Linear-Nonlinear Stiffness Responses of Carbon Fiber-Reinforced Polymer Composite Materials and Structures: A Numerical Study.

S S R Koloor,M R Abdullah,N Yidris,M N Tamin,S M Sapuan,A Karimzadeh,M Petrů

doi:10.3390/polym13030344

Abstract

The stiffness response or load-deformation/displacement behavior is the most important mechanical behavior that frequently being utilized for validation of the mathematical-physical models representing the mechanical behavior of solid objects in numerical method, compared to actual experimental data. This numerical study aims to investigate the linear-nonlinear stiffness behavior of carbon fiber-reinforced polymer (CFRP) composites at material and structural levels, and its dependency to the sets of individual/group elastic and damage model parameters. In this regard, a validated constitutive damage model, elastic-damage properties as reference data, and simulation process, that account for elastic, yielding, and damage evolution, are considered in the finite element model development process. The linear-nonlinear stiffness responses of four cases are examined, including a unidirectional CFRP composite laminate (material level) under tensile load, and also three multidirectional composite structures under flexural loads. The result indicated a direct dependency of the stiffness response at the material level to the elastic properties. However, the stiffness behavior of the composite structures depends both on the structural configuration, geometry, lay-ups as well as the mechanical properties of the CFRP composite. The value of maximum reaction force and displacement of the composite structures, as well as the nonlinear response of the structures are highly dependent not only to the mechanical properties, but also to the geometry and the configuration of the structures.

Highlights

As a widely used material in advanced industries—such as aerospace, automotive, etc.—fiber-reinforced polymer (FRP) composites have been the subject of many studies [1,2]
The reference curve that has been validated by the experiment is shown using green color, while the results obtained from one-half and third-half elastic properties are shown using blue and red color curves, respectively
Since the composite laminate is selected with 45◦ laminas angle specification, both elastic and shear moduli affect the slope of the global load-displacement response

Summary

Introduction

As a widely used material in advanced industries—such as aerospace, automotive, etc.—fiber-reinforced polymer (FRP) composites have been the subject of many studies [1,2]. In many case studies—including material or structures at different micro-macro scales—the validation of FE models has been frequently done by comparing the stiffness curve of solid objects that obtained through FE simulation and compared with their actual behavior measured in the experiments or numerical approach [1,11,13]. This curve is called either stiffness response or load-deformation/displacement, that generally comprise of two parts, that start with an initial linear response to a maximum reaction force at specific displacement, and continued with a nonlinear part to a stage where the load drop is seen [10,14,15]. Different modes of loading such as tensile, compression, and bending has been investigated [1,17,18,19]

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Results

Conclusion