffness and strength as compared with the 0th and the 1st hierarchies. Furthermore, the addition of carbon fibers in the ABS matrix improved the stiffness, the strength and the hardness of the FFF printed specimens as well as the compression performance of the honeycomb structures.

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 Ductile failure analysis of epoxy resin plates containing multiple circular arc cracks by means of the equivalent material concept

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
M. Pourseifi ◽  
A. S. Rahimi
Keyword(s):  
Ductile Failure ◽  
Equivalent Material ◽  
Circular Arc ◽  
Equivalent Material Concept ◽  
Crack Tips ◽  
Fracture Tests ◽  
Polymeric Samples ◽  
Cracked Specimens ◽  
Brittle Fracture Criterion ◽  
Material Concept

AbstractDuctile failure of polymeric samples weakened by circular arc cracks is studied theoretically and experimentally in this research. Various arrangements of cracks with different arc angles are considered in the specimens such that crack tips experienced the mixed mode I/II loading conditions. Fracture tests are conducted on the multi-cracked specimens and their fracture loads are achieved. To provide the results, the equivalent material concept (EMC) is used in conjunction of dislocation method and a brittle fracture criterion such that there is no necessity for performing complex and time-consuming elastic-plastic damage analyses. Theoretical and experimental stress intensity factors are computed and compared with each other by employing the fracture curves which demonstrate the appropriate efficiency of proposed method to predict the tests results.

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 Essential work of fracture assessment of acrylonitrile butadiene styrene (ABS) processed via fused filament fabrication additive manufacturing

2021 ◽  
Author(s):  
Pawan Verma ◽  
Jabir Ubaid ◽  
Andreas Schiffer ◽  
Atul Jain ◽  
Emilio Martínez-Pañeda ◽  
...  
Keyword(s):  
Acrylonitrile Butadiene Styrene ◽  
Essential Work ◽  
Fused Filament Fabrication ◽  
Essential Work Of Fracture ◽  
Fracture Properties ◽  
Raster Angle ◽  
3D Printed ◽  
Printing Direction ◽  
Work Of Fracture ◽  
Butadiene Styrene

AbstractExperiments and finite element (FE) calculations were performed to study the raster angle–dependent fracture behaviour of acrylonitrile butadiene styrene (ABS) thermoplastic processed via fused filament fabrication (FFF) additive manufacturing (AM). The fracture properties of 3D-printed ABS were characterized based on the concept of essential work of fracture (EWF), utilizing double-edge-notched tension (DENT) specimens considering rectilinear infill patterns with different raster angles (0°, 90° and + 45/− 45°). The measurements showed that the resistance to fracture initiation of 3D-printed ABS specimens is substantially higher for the printing direction perpendicular to the crack plane (0° raster angle) as compared to that of the samples wherein the printing direction is parallel to the crack (90° raster angle), reporting EWF values of 7.24 kJ m−2 and 3.61 kJ m−2, respectively. A relatively high EWF value was also reported for the specimens with + 45/− 45° raster angle (7.40 kJ m−2). Strain field analysis performed via digital image correlation showed that connected plastic zones existed in the ligaments of the DENT specimens prior to the onset of fracture, and this was corroborated by SEM fractography which showed that fracture proceeded by a ductile mechanism involving void growth and coalescence followed by drawing and ductile tearing of fibrils. It was further shown that the raster angle–dependent strength and fracture properties of 3D-printed ABS can be predicted with an acceptable accuracy by a relatively simple FE model considering the anisotropic elasticity and failure properties of FFF specimens. The findings of this study offer guidelines for fracture-resistant design of AM-enabled thermoplastics. Graphical abstract

scholarly journals Additively Manufactured Parts Made of a Polymer Material Used for the Experimental Verification of a Component of a High-Speed Machine with an Optimised Geometry—Preliminary Research

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 137
Author(s):  
Artur Andrearczyk ◽  
Bartlomiej Konieczny ◽  
Jerzy Sokołowski
Keyword(s):  
Polymer Material ◽  
High Speed ◽  
Numerical Models ◽  
Flow Analysis ◽  
Experimental Tests ◽  
Strength Analysis ◽  
Compressor Wheel ◽  
Operational Characteristics ◽  
3D Printed ◽  
Novel Method

This paper describes a novel method for the experimental validation of numerically optimised turbomachinery components. In the field of additive manufacturing, numerical models still need to be improved, especially with the experimental data. The paper presents the operational characteristics of a compressor wheel, measured during experimental research. The validation process included conducting a computational flow analysis and experimental tests of two compressor wheels: The aluminium wheel and the 3D printed wheel (made of a polymer material). The chosen manufacturing technology and the results obtained made it possible to determine the speed range in which the operation of the tested machine is stable. In addition, dynamic destructive tests were performed on the polymer disc and their results were compared with the results of the strength analysis. The tests were carried out at high rotational speeds (up to 120,000 rpm). The results of the research described above have proven the utility of this technology in the research and development of high-speed turbomachines operating at speeds up to 90,000 rpm. The research results obtained show that the technology used is suitable for multi-variant optimization of the tested machine part. This work has also contributed to the further development of numerical models.

scholarly journals Metallization of Thermoplastic Polymers and Composites 3D Printed by Fused Filament Fabrication

Technologies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 49
Author(s):  
Alessia Romani ◽  
Andrea Mantelli ◽  
Paolo Tralli ◽  
Stefano Turri ◽  
Marinella Levi ◽  
...  
Keyword(s):  
Physical Vapor Deposition ◽  
Test Sample ◽  
Tensile Tests ◽  
Layer By Layer ◽  
Post Processing ◽  
Thermoplastic Polymers ◽  
Fused Filament Fabrication ◽  
Scanning Calorimetry ◽  
3D Printed ◽  
Manufacturing Technologies

Fused filament fabrication allows the direct manufacturing of customized and complex products although the layer-by-layer appearance of this process strongly affects the surface quality of the final parts. In recent years, an increasing number of post-processing treatments has been developed for the most used materials. Contrarily to other additive manufacturing technologies, metallization is not a common surface treatment for this process despite the increasing range of high-performing 3D printable materials. The objective of this work is to explore the use of physical vapor deposition sputtering for the chromium metallization of thermoplastic polymers and composites obtained by fused filament fabrication. The thermal and mechanical properties of five materials were firstly evaluated by means of differential scanning calorimetry and tensile tests. Meanwhile, a specific finishing torture test sample was designed and 3D printed to perform the metallization process and evaluate the finishing on different geometrical features. Furthermore, the roughness of the samples was measured before and after the metallization, and a cost analysis was performed to assess the cost-efficiency. To sum up, the metallization of five samples made with different materials was successfully achieved. Although some 3D printing defects worsened after the post-processing treatment, good homogeneity on the finest details was reached. These promising results may encourage further experimentations as well as the development of new applications, i.e., for the automotive and furniture fields.

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