scholarly journals A Finite Element Method to Predict the Mechanical Behavior of a Pre-Structured Material Manufactured by Fused Filament Fabrication in 3D Printing

2021 ◽  
Vol 11 (11) ◽  
pp. 5075
Author(s):  
Marouene Zouaoui ◽  
Julien Gardan ◽  
Pascal Lafon ◽  
Ali Makke ◽  
Carl Labergere ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Elastic Behavior ◽  
Fused Filament Fabrication ◽  
Elastoplastic Behavior ◽  
Hill Criterion ◽  
G Code ◽  
The Hill ◽  
Gauss Points

In this paper, a numerical method is proposed to simulate the mechanical behavior of a new polymeric pre-structured material manufactured by fused filament fabrication (FFF), where the filaments are oriented along the principal stress directions. The model implements optimized filament orientations, obtained from the G code by assigning materials references in mesh elements. The Gauss points are later configured with the physical behavior while considering a homogeneous solid structure. The objective of this study is to identify the elastoplastic behavior. Therefore, tensile tests were conducted with different filament orientations. The results show that using appropriate material constants is efficient in describing the built anisotropy and incorporating the air gap volume fraction. The suggested method is proved very efficient in implementing multiplex G code orientations. The elastic behavior of the pre-structured material is quasi-isotropic. However, the anisotropy was observed at the yield point and the ultimate stress. Using the Hill criterion coupled with an experimental tabular law of the plastic flow turns out to be suitable for predicting the response of various specimens.

Stress-Strain Equations for Some Near-Eutectic Tin-Lead Solders

1991 ◽  
Vol 113 (4) ◽  
pp. 475-484 ◽  
Author(s):  
K. P. Jen ◽  
J. N. Majerus
Keyword(s):  
Strain Rate ◽  
Printed Circuit Boards ◽  
Volume Fraction ◽  
Total Error ◽  
Tensile Tests ◽  
Elastic Behavior ◽  
Plastic Behavior ◽  
Strain Rates ◽  
Stress Strain ◽  
Engineering Strain

This paper presents the evaluation of the stress-strain behavior, as a function of strain-rate, for three tin-lead solders at room temperature. This behavior is critically needed for reliability analysis of printed circuit boards (PCB) since handbooks list minimal mechanical properties for the eutectic solder used in PCBs. Furthermore, most handbook data are for stable eutectic microstructure whereas PCB solder has a metastable microstructure. All three materials were purchased as “eutectics.” However, chemical analysis, volume fraction determination, and microhardness tests show some major variations between the three materials. Two of the materials have a eutectic composition, and one does not. The true stress-strain equations of one eutectic and the one noneutectic material are determined from compressive tests at engineering strain-rates between 0.0002/s and 0.2/s. The second eutectic material is evaluated using tensile tests with strain-rates between 0.00017/s and 0.042/s. The materials appear to exhibit linear elastic behavior only at extremely small strains, i.e., less than 0.0005. However, this “elastic” behavior showed considerable variation, and depended upon the strain rate. In both tension and compression the eutectic alloy exhibits nonlinear plastic behavior, i.e., strain-softening followed by strain-hardening, which depends upon the strain rate. A quadratic equation σy = σy(ε˚/ε˚0) + A(ε˚/ε˚0)ε + B(ε˚/ε˚0)ε2 fit to the data gives correlation coefficients R2 > 0.91. The coefficients σy(ε˚/ε˚0), A(ε˚/ε˚0), B(ε˚/ε˚0) are fitted functions of the normalized engineering strain rate ε˚/ε˚0. Replicated experiments are used at each strain-rate so that a measure of the statistical variation could be estimated. Measures of error associated with the regression analysis are also obtained so that an estimate of the total error in the stress-strain relations can be made.

Study of Mechanical Behavior of Concrete in Direct Tensile Fiber Chips

2011 ◽  
Vol 146 ◽  
pp. 64-73
Author(s):  
Youcef Bouafia ◽  
M. Said Kachi ◽  
Djamel Atlaoui ◽  
Said Djebali
Keyword(s):  
Mechanical Behavior ◽  
Fiber Length ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Cement Matrix ◽  
Direct Tension ◽  
Cracking Behavior ◽  
Machine Type ◽  
Direct Tensile ◽  
Local Fiber

In this experimental study, we are interested in local fiber wavy chips derived from waste machining steel parts. This work has focused on studying the mechanical behavior of reinforced concrete, with this type of fiber, in direct tensile. Direct tensile tests were carried out on samples in free weights section and square (100x100) mm2. This test involves the design and the implementation of special mounting specimens on the tensile machine type Ibertest. Five (05) fibers percentages were retained in (W = 0.5%. W = 0.8%, W = 1%, W = 1.2%, W = 1.5% with W: volume fraction of added fiber) and two (02) concrete witness whose report on gravel sand is equal to: S / G = 0.8 and S / G = 1. The fibers have been characterized to the strength and tear by the tensile test. The interest lies in optimizing the fiber length and the number of undulations to use in a cement matrix, which will improve the mechanical properties especially tensile strength and post-cracking behavior. The comparison of different results obtained in direct tension on different percentages of fiber, as well as two reports showed that the fibers have conferred a significant ductility to the material after cracking of concrete for different percentages of fiber and a strength for improving the S / G = 0.8.

scholarly journals Multi-scale reinforcements stimulated dynamic recrystallization and mechanical behavior of as-extruded titanium matrix composites

2020 ◽  
Vol 321 ◽  
pp. 08005
Author(s):  
Peikun Qiu ◽  
Yuanfei Han ◽  
Guangfa Huang ◽  
Jianwen Le ◽  
Lihua Du ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Mechanical Behavior ◽  
Volume Fraction ◽  
Extrusion Direction ◽  
Hot Extrusion ◽  
Tensile Tests ◽  
Matrix Composites ◽  
Multi Scale ◽  
Complex Process ◽  
Submicron Scale

Different volume fraction of TiB, TiC and La2O3 multiple-reinforced Ti6Al4V composites were fabricated by casting and followed by forging and hot extrusion. The microstructural evolution and mechanical behavior of (TiB+TiC+La2O3)/Ti6Al4V composites during hot extrusion were investigated. The microstructural observations showed that the TiBw and TiCp agglomeration disappeared and distributed more homogeneously in the Ti matrix after hot extrusion. Besides, TiBw exhibited highly preferred alignment along the extrusion direction and TiCp distributed along the same direction. Besides, two kinds of microstructure bands with distinctive spatial distributions of reinforcements were formed after hot extrusion: equiaxial bands embedded with fairly substantial reinforcements and finer basket-weave bands containing few reinforcements, in which the micron-scale TiBw, TiCp and submicron-scale La2O3 particle stimulating nucleation occurred and resulting dynamic recrystallization were the main mechanisms responsible for grain refinement. The tensile tests revealed that hot extrusion significantly increased elongation of (TiB+TiC+La2O3)/Ti6Al4V composites from 2.71% to 13.2% accompanied by slightly decreasing ultimate tensile strength from 954MPa to 903MPa, compared with that of the as-forged composites, which due to a complex process of reinforcements/matrix interaction during extrusion and dynamic recrystallization.

Bending Mechanical Behavior of Epoxy Matrix Reinforced with Buriti Fiber

2016 ◽  
Vol 869 ◽  
pp. 243-248 ◽  
Author(s):  
Anderson de Paula Barbosa ◽  
Giulio Rodrigues Altoé ◽  
Rômulo Leite Loiola ◽  
Frederico Muylaert Margem ◽  
Fabio de Oliveira Braga ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Epoxy Matrix ◽  
Volume Fraction ◽  
Natural Fibers ◽  
Tensile Tests ◽  
Entire Length ◽  
Bending Test ◽  
Flexural Properties ◽  
Matrix Composites ◽  
Astm Standard

Environmentally correct composites, made from natural fibers, are among the most investigated and applied today. In this paper, the mechanical behavior of epoxy matrix composites reinforced with continuous buriti fiber, through bending tensile tests was investigated. Specimens containing 0, 10, 20 and 30% in volume of buriti fiber were aligned along the entire length of a mold to create plates of these composites. The plates were cut following the ASTM standard to obtained bending test specimens. The test was conducted in an Instron Machine and the fractured specimens were analyzed by SEM. The results showed an increase in the materials flexural properties with the increase in volume fraction of buriti fiber.

