Validating a Failure Surface Developed for ABS Fused Filament Fabrication Parts through Complex Loading Experiments

Fused Filament Fabrication (FFF) is arguably the most widely available additive manufacturing technology at the moment. Offering the possibility of producing complex geometries in a compressed product development cycle and in a plethora of materials, it has gradually started to become attractive to multiple industrial segments, slowly being implemented in diverse applications. However, the high anisotropy of parts developed through this technique renders failure prediction difficult. The proper performance of the part, or even the safety of the final user, cannot be guaranteed under demanding mechanical requirements. This problem can be tackled through the development of a failure envelope that allows engineers to predict failure by using the knowledge of the stress state of the part. Previous research by the authors developed a failure envelope for acrylonitrile butadiene styrene (ABS) based, Fused Filament Fabrication (FFF) parts by use of a criterion that incorporates stress interactions. This work validates the first quadrant of the envelope by performing uniaxial tensile tests with coupons produced with a variety of raster angles, creating a combined loading stress state in the localized coordinate system. Results show the safe zone encompassed by the failure envelope proved adequate.

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Mechanical Characterization and Failure Analysis of ABS Material Submitted to Static Tests under the Effect of Temperature

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.820.159 ◽

2019 ◽

Vol 820 ◽

pp. 159-172

Author(s):

Abderrazak En-Naji ◽

Nadia Mouhib ◽

Mohamed El Ghorba

Keyword(s):

Amorphous Polymer ◽

Acrylonitrile Butadiene Styrene ◽

Tensile Tests ◽

Effect Of Temperature ◽

Uniaxial Tensile ◽

Industrial Zone ◽

Static Tests ◽

Damage Process ◽

The Moment ◽

Experimental Values

In this work, we study the influence of temperature on the mechanical behavior of an amorphous polymer, acrylonitrile butadiene styrene "ABS", based on a series of uniaxial tensile tests on smooth specimens at different temperatures.The results obtained show that the failure of the studied material (ABS) depends strongly on the temperature. Indeed, two zones have been identified: industrial zone T<Tg and thermoforming zone T>Tg (Tg is the glass transition temperature of ABS material).In the industrial zone, we conducted a study of the experimental and theoretical damage via the model of the unified theory. The comparison showed a good agreement concerning the acceleration of the damage process as the temperature increases. In the thermoforming zone, we adopted the same methods to follow the process of flow as a function of the temperature increase. Likewise, we compared theoretical and experimental values which in turn showed a good match. Different stages have been determined in each separate zone, that allows to predict the moment of the critical damage or flow and therefore to intervene in time for a predictive maintenance.

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

Polymers ◽

10.3390/polym13111766 ◽

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.

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Tensile properties of the FFF-processed thermoplastic polyurethane (TPU) elastomer

10.21203/rs.3.rs-299979/v1 ◽

2021 ◽

Author(s):

Budi Arifvianto ◽

Teguh Nur Iman ◽

Benidiktus Tulung Prayoga ◽

Rini Dharmastiti ◽

Urip Agus Salim ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Low Cost ◽

Thermoplastic Polyurethane ◽

High Strength ◽

Tensile Tests ◽

Uniaxial Tensile ◽

Fused Filament Fabrication ◽

Raster Angle ◽

Manufacturing Techniques

Abstract Fused filament fabrication (FFF) has become one of the most popular, practical, and low-cost additive manufacturing techniques for fabricating geometrically-complex thermoplastic polyurethane (TPU) elastomer. However, there are still some uncertainties concerning the relationship between several operating parameters applied in this technique and the mechanical properties of the processed material. In this research, the influences of extruder temperature and raster orientation on the mechanical properties of the FFF-processed TPU elastomer were studied. A series of uniaxial tensile tests was carried out to determine tensile strength, strain, and elastic modulus of TPU elastomer that had been printed with various extruder temperatures, i.e., 190–230 °C, and raster angles, i.e., 0–90°. Thermal and chemical characterizations were also conducted to support the analysis in this research. The results obviously showed the ductile and elastic characteristics of the FFF-processed TPU, with specific tensile strength and strain that could reach up to 39 MPa and 600%, respectively. The failure mechanisms operating on the FFF-processed TPU and the result of stress analysis by using the developed Mohr’s circle are also discussed in this paper. In conclusion, the extrusion temperature of 200 °C and raster angle of 0° could be preferred to be applied in the FFF process to achieve high strength and ductile TPU elastomer.

