Mechanical response and critical failure mechanism characterization of notched carbon fiber reinforced polymer laminate subjected to tensile loading

Abstract

The purpose of this article is to investigate the mechanical responses and critical failure mechanisms of notched composite laminates with the aid of numerical and experimental approaches, considering the effect of notch geometry, notch size and off-axis angle. Quasi-static tensile tests are implemented to study the influence of design variables on the mechanical response, during which the relationship of force vs displacement and strain distributions are collected by means of digital image correlation technique. Subsequently, the numerical simulation is implemented in ABAQUS/Explicit through a progressive damage model integrated with a VUMAT subroutine. Meanwhile, the initiation and propagation of damage are explored through the damage morphologies, combining with the logarithmic strain components from numerical predictions. Results show that notch strength and failure strain are more closely associated with off-axis angle and notch size compared with notch geometry. In addition, with the increase of off-axis angle, the contribution of fiber is increasingly weakened, the damage mode gradually varies from fiber fracture to pull out accompanied with the damage near the notch changing from fiber fracture to delamination. Meanwhile, the critical failure mechanism varies from tension dominated to tension-shear/ shear dominated as the off-axis angle grows larger. K E Y W O R D S composite laminates, digital image correlation, failure mechanism, notch strength 1 | INTRODUCTION Carbon fiber reinforced polymer (CFRP) laminate has been increasingly applied in light of its outstanding performance and superior damage tolerance. Compared with traditional materials, it has many typical advantages, such as high specific strength and stiffness, [1-3] improved impact and fatigue resistance, [4-6] perfect corrosion resistance and moistureproof ability, [7] and so forth. During the application, in addition to the complicated loading conditions, the unavoidable notches for mechanical connections also pose a risk to the load-bearing capacity and service life. In addition, notch geometry and notch size are usually diversified to facilitate the connection of structural components, which significantly diminishes the mechanical properties and further complicates the exploration of mechanical behaviors. Furthermore, due to the anisotropy, brittleness, heterogeneity, and obvious difference between the interlaminar and intralaminar property, damage patterns, and failure mechanisms of composites also present complexity and diversity. [8]

Dynamic response and failure mechanism characterization of composite‐metal sandwich structures under slamming impact utilizing CEL method

“…To accurately characterize the damage initiation and evolution of aluminum material, ductile criterion and exponential evolution model are adopted. [13] Damage initiates when the following condition is met, [26] ω…”

Hybrid multiscale procedure for damage in notched unidirectional composite monitored by thermography

“…[19] On the one hand, analytical investigations have the advantage of good approximations and attractive formulae for optimization procedures. [20,21] In addition, numerical simulations can improve the modeling effort to include nonlinear effects [22,23] For damage onset in notched unidirectional plates, Vignoli et al [24] investigated the influence of different failure criteria considering elliptical holes in infinity plates. Vignoli et al [25] proposed a multiscale analytical formulation to study the influence of fiber volume fraction for infinity plates with circular holes.…”

Effect of Hole Arrangement on Failure Mechanism of Multiple-Hole Fiber Metal Laminate under On-Axis and Off-Axis Loading

“…In prior investigations, the effects of geometric parameters (notch shape and sizes of notch and specimen) [ 9 , 10 , 11 , 12 , 13 , 14 ], types and fractions of constituents [ 15 , 16 , 17 ], and interface adhesion [ 18 ] on mechanical response and damage behavior of FML with blunt notches were experimentally revealed. Moreover, finite element models [ 12 , 13 , 14 , 19 , 20 , 21 , 22 ] and analytical models, e.g., the point and average stress criteria [ 11 , 23 ] and effective crack growth model [ 24 ], were used to predict the notched strength, damage patterns, and damage evolution process.…”

“…In prior investigations, the effects of geometric parameters (notch shape and sizes of notch and specimen) [ 9 , 10 , 11 , 12 , 13 , 14 ], types and fractions of constituents [ 15 , 16 , 17 ], and interface adhesion [ 18 ] on mechanical response and damage behavior of FML with blunt notches were experimentally revealed. Moreover, finite element models [ 12 , 13 , 14 , 19 , 20 , 21 , 22 ] and analytical models, e.g., the point and average stress criteria [ 11 , 23 ] and effective crack growth model [ 24 ], were used to predict the notched strength, damage patterns, and damage evolution process. In addition to the common on-axis loading strategy, the influence of off-axis angle on notched behavior of FML was also investigated [ 12 , 13 , 14 , 16 , 21 , 22 , 25 , 26 ], where the evident off-axis dependence of notched strength, notch sensitivity, and failure mechanism were elaborated.…”

“…Moreover, finite element models [ 12 , 13 , 14 , 19 , 20 , 21 , 22 ] and analytical models, e.g., the point and average stress criteria [ 11 , 23 ] and effective crack growth model [ 24 ], were used to predict the notched strength, damage patterns, and damage evolution process. In addition to the common on-axis loading strategy, the influence of off-axis angle on notched behavior of FML was also investigated [ 12 , 13 , 14 , 16 , 21 , 22 , 25 , 26 ], where the evident off-axis dependence of notched strength, notch sensitivity, and failure mechanism were elaborated. Moreover, analytical methods for off-axis notched strength were also proposed based on the Norris theory criterion [ 25 ] and multi-axial criterion [ 26 ].…”