Molecular Contact Pressure in Tribology

1988 ◽  
Vol 140 ◽  
Author(s):  
Georges J.M. ◽  
Loubet J.L. ◽  
Tonck A. ◽  
Ecole Centrale De Lyon
Keyword(s):  
Calcium Carbonate ◽  
Volume Fraction ◽  
Elastoplastic Behavior ◽  
Long Term Study ◽  
Current Voltage ◽  
Dynamic Forces ◽  
Steel Surfaces ◽  
Repulsive Forces ◽  
The Hill

AbstractThis paper is a part of a long-term study of the physics of boundary lubrication. In this regime, the shape and pressure of the film are controlled by two phenomena: first, the elastic or plastic deformation of the substrate, and second, the physical state of the film. Three physical states can be detected: the condensed solid, granular and colloidal states. A new piece of apparatus, allowing the continuous and simultaneous measurement of static and dynamic forces, displacement and current voltage between a sphere and a plane, is used to determine surface forces and rheological properties of the film. The viscous and elastoplastic behavior of the interface is given by a transfer function. The lubricant we studied was calcium dialkylbenzenesulfonate solution containing encapsulated calcium carbonate and dissolved in pure dodecane (volume fraction 5.10-). While a pure dodecane solution behaves like a Newtonian fluid, with its bulk viscosity, the colloidal solution shows an increase of the viscosity near the steel surfaces suggesting adsorption. After 8 hours, each steel surface is covered with a layer, which includes an almost complete “monolayer” of calcium carbonate particles, with some incomplete layers on top of it. During indentation of the layer the repulsive forces vary exponentially with the thickness of the layer. This result is consistent with two effects: the consolidation of the layer during the process and scaling factors such as the Hill number (a/D).

Multiscale Material Modeling and Simulation of the Mechanical Behavior of Dual Phase Steels Under Different Strain Rates: Parametric Study and Optimization

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Tarek M. Belgasam ◽  
Hussein M. Zbib
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Volume Fraction ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Dual Phase ◽  
Strain Rates ◽  
Microstructure Parameters ◽  
Dp Steels

Recent studies on developing dual phase (DP) steels showed that the combination of strength/ductility could be significantly improved when changing the volume fraction and grain size of phases in the microstructure depending on microstructure properties. Consequently, DP steel manufacturers are interested in predicting microstructure properties as well as optimizing microstructure design at different strain rate conditions. In this work, a microstructure-based approach using a multiscale material and structure model was developed. The approach examined the mechanical behavior of DP steels using virtual tensile tests with a full micro-macro multiscale material model to identify specific mechanical properties. Microstructures with varied ferrite grain sizes, martensite volume fractions, and carbon content in DP steels were also studied. The influence of these microscopic parameters at different strain rates on the mechanical properties of DP steels was examined numerically using a full micro-macro multiscale finite element method. An elasto-viscoplastic constitutive model and a response surface methodology (RSM) were used to determine the optimum microstructure parameters for a required combination of strength/ductility at different strain rates. The results from the numerical simulations were compared with experimental results found in the literature. The developed methodology proved to be a powerful tool for studying the effect and interaction of key strain rate sensitivity and microstructure parameters on mechanical behavior and thus can be used to identify optimum microstructural conditions at different strain rates.

scholarly journals Low-carbon cast microalloyed steel intercritically heat-treated at different temperatures: microstructure and mechanical properties

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Hadi Torkamani ◽  
Shahram Raygan ◽  
Carlos Garcia Mateo ◽  
Yahya Palizdar ◽  
Jafar Rassizadehghani ◽  
...  
Keyword(s):  
Carbon Content ◽  
Volume Fraction ◽  
Block Size ◽  
Tensile Tests ◽  
Total Elongation ◽  
Martensite Phase ◽  
Low Carbon ◽  
Steel Increase ◽  
Different Temperatures ◽  
The Impact