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Lattice Fracture Model for Concrete Fracture Revisited: Calibration and Validation

Applied Sciences ◽

10.3390/app10144822 ◽

2020 ◽

Vol 10 (14) ◽

pp. 4822

Author(s):

Ze Chang ◽

Hongzhi Zhang ◽

Erik Schlangen ◽

Branko Šavija

Keyword(s):

Boundary Conditions ◽

Complex Loading ◽

Tensile Tests ◽

Calibration Procedure ◽

Cementitious Materials ◽

Fracture Model ◽

Uniaxial Tensile ◽

Concrete Fracture ◽

Beam Shear ◽

Experimental Findings

The lattice fracture model is a discrete model that can simulate the fracture process of cementitious materials. In this work, the Delft lattice fracture model is reviewed and utilized for fracture analysis. First, a systematic calibration procedure that relies on the combination of two uniaxial tensile tests is proposed to determine the input parameters of lattice elements—tensile strength, compressive strength and elastic modulus. The procedure is then validated by simulating concrete fracture under complex loading and boundary conditions: Uniaxial compression, three-point bending, tensile splitting, and double-edge-notch beam shear. Simulation results are compared to experimental findings in all cases. The focus of this publication is therefore not only on summarizing existing knowledge and showing the capabilities of the lattice fracture model; but also to fill in an important gap in the field of lattice modeling of concrete fracture; namely, to provide a recommendation for a systematic model calibration using experimental data. Through this research, numerical analyses are performed to fully understand the failure mechanisms of cementitious materials under various loading and boundary conditions. While the model presented herein does not aim to completely reproduce the load-displacement curves, and due to its simplicity results in relatively brittle post-peak behavior, possible solutions for this issue are also discussed in this work.

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Effect of extrusion temperature on fused filament fabrication parts orthotropic behaviour

Rapid Prototyping Journal ◽

10.1108/rpj-08-2019-0207 ◽

2019 ◽

Vol 26 (4) ◽

pp. 639-647

Author(s):

Michele Angelo Attolico ◽

Caterina Casavola ◽

Alberto Cazzato ◽

Vincenzo Moramarco ◽

Gilda Renna

Keyword(s):

Mechanical Properties ◽

Morphological Characteristics ◽

Single Layer ◽

Acrylonitrile Butadiene Styrene ◽

Surface Characteristics ◽

Tensile Tests ◽

Extrusion Temperature ◽

Fused Filament Fabrication ◽

Bonding Quality ◽

Content Type

Purpose The purpose of this paper is to verify the effects of extrusion temperature on orthotropic behaviour of the mechanical properties of parts obtained by fused filament fabrication (FFF) under quasi-static tensile loads. Design/methodology/approach Tensile tests were performed on single layer specimens fabricated in polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) to evaluate the mechanical properties at different extrusion temperatures and raster orientations (0°, 45° and 90°). Furthermore, a detailed study of morphological characteristics of the single layer samples cross-section and of the bonding quality among adjacent deposited filaments was performed by scanning electron microscopy to correlate the morphology of materials with mechanical behaviour. Findings The results show that the orthotropic behaviour of FFF-printed parts tends to reduce, while the mechanical properties improved with increase in extrusion temperature. Furthermore, the increase in extrusion temperature led to an improvement in inter-raster bonding quality and in the compactness and homogeneity of the parts. Originality/value The relation between the extrusion temperature, orthotropic behaviour and morphological surface characteristics of the single layer specimen obtained by FFF has not been previously reported.

