scholarly journals AN ANALYSIS TOOL FOR DESIGN AND CERTIFICATION OF POSTBUCKLING COMPOSITE AEROSPACE STRUCTURES

2010 ◽  
Vol 10 (04) ◽  
pp. 669-681 ◽  
Author(s):  
ADRIAN C. ORIFICI ◽  
RODNEY S. THOMSON ◽  
RICHARD DEGENHARDT ◽  
CHIARA BISAGNI ◽  
JAVID BAYANDOR
Keyword(s):  
Composite Structures ◽  
Experimental Testing ◽  
Matrix Cracking ◽  
Local Analysis ◽  
Analysis Tool ◽  
Element Analysis ◽  
Damage Mechanisms ◽  
Aerospace Structures ◽  
Damage Initiation ◽  
Interlaminar Damage

In aerospace, carbon-fiber-reinforced polymer (CFRP) composites and postbuckling skin-stiffened structures are key technologies that have been used to improve structural efficiency. However, the application of composite postbuckling structures in aircraft has been limited due to concerns related to both the durability of composite structures and the accuracy of design tools. In this work, a finite element analysis tool for design and certification of aerospace structures is presented, which predicts collapse by taking the critical damage mechanisms into account. The tool incorporates a global–local analysis technique for predicting interlaminar damage initiation, and degradation models to capture the growth of a pre-existing interlaminar damage region, such as a delamination or skin–stiffener debond, and in-plane ply damage mechanisms such as fiber fracture and matrix cracking. The analysis tool has been applied to single- and multistiffener fuselage-representative composite panels, in both intact and predamaged configurations. This has been performed in a design context, in which panel configurations are selected based on their suitability for experimental testing, and in an analysis context for comparison with experimental results as being representative of aircraft certification studies. For all cases, the tool was capable of accurately capturing the key damage mechanisms contributing to final structural collapse, and suitable for the design of next-generation composite aerospace structures.

Predictive analysis of stitched aerospace structures for advanced aircraft

2019 ◽  
Vol 124 (1271) ◽  
pp. 44-54
Author(s):  
B. Horton ◽  
Y. Song ◽  
D. Jegley ◽  
F. Collier ◽  
J. Bayandor
Keyword(s):  
Composite Structures ◽  
Experimental Validation ◽  
Aviation Industry ◽  
Body Structure ◽  
Element Analysis ◽  
Aerospace Structures ◽  
New Approach ◽  
Leading Role ◽  
Modeling Techniques ◽  
Analysis Environment

ABSTRACTIn recent years, the aviation industry has taken a leading role in the integration of composite structures to develop lighter and more fuel efficient aircraft. Among the leading concepts to achieve this goal is the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept. The focus of most PRSEUS studies has been on developing an hybrid wing body structure, with only a few discussing the application of PRSEUS to a tube-wing fuselage structure. Additionally, the majority of investigations for PRSEUS have focused on experimental validation of anticipated benefits rather than developing a methodology to capture the behavior of stitched structure analytically. This paper presents an overview of a numerical methodology capable of accurately describing PRSEUS’ construction and how it may be implemented in a barrel fuselage platform resorting to high-fidelity mesoscale modeling techniques. The methodology benefits from fresh user defined strategies developed in a commercially available finite element analysis environment. It further proposes a new approach for improving the ability to predict deformation in stitched composites, allowing for a better understanding of the intricate behavior and subtleties of stitched aerospace structures.

Simulation of Low Velocity Impact Test on Carbon/Epoxy Composite Plates

2015 ◽  
Vol 1115 ◽  
pp. 523-526
Author(s):  
Ziamah B. Buang ◽  
S.M. Kashif
Keyword(s):  
Numerical Simulation ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Structures ◽  
Composite Plates ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Element Analysis ◽  
Velocity Impact

Composite materials that have low weight and high strength properties are currently one of the promising materials for a vehicle’s body. However, the effect of low velocity impact on composite may cause failure through matrix cracking, fibre breakage and delamination which may reduce the structure strength. Low velocity impact can be analysed either by experimentation or numerical simulation. Numerical simulation which is also known as finite element analysis can show the degradation of the composite structure properties after an impact loading condition without doing any experimentation. Thus, in this paper, LS-DYNA is the finite element analysis software that is used to simulate a low velocity impact on composite structures.

