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102 Mechanical Behaviour of Plastics
0.1
0.08
-
Sp
B 0.06
65
0.04
0.02
0
0 50 100 150 200
(SI
Fig. 2.46 Variation of strain with time
Stress (MN/m*)
-
0 100 Time (s)
Fig. 2.47 Stress history: Example 2.15(a)
(b) If the stress was completely removed after 100 seconds as shown in
Fig. 2.48 then the effective change in stress would be given by
change in stress, a(t) = -Kl(t - T) - Au
da) - -K1
--
dt
