Numerical and experimental study of multimode failure phenomena in GFRP laminates of different lay-ups
TL;DR: In this article, size, shape and orientation of delamination that occur due to low velocity impact is obtained by numerical modelling and results are validated through experiments, and a good match is obtained between simulations and experiments.
Abstract: Induced delamination due to low velocity impact results in degradation of load-carrying capacity of composite structures especially when loading is predominantly in compression. In this paper, size, shape and orientation of delamination that occur due to low velocity impact is obtained by numerical modelling and results are validated through experiments. Initially, numerical model is validated for single-mode fracture tests like double cantilever beam and end-notch flexure. Multimode failure phenomenon like low velocity impact was also simulated for different lay-ups such as cross-ply, angle-ply and quasi-isotropic and validated through experiments. Low velocity impact testing of laminates was done using drop weight impactor, and experimentally obtained force–time and energy–time history were compared with numerical results. Good match is obtained between simulations and experiments. Delamination size was also compared and it is found that numerical model correctly predicts the size, shape and ori...
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TL;DR: In this article, a comprehensive analysis of fracture to fracture toughness is presented, where the authors analyze the impact of fracture toughness on interlaminar fracture toughness in a variety of medical conditions.
Abstract: Interlaminar fracture toughness had been the subject of great interest for several years and is still interesting to the research community. In this article, a comprehensive analysis of fracture to...
40 citations
Cites background from "Numerical and experimental study of..."
...Gupta et al.([34]) found that for delamination characterization in a GF/EP laminate, stiffness value of 10(6) N/mm(3) and element size of 0....
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...and Gupta et al.([34]) concluded that maximum traction, interface shear strength, penalty shear stiffness, mesh/element size, viscosity parameter and fracture toughness are crucial factors for correct representation of load-displacement graph....
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...[44] Gupta et al.[34] found that for delamination characterization in a GF/EP laminate, stiffness value of 106 N/mm3 and element size of 0.25 and 0.125 are desirable, where layups are cross-ply, angle ply and quasi-isotropic in nature....
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...Numerical methods are also gaining wide acceptability for fracture characterization, for which tensile, compressive shear strength and fracture energies of the material([34]) need to be established....
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...Kharratzadeha et al.,[88] Johar,[91] Lu et al.[102] and Gupta et al.[34] concluded that maximum traction, interface shear strength, penalty shear stiffness, mesh/element size, viscosity parameter and fracture toughness are crucial factors for correct representation of load-displacement graph....
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TL;DR: In this paper, low velocity impact analyses of unidirectional and crossply flax/epoxy laminates are performed experimentally and numerically using the commercially available software LS DYNA.
Abstract: Many researchers have experimentally evaluated the mechanical characteristics of flax-based laminates to understand their behaviour under different loading conditions; however, doing so required significant investment in time, money and other resources. An alternative solution is to use advanced numerical and computational tools like FEA. In this study, low velocity impact analyses of unidirectional and crossply flax/epoxy laminates are performed experimentally and numerically. The numerical simulations are conducted using the commercially available software LS DYNA. The goal is to develop a correlated numerical model, which is able to predict the laminates’ energy absorption capability and damage response. The obtained results show good correlation between the experimental findings and numerical model simulations for the rebounding cases. The results also reveal one major limitation of the current model in that it only yields accurate predictions for impact energies below penetration.
22 citations
TL;DR: In this article, shape memory alloys (SMAs) are used in composites to resist impact loading in order to improve damage mitigation in composite composites, and an attempt is made to quantify the improvement in damage mitigation.
Abstract: Embedding shape memory alloys (SMAs) in composites is a promising method resistance against impact loadingIn the present paper, an attempt is made to quantify the improvement in damage mitigation
15 citations
Cites background from "Numerical and experimental study of..."
...Cohesive zone element COH3D8 is used to model the interface between plies that break during impact loading resulting into delamination [18]....
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TL;DR: In this paper , a finite element model (FEM) using ABAQUS FEM software is developed, aiming to provide a benchmark modelling procedure for timber beams with GFRP pultruded beam reinforcement subjected to flexure.
