TY - THES

T1 - Stress- and Strain-based Fatigue Life Calculation for Short Fiber Reinforced Polymers by Use of fe-safe

AU - Kaylani, Dario

N1 - no embargo

PY - 2022

Y1 - 2022

N2 - Increasing demands in terms of emission reduction and lightweight construction require the use of optimized materials. Thus, more and more components subjected to mechanical stresses are manufactured from short fiber reinforced thermoplastic polymers (SFRPs). To ensure an efficient use, lifetime assessment at an early stage of development is crucial. Not only the part geometry has to be optimized but also changes in material behavior during the entire life cycle must be considered. The present work aims to establish a continuous workflow for fatigue life calculation of SFRPs, using the fatigue analysis software fe-safe®. Therefore, an existing integrative simulation chain should be adapted. This includes the development of an interface linking together the different entities of the simulation chain and the determination of a dataset for a short fiber reinforced semi-aromatic polyamide-blend with a fiber content of 50 % by weight. Material properties are derived from fatigue test data and used alongside predicted process-induced fiber orientation and a structural simulation to calculate fatigue life based on local anisotropic material behavior. Furthermore, a comparative study of different algorithms, implemented in the utilized software tool, is conducted and a suggestion on the appropriate selection regarding the investigated material is given. To demonstrate the applicability of underlying models and validate the established workflow a dispenser lever, provided by Medmix AG, is analyzed. The achieved results show that the developed method offers the possibility to consider local fiber orientation without the need of using additional composite materials modelling software.

AB - Increasing demands in terms of emission reduction and lightweight construction require the use of optimized materials. Thus, more and more components subjected to mechanical stresses are manufactured from short fiber reinforced thermoplastic polymers (SFRPs). To ensure an efficient use, lifetime assessment at an early stage of development is crucial. Not only the part geometry has to be optimized but also changes in material behavior during the entire life cycle must be considered. The present work aims to establish a continuous workflow for fatigue life calculation of SFRPs, using the fatigue analysis software fe-safe®. Therefore, an existing integrative simulation chain should be adapted. This includes the development of an interface linking together the different entities of the simulation chain and the determination of a dataset for a short fiber reinforced semi-aromatic polyamide-blend with a fiber content of 50 % by weight. Material properties are derived from fatigue test data and used alongside predicted process-induced fiber orientation and a structural simulation to calculate fatigue life based on local anisotropic material behavior. Furthermore, a comparative study of different algorithms, implemented in the utilized software tool, is conducted and a suggestion on the appropriate selection regarding the investigated material is given. To demonstrate the applicability of underlying models and validate the established workflow a dispenser lever, provided by Medmix AG, is analyzed. The achieved results show that the developed method offers the possibility to consider local fiber orientation without the need of using additional composite materials modelling software.

KW - Fatigue

KW - Simulation

KW - Lifetime

KW - Short Fiber Reinforced Polymers

KW - fe-safe

KW - Betriebsfestigkeit

KW - Simulation

KW - Lebensdauerberechnung

KW - Kurzfaserverstärkte Kunststoffe

KW - fe-safe

M3 - Master's Thesis

ER -