Zerilli-Armstrong Plasticity Model (LAW2)

This law is similar to the Johnson-Cook plasticity model. The same parameters are used to define the work hardening curve.

However, the equation that describes stress during plastic deformation is:(1)
σ = C 0 + ( C 1 exp ( ( C 3 T + C 4 T In ( ε ˙ ε ˙ 0 ) ) ) ) + C 5 ε p n MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacqaHdpWCcqGH9aqpcaWGdbWaaSbaaSqaaiaaicdaaeqaaOGaey4k aSYaaeWaaeaacaWGdbWaaSbaaSqaaiaaigdaaeqaaOGaciyzaiaacI hacaGGWbGaaGjcVlaaysW7daqadaqaamaabmaabaGaeyOeI0Iaam4q amaaBaaaleaacaaIZaaabeaakiGacsfacqGHRaWkcaWGdbWaaSbaaS qaaiaaisdaaeqaaOGaciivaiaayIW7caaMi8Uaciysaiaac6gadaqa daqaamaalaaabaGafqyTduMbaiaaaeaacuaH1oqzgaGaamaaBaaale aacaaIWaaabeaaaaaakiaawIcacaGLPaaaaiaawIcacaGLPaaaaiaa wIcacaGLPaaaaiaawIcacaGLPaaacqGHRaWkcaWGdbWaaSbaaSqaai aaiwdaaeqaaOGaeqyTdu2aa0baaSqaaiaadchaaeaacaWGUbaaaaaa @62A8@
Where,
σ
Stress (Elastic + Plastic Components)
ε p
Plastic strain
τ
Temperature (computed as in Johnson-Cook plasticity)
C 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4qamaaBa aaleaacaaIWaaabeaaaaa@37A4@
Yield stress
n MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbiqaaq1acaWGPb aaaa@373E@
Hardening exponent
ε ˙
Strain rate, must be 1 s-1 converted into user's time unit
ε ˙ 0
Reference strain rate
Additional inputs are:
σ max 0
Maximum flow stress
ε max
Plastic strain at rupture

The ε max enables to define element rupture as in the former law. The theoretical aspects related to strain rate computation and filtering are also the same.