NOVEL APPROACHES FOR LIFETIME PREDICTION OF COMPOSITE MATERIALS FOR STRUCTURAL APPLICATIONS UNDER STATIC LOADS

The use of polymer matrix composite materials for structural applications in the building sector with longterm service ranges up to several decades of time requires proper accelerated test methods for reliablelifetime estimation. In this respect, the Stress Rate accelerated Creep Rupture test method (SRCR) wasdeveloped, in which an initial stress level si is applied, followed by a constant stress ramp until ruptureand stepwise lowered stress rates in consecutive SRCR tests. Finally, the extrapolation to a virtualstress rate of "0" reveals the creep rupture time for the given stress level. The implementation of SRCRfor various glass fiber reinforced composite materials shows a good applicability of this method as longas the underlying fracture mechanism stays unchanged. Another approach for further acceleratedtesting is the performance of short-term ramp tests at various loading rates until fracture and thesubsequent correlation of the rate dependent rupture points with corresponding creep rupture times. Inthe present work the applicability of this ramp test method originally established for ductile materials isevaluated for fiber reinforced composites with brittle failure behavior.