scholarly journals Interlayer Bonding Capability of Additively Manufactured Polymer Structures under High Strain Rate Tensile and Shear Loading

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1301
Author(s):  
Patrick Striemann ◽  
Lars Gerdes ◽  
Daniel Huelsbusch ◽  
Michael Niedermeier ◽  
Frank Walther
Keyword(s):  
Strain Rate ◽  
Contact Area ◽  
High Strain ◽  
Force Measurement ◽  
Tensile Tests ◽  
Shear Loading ◽  
Specimen Geometry ◽  
Strain Rates ◽  
Layer Height ◽  
The Impact

Additive manufacturing of polymers via material extrusion and its future applications are gaining interest. Supporting the evolution from prototype to serial applications, additional testing conditions are needed. The additively manufactured and anisotropic polymers often show a weak point in the interlayer contact area in the manufacturing direction. Different process parameters, such as layer height, play a key role for generating the interlayer contact area. Since the manufacturing productivity depends on the layer height as well, a special focus is placed on this process parameter. A small layer height has the objective of achieving better material performance, whereas a larger layer height is characterized by better economy. Therefore, the capability- and economy-oriented variation was investigated for strain rates between 2.5 and 250 s−1 under tensile and shear load conditions. The test series with dynamic loadings were designed monitoring future applications. The interlayer tensile tests were performed with a special specimen geometry, which enables a correction of the force measurement. By using a small specimen geometry with a force measurement directly on the specimen, the influence of travelling stress waves, which occur due to the impact at high strain rates, is reduced. The interlayer tensile tests indicate a strain rate dependency of additively manufactured polymers. The capability-oriented variation achieves a higher ultimate tensile and shear strength compared to the economy-oriented variation. The external and internal quality assessment indicates an increasing primary surface profile and void volume content for increasing the layer height.

Coupling effect of strain rate and temperature on tensile damage mechanism of polyphenylene sulfide reinforced by glass fiber (PPS/GF30)

2020 ◽  
pp. 089270572094422
Author(s):  
Mohammadali Shirinbayan ◽  
Joseph Fitoussi ◽  
Farid Kheradmand ◽  
Arash Montazeri ◽  
Peiyuan Zuo ◽  
...  
Keyword(s):  
Strain Rate ◽  
Glass Fiber ◽  
High Strain ◽  
Coupling Effect ◽  
Damage Mechanism ◽  
Tensile Tests ◽  
Ultimate Stress ◽  
Polyphenylene Sulfide ◽  
Stress And Strain ◽  
Strain Rates

Influence of loading temperature on the damage mechanism of polyphenylene sulfide (PPS) reinforced by glass fiber (PPS/GF30) under tension was experimentally studied from quasi-static (QS) to high strain rates. Two kinds of PPS/GF30 samples were prepared: PPS-0° and PPS-90° (correspond to fibers oriented parallel and perpendicular to the injection direction, respectively). After microscopic observation and thermomechanical characterizations by dynamic mechanical analysis, tensile tests up to failure with strain rates varying from 10−3 s−1 to 100 s−1 have been carried out at 25°C and 120°C with regard to PPS/GF30 glass transition temperature. To achieve the coupling effect of high strain rate and high temperature, a special chamber was designed to install on the servo-hydraulic machine. The results of QS tensile tests confirm the significant effect of fiber orientation and temperature on the Young’s modulus, the ultimate stress, and strain. High strain tensile test results showed that the PPS/GF30 composite is strain rate dependent at both temperatures. The results indicated that Young’s modulus remains constant by strain rate increasing at both temperatures while ultimate stress and strain are increased. No significant damage has been observed at 25°C in QS loading, whereas the macroscopic damage variable is increased to 20% at 120°C. Debonding at the fiber–matrix interface is the main damage mechanism at 120°C.

scholarly journals FE Analysis of Critical Testing Parameters in Kolsky Bar Experiments for Elastomers at High Strain Rate

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3817
Author(s):  
Chaudhry ◽  
Czekanski
Keyword(s):  
Finite Element ◽  
High Strain Rate ◽  
Strain Rate ◽  
Pulse Shaping ◽  
High Strain ◽  
Kolsky Bar ◽  
Specimen Geometry ◽  
Strain Rates ◽  
Butadiene Rubber ◽  
Testing Apparatus

The main aim of this research is to present complete methodological guidelines for dynamic characterization of elastomers when subjected to strain rates of 100/s–10,000/s. We consider the following three aspects: (i) the design of high strain rate testing apparatus, (ii) finite element analysis for the optimization of the experimental setup, and (iii) experimental parameters and validation for the response of an elastomeric specimen. To test low impedance soft materials, design of a modified Kolsky bar is discussed. Based on this design, the testing apparatus was constructed, validated, and optimized numerically using finite element methods. Furthermore, investigations on traditional pulse shaping techniques and a new design for pulse shaper are described. The effect of specimen geometry on the homogeneous deformation has been thoroughly accounted for. Using the optimized specimen geometry and pulse shaping technique, nitrile butadiene rubber was tested at different strain rates, and the experimental findings were compared to numerical predictions.

Numerical simulation of welding stresses and distortions under consideration of temporal and local changes of strain rate

2004 ◽  
Vol 120 ◽  
pp. 169-175
Author(s):  
R. Ossenbrink ◽  
H. Wohlfahrt ◽  
V. Michailov
Keyword(s):  
Numerical Simulation ◽  
Strain Rate ◽  
High Strain ◽  
Local Strain ◽  
Tensile Tests ◽  
Strain Rates ◽  
Current Yield ◽  
Strain Rate Effects ◽  
Rate Effects ◽  
High Influence

As a result of high temperature changing rates in the heat affected zone (HAZ) the elevated strain rates during welding may have a high influence of the yield stresses. Higher yield stresses as a result of high strain rates can be observed in hot tensile tests for several materials. A model has been developed and integrated in a multi-purpose FEA-program (ANSYS®) to investigate strain rate effects in numerical welding simulation. The routine calculates the current yield stress as a function of the local strain rates. The influence of the resulting stresses and distortions has been analyzed in comparative numerical welding simulations.

Enhanced Plasticity of WE54/SiC Composite Prepared by Powder Metallurgy

2011 ◽  
Vol 465 ◽  
pp. 419-422 ◽  
Author(s):  
Zoltán Száraz ◽  
Zuzanka Trojanová
Keyword(s):  
Powder Metallurgy ◽  
Strain Rate ◽  
Elevated Temperatures ◽  
High Strain ◽  
Constant Strain Rate ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Strain Rates ◽  
Deformation Characteristics ◽  
Powder Metallurgy Technique

The deformation characteristics of the WE54 magnesium alloy reinforced by 13% of SiC particles have been investigated in tension at elevated temperatures. Composite material was prepared by powder metallurgy technique. The strain rate sensitivity parameter m has been estimated by the abrupt strain rate changes (SRC) method. SRC tests and tensile tests with constant strain rate ( ) were performed at temperatures from 350 to 500 °C. Increased ductility has been found at high strain rates. The corresponding m value was 0.3. The activation energy Q has been estimated. Microstructure evolution has been observed by the light microscope and scanning electron microscope.

scholarly journals Study on the Impact of Strain Rate and Loading Speed on Geogrid-Reinforced Soil

2017 ◽  
Vol 10 (2) ◽  
pp. 238
Author(s):  
Mohammadehsan Zarringol ◽  
Mohammadreza Zarringol
Keyword(s):  
Shear Strength ◽  
Strain Rate ◽  
Contact Area ◽  
Reinforced Soil ◽  
Vertical Stress ◽  
Coarse Grained ◽  
Strain Rates ◽  
The Past ◽  
The Impact ◽  
Coarse Grained Soil

During the past decades, reinforced soil has normally been constructed by coarse grained soil. Recently, low quality and locally accessible materials have been successfully used in reinforced soil due to economic observations. Loading speed is one of the effective factors in soil-geosynthetic interaction. In order to determine the impact of this factor, we carried out a pullout test on the samples with dimensions of 30×30×17 cm under four strain rates of 0.75, 1.25, 1.75 and 2.25 mm/min and three vertical stress rates of 20, 50 and 80 KN/m2. The results of this study indicated that the mobilization of geosynthetic strength in contact area depends on the amount of vertical stress. The increased vertical stress results in the increased shear strength in clay-geogrid contact area. Furthermore, the increased strain rate results in the reduced shear strength.

Research on the Mechanical Behavior of Styropor Concrete at High Strain Rates

2010 ◽  
Vol 168-170 ◽  
pp. 2086-2091
Author(s):  
Ze Bin Hu ◽  
Jin Yu Xu ◽  
Jie Zhu ◽  
Qiang He ◽  
Gang Li ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
High Strain ◽  
Dynamic Strength ◽  
Strain Rates ◽  
Average Strain ◽  
High Strain Rates ◽  
Average Strain Rate ◽  
The Impact

Mechanical behavior of Styropor concrete(EPSC) added with various volumetric fractions of EPS subjected to high strain rates were studied by using the Large-Diameter-SHPB. The infection of volumetric fractions and average strain rate to dynamic properties of EPSC were investigated. The experimental results show that under high strain rate condition, the dynamic strength, dynamic strength increase factor(DIF) and limit strain of EPSC are strain rate dependent, the strain rate effect can be expressed by linear approximations, and the relationship between elastic modulus and average strain rate is independent.With the addition of volumetric fractions of EPS, the impact compressive strength and elastic modulus of EPSC declines, and the toughness of EPSC is reinforced.

