A Fatigue Damage Model for FRP Composite Laminate Systems Based on Stiffness Reduction

Abstract

This paper introduces a stiffness reduction based model developed by the authors to characterize accumulative fatigue damage in unidirectional plies and (0/θ/0) composite laminates in fiber reinforced polymer (FRP) composite laminates. The proposed damage detection model is developed based on a damage evolution mechanism, including crack initiation and crack damage progress in matrix, matrix-fiber interface and fibers. Research result demonstrates that the corresponding stiffness of unidirectional composite laminates is reduced as the number of loading cycles progresses. First, three common models in literatures are presented and compared. Tensile viscosity, Young's modulus and ultimate tensile stress of composites are incorporated as key factors in this model and are modified in accordance with temperature. Four types of FRP composite property parameters, including Carbon Fiber Reinforced Polymer (CFRP), Aramid Fiber Reinforced Polymer (AFRP), Glass Fiber Reinforced Polymer (GFRP), and Basalt Fiber Reinforced Polymer (BFRP), are considered in this research, and a comparative parameter study of FRP unidirectional composite laminates with different off-angle plies using control variate method are discussed. It is concluded that the relationship between the drop in stiffness and the number of cycles also shows three different regions, following the mechanism of damage of FRP composites and the matrix is the dominant factor determined by temperature, while fiber strength is the dominant factor that determine the reliability of composite.

Mecanismos de dano em reparos de materiais poliméricos e compósitos em tubulações offshore: uma revisão integrativa

“…As tubulações das unidades offshore também sofrem fadiga devido aos deslocamentos e acelerações impostas pelas ondas do mar ao navio (ZHANG; NI; SUN, 2022). Apesar de se saber que fadiga é um processo com um dano acumulativo associado a carregamentos dinâmicos, nem sempre é possível dimensionar o momento no Devido a isso, o desenvolvimento de modelos matemáticos para previsão dos danos e estimativa de vida remanescente do reparo é essencial (ZHAO et al, 2019).…”

Identification of cracks in an Euler–Bernoulli beam using Bayesian inference and closed-form solution of vibration modes

“…The vibration of a cracked beam can be considered to be a linear vibration. Suppose that the cracks are equivalent to massless springs connecting the sub-beams, the flexural stiffness of the beam can be expressed as a uniform expression represented by the following equation as 62–64 where |EIe is the uniform flexural stiffness that varies with the coordinates of the beam section, |EI0 is the stiffness of an un-cracked beam, and δ is the Dirac delta function.…”

An Enhanced Lemaitre Model and Fracture Map for Cr5 Alloy Steel during High-Temperature Forming Process

“…In recent decades, many scholars have performed systematic research on the mechanism of crack generation and the establishment of related models in the material forming process. Freudenthal [ 9 ] believed that when the material strain energy reached a critical value, the material would fracture, and proposed the Freudenthal damage model. Cockcroft and Latham [ 10 ] believed that the maximum tensile stress in the material deformation process was the cause of material fracture, and proposed the Cockcroft and Latham (CL) damage model.…”