scholarly journals Delamination buckling of a laminated composite shell panel using cohesive zone modelling

2021 ◽  
Keyword(s):  
Failure Modes ◽  
Structural Integrity ◽  
Composite Shell ◽  
Laminated Composite ◽  
Composite Panel ◽  
Complex Nature ◽  
Interface Failure ◽  
Engineering Structures ◽  
Fiber Failure ◽  
Delamination Buckling

Abstract Laminated composite shell panels take part in several engineering structures. Due to their complex nature, failure modes in composites are highly dependent on the geometry, direction of loading and orientation of the fibers. However, the design of composite parts is still a delicate task because of these fiber failure modes, which includes matrix failure modes or other so-called interlaminar interface failure such as delamination, that corresponds to the separation of adjacent layers of the laminate as a consequence of the weakening of interface layer between them. In this work, impact-induced delamination represented as a circular single delamination is investigated, as it can reduce greatly the structural integrity without getting detected. Furthermore, attention is focused on its effect upon the post-buckling response and the compressive strength of a composite panel. The delamination buckling was modelled using the cohesive element technique under Abaqus software, in order to predict delamination growth and damage propagation while observing their effects on the critical buckling load.

Failure Analysis of Composite Structures Using Multiscale Technique

2020 ◽  
Vol 995 ◽  
pp. 209-213
Author(s):  
Young W. Kwon
Keyword(s):  
Composite Structures ◽  
Failure Modes ◽  
Cell Model ◽  
Fibrous Composite ◽  
Failure Criteria ◽  
Multiscale Approach ◽  
Interface Failure ◽  
Fiber Failure ◽  
Strain Rate Effects ◽  
Constituent Material

Failure analyses of laminated fibrous composite structures were conducted using the failure criteria based on a multiscale approach. The failure criteria used the stresses and strains in the fiber and matrix materials, respectively, rather than those smeared values at the lamina level. The failure modes and their respective failure criteria consist of fiber failure, matrix failure and their interface failure explicitly. In order to determine the stresses and strains at the constituent material level (i.e. fiber and matrix materials), analytical expressions were derived using a unit-cell model. This model was used for the multiscale approach for both upscaling and downscaling processes. The failure criteria are applicable to both quasi-static loading as well as dynamic loading with strain rate effects.

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.

Fitness for Service Analysis of Structures Using the FITNET Procedure: An Overview

2005 ◽  
Author(s):  
Mustafa Koc¸ak
Keyword(s):  
Nuclear Power ◽  
Failure Modes ◽  
Structural Integrity ◽  
Cost Savings ◽  
Industrial Sector ◽  
Structural Instability ◽  
General Purpose ◽  
Engineering Structures ◽  
Industrial Sectors ◽  
Size Limits

A number of Fitness-for-Service (FFS) procedures (include analytical methods) have been specifically developed and used to address the components of a particular industrial sector. A number of industrial sectors, such as nuclear power, petrochemical, offshore, aerospace or pipeline girth weld applications have established FFS standards in place for the assessment of flaws found in-service. Some methods for design and remaining life assessments of fatigue-loaded structures are still unduly conservative in different loading regimes. Hence, there is still a need to generate a general purpose, unified, comprehensive and updated FFS methodology in Europe by covering four major failure modes (fracture, fatigue, creep and corrosion) in metallic load bearing components with or without welds. As a result, the European Community funded the project FITNET in the form of a Thematic Network (TN) organisation to review the existing FFS procedures and develop an updated, unified and verified European FITNET FFS Procedure to cover structural integrity analysis to avoid failures due to fracture, fatigue, creep and corrosion. FITNET TN is a four year project with the objective of developing and extending the use of FITNET FFS Procedure for welded and non-welded metallic structures throughout Europe. It is partly funded by the European Commission within the fifth framework programme and launched at February 2002. The network currently consists of 50 organisations from 16 European and three non-European countries representing various industrial sectors and academia. Further information can be found in the FITNET TN website: http://www.eurofitnet.org. FITNET Fitness-for-Service analysis of engineering structures aims to provide better design principles, support for fabrication of new components, prevention of service failures due to fracture, fatigue, creep and corrosion damages (no coverage of structural instability due to buckling). FITNET FFS criteria can be used to establish the size limits for defects in various engineering structures and can provide substantial cost savings in operating such structures. The use of the FITNET FFS Procedure involves making an assessment of a component containing a defect to ensure its structural integrity for its intended design life or until its next inspection period. The outcome of the assessment of a component in service is a decision to operate as is, repair, monitor (including re-setting of inspection intervals), or replace. The aim of this paper is to give an overview of the objectives and technical content of the FITNET FFS Procedure currently developed and validated by the European Fitness for Service Network FITNET and hence inform the offshore technical community.

