scholarly journals Hybrid Damage Prediction Procedure for Composite Laminates Submitted to Spectra Loading

2021 ◽  
Vol 15 ◽  
pp. 248-257
Author(s):  
Mohammed Bousfia ◽  
Mohammed Aboussaleh ◽  
Brahim Ouhbi
Keyword(s):  
Composite Laminates ◽  
Composite Structures ◽  
Composite Laminate ◽  
Differential Quadrature Method ◽  
Load Ratