A Study of Shear Localization Chip Formation in Metal Cutting Process os An AISI 4340 Steel
碩士 === 國立中正大學 === 機械工程學系 === 85 === The shear localization phenomena during serrated chip formation in high speed metal cutting process have been studied by using the explicit finite element analysis. A three dimensional computational mode...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
1997
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| Online Access: | http://ndltd.ncl.edu.tw/handle/00153758084387354462 |
| Summary: | 碩士 === 國立中正大學 === 機械工程學系 === 85 === The shear localization phenomena during serrated chip formation
in high speed metal cutting process have been studied by using
the explicit finite element analysis. A three dimensional
computational model has been developed for analyzing dynamic
ther-mo-mechanical deformations of a thermally softening
viscoplastic workpiece material subjected to various tool
cutting speeds、tool rake angles and workpieces material
hardness. The shear band characteristics such as effective
plastic stress, effective plastic strain and shear banding angle
are investigated for each cases. Cutting forces also can be
estimated by this 3D model for the reason to reduce cost and
time in experiment. The predictions of the finite element
analysis are shown that above a critical high cutting speeds the
Catastropic shear chip will be form due to shear localization in
the primary shear zone and different kinds of cutting condition.
The secondary shear zone of the chip on rake surface appear not
to be a negligible effect which indicated the tool life during
metal cutting process. Chip segments can be separated completely
due to extensive shear in the primary shear zone; These
phenomena during our metal cutting experiments in lathes agreed
well with the experimental observations from literature so as to
verify the accuracy of our numerical analysis. The numerical
model presented here also applied to study the oblique cutting
process.
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