Damage assessment of random multiwalled carbon nanotube-reinforced polymer nanocomposites

2018 ◽  
Vol 25 (5) ◽  
pp. 847-853
Author(s):  
Belkacem Kada ◽  
Abdullah Algarni ◽  
Mostefa Bourchak ◽  
Mahmoud N. Nahas
Keyword(s):  
Carbon Nanotube ◽  
Prediction Model ◽  
Polymer Nanocomposites ◽  
Experimental Testing ◽  
Numerical Procedure ◽  
Multiwalled Carbon Nanotube ◽  
Multiwalled Carbon ◽  
Element Analysis ◽  
Damage Initiation ◽  
Reinforced Polymer

AbstractThe paper presents a numerical procedure to evaluate the mechanical properties and predict the damage initiation of random multiwalled carbon nanotube-reinforced polymer nanocomposites (MWCNT-RPNC). The Hashin-Shtrikman (H-S) random prediction model is used to compute the properties of the reinforced polymer matrix, whereas the Chamis model is used to compute the lamina properties and the Hashin progressive damage model within the ABAQUS environment is used as a finite element analysis (FEA) tool to predict the damage initiation in the reinforced composite material. Experimental testing is employed to validate the numerical results and to adjust the H-S prediction model for MWCNT-RPNC.

Probabilistic Failure of Graphite Epoxy Composite Plates Due to Low Velocity Impact

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Shivdayal Patel ◽  
Suhail Ahmad
Keyword(s):  
Damage Mechanics ◽  
Optimization Procedure ◽  
Composite Plates ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Stochastic Dynamic ◽  
Low Velocity ◽  
Element Analysis ◽  
Velocity Impact ◽  
Damage Initiation

Stochastic finite-element analysis of composite plates due to low velocity impact (LVI) is studied, considering the material properties (Young's modulii, Poisson's ratio, strengths, and fracture energy) and initial velocity as random parameters. Damage initiation and propagation failure due to matrix cracking are investigated for safety criteria for the LVI. Progressive damage mechanics is employed to predict the stochastic dynamic response of the plates. The Gaussian process response surface method (GPRSM) is presently adopted to determine the probability of failure (Pf). There is a possibility of underestimation of the peak contact force and displacement by 10.7% and 11.03%, respectively, if the scatter in the properties is not considered. The sensitivity-based probabilistic design optimization procedure is investigated to achieve better strength and lighter weight of composite for body armors.

scholarly journals Application of discrete damage mechanics for determination of the crack density in composite laminates

2020 ◽  
Vol 310 ◽  
pp. 00002
Author(s):  
Milan Žmindák ◽  
Eva Kormaníková ◽  
Pavol Novák ◽  
Josef Soukup ◽  
Kamila Kotrasová
Keyword(s):  
Fracture Toughness ◽  
Composite Laminates ◽  
Composite Structures ◽  
Damage Mechanics ◽  
Crack Density ◽  
Matrix Cracking ◽  
Mapping Algorithm ◽  
Damage Initiation ◽  
Return Mapping

The finite element method (FEM) is one of the most widely and most popular numerical methods for analyzing damage of composite structures, In this paper discrete damage mechanics (DDM) is used to predict inter-laminar transverse and shear damage initiation and evolution in terms of the fracture toughness of the laminate. ANSYS commercial software is used for analysis of layered plate composite structure reinforced with long unidirectional fibers with Carbon/Epoxy material. Because ANSYS does not have a built-in capability for calculating crack density, we have to use plagin. A methodology for determination of the fracture toughness is based on fitting DDM model and these data are obtained from literature. Also, prediction of modulus vs. applied strain is contrasted with ply discount results and the effect of in situ correction of strength is highlighted. Evaluation of matrix cracking detected in lamina has been solved using return mapping algorithm.

scholarly journals A model of low-velocity impact damage assessment of laminated composite structures

2018 ◽  
Vol 188 ◽  
pp. 01012 ◽  
Author(s):  
Konstantinos P. Stamoulis ◽  
Stylianos K. Georgantzinos ◽  
Georgios I. Giannopoulos
Keyword(s):  
Composite Structures ◽  
Mechanical Performance ◽  
Impact Damage ◽  
Experimental Testing ◽  
Laminated Composite ◽  
Element Model ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Damage Initiation ◽  
Laminated Composite Structures

Laminated composites have important applications in modern aeronautical structures due to their extraordinary mechanical and environmental behaviour. Nevertheless, aircraft composite structures are highly vulnerable to impact damage, either by low-velocity sources during maintenance or high-velocity sources during in-flight events. Even barely visible impact damage induced by low-velocity loading, substantially reduces the residual mechanical performance and the safe-service life of the composites structures. Despite the extensive research already carried out, impact damage of laminated composite structures is still not well understood and it is an area of on-going research. Numerical modelling is considered as the most efficient tool as compared to the expensive and time-consuming experimental testing. In this paper, a finite element model based on explicit dynamics formulations is adopted. Hashin criterion is applied to predict the intra-laminar damage initiation and evolution. The numerical analysis is performed using the ABAQUS® programme. The employed modelling approach is validated using numerical results found in the literature and the presented results show an acceptable correlation to the available literature data. It is demonstrated that the presented model is able to capture force-time response as well as damage evolution map for a range of impact energies.

