scholarly journals On the Temperature Dependent Mechanical Response of Dynamically-loaded Shear-dominated Adhesive Structures

2021 ◽  
Vol 250 ◽  
pp. 02016
Author(s):  
Borja Erice ◽  
Maria Lißner ◽  
Jan Wittig ◽  
Andreas Hornig ◽  
Maik Gude ◽  
...  
Keyword(s):  
Composite Laminates ◽  
Mechanical Response ◽  
Cohesive Zone Model ◽  
Split Hopkinson Pressure Bar ◽  
Adhesive Joints ◽  
Zone Model ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson Tensile Bar ◽  
Carbon Fibre Reinforced Polymer ◽  
Split Hopkinson

A mode II mechanical characterisation of the adhesive joints is performed testing shear lap joint specimens in a Split Hopkinson Tensile Bar (SHTB), equipped with a temperature chamber. The experimentallyobtained traction-separation curves were used to develop a Cohesive Zone Model (CZM) capable of representing the strain-rate and temperaturedependent mechanical response of the adhesive joints. To validate the model, End Notch Flexure (ENF) multi-material specimens made from titanium and carbon fibre reinforced polymer composite laminates were tested at different temperatures using a Split Hopkinson Pressure Bar setup with an in-house made temperature chamber. The finite element (FE) simulations of such tests employing the developed CZM showed the model’s ability to accurately predict the adhesive joints’ failure as well as to understand the failure sequence of multi-material adhesive joint combinations.

Simultaneous effects of strain rate and temperature on mechanical response of fabricated Mg–SiC nanocomposite

2019 ◽  
Vol 54 (5) ◽  
pp. 659-668 ◽  
Author(s):  
K Rahmani ◽  
GH Majzoobi ◽  
A Atrian
Keyword(s):  
Strain Rate ◽  
Mechanical Response ◽  
Split Hopkinson Pressure Bar ◽  
High Rate ◽  
Dynamic Tests ◽  
Hopkinson Pressure Bar ◽  
Compaction Temperature ◽  
Static Tests ◽  
Split Hopkinson ◽  
Pressure Bar

Mg–SiC nanocomposite samples were fabricated using split Hopkinson pressure bar for different SiC volume fractions and under different temperature conditions. The microstructures and mechanical properties of the samples including microhardness and stress–strain curves were captured from quasi-static and dynamic tests carried out using Instron and split Hopkinson pressure bar, respectively. Nanocomposites were produced by hot and high-rate compaction method using split Hopkinson pressure bar. Temperature also significantly affects relative density and can lead to 2.5% increase in density. Adding SiC-reinforcing particles to samples increased their Vickers microhardness from 46 VH to 68 VH (45% increase) depending on the compaction temperature. X-ray diffraction analysis showed that by increasing temperature from 25℃ to 450℃, the Mg crystallite size increases from 37 nm to 72 nm and decreases the lattice strain from 45% to 30%. In quasi-static tests, the ultimate compressive strength for the compaction temperature of 450℃ was improved from 123% for Mg–0 vol.% SiC to 200% for the Mg–10 vol.% SiC samples compared with those of the compaction at room temperature. In dynamic tests, the ultimate strength for Mg–10 vol.% SiC sample compacted at high strain rate increased remarkably by 110% compared with that for Mg–0 vol.% SiC sample compacted at low strain rate.

INFLUENCE OF THE BONE MORPHOLOGY ON MECHANICAL BEHAVIOR OF HUMAN SKULL FOR TWO STRAIN RATE CASES

2018 ◽  
Vol 18 (04) ◽  
pp. 1850046
Author(s):  
MANAF KARKAR ◽  
CHRISTOPHE MARECHAL ◽  
REMI DELILLE ◽  
GREGORY HAUGOU ◽  
FRANCOIS BRESSON ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Mechanical Response ◽  
Split Hopkinson Pressure Bar ◽  
Parietal Bone ◽  
Hopkinson Pressure Bar ◽  
Bone Morphology ◽  
Split Hopkinson ◽  
Micro Tomography ◽  
Human Skulls ◽  
Pressure Bar

Modeling the mechanical behavior of bone is very complex due to substantial variability of the mechanical response of bone. The objective of this study is to investigate the link between morphology of the human parietal bone and its mechanical behavior in compression with two different strain rates. Five formalin-preserved human skulls were used, and 10 specimens were taken from the parietal bone of each subject. The internal geometry of the osseous material was studied with a micro-tomography device. For mechanical testing, quasi-static (0.02 s–1) tests on a conventional compression machine and dynamic tests (1500 s–1) on a split Hopkinson pressure bar (SHPB) were conducted on 9 mm diameter samples. The results were used to examine relationships between the morphological parameters to find morphological correlations. Linkages between mechanical behavior and morphology of the human parietal bone were also analyzed to develop a behavior model based on micro-structure parameters as determined by micro-scanning.

Dynamic Compressive Strength of Aluminum Alloy Foams

2006 ◽  
Vol 326-328 ◽  
pp. 1653-1656
Author(s):  
Zhi Hua Wang ◽  
Hong Wei Ma ◽  
Long Mao Zhao ◽  
Gui Tong Yang
Keyword(s):  
Aluminum Alloy ◽  
Mechanical Response ◽  
Split Hopkinson Pressure Bar ◽  
Compressive Behavior ◽  
Hopkinson Pressure Bar ◽  
Open Cell ◽  
Plastic Strength ◽  
Split Hopkinson ◽  
Dynamic Compressive Strength ◽  
Pressure Bar

The dynamic compressive behavior of open-cell aluminum alloy foams with different length of specimens was investigated using the split Hopkinson pressure bar technique. Plastic strength was measured for aluminum alloy foam specimens having the three cell sizes but similar cell microstructure. Longer specimens exhibited lower mean strength and broader scattering of the strength values than the shorter ones. It can be observed that mechanical response of aluminum alloy foams appear to be dependent of the cell size for both the shorter and longer specimens.

High-Strain-Rate Failure of a Porous Heterogeneous Composite: Balsa Wood

2001 ◽  
Author(s):  
M. Vural ◽  
G. Ravichandran
Keyword(s):  
Strain Rate ◽  
Mechanical Response ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Balsa Wood ◽  
Split Hopkinson ◽  
Pressure Bar

Abstract The compression behavior of a naturally occurring porous and heterogeneous biocomposite, balsa wood, along the grain direction is investigated at strain rates 10−3 to 104 s−1. Specimens with different densities, ranging from 55 to 380 kg/m3, were loaded by a modified Kolsky (split Hopkinson) pressure bar apparatus at varying high strain rates and by a screw-driven testing machine at quasi-static strain rates. The mechanical response of balsa wood is documented and the variation of compressive strength, crushing stress and densification strain as a function of density and strain rate is presented. Results show that characteristics of mechanical response for balsa wood are significantly affected by the strain rate and density.

Uncertainty Analysis of the Mechanical Response of Porcine Brain at High Strain Rate Compression

2011 ◽  
Author(s):  
Rajkumar Prabhu ◽  
W. Glenn Steele ◽  
M. F. Horstemeyer ◽  
Stephanie Ryland ◽  
Erin E. Colebeck ◽  
...  
Keyword(s):  
Biological Material ◽  
Mechanical Response ◽  
Split Hopkinson Pressure Bar ◽  
Hopkinson Pressure Bar ◽  
Measured Variable ◽  
Vast Number ◽  
Strain Behavior ◽  
Material Uncertainties ◽  
Split Hopkinson ◽  
Pressure Bar

The Split-Hopkinson Pressure Bar (SHPB) apparatus presents a unique capability in studying the dynamic response of a material, but it is accompanied with a moderately high noise level, giving a rather large standard deviation for the stress-strain behavior of the soft biological material being tested [1]. Compounding the errors in a SHPB setup is the uncertainty arising from sample-to-sample variability in a soft biological material. Uncertainties arise in a measured variable through a vast number of sources such as an imperfect instrument calibration process, standards used for calibration, and the influence of the measured variable due to inconsistencies in ambient temperature, pressure, humidity and vibrations.

Analysis of the Impact of the Frequency Range of the Tensometer Bridge and Projectile Geometry on the Results of Measurements by the Split Hopkinson Pressure Bar Method

2013 ◽  
Vol 20 (4) ◽  
pp. 555-564 ◽  
Author(s):  
Wojciech Moćko
Keyword(s):  
Test Bench ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Deformation ◽  
Spectral Width ◽  
Hopkinson Pressure Bar ◽  
Computing Environment ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
The Impact ◽  
Bench Model

Abstract The paper presents the results of the analysis of the striker shape impact on the shape of the mechanical elastic wave generated in the Hopkinson bar. The influence of the tensometer amplifier bandwidth on the stress-strain characteristics obtained in this method was analyzed too. For the purposes of analyzing under the computing environment ABAQUS / Explicit the test bench model was created, and then the analysis of the process of dynamic deformation of the specimen with specific mechanical parameters was carried out. Based on those tests, it was found that the geometry of the end of the striker has an effect on the form of the loading wave and the spectral width of the signal of that wave. Reduction of the striker end diameter reduces unwanted oscillations, however, adversely affects the time of strain rate stabilization. It was determined for the assumed test bench configuration that a tensometric measurement system with a bandwidth equal to 50 kHz is sufficient

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