scholarly journals Damage Characterisation for Cement and Concrete Using Microwave Induced Damage

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 525 ◽  
Author(s):  
Gareth R. Tear ◽  
Amitay H. Cohen ◽  
Danyal Magnus ◽  
David R. Sory ◽  
William G. Proud
Keyword(s):  
High Strain Rate ◽  
Granular Flow ◽  
High Strain ◽  
Ballistic Impact ◽  
Material Strength ◽  
Material Failure ◽  
Complex Behavior ◽  
Local Material ◽  
Impact Experiments ◽  
Numerical Approaches

Damage leading to failure in concrete and related materials is a complex behavior. Whilst many numerical approaches are available for simulating the degradation of material strength, it is difficult to discriminate between these models experimentally in the high strain rate ballistic impact regime. An experimental method has been developed to determine when local material failure has occurred, and whether the failure can be classed as fracture or granular flow. This method is tested on Kolsky bar and ballistic impact experiments. Comparison with numerical simulations is presented.

Experimental results of tantalum material strength at high pressure and high strain rate

2012 ◽  
Author(s):  
Hye-Sook Park ◽  
Nathan Barton ◽  
Jonathan L Belof ◽  
K. J. M. Blobaum ◽  
R. M. Cavallo ◽  
...  
Keyword(s):  
High Pressure ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Experimental Results ◽  
Material Strength

Characterization of Adhesively Bonded Composite Joints Under High Strain Rate Loading

2017 ◽  
Author(s):  
Kenneth Gollins ◽  
Jack Chiu ◽  
Céline Baudrand ◽  
Feridun Delale
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Failure Modes ◽  
High Strain ◽  
Ballistic Impact ◽  
Mode I ◽  
Adhesively Bonded ◽  
Composite Joint ◽  
Strain Rate Loading ◽  
Adhesively Bonded Joint

With the advantage of having a high strength to weight ratio, composite materials are frequently being implemented as alternatives to steel and aluminum in military vehicles. To perform satisfactorily, joined composite laminates on a vehicle must be able to absorb a significant amount of energy under high strain rate loading events such as ballistic impact. In this paper the dynamic behavior and failure modes of adhesively bonded S2-glass/epoxy laminate joints are investigated. For this experiment, two structural adhesives are selected for comparison: a brittle methacrylate and a more compliant epoxy. The tests are conducted on an in-house assembled gas-gun to achieve the high strain rates necessary to break the adhesive bonds in two configurations, Mode I and II. Results obtained from the ballistic impact tests are compared to quasi-static test results to emphasize the rate-sensitivity of the bonded joints. Irrespective of the material configuration, the failure load of the adhesively bonded joint is seen to increase with the loading rate. Overall, epoxy appears to be 35–50% stronger than methacrylate by most measures. Under bending loading (mode I), most cases exhibit some amount of damage within the composite surrounding the bonded area, demonstrating a fiber-tear failure rather than a cohesive failure. The failure strength of the composite joint is thus not always proportional to the adhesion strength of the adhesive due to the weakness of delamination of the composite material, especially when loaded through the thickness of the composite. As compared with metal adherends, the composites are shown to absorb three times more energy per unit area.

scholarly journals Analysis of Shear Band Effects in Titanium Relative to High Strain-Rate Laboratory/Ballistic Impact Tests

1997 ◽  
Vol 07 (C3) ◽  
pp. C3-415-C3-422 ◽  
Author(s):  
L. W. Meyer ◽  
L. Krueger ◽  
M. Gooch ◽  
M. Burkins
Keyword(s):  
Shear Band ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Ballistic Impact ◽  
Impact Tests

Microstructure Properties and Fracture Behaviors of Tungsten Alloys

2007 ◽  
Vol 567-568 ◽  
pp. 417-420
Author(s):  
Wei Dong Song ◽  
Hai Yan Liu ◽  
Jian Guo Ning
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Dynamic Behavior ◽  
High Strain ◽  
Time History ◽  
Lagrangian Analysis ◽  
Tungsten Alloys ◽  
Analysis Technique ◽  
Fracture Behaviors ◽  
Impact Experiments

The plate impact experiments have been conducted to investigate the dynamic behavior of 91W-6.3Ni-2.7Fe with three kinds grain sizes of 1− 3μm, 10 −15μmand 30 − 40μm . The stress-time history curves at different Lagrangian positions were obtained for tungsten alloys at different impact velocities. Lagrangian analysis technique was adopted to discuss the mechanical properties of the tungsten alloys under high strain rate. SEM was introduced to analyze the microstructure properties of tungsten alloys. The influence of grain size on the dynamic behavior of tungsten alloys under high strain rate was obtained and the stress-strain curves ( 4 5 1 10 ~ 10 s− ) of the tungsten alloys were given.

Mechanical Behavior of Thermosetting Polymers Undergoing High Strain-Rate Impact

2019 ◽  
Author(s):  
Peter Sable ◽  
John P. Borg
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Back Surface ◽  
Thermosetting Polymers ◽  
Viscoelastic Effects ◽  
Polymer Metal ◽  
Impact Experiments ◽  
Rate Dynamic

Abstract A series of uniaxial and oblique flyer-plate impact experiments were conducted on fully dense, high durometer, polyurethane and epoxy formulations to investigate the high strain-rate dynamic material response. Samples were impacted at velocities ranging from 50 to 1,200 m/s at strain-rates of 105 – 106 s−1. The Hugoniot constants, yield strengths, and friction coefficients were inferred from velocity measurements taken from the back surface of the targets. Polymer Hugoniots were found to closely approximate those previously found in literature, with nonlinear curvature at low impact speeds due to viscoelastic effects. Strength behavior demonstrated pressure dependence which fit into a Mohr-Coulomb or Drucker-Prager yield surface criterion. Coefficients of friction between both epoxy and polyurethane, alongside a 7075-T6 aluminum tribological partner were quantified and results were used in conjunction with yield observations to hypothesize on the role of adhesion in high strain-rate shear of polymer-metal interfaces.

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