Thermally Induced Delamination Buckling of a Thin Metal Layer on a Ceramic Substrate

2003 ◽  
Vol 125 (4) ◽  
pp. 512-519 ◽  
Author(s):  
C. J. Liu ◽  
L. J. Ernst ◽  
G. Wisse ◽  
G. Q. Zhang ◽  
M. Vervoort
Keyword(s):  
Failure Modes ◽  
Research Effort ◽  
Metal Layer ◽  
Electronic Packages ◽  
Ceramic Substrates ◽  
Thermally Induced ◽  
Thermal Expansion Coefficients ◽  
Interface Delamination ◽  
Delamination Buckling ◽  
Expansion Coefficients

Interface delamination failure caused by thermomechanical loading and mismatch of thermal expansion coefficients and other material properties is one of the important failure modes occurring in electronic packages, thus a threat for package reliability. To solve this problem, both academic institutions and industry have been spending tremendous research effort in order to understand the inherent failure mechanisms and to develop advanced and reliable experimental and simulation methodologies, thus to be able to predict and to avoid interface delamination before physical prototyping. Various damage mechanisms can be involved and can result in interface delamination phenomena. These are not all sufficiently addressed and/or reported so far, probably because of the complexities caused by the occurrence of strong geometric and materials nonlinearities. One of the phenomena being insufficiently understood so far is the so-called buckling-driven delamination of thin metalic layers on ceramic substrates. This phenomenon will be discussed in the present paper.

scholarly journals Physical modelling of failure in composites

2016 ◽  
Vol 374 (2071) ◽  
pp. 20150280 ◽  
Author(s):  
Ramesh Talreja
Keyword(s):  
Composite Materials ◽  
Failure Modes ◽  
Structural Integrity ◽  
Failure Mechanisms ◽  
Local Stress ◽  
Physical Modelling ◽  
Stress Fields ◽  
Systematic Analysis ◽  
Composite Failure ◽  
Failure Theories

Structural integrity of composite materials is governed by failure mechanisms that initiate at the scale of the microstructure. The local stress fields evolve with the progression of the failure mechanisms. Within the full span from initiation to criticality of the failure mechanisms, the governing length scales in a fibre-reinforced composite change from the fibre size to the characteristic fibre-architecture sizes, and eventually to a structural size, depending on the composite configuration and structural geometry as well as the imposed loading environment. Thus, a physical modelling of failure in composites must necessarily be of multi-scale nature, although not always with the same hierarchy for each failure mode. With this background, the paper examines the currently available main composite failure theories to assess their ability to capture the essential features of failure. A case is made for an alternative in the form of physical modelling and its skeleton is constructed based on physical observations and systematic analysis of the basic failure modes and associated stress fields and energy balances. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’.

Evaluation of the Effect of Yield to Tensile (Y/T) Ratio on the Structural Integrity of Offshore Pipeline by Limit State Design Approach

2006 ◽  
Author(s):  
Gianluca Mannucci ◽  
Giuliano Malatesta ◽  
Giuseppe Demofonti ◽  
Marco Tivelli ◽  
Hector Quintanilla ◽  
...  
Keyword(s):  
Structural Reliability ◽  
Failure Modes ◽  
Structural Integrity ◽  
Limit State ◽  
Minor Effect ◽  
Offshore Pipelines ◽  
Limit State Design ◽  
A Minor ◽  
Probabilistic Failure Analysis ◽  
Failure Probabilities

Nowadays specifications require strict Yield to Tensile ratio limitation, nevertheless a fully accepted engineering assessment of its influence on pipeline integrity is still lacking. Probabilistic analysis based on structural reliability approach (Limit State Design, LSD) aimed at quantifying the yield to tensile strength ratio (Y/T) influence on failure probabilities of offshore pipelines was made. In particular, Tenaris seamless pipe data were used as input for the probabilistic failure analysis. The LSD approach has been applied to two actual deepwater design cases that have been on purpose selected, and the most relevant failure modes have been considered. Main result of the work is that the quantitative effect of the Y/T ratio on failure probabilities of a deepwater pipeline resulted not so big as expected; it has a minor effect, especially when Y only governs failure modes.