Effects of Fibre Surface Treatment on Dynamic Tensile Properties of Glass Woven Fabric Reinforced Vinylester Composites

2005 ◽  
Vol 13 (5) ◽  
pp. 453-466 ◽  
Author(s):  
Jang-Kyo Kim ◽  
Man-Lung Sham ◽  
Min-Seok Sohn ◽  
Shisheng Hu
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
Surface Treatment ◽  
Glass Fibre ◽  
High Strain ◽  
Fibre Surface ◽  
Woven Fabric ◽  
Strain Rates ◽  
The Matrix ◽  
The Impact

Glass fibre has been recognized as a strain rate dependent material. Its failure behaviour changes from brittle to ductile as the strain rate increases. As a consequence, the strength of the glass fibre increases, but the fibres within a composite become more prone to debond from the matrix because of the brittleness of the matrix material, promoted by the high strain rate. In the present study, the tensile responses of glass woven fabric reinforced vinyl ester composites with various fibre surface treatments are examined under static and dynamic loading conditions. The results show that both the ductility and the strength of the composites increased with increasing strain rate. The tensile strength was lower and the failure strain was higher in the weft direction than in the warp direction, because of excessive crimping in the former direction. The tensile strength in general increased with increasing silane concentration, for the majority of strain rates studied. The influence of fibre surface treatment on the impact tensile strength and modulus of composites were functionally similar, confirming the influence of fibre-matrix interphase properties on composite fracture behaviour at high strain rates.

High Strain-Rate Constitutive Behavior of SAC305 Solder During Operation at High Temperature

2014 ◽  
Author(s):  
Pradeep Lall ◽  
Di Zhang ◽  
Vikas Yadav
Keyword(s):  
Strain Rate ◽  
High Strain ◽  
Tensile Tests ◽  
Image Correlation ◽  
Dynamic Strain ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
High Strain Rates ◽  
Wide Range ◽  
Thermal Chamber

Leadfree solders have been used as interconnects in electronic packaging, due to its environmental friendly chemical property. However, those materials may experience high strain rates when subjected to shock and vibration. Consequently, failure will occur to electronics in those situations. Therefore, knowing the material properties of lead-free solders are extremely important, but research on mechanical behaviors of those solder alloys at high strain rates are scarce. Anand’s viscoplastic constitutive model has been widely used to describe the inelastic deformation behavior of solders in electronic components under thermo-mechanical deformation. However, Anand’s model constants for the transient dynamic strain rates are scarce. In this paper, the nine material parameters to fit the Anand viscoplastic model at high strain rates have been presented. In order to develop the constants for this model, uniaxial tensile tests at several strain rates and temperatures have been completed. A constant strain rate impact hammer which enables attaining strain rates around 1 to 100 per sec has been employed to implement tensile tests and a small thermal chamber is applied to control testing temperature. High speed cameras operating at 70,000 fps have been used to capture images of specimen and then digital image correlation method is used to calculate tensile strain. Uniaxial stress-strain curves have been plotted over a wide range of strain rates (ε̇ = 10, 35, 50, 75 /sec) and temperatures (T = 25, 50, 75, 100, 125°C). Anand viscoplasticity constants have been calculated by nonlinear fitting procedures. In addition, the accuracy of the extracted Anand constants has been evaluated by comparing the model prediction and experimental data.

scholarly journals Experimental methodology for the measurement of plasticity on metals at high strain-rates

2018 ◽  
Vol 183 ◽  
pp. 02063 ◽  
Author(s):  
Alexander Sancho ◽  
Mike J. Cox ◽  
Giles Aldrich-Smith ◽  
Tim Cartwright ◽  
Catrin M. Davies ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Speed ◽  
High Strain ◽  
Tensile Tests ◽  
Detection Algorithm ◽  
Image Correlation ◽  
Experimental Methodology ◽  
Tensile Behaviour ◽  
Strain Rates

An experimental methodology has been developed for the tensile characterisation of ductile isotropic metals at high strain-rate. This study includes the region beyond plastic instability or necking, which is rarely analysed for conventional applications. The research explores an imaging technique used to track the geometry of the specimen during tensile tests and calculate true local values of stress and strain by applying Bridgman theory [1]. To improve the quality of the images taken at high strain-rate an in-situ high speed shadowgraph technique has been developed, and to obtain better results from the images a sub-pixel accuracy edge detection algorithm has been implemented. The technique has been applied to an austenitic stainless steel. Its tensile behaviour has been assessed by testing round samples at strain-rates ranging from quasi-static to ~103 s-1. The results obtained with the proposed methodology have been validated by comparison with more conventional techniques such as video-extensometer and digital image correlation in the pre-necking region and good performance even at the highest strain-rate tested has been proved.

Influence of Morphology on Fracture Propagation of PMMAe/PC Blend in Tensile Tests at High Strain Rate

2020 ◽  
Vol 394 (1) ◽  
pp. 2000153
Author(s):  
Felipe Pedro da Costa Gomes ◽  
Juciklécia da Silva Reinaldo ◽  
Antônio Henrique Venâncio Rodrigues ◽  
Thatiana Cristina Pereira Macedo ◽  
Bismarck Luiz Silva ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Fracture Propagation ◽  
Tensile Tests
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