کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
797412 1467138 2009 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermal softening induced plastic instability in rate-dependent materials
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی مکانیک
پیش نمایش صفحه اول مقاله
Thermal softening induced plastic instability in rate-dependent materials
چکیده انگلیسی

A linear perturbation analysis is performed for a class of rate-dependent materials, such as the Johnson–Cook model, in which the rate contribution to the stress can be separated from that of the plastic strain and temperature and in which the temperature rises adiabatically. The analysis is facilitated by perturbing both the rate of momentum equation and the momentum equation. An identical material stability/instability criterion is deduced from the characteristic spectral equations for one-dimensional deformation, one-dimensional shearing, and general three-dimensional field equations, and thus shows that the instability derived here is a material constitutive instability.The criteria indicate that the materials become unstable once the thermal softening overcomes the strain hardening, regardless of the strain rate. The strain rate enters the criteria through its effects on the accumulated temperature and the current stress. Based on the criterion, the three-dimensional instability surface is established in the space of plastic strain, plastic strain rate, and temperature. Instability surface is shown as a material property and independent of deformation histories or modes. Both necking and shear banding are simulated to validate the excellent predictive capability of the criterion.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of the Mechanics and Physics of Solids - Volume 57, Issue 4, April 2009, Pages 788–802
نویسندگان
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