Rainwater effect on bearing strength of glass–epoxy laminated composite pinned joints

2016 ◽  
Vol 50 (30) ◽  
pp. 4269-4278 ◽  
Author(s):  
Onur Sayman ◽  
Ümran Esendemir
Keyword(s):  
Room Temperature ◽  
Failure Modes ◽  
Failure Load ◽  
Weight Ratio ◽  
Laminated Composite ◽  
Hole Diameter ◽  
Plastic Container ◽  
Specimen Width ◽  
Bearing Load ◽  
Pinned Joints

Composite materials are used in areas that have varying environmental conditions due to their advantages such as generally higher stiffness- and strength-to-weight ratio, and corrosion resistance compared to metallic alloys. This experimental study is carried out to investigate the bearing strengths and failure modes of woven glass–epoxy composite pinned joints subjected to rainwater. The specimens were immersed in rainwater in a closed plastic container indoors for 20 month periods at room temperature. The ratio of edge-distance-to-hole diameter (E/D) and the ratio of the specimen width-to-hole-diameter (W/D) were selected as parameters. Failure modes were determined by observing the failure regions on the specimens. Damage of immersed and unimmersed specimens was examined using scanning electron misroscopy for the same failure load. Experimental results showed that the bearing load values obtained from the specimens immersed in rainwater decreased in comparison to unimmersed specimens.

Probabilistic Finite-Element Analysis of S2-Glass Epoxy Composite Beams for Damage Initiation Due to High-Velocity Impact

2016 ◽  
Vol 2 (4) ◽  
Author(s):  
Shivdayal Patel ◽  
Suhail Ahmad ◽  
Puneet Mahajan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Velocity ◽  
Laminated Composite ◽  
Composite Plates ◽  
High Velocity Impact ◽  
Element Analysis ◽  
Fiber Failure ◽  
Velocity Impact ◽  
Damage Initiation

The safety predictions of composite armors require a probabilistic analysis to take into consideration scatters in the material properties and initial velocity. Damage initiation laws are used to account for matrix and fiber failure during high-velocity impact. A three-dimensional (3D) stochastic finite-element analysis of laminated composite plates under impact is performed to determine the probability of failure (Pf). The objective is to achieve the safest design of lightweight composite through the most efficient ply arrangement of S2 glass epoxy. Realistic damage initiation models are implemented. The Pf is obtained through the Gaussian process response surface method (GPRSM). The antisymmetric cross-ply arrangement is found to be the safest based on maximum stress and Yen and Hashin criteria simultaneously. Sensitivity analysis is performed to achieve the target reliability.

scholarly journals Size effect on the methodology with cylinder specimens for FRP-to-concrete debonding analysis

2021 ◽  
Vol 14 (3) ◽  
Author(s):  
Luana Ferreira Borges ◽  
Antonio Carlos dos Santos
Keyword(s):  
Size Effect ◽  
Failure Modes ◽  
Tensile Force ◽  
Size Variation ◽  
Concrete Specimen ◽  
Three Dimensions ◽  
Tensile Failure ◽  
Interface Failure ◽  
Reinforced Polymer ◽  
Direct Tensile

Abstract This is a study about the size effect on the methodology with concrete cylinder specimens for analysis of the debonding phenomenon at the interface between concrete and carbon fiber reinforced polymer (FRP). The influence of the concrete specimen size variation is analyzed by maintaining the same geometry in adhered FRP. Direct tensile experiments were performed with three dimensions of cylindrical concrete specimens (diameter × height) for analysis of size effect: 50 mm × 100 mm, 100 mm × 200 mm, and 150 mm × 300 mm. Ten different geometries of the composite material were tested. Two failure modes were observed in the experiments: debonding between the two materials and tensile failure in concrete specimens. In experiments with interface failure, the size of concrete specimens has no significant influence on maximum force, shear stress to peak, and stiffness in debonding between concrete and FRP. However, the use of smaller specimens for analysis of interface collapse is limited because the concrete reaches its normal stress capacity with a lower tensile force, and therefore, the failure often occurs in the concrete.

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