The Assessing of the Failure Behavior of Glass/Polyester Composites Subject to Quasi Static Stresses

International Conference on Innovative Research - ICIR Euroinvent 2017

Stanciu, M.D.^1 ; Savin, A.^2 ; Teodorescu-Drghicescu, H.^1

Transylvania University of Brasov, Faculty of Mechanical Engineering, 29 Eroilor Blvd, 500036, Romania^1

National Institute of Research and Development for Technical Physics, Nondestructive Testing Department, 47 D. Mangeron Blvd, Iasi

700050, Romania^2

关键词: Energy of deformation;    Glass/polyester composites;    High mechanical strength;    Large displacements;    Quasi-static regime;    Quasi-static stress;    Stiffness variations;    Tensile cyclic loadings;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/209/1/012007/pdf
DOI  :  10.1088/1757-899X/209/1/012007

来源: IOP

【 摘 要 】

Using glass fabric reinforced composites for structure of wind turbine blades requires high mechanical strengths especially to cyclic stresses. Studies have shown that approximately 50% of composite material failure occurs because of fatigue. Composites behavior to cyclic stresses involves three stages regarding to stiffness variation: the first stage is characterized by the accelerated decline of stiffness with micro-cracks, the second stage - a slight decrease of stiffness characterized by the occurrence of delamination and third stage characterized by higher decreases of resistance and occurrence of fracture thereof. The aim of the paper is to analyzed the behavior of composites reinforced with glass fibers fabric type RT500 and polyester resin subjected to tensile cyclic loading with pulsating quasi-static regime with asymmetry coefficient R = 0. The samples were tested with the universal tensile machine LS100 Lloyd Instruments Plus, with a load capacity of 100 kN. The load was applied with different speeds of 1 mm/min, 10 mm/min and 20 mm/min. After tests, it was observed that the greatest permanent strains were recorded in the first load cycles when the total energy storage by material was lost due to internal friction. With increasing number of cycles, the glass/polyester composites ability to store energy of deformation decreases, the flow phenomenon characterized by large displacements to smaller loading forces appearing.