Author： Basak D. Yoon H. W. Rhorer R. Burns T. J. Matsumoto T.
Publisher： Springer Publishing Company
ISSN： 0195-928X
Source： International Journal of Thermophysics, Vol.25, Iss.2, 2004-03, pp. : 561-574
Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.
Abstract
Analysis of machining processes is important in the understanding and improving of manufacturing methods. The modeling of machining processes relies on high-strain-rate, high-temperature material properties. A Split–Hopkinson (or Kolsky) bar has been developed at NIST for this purpose. By heating the material specimen rapidly with a controlled current pulse prior to the mechanical impact of the bar, structural changes in the specimen are inhibited, thus better simulating conditions during machining. A stress-strain relationship can be determined at various temperatures for a range of materials. For the elevated temperature Kolsky experiments it is essential for the specimen to be maintained at a constant and uniform temperature prior to dynamic loading. The development and implementation of a near-infrared micro-pyrometer (NIMPY) for the precision control of the Kolsky specimen temperature by using a pulse heating system preceding the mechanical impact are described. The pulse-heating system can be operated either in the transient mode, where the current to the specimen is switched off at a preset temperature or time; or in the brief steady-state mode, where the specimen is heated rapidly to achieve the preset temperature (in the range from 400 to 1300 K) in a short time (about 200 ms) and then held isothermally for a brief period (<2s). A brief description of a model of the pulse heating process is provided, and the predicted specimen temperature history is compared with measured temperature data.
Related content
Access to resources
Recommend
By Plyasunova N. V. Plyasunov A. V. Shock E. L.
International Journal of Thermophysics, Vol. 25, Iss. 2, 2004-03 ,pp. :
By Dillon H. E. Penoncello S. G.
International Journal of Thermophysics, Vol. 25, Iss. 2, 2004-03 ,pp. :
By Cernuschi F. Bison P. G. Figari A. Marinetti S. Grinzato E.
International Journal of Thermophysics, Vol. 25, Iss. 2, 2004-03 ,pp. :