Damage mechanics of composites under fatigue loads
Research output: Thesis › Master's Thesis
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2016.
Research output: Thesis › Master's Thesis
Harvard
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TY - THES
T1 - Damage mechanics of composites under fatigue loads
AU - Rieser, René
N1 - embargoed until null
PY - 2016
Y1 - 2016
N2 - This study investigates the fatigue behaviour of glass fibre reinforced polymer (GFRP) laminates. Unidirectional layups (UD), biaxial layups from ±15° to ±75° in 15° steps and a 0° dominated multiaxial layup were manufactured. Specimens were produced with the vacuum pressing technology. Damage evolution was observed in detail during the cyclic tension-tension fatigue test. It was linked to the decreasing cycle-dependent linear-elastic properties. Damage initiation and growth until specimen failure were observed using a camera system and transmitted light. It was found, that some layups do not develop a characteristic damage state (CDS) because delaminations evolved before crack accumulation in the entire specimen. The applied stresses in the fatigue tests were calculated with the classical laminate theory (CLT) and Puck’s failure criterion for static loads. It was used to show the unsuitability of a static approach under cyclic loads. Non-destructive testing (NDT) methods were evaluated for their applicability to damage monitoring during fatigue tests.
AB - This study investigates the fatigue behaviour of glass fibre reinforced polymer (GFRP) laminates. Unidirectional layups (UD), biaxial layups from ±15° to ±75° in 15° steps and a 0° dominated multiaxial layup were manufactured. Specimens were produced with the vacuum pressing technology. Damage evolution was observed in detail during the cyclic tension-tension fatigue test. It was linked to the decreasing cycle-dependent linear-elastic properties. Damage initiation and growth until specimen failure were observed using a camera system and transmitted light. It was found, that some layups do not develop a characteristic damage state (CDS) because delaminations evolved before crack accumulation in the entire specimen. The applied stresses in the fatigue tests were calculated with the classical laminate theory (CLT) and Puck’s failure criterion for static loads. It was used to show the unsuitability of a static approach under cyclic loads. Non-destructive testing (NDT) methods were evaluated for their applicability to damage monitoring during fatigue tests.
KW - Schädigungsmechanik
KW - faserverstärkte Kunststoffe
KW - Zerstörungsfreie Prüfung
KW - damage mechanics
KW - fatigue
KW - NDT
KW - non-destructive testing
KW - damage evolution
M3 - Master's Thesis
ER -