Acoustic Emission Characterization of Damage Patterns in Composite Scarf Joints Using Unsupervised Learning

2020 ◽  
Author(s):  
D. Xu ◽  
Z. P. Chen ◽  
P. F. Liu ◽  
J. H. Wu ◽  
P. Jiao ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Acoustic Emission ◽  
Composite Structures ◽  
Tensile Loading ◽  
Matrix Cracking ◽  
Interface Debonding ◽  
Engineering Structures ◽  
Damage Pattern ◽  
Damage Initiation ◽  
Non Destructive

Abstract Interest in damage detection and damage pattern recognition of engineering structures by non-destructive techniques has been increasingly growing. As a non-destructive technique, acoustic emission (AE) has developed rapidly to detect dynamic defects and their evolution behaviors of composite structures, based on the transient elastic waves produced by rapid energy release due to the geometry change of structures. In this paper, AE technology is utilized to monitor the real-time condition of the composite scarf joint (SJ) under tensile loading. First, after AE signal acquisition, dimensionality reduction of eight AE features is realized by employing principal component analysis such that the Curse of Dimensionality can be avoided. Second, feature selection is continued by introducing two evaluation indexes, i.e., correlation coefficient and Laplacian score. Third, after the optimal cluster number is determined, damage pattern recognition is accomplished by introducing k-means++ algorithm which explores the distribution of each pattern in the space constructed by four informative AE features. Based on the clustering results, damage initiation and evolution in SJ specimens under tensile loading are subsequently explored. The shear failure of the adhesive layer which is a characteristic damage pattern for SJ specimens shows a relatively-high activity after the early stage. Matrix cracking and fiber/matrix interface debonding are two fundamental damage patterns which keep active in the whole process.

scholarly journals Determination of the laminate strains using discrete damage mechanics

2019 ◽  
Vol 254 ◽  
pp. 06005
Author(s):  
Milan Žmindák ◽  
Michal Kaco ◽  
Pavol Novák ◽  
Leszek Radziszewski ◽  
Josef Soukup
Keyword(s):  
Fracture Toughness ◽  
Composite Structures ◽  
Damage Mechanics ◽  
Crack Density ◽  
Matrix Cracking ◽  
Mapping Algorithm ◽  
Damage Initiation ◽  
Return Mapping ◽  
Epoxy Material

In this paper discrete damage mechanics (DDM) is used to predict inter-laminar transverse and shear damage initiation and evolution in terms of the fracture toughness of the laminate. The finite element method (FEM) is one of the most widely and most popular numerical methods for analyzing composite structures, therefore ANSYS commercial software is used for analysis of layered plate composite structure reinforced with long unidirectional fibers with Carbon/Epoxy material. Because ANSYS does not have a built-in capability for calculating crack density, we have to use plugin. A methodology for determination of the fracture toughness is based on fitting DDM model and these data are obtained from literature. Also, prediction of modulus vs. applied strain is contrasted with ply discount results and the effect of in situ correction of strength is highlighted. Evaluation of matrix cracking detected in lamina has been solved using return mapping algorithm.

scholarly journals Approaches Looking Finite Elements Analysis of a Structural Model of Lid Stratified with Cellular Polymeric Core Specific to a Pressure Vessel

2019 ◽  
Vol 56 (1) ◽  
pp. 156-162
Author(s):  
Ion Durbaca ◽  
Radu Iatan ◽  
Adrian Costin Durbaca ◽  
Vasile Sacuiu ◽  
Melania Mituca Corleciuc ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Pressure Vessel ◽  
Composite Structures ◽  
Structural Model ◽  
Experimental Testing ◽  
Layered Composite ◽  
Finite Elements Analysis ◽  
Element Analysis ◽  
Important Place ◽  
Cellular Polymer

The paper treats Finite Element Analysis (FEA) specific to the mechanical behavior of a structural layer cap type with polymer cellular cores within a pressure vessel. The layered composite structure comprises two outer polymer shells (synthetic glass/ plexiglass) and cellular polymer core with triangular shaped cells. This analysis uses the Autodesk Inventor 2016 Professional 3D design and modeling software, in conjunction with the FEA analysis program, ANSYS 14.5 - Workbench, using the Mesh module. Mechanical behavior of the structural models specific to the four types of test caps, each having different cellular polymer core (ABS, PLA, PC and CF, 3 and 5 mm thickness), is revealed through the analysis of the state of stresses and deformations and correlating the FEA simulation results with experimental testing. Since the analysis leads to quasi-equivalent results under identical conditions of application until the fracture of the caps, it is found that such an FEA approach of the mechanical system components occupies an important place in the modern design process, being one of the ways of identifying the deformation fields and equivalent stresses in the analyzed composite structures.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

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