Experimental investigation and numerical modeling of creep response of glass fiber reinforced polymer composites

Abstract

Predictive models play an important role for increasing the reliability of composite structures over time, but a great deal of experimental data is requested. In this paper, results from creep experiments on uniaxial E‐glass fiber reinforced polymer (FRP) single ply laminates, performed at different stress levels, are presented. The tests duration was of 42 months. Analytical modeling of the viscous behavior of the tested GFRP composite, under linear and nonlinear viscoelastic hypotheses, is reported. A discussion on the comparison of creep strain response by Burgers model, with parameters obtained from fitting of data for different test duration, is also proposed. Finally, predictive finite element method (FEM) simulations were carried out for discussing the deferred behavior induced by creep, for composite layers used for repair purposes in hydrogen transportation pipes. Numerical results highlighted a non‐negligible difference in creep strain values, pointing out that a model based on experimental tests with shorter duration leads to a conservative composite design.

Creep modeling of composite materials based on improved gene expression programming

“…The phenomenological model developed by Findley introduces a mathematical expression to describe creep behavior of composite materials that is more suitable for the prediction of creep deformation, it can effectively predict mechanical performance of composites. In this model, the creep response can be divided into time-independent and time-dependent strains, creep strain can be expressed as follows: where is the initial stress-dependent and time-independent elastic strain, is a coefficient related to stress and temperature, t is the time, n is a stress-independent and temperature-dependent material constant 40 . Under constant stress, the subsequent form (7) could be derived, where C 0 is the initial temperature-dependent creep, m is a temperature-related coefficient, and n is a dimensionless material parameter that is dependent of temperature.…”

A new phenomenological creep residual strength model for the life prediction of the laminated composites

“…In comparison to metals, there is a lack of comprehensive understanding of the long‐term response of composite materials in these new applications. The macro‐mechanical response prediction of laminates has been well developed using classical lamination theory and the thermoelastic properties of the constituent lamina 2–4 . However, predicting the strength of a multidirectional laminate is very complex and not well developed due to various damage modes and the progressive development of damage after the first ply failure.…”

“…The macro-mechanical response prediction of laminates has been well developed using classical lamination theory and the thermoelastic properties of the constituent lamina. [2][3][4] However, predicting the strength of a multidirectional laminate is very complex and not well developed due to various damage modes and the progressive development of damage after the first ply failure. Furthermore, the elastic and thermal behavior of unidirectional laminates made of long fibers have been well developed using micromechanical methods and the thermo-mechanical properties of the fiber and matrix.…”