DAMAGE DETECTION IN LAMINATED COMPOSITES BY NEURAL NETWORKS AND HIGH ORDER FINITE ELEMENTS

2021 ◽  
Author(s):  
ALFONSO PAGANI ◽  
MARCO ENEA ◽  
ERASMO CARRERA
Keyword(s):  
Neural Networks ◽  
Damage Detection ◽  
Composite Laminates ◽  
Composite Structures ◽  
Laminated Composite ◽  
Machine Learning Techniques ◽  
Damage Scenarios ◽  
Complete Mapping ◽  
Vibrational Characteristics ◽  
Local Defects

In the aerospace industry, machine learning techniques are becoming more and more important for Structural Health Monitoring (SHM). In fact, they could be useful in giving a precise and complete mapping of damage distribution in a structure, including low-intensities or local defects, which cannot be detected via traditional tests. In this work, feedforward artificial neural networks (ANN) are employed for vibration-based damage detection in composite laminates. In the framework of Carrera Unified formulation (CUF), one-dimensional refined models in conjunction with layer-wise (LW) theory are adopted. CUF-based Monte Carlo simulations have been used for the creation of a dataset of damage scenarios for the training of the ANN. Therefore, the latter is fed with the vibrational characteristics of these structures. The trained ANN, given these dynamic parameters, is able to predict location and intensity of all damages in the laminated composite structures.

Robust Autonomous Damage Detection and Assessment in Polymeric Composite Structures

2008 ◽  
Author(s):  
Ajay Kesavan ◽  
Sabu John ◽  
Henry Li ◽  
Israel Herszberg
Keyword(s):  
Damage Detection ◽  
Composite Structures ◽  
Research Study ◽  
Polymeric Composite ◽  
Variable Loading ◽  
Damage Scenarios ◽  
Damage Location ◽  
Joint Structure ◽  
Analytical Work ◽  
Load Angle

This paper introduces the some of the experimental and analytical work behind the autonomous damage detection technique. The research study conducted here resulted in the development of a Structural Health Monitoring (SHM) system for a 2-D polymeric composite T-joint, used in maritime structures. Two methods of damage detection are discussed — A statistics-based outlier technique and one using Artificial Neural Networks (ANNs). The SHM using ANNs system was found to be capable of not only detecting the presence of multiple delaminations in a composite structure, but also capable of determining the location and extent of all the delaminations present in the T-joint structure, regardless of the load (angle and magnitude) acting on the structure. The system developed relies on the examination of the strain distribution of the structure under operational loading. Finally, on testing the SHM system developed with strain signatures of composite T-joint structures, subjected to variable loading, embedded with all possible damage configurations (including multiple damage scenarios), an overall damage (location & extent) prediction accuracy of 94.1% was achieved. These results are presented and discussed in detail in this paper.

Modelling the Effect of Microstructural Randomness on the Fracture of Composite Laminates with Stochastic Cohesive Zone Elements

2009 ◽  
Vol 417-418 ◽  
pp. 13-16
Author(s):  
Zahid R. Khokhar ◽  
Ian A. Ashcroft ◽  
Vadim V. Silberschmidt
Keyword(s):  
Cohesive Zone ◽  
Composite Laminates ◽  
Composite Structures ◽  
Laminated Composite ◽  
Specific Strength ◽  
Laminated Composite Structures ◽  
Structural Applications ◽  
Fibre Reinforced Polymer ◽  
Strength And Stiffness ◽  
Cohesive Zone Elements

Fibre reinforced polymer composites (FRPCs) are being increasingly used in structural applications where high specific strength and stiffness are required. The performance of FRPCs is affected by multi-mechanism damage evolution under loading which in turn is affected by microstructural stochasticity in the material. This means that the fracture of a FRPC is a stochastic process. However, to date most analyses of these materials have treated them in a deterministic way. In this paper the effect of stochasticity in FRPCs is investigated through the application of cohesive zone elements in which random properties are introduced. These may be termed ‘stochastic cohesive zone elements’ and are used in this paper to investigate the effect of microstructural randomness on the fracture behaviour of cross-ply laminate specimens loaded in tension. It is seen from this investigation that microstructure can significantly affect the macroscopic response of FRPC’s, emphasizing the need to account for microstructural randomness in order to make accurate prediction of the performance of laminated composite structures.

