CREEP FAILURE CRITERIA FOR POLYMER BASED MATERIALS

• Type: Article in International Conference Proceedings Book
• Date: 2012

Authors

Rui Miranda Guedes (Author) FEUP

Conference proceedings International

Title: Proceedings ICEM15 - 15th International Conference on Experimental Mechanics

ICEM15 - 15th International Conference on Experimental Mechanics

Porto, 22-27 July 2012

Indexing

ISI Web of Knowledge - 0 Citations

Scientific classification

FOS: Engineering and technology > Mechanical engineering

Other information

Authenticus ID: P-005-K4C

Abstract (EN): The extensive use of polymers in structural applications leaded to structural elements with high specific stiffness and strength. Initially these elements present high mechanical performance which may decay strongly over time due to the viscoelastic nature of polymers. Moreover the fiber reinforced polymers exhibit damage accumulation and propagation within the polymeric matrix and fibre breaking. A result of creep and fatigue is catastrophic premature failure. However in civil engineering applications, the structural components are supposed to remain in service for 50 years or more in safety conditions. Usually it is assumed that polymer-matrix composites possess superior corrosion resistance. Yet stress corrosion of glass fibres takes place as soon as moisture reaches the fibre by absorption, accelerating fibre breaking. This may be a problem, since glass-fibre reinforced polymers (GRP) is the most common material used in civil engineering applications, due to its low cost. The lack of full understanding of the fundamental parameters controlling long-term materials performance necessarily leads to over-design and, furthermore, may inhibit greater utilization. In this context, lifetime prediction of these structures is an important issue to be solved before wider dissemination of civil engineering applications can take place. As an example, standards dealing with certification of GRP pipes require at least 10000 hours of testing for a high number of specimens. Even though these strong requirements may be foreseen as reasonable, concerning the safety of civil engineering applications, they severely restrict the improvement and innovation of new products. Theoretical approaches for long-term criteria are reviewed. Fracture mechanics and energy-based failure criteria will be presented and developed for practical applications and illustrated with an experimental case, short and long-term performance of GFRP pipes under ring compressive loading in a wet environment.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 2