iMechanica - creep - Comments

Thank you Biswajit!

HariKrishna — Mon, 16 Jun 2008 09:39:32 -0400

Thank you Biswajit!

re: Strain rate

Biswajit Banerjee — Fri, 13 Jun 2008 01:23:26 -0400

Consider a test where you put a specimen in a loading machine and apply a displacement. The displacement starts at u=0 at t=0 and reaches a value of u=d_1 at t=t_1. If the plot of u vs. t is linear, i.e. u = (d_1/t_1) t, then the rate at which the displacement is applied (du/dt) is constant and equal to d_1/t_1. This is the displacement rate.

Associated with the displacement is a strain e=du/dx (say). For a linear elastic material, at t=0 the strain is e=0 and at t=t_1 the strain is e=d_1/L The strain rate is the quantity de/dt = d_1/(t_1 L).

For plastic deformations we use a similar idea of incremental linearity and can therefore calculate a strain rate associated with small increments of time. Read Hill's book on the theory of plasticity for more details.

-- Biswajit

Re:Time dependent vs Independent

HariKrishna — Thu, 12 Jun 2008 13:02:47 -0400

Can Someone please point me to some source where I can read about this?

Thank you

HI T'm sorry I can't

ellabou leila — Tue, 26 Feb 2008 03:23:35 -0500

T'm sorry I can't help you, but I don't understand why you calculate the Energy in subroutine. Abaqus can calculate J-integral directly.

I work about Modelling and digital simulation of the structures fissured under residual stresses, I have the problem to calculate the J-integral when I have in initial condition residuel stress, because Abaqus define that

Initial stresses are not considered in the definition of contour integrals. Therefore, contour integral calculations for analyses including initial stresses in the regions used for the contour integral calculations will not be correct

I have may others problems see: Modelling and digital simulation of the structures fissured under residual stresses

Can you help me