Failure Analysis of Laminated Composites under in-Plane Compressive Loading

2012 ◽  
Vol 476-478 ◽  
pp. 583-586
Author(s):  
Yin Huan Yang
Keyword(s):  
Failure Analysis ◽  
Composite Laminates ◽  
Composite Structures ◽  
Parametric Design ◽  
Laminated Composites ◽  
Progressive Failure ◽  
Compressive Loading ◽  
Laminated Composite ◽  
Progressive Failure Analysis ◽  
Ultimate Failure

Failure prediction of laminated composites is performed by progressive failure analysis method. A modified form of Hashin’s failure criterion by Shokrieh is used to detect the failure, where a sudden degradation model is proposed to reduce engineering material constants. The numerical analysis of composite laminates is implemented in ANSYS Parametric Design Language (APDL) with commercial finite element codes ANSYS. The method can predict the initiation and propagation of local damage and response of laminated composite structures from initial loading and ultimate failure. The model has been validated by comparing numerical results with existing experimental results. And then failure analysis specimen fabricated from M40J/Ag80 and investigation on influence of stacking sequences and fiber orientations under in-plane compressive loading have been performed by the proposed model.

scholarly journals Analysis of Delaminated Hybrid Carbon Fiber Composites in MODE-I

2021 ◽  
Vol 9 (2) ◽  
pp. 605-624
Author(s):  
Hassan A. Alessa, Et. al.
Keyword(s):  
Failure Analysis ◽  
Composite Laminates ◽  
Composite Structures ◽  
High Performance ◽  
Failure Modes ◽  
Matrix Material ◽  
Structural Response ◽  
Laminated Composite ◽  
Carbon Fiber Composites ◽  
Wide Range

Failure analysis of laminated composite structures has attracted a great deal of interest in recent years due to the increased application of composite materials in a wide range of high-performance structures. Intensive experimental and theoretical studies of failure analysis and prediction are being reviewed. Delamination, the separation of two adjacent plies in composite laminates, represents one of the most critical failure modes in composite laminates. In fact, it is an essential issue in the evaluation of composite laminates for durability and damage tolerance. Thus, broken fibers, delaminated regions, cracks in the matrix material, as well as holes, foreign inclusions and small voids constitute material and structural imperfections that can exist in composite structures. Imperfections have always existed and their effect on the structural response of a system has been very significant in many cases. These imperfections can be classified into two broad categories: initial geometrical imperfections and material or constructional imperfections

Progressive failure analysis for the interaction of interlaminar and intralaminar failure modes in composite structures with an initial delamination

2013 ◽  
Vol 117 (1187) ◽  
pp. 71-85 ◽  
Author(s):  
W. Ji ◽  
A. M. Waas
Keyword(s):  
Failure Analysis ◽  
Composite Laminates ◽  
Composite Structures ◽  
Failure Modes ◽  
Progressive Failure ◽  
Laminated Composite ◽  
Composite Panel ◽  
Analysis Tool ◽  
Plane Failure ◽  
Progressive Failure Analysis

AbstractThis paper is concerned with the development of a failure initiation and progressive failure analysis (PFA) method for advanced composite structures. The present PFA model is capable of predicting interactive out-of-plane and in-plane failure modes observed in fiber reinforced composite laminates including interlaminar behavior and matrix microdamage at the mesoscale. A probability analysis tool is coupled with the PFA to account for uncertainty in modelling parameters caused by material variability and manufacturing inconsistencies. The progressive damage response of a laminated composite panel with an initial delamination is studied and used to demonstrate the PFA modelling framework that is presented here.

Damage Tolerance of Composite Structures: The Role of Interlaminar Fracture Mechanics

1991 ◽  
Vol 113 (3) ◽  
pp. 247-252 ◽  
Author(s):  
J. W. Gillespie
Keyword(s):  
Fracture Mechanics ◽  
Composite Laminates ◽  
Composite Structures ◽  
Failure Modes ◽  
Damage Tolerance ◽  
Laminated Composite ◽  
Test Methods ◽  
Interlaminar Fracture ◽  
Delamination Growth

Layered fiber-reinforced composite structures are susceptible to crack initiation and growth in the resin-rich layer between plies. Delamination represents one of the most prevalent life-limiting failure modes in laminated composite structures. Interlaminar fracture mechanics represents one approach to assess the damage tolerance of composite structures. This paper is organized into two major sections. The first sections introduces interlaminar fracture mechanics and test methods that have been developed to characterize the Mode I, II and III interlaminar fracture toughness of composite laminates. In the second section, the role of interlaminar fracture mechanics in assessing damage tolerance of composite structures is defined through the following case studies: residual compression after impact strength, instability related delamination growth in compressively loaded laminates and delamination growth in composite laminates with discontinuous internal plies.

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