Abstract: Timber structural members have been widely adopted and used in construction due to their inherent characteristics. The main objective of this work is to assess the performance of timber beams with GFRP pultruded beam reinforcement subjected to flexure. A finite element model (FEM) using ABAQUS FEM software is developed, aiming to provide a benchmark modelling procedure. The modelling method considers the fundamental role of the connections among timber beams, the reinforcing GFRP pultruded profile (adhesive and screw connections), and the grain direction in the timber. To understand the influence of the grain direction, different angles of deviations between the longitudinal direction (along the grain) and the beam axis are considered. The robustness of the developed FEM procedure is validated by the experimental results of timber beams with and without GFRP pultruded reinforcement under flexure. It is demonstrated that the angle of deviation (grain deviation) produces high reductions in the strength of unreinforced timber beams. However, this effect is minimal for GFRP-reinforced timber beams. The experimentally derived benchmark FEM procedure can be used as a computational tool for timber beams with GFRP pultruded reinforcement to capture the capacity, failure mode, and load–displacement response.
1 citations
01 Jan 2022
TL;DR: The research on epoxy/natural fiber composites and their modeling and simulation methods developed in recent years is summarized in this paper , where the main application theories and methods in this field are extensively outlined to feed the readers with the research findings and provide some guidance and idea for related research.
Abstract: The research on epoxy/natural fiber composites and their modeling and simulation methods developed in recent years is summarized. Natural fiber reinforced composites (NFRC), also known as a biological composite material due to their proportion, are abundant with natural ingredients, coupled with the most essential environmental factors, such as biodegradability, renewability, and recyclability. Epoxy/natural fiber composites are known for their low cost, light weight, and relatively high specific strength and renowned for its durability. Therefore, epoxy/natural fiber composites provide a sustainable and resilient alternative to the existing synthetic fiber composites. Researchers are studying the properties of NFRC materials in depth to consider their reliability to be used in, but not limited to, aircraft, automobiles, ships, sports equipment, and composite materials for other engineering fields. The modeling and simulation of epoxy/natural fiber composites are an effective means to improve the design and overall performance of the products. The progress of modeling and simulation of epoxy/natural fiber composites on mechanical properties, moisture absorption, and thermal conductivity in recent years is comprehensively summarized from various aspects/types of analysis, types of natural fiber composites, types of the model employed, simulation platforms, and parameters and research results. The main application theories and methods in this field are extensively outlined to feed the readers with the research findings in this field and provide some guidance and idea for related research. The modeling and simulation technique of epoxy/natural fiber composites is an effective way to optimize the structure design and overall performance of the products.
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01 Jan 2008
TL;DR: In this article, fracture mechanics is introduced into finite element analysis by means of a model where stresses are assumed to act across a crack as long as it is narrowly opened, which may be regarded as a way of expressing the energy adsorption in the energy balance approach.
Abstract: A method is presented in which fracture mechanics is introduced into finite element analysis by means of a model where stresses are assumed to act across a crack as long as it is narrowly opened. This assumption may be regarded as a way of expressing the energy adsorption GC in the energy balance approach, but it is also in agreement with results of tension tests. As a demonstration the method has been applied to the bending of an unreinforced beam, which has led to an explanation of the difference between bending strength and tensile strength, and of the variation in bending strength with beam depth.
5,564 citations
"Numerical and experimental study of..." refers methods in this paper
...To get the length of cohesive zon,e different models are present, but the most commonly used model is Hillerborg's model [15,28]....
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TL;DR: In this article, fracture mechanics is introduced into finite element analysis by means of a model where stresses are assumed to act across a crack as long as it is narrowly opened, which may be regarded as a way of expressing the energy adsorption in the energy balance approach.
5,505 citations
3,622 citations
TL;DR: In this article, the authors proposed fracture analysis of structural members made of FRP composites and derived the fracture angle which is the key for this evaluation, which is derived in the present paper.
1,529 citations
"Numerical and experimental study of..." refers background in this paper
...Puck failure criteria are used modelling matrix cracking [21,22]....
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TL;DR: An overview of the virtual crack closure technique is presented, the approach used is discussed, the history summarized, and insight into its applications provided.
Abstract: : An overview of the virtual crack closure technique is presented. The approach used is discussed, the history summarized, and insight into its applications provided. Equations for two-dimensional quadrilateral elements with linear and quadratic shape functions are given. Formula for applying the technique in conjuction with three-dimensional solid elements as well as plate/shell elements are also provided. Necessary modifications for the use of the method with geometrically nonlinear finite element analysis and corrections required for elements at the crack tip with different lengths and widths are discussed. The problems associated with cracks or delaminations propagating between different materials are mentioned briefly, as well as a strategy to minimize these problems. Due to an increased interest in using a fracture mechanics based approach to assess the damage tolerance of composite structures in the design phase and during certification, the engineering problems selected as examples and given as references focus on the application of the technique to components made of composite materials.
1,354 citations