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The Experimental Prediction of the Lifetime of Acrylonitrile Butadiene Styrene (ABS) by the Energetic Method

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.820.147 ◽

2019 ◽

Vol 820 ◽

pp. 147-158

Author(s):

Abderrazak En-Naji ◽

Nadia Mouhib ◽

Fatima Majid ◽

Hicham ElKihal ◽

Mohamed El Ghorba

Keyword(s):

Amorphous Polymer ◽

Energy Parameter ◽

Acrylonitrile Butadiene Styrene ◽

Tensile Tests ◽

Experimental Models ◽

Uniaxial Tensile ◽

Unified Theory ◽

Theoretical Evaluation ◽

Life Fraction ◽

Butadiene Styrene

In this paper, we are dealing with the study of the mechanical behavior of an amorphous polymer, acrylonitrile butadiene styrene "ABS". In fact, uniaxial tensile tests on rectangular specimens containing a combined defect, with simple and double notches, has been done. The proposed approach develop a method, based on energy parameter, to calculate the evolution of damage over the materials’ life. This method can be used to predict quantitatively the risk of sudden rupture in a structure. Therefore, the damage evaluation based on the residual energy method was compared to the unified theory one for different loading levels. The prediction of damage by experimental models has led to the determination of the three stages of damage evolution, which are the initiation, propagation and complete deterioration of the material. Thus, the concept of reliability is used to specify the critical life fraction, which is similar to the notch depth (βc) of a modeled defect as a combined defect on an ABS sample. In addition, the unified theory was used in this work, to define on the one hand, the parameter of damage which is the internal variable which describes the failure level of the structure in function of life fraction, on the other hand, for the theoretical evaluation of the level of damage. Finally, we have proved that the theoretical and experimental results show a good agreement.

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Residual Stress State at Different Scales in Deep Drawn Cup of Unstable Austenitic Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.524-525.95 ◽

2006 ◽

Vol 524-525 ◽

pp. 95-100 ◽

Cited By ~ 4

Author(s):

M. Reda Berrahmoune ◽

Sophie Berveiller ◽

Karim Inal ◽

Etienne Patoor

Keyword(s):

Stress State ◽

Residual Stresses ◽

Austenitic Steel ◽

Deep Drawing ◽

Complex Loading ◽

Tensile Tests ◽

Loading Path ◽

Internal Stresses ◽

Drawing Ratio ◽

Unstable Austenitic Steel

In this study, residual stresses state at different scales in the 301LN unstable austenitic steel after deep drawing was determined. The first part of the work deals with the characterization of the martensitic transformation during uniaxial loading. The austenite/martensite content which was determined by X-Ray Diffraction increases until a maximum of 0.6 for 30% strain. Internal stress distribution was determined by coupling in-situ tensile tests with sin²ψ method. As soon as martensite appears, the magnitudes of the internal stresses in this phase were found to be 400 MPa higher than in the austenite. To establish a relation between the complex loading path effect and the phase stress state, deep drawing tests were carried out for different drawing ratios. Both macroscopic tangential residual stresses and residual stresses in the martensite were determined. It appears that the macroscopic tangential residual stresses are positive and increase with increasing drawing ratios and the maximum value is located at middle height of the cup. It is about 850MPa for the Drawing Ratio (DR)=2.00. The tangential residual stresses in the martensite were found to be positive in the external face and have a same evolution as the macroscopic ones.

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A Comparative Analysis of Selected Methods for Determining Young’s Modulus in Polylactic Acid Samples Manufactured with the FDM Method

Materials ◽

10.3390/ma15010149 ◽

2021 ◽

Vol 15 (1) ◽

pp. 149

Author(s):

Bartosz Pszczółkowski ◽

Konrad W. Nowak ◽

Wojciech Rejmer ◽

Mirosław Bramowicz ◽

Łukasz Dzadz ◽

...