AbstractIn this study, dual-phase (DP, ferrite + martensite) microstructures were obtained by performing intercritical heat treatments (IHT) at 750 and 800 °C followed by quenching. Decreasing the IHT temperature from 800 to 750 °C leads to: (i) a decrease in the volume fraction of austenite (martensite after quenching) from 0.68 to 0.36; (ii) ~ 100 °C decrease in martensite start temperature (Ms), mainly due to the higher carbon content of austenite and its smaller grains at 750 °C; (iii) a reduction in the block size of martensite from 1.9 to 1.2 μm as measured by EBSD. Having a higher carbon content and a finer block size, the localized microhardness of martensite islands increases from 380 HV (800 °C) to 504 HV (750 °C). Moreover, despite the different volume fractions of martensite obtained in DP microstructures, the hardness of the steels remained unchanged by changing the IHT temperature (~ 234 to 238 HV). Applying lower IHT temperature (lower fraction of martensite), the impact energy even decreased from 12 to 9 J due to the brittleness of the martensite phase. The results of the tensile tests indicate that by increasing the IHT temperature, the yield and ultimate tensile strengths of the DP steel increase from 493 to 770 MPa, and from 908 to 1080 MPa, respectively, while the total elongation decreases from 9.8 to 4.5%. In contrast to the normalized sample, formation of martensite in the DP steels could eliminate the yield point phenomenon in the tensile curves, as it generates free dislocations in adjacent ferrite.

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.

scholarly journals A Material Model for the Orthotropic and Viscous Behavior of Separators in Lithium-Ion Batteries under High Mechanical Loads

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4585
Author(s):  
Marian Bulla ◽  
Stefan Kolling ◽  
Elham Sahraei
Keyword(s):  
Mechanical Behavior ◽  
Lithium Ion ◽  
Material Model ◽  
Tensile Tests ◽  
Element Analysis ◽  
Rate Dependent ◽  
Novel Material ◽  
Li Ion ◽  
Role Based ◽  
Drive Systems

The present study is focused on the development of a material model where the orthotropic-visco-elastic and orthotropic-visco-plastic mechanical behavior of a polymeric material is considered. The increasing need to reduce the climate-damaging exhaust gases in the automotive industry leads to an increasing usage of electric powered drive systems using Lithium-ion (Li-ion) batteries. For the safety and crashworthiness investigations, a deeper understanding of the mechanical behavior under high and dynamic loads is needed. In order to prevent internal short circuits and thermal runaways within a Li-ion battery, the separator plays a crucial role. Based on results of material tests, a novel material model for finite element analysis (FEA) is developed using the explicit solver Altair Radioss. Based on this model, the visco-elastic-orthotropic, as well as the visco-plastic-orthotropic, behavior until failure can be modeled. Finally, a FE simulation model of the separator material is performed, using the results of different tensile tests conducted at three different velocities, 0.1 mm·s−1, 1.0 mm·s−1 and 10.0 mm·s−1 and different orientations of the specimen. The purpose is to predict the anisotropic, rate-dependent stiffness behavior of separator materials in order to improve FE simulations of the mechanical behavior of batteries and therefore reduce the development time of electrically powered vehicles and consumer goods. The present novel material model in combination with a well-suited failure criterion, which considers the different states of stress and anisotropic-visco-dependent failure limits, can be applied for crashworthiness FE analysis. The model succeeded in predicting anisotropic, visco-elastic orthotropic and visco-plastic orthotropic stiffness behavior up to failure.

MICROSTRUCTURE AND MECHANICAL BEHAVIOR OF AMORPHOUS Al–Cu–Ti METAL FOAMS SYNTHESIZED BY SPARK PLASMA SINTERING

2017 ◽  
Vol 24 (Supp02) ◽  
pp. 1850022
Author(s):  
MAOYUAN LI ◽  
LIN LU ◽  
ZHEN DAI ◽  
YIQIANG HONG ◽  
WEIWEI CHEN ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Intermetallic Compounds ◽  
Spark Plasma Sintering ◽  
Elevated Temperatures ◽  
Volume Fraction ◽  
Metal Foams ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Xrd Patterns

Amorphous Al–Cu–Ti metal foams were prepared by spark plasma sintering (SPS) process with the diameter of 10[Formula: see text]mm. The SPS process was conducted at the pressure of 200 and 300[Formula: see text]MPa with the temperature of 653–723[Formula: see text]K, respectively. NaCl was used as the space-holder, forming almost separated pores with the porosity of 65 vol%. The microstructure and mechanical behavior of the amorphous Al–Cu–Ti metal foams were systematically investigated. The results show that the crystallinity increased at elevated temperatures. The effect of pressure and holding time on the crystallization was almost negligible. The intermetallic compounds, i.e. Al–Ti, Al–Cu and Al–Cu–Ti were identified from X-ray diffraction (XRD) patterns. It was found that weak adhesion and brittle intermetallic compounds reduced the mechanical properties, while lower volume fraction and smaller size of NaCl powders improved the mechanical properties.

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