An Experimental Technique for Developing Intermediate Strain Rates in Ductile Metals

<p>Quantifying the strain-rate sensitive dynamic properties of structural materials is an important area of research in the solid mechanics field. Property evaluation is typically accomplished using dynamic tests which involve rapid loading or impact of specimens. In these tests inertial forces and wave propagation make it difficult to accurately record the material response to a loading condition at an equivalent location. Furthermore these tests typically generate high strain rates (in excess of 10 3 s - 1 and an experimental method for generating rates of strain in the intermediate strain rate regime which is relatively simple low cost and reliable is still lacking. This research effort develops an experimental technique for generating tensile plastic strain rates up to 10 2 s -1 in ductile metals. The technique relies on an impact from a load cell instrumented drop weight machine capable of delivering a suitable impact velocity and energy to globally deform a slotted beam specimen. At impact a state of plastic uniaxial tensile stress is created in the ligament underneath a slot. The ligament is instrumented with an electrical-resistance strain gauge and the strain history from the gauge is measured and stored in a digital oscilloscope. The Johnson-Cook constitutive equation is assumed to reflect the material behavior and its parameters are determined through a matching of the experimental strain history with a finite element simulation.</p><p>This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact and remains as true to the original work as possible. Therefore you will see the original copyright references library stamps (as most of these works have been housed in our most important libraries around the world) and other notations in the work.</p><p>This work is in the public domain in the United States of America and possibly other nations. Within the United States you may freely copy and distribute this work as no entity (individual or corporate) has a copyright on the body of the work.</p><p>As a reproduction of a historical artifact this work may contain missing or blurred pages poor pictures errant marks etc. Scholars believe and we concur that this work is important enough to be preserved reproduced and made generally available to the public. We appreciate your support of the preservation process and thank you for being an important part of keeping this knowledge alive and relevant.</p>