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Life estimation methodology for short fiber reinforced polymers under thermo‐mechanical loading in automotive applications
Author(s) -
Schaaf A.,
De Monte M.,
Moosbrugger E.,
Vormwald M.,
Quaresimin M.
Publication year - 2015
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.201400377
Subject(s) - materials science , polybutylene terephthalate , isothermal process , composite material , creep , fracture mechanics , fracture (geology) , physics , polyester , thermodynamics
In this paper a FE based lifetime assessment methodology for short glass fiber reinforced polybutylene terephthalate (PBT‐GF30) under thermo‐mechanical fatigue (TMF) loading is presented. In order to investigate the fatigue behavior of the material both isothermal strain controlled fatigue (ISCF) tests at four different temperatures and thermo‐mechanical fatigue tests were conducted on plain and notched specimens. Through a comparative microscopic investigation of thermo‐mechanical fatigue fracture surfaces and isothermal strain controlled fatigue fracture surfaces created at different temperatures the material state (i.e. the temperature) at which thermo‐mechanical fatigue failure occurs was determined. On the basis of this insight a life estimation methodology derived from a strain energy density (SED) based approach was developed for the corresponding isothermal strain controlled fatigue load case [1]. Through consideration of additional effects occurring during thermo‐mechanical fatigue testing (i.e. relaxation, spatial temperature gradients, creep damage due to low testing frequencies and plastic overloads) the isothermal approach was successfully adapted to the thermo‐mechanical fatigue load case.