Keyword(s):

Young’S Modulus ◽

Polylactic Acid ◽

Fused Deposition Modeling ◽

Young's Modulus ◽

Acrylonitrile Butadiene Styrene ◽

Tensile Tests ◽

Fused Filament Fabrication ◽

Fused Deposition ◽

Static Tensile ◽

Deposition Modeling

The objective of this study was to compare three methods for determining the Young’s modulus of polylactic acid (PLA) and acrylonitrile-butadiene-styrene (ABS) samples. The samples were manufactured viathe fused filament fabrication/fused deposition modeling (FFF/FDM) 3D printing technique. Samples for analysis were obtained at processing temperatures of 180 °C to 230 °C. Measurements were performed with the use of two nondestructive techniques: the impulse excitation technique (IET) and the ultrasonic (US) method. The results were compared with values obtained in static tensile tests (STT), which ranged from 2.06 ± 0.03 to 2.15 ± 0.05 GPa. Similar changes in Young’s modulus were observed in response to the processing temperatures of the compared methods. The values generated by the US method were closer to the results of the STT, but still diverged considerably, and the error exceeded 10% in all cases. Based on the present findings, it might be concluded that the results of destructive and nondestructive tests differ by approximately 1 GPa.

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Deterioration of the Mechanical Properties of FFF 3D-Printed PLA Structures

Inventions ◽

10.3390/inventions6010001 ◽

2020 ◽

Vol 6 (1) ◽

pp. 1

Author(s):

Asahi Yonezawa ◽

Akira Yamada

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

Test Piece ◽

Tensile Tests ◽

Poly Lactic Acid ◽

Uniaxial Tensile ◽

Layer By Layer ◽

Fused Filament Fabrication ◽

Test Pieces ◽

3D Printed

Poly(lactic acid) (PLA) is a biodegradable polymer material used for the fabrication of objects by fused filament fabrication (FFF) 3D printing. FFF 3D printing technology has been quickly spreading over the past few years. An FFF-3D-printed object is formed from melted polymer extruded from a nozzle layer-by-layer. The mechanical properties of the object, and the changes in those properties as the object degrades, differ from the properties and changes observed in bulk objects. In this study we evaluated FFF-3D-printed objects by uniaxial tensile tests and four-point flexural tests to characterize the changes of three mechanical properties, namely, the maximum stress, elastic modulus, and breaking energy. Eight types of test pieces printed directly by an FFF 3D printer using two scan patterns and two interior fill percentages (IFPs) were tested by the aforesaid methods. The test pieces were immersed in saline and kept in an incubator at 37 °C for 30, 60, or 90 days before the mechanical testing. The changes in the mechanical properties differed largely between the test piece types. In some of the test pieces, transient increases in strength were observed before the immersion degraded the strength. Several of the test piece types were found to have superior specific strength in the tests. The results obtained in this research will be helpful for the design of PLA structures fabricated by FFF 3D printing.

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Feasible Evaluation of Flow Properties and Stress State of Structural Materials Using Instrumented Indentation Tests

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.487 ◽

2006 ◽

Vol 326-328 ◽

pp. 487-492 ◽

Cited By ~ 1

Author(s):

Ju Young Kim ◽

Jung Suk Lee ◽

Kyung Woo Lee ◽

Kwang Ho Kim ◽

Dong Il Kwon

Keyword(s):

Stress State ◽

Structural Materials ◽

Tensile Tests ◽

Indentation Load ◽

Uniaxial Tensile ◽

Instrumented Indentation ◽

Flow Properties ◽

Friction Stir ◽

Indentation Tests ◽

Quantitative Stress

Flow properties and stress state are indispensable factors for safety assessment of structural materials in operation, which were evaluated using instrumented indentation tests (IITs). Flow properties were obtained by defining representative stress and strain, and IIT results for 10 steel materials were discussed by comparing with those from uniaxial tensile tests. The indentation load-depth curve is significantly affected by the presence of residual stress, and the stress-induced load change was converted to a quantitative stress value. The stress state of a friction stir-welded joint of API X80 steel was evaluated and compared with that measured by energy-dispersive X-ray diffraction.

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