Damage and fracture of PVDF at 20°C

Abstract

International audienceFlexible oil pipelines are multilayered structures used for the transport of crude oil or natural gas from the seabed to the surface in offshore oil fields. Because of severe service conditions, composite structure made of metallic and polymeric layers must be used. PVDF is a good candidate as it accommodates tensile and flexural deformations and guarantees watertightness. The present paper focuses on the mechanical properties of PVDF at 20°C. Several specimens with different geometries were tested: notched specimen and cracked specimen under tension. Fracture surfaces were examined to determine fracture mechanisms. Based on mechanical testing and microscopic observations, a modified Gurson-Tvergaard-Needleman model for semi-crystalline polymers is proposed. The model allows to represent the non-linear behavior and the cracking of polymer structures