Calibration prodcedure to determine Prony Parameters from tensile creep data - Constitutive Models
https://polymerfem.com/community/constitutive-models/calibration-prodcedure-to-determine-prony-parameters-from-tensile-creep-data770/
PolymerFEM.com Discussion Boarden-USThu, 18 Jul 2024 17:33:34 +0000wpForo60
https://polymerfem.com/community/constitutive-models/calibration-prodcedure-to-determine-prony-parameters-from-tensile-creep-data770/#post-11893
Sat, 14 May 2016 20:43:34 +0000Constitutive ModelsJorgenhttps://polymerfem.com/community/constitutive-models/calibration-prodcedure-to-determine-prony-parameters-from-tensile-creep-data770/#post-11893
https://polymerfem.com/community/constitutive-models/calibration-prodcedure-to-determine-prony-parameters-from-tensile-creep-data770/#post-11817
Fri, 15 Jan 2016 09:13:13 +0000Would you recommend in general to always go back to non-linear viscoelastic models as the stress-strain relation of most materials (in my case polypropylene) is non-linear and linear-elastic models only can be used for a specific load level?]]>Constitutive Modelsfepgyouhttps://polymerfem.com/community/constitutive-models/calibration-prodcedure-to-determine-prony-parameters-from-tensile-creep-data770/#post-11817
https://polymerfem.com/community/constitutive-models/calibration-prodcedure-to-determine-prony-parameters-from-tensile-creep-data770/#post-11767
Wed, 30 Dec 2015 16:31:12 +0000Constitutive ModelsJorgenhttps://polymerfem.com/community/constitutive-models/calibration-prodcedure-to-determine-prony-parameters-from-tensile-creep-data770/#post-11767Calibration prodcedure to determine Prony Parameters from tensile creep data
https://polymerfem.com/community/constitutive-models/calibration-prodcedure-to-determine-prony-parameters-from-tensile-creep-data770/#post-29426
Fri, 04 Dec 2015 05:14:15 +0000from tensile creep experiments I have test data for different nominal stresses. I want to use this data to calibrate a generalized Maxwell model of the formE(t) = E_inf + sum_i (E_i * exp(-t / tau_i)I came across a procedure with the following steps:1. Calculate creep modulus E(t) = sig_nom / eps (t), with sig_nom as the nominal stress and eps (t) as the time-dependent creep strain2. Find E_inf, hence E(t=t_inf) with t_inf as the last point in time3. Calculate the first Prony parameter N=1 (E_1, tau_1) --> E(t) = R_1(t) + E_1*exp(-t/tau_1), using logarithmic transformation LN ( E(t) ) ~ LN (E_1) - (1/tau_1)*t with linear regression4. Follow same steps as in 3. using R_1(t) = E(t) - E1*exp(-t/tau_1) --> R_1(t) ~ E_2*exp(-t/tau_2)Now my question is how should I preferably determine E_inf (long-time creep modulus)? If it is exactly E(t=t_inf) the slope of LN ( E(t) ) does not remain constant for t--> inf. However this is needed to perform the linear regression.Does anyone have some hints or different approaches to determine E(t)?Thanks in advance!]]>Constitutive Modelsfepgyouhttps://polymerfem.com/community/constitutive-models/calibration-prodcedure-to-determine-prony-parameters-from-tensile-creep-data770/#post-29426