scholarly journals High strain-rate compressive stress–strain response of friction stir welded 7075-T651 aluminum alloy joints in through-thickness direction

2007 ◽  
Vol 57 (11) ◽  
pp. 518-523 ◽  
Author(s):  
Takashi YOKOYAMA ◽  
Kenji NAKAI ◽  
Yoshitaka KOTAKE
Keyword(s):  
Aluminum Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
Compressive Stress ◽  
High Strain ◽  
Strain Response ◽  
Thickness Direction ◽  
Stress Strain ◽  
Friction Stir

scholarly journals High strain rate stress-strain response of soils - A review

2015 ◽  
Vol 3 (2) ◽  
pp. 80-85
Author(s):  
Sunita Mishra ◽  
Tanusree Chakraborty ◽  
Dipanjan Basu
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Strain Response ◽  
Stress Strain

High Strain-Rate Compressive Behavior and Constitutive Modeling of Selected Polymers Using Modified Ramberg-Osgood Equation

2014 ◽  
Vol 566 ◽  
pp. 80-85
Author(s):  
Kenji Nakai ◽  
Takashi Yokoyama
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Compressive Stress ◽  
Constitutive Modeling ◽  
High Strain ◽  
Strain Rates ◽  
Stress Strain ◽  
Strain Behavior ◽  
Least Squares Fit ◽  
Wide Range

The present paper is concerned with constitutive modeling of the compressive stress-strain behavior of selected polymers at strain rates from 10-3 to 103/s using a modified Ramberg-Osgood equation. High strain-rate compressive stress-strain curves up to strains of nearly 0.08 for four different commercially available extruded polymers were determined on the standard split Hopkinson pressure bar (SHPB). The low and intermediate strain-rate compressive stress-strain relations were measured in an Instron testing machine. Six parameters in the modified Ramberg-Osgood equation were determined by fitting to the experimental stress-strain data using a least-squares fit. It was shown that the monotonic compressive stress-strain behavior over a wide range of strain rates can successfully be described by the modified Ramberg-Osgood constitutive model. The limitations of the model were discussed.

High Strain-Rate Compressive Stress-Strain Loops for Structural Adhesive

2011 ◽  
Vol 83 ◽  
pp. 130-135 ◽  
Author(s):  
Takashi Yokoyama ◽  
Kenji Nakai ◽  
Norfazrina Hayati Mohd Yatim
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Compressive Stress ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Dissipation Energy ◽  
Wide Range ◽  
Structural Adhesive

The high strain-rate compressive stress-strain loops for bulk specimens of an epoxy structural adhesive are determined on the standard split Hopkinson pressure bar. The compressive stress-strain data including unloading curves are obtained over a wide range of strain rates from 10-3to 103/s. The effects of strain rate on the initial (secant) modulus, flow stress, dissipation energy and hysteresis loss ratio are discussed. The experimental results show that the bulk structural adhesive exhibits dynamic viscoelastic behavior like polymers.

High Strain Rate Superplasticity in a Zr and Sc Modified 7075 Aluminum Alloy Produced by ECAP

2008 ◽  
Vol 584-586 ◽  
pp. 164-169 ◽  
Author(s):  
Krystof Turba ◽  
Premysl Malek ◽  
Edgar F. Rauch ◽  
Miroslav Cieslar
Keyword(s):  
Aluminum Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Rate Sensitivity ◽  
7075 Aluminum Alloy ◽  
Fine Grained ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Elongation To Failure

Equal-channel angular pressing (ECAP) at 443 K was used to introduce an ultra-fine grained (UFG) microstructure to a Zr and Sc modified 7075 aluminum alloy. Using the methods of TEM and EBSD, an average grain size of 0.6 1m was recorded after the pressing. The UFG microstructure remained very stable up to the temperature of 723 K, where the material exhibited high strain rate superplasticity (HSRSP) with elongations to failure of 610 % and 410 % at initial strain rates of 6.4 x 10-2 s-1 and 1 x 10-1 s-1, respectively. A strain rate sensitivity parameter m in the vicinity of 0.45 was observed at temperatures as high as 773 K. At this temperature, the material still reached an elongation to failure of 430 % at 2 x 10-2 s-1. These results confirm the stabilizing effect of the Zr and Sc additions on the UFG microstructure in a 7XXX series aluminum alloy produced by severe plastic deformation.

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