Mechanisms for Kink Band Evolution in Polymer Matrix Composites: A Digital Image Correlation and Finite Element Study

Abstract

Polymer matrix composites (PMCs) are attractive structural materials due to their high stiffness to low weight ratio. However, unidirectional PMCs have low shear strength and failure can occur along kink bands that develop on compression due to plastic microbuckling that carry strains large enough to induce nonlinear matrix deformation.Reviewing the literature, a large fraction of the existing work is for uniaxial compression, and the effects of stress gradients, such as those present during bending, have not been as well explored, and these effects are bound to make difference in terms of kink band nucleation and growth. Furthermore, reports on experimental measurements of strain fields leading to and developing inside these bands in the presence of stress gradients are also scarce and need to be addressed to gain a full understanding of their behavior when UDCs are used under bending and other spatially complex stress states.In a light to bridge the aforementioned gaps, the primary focus of this work is to understand mechanisms for kink band evolution under an influence of stress-gradients

Visual Methods to Assess Strain Fields in Armour Materials Subjected to Dynamic Deformation—A Review

“…Given the finite resolution of high and ultra-high-speed cameras, resolving the strain field for small scale localized deformation events can be at odds with determining the overall global strain field of the object being examined. An example of this is Patel and Peralta [10], where the authors examine the evolution of microbuckling in an UHMWPE laminate beam, using 2D DIC and the ARAMIS DIC software (GOM GmbH, Braunschweig, Germany), with a supported length of 152 mm. In comparison, the scale of the microbuckling is in the order of 600 µm [10].…”

“…An example of this is Patel and Peralta [10], where the authors examine the evolution of microbuckling in an UHMWPE laminate beam, using 2D DIC and the ARAMIS DIC software (GOM GmbH, Braunschweig, Germany), with a supported length of 152 mm. In comparison, the scale of the microbuckling is in the order of 600 µm [10]. Patel and Peralta [10] used a 100 µm thickness adhesive transfer tape and copper microparticles to generate a speckle pattern with a mean dot size of 15-20 µm and an inter-dot spacing of less than 10 µm.…”

“…In comparison, the scale of the microbuckling is in the order of 600 µm [10]. Patel and Peralta [10] used a 100 µm thickness adhesive transfer tape and copper microparticles to generate a speckle pattern with a mean dot size of 15-20 µm and an inter-dot spacing of less than 10 µm. Applying a speckle pattern on a scale that can measure this microbuckling, but also being able to determine global strains can be challenging, especially when examined in three dimensions.…”

Determination of mode I dynamic fracture toughness of IM7-8552 composites by digital image correlation and machine learning

“…The connection weights (CWM) method was used to estimate RI for each variable based on the weights of a trained artificial neural network (ANN) [57]. The relative importance of a given input variable can be defined by Equation 6, for the case of a single hidden layer.…”

“…The compression failure in notched composites has been thoroughly studied with during the past decades [1] [2] [3] [4] [5]. Fiber-reinforced composites exhibit in compression a failure mechanism through the onset and propagation of kink bands [6,2,7,8] that may be represented as cracks. Therefore, a fracture toughness is associated to the kink band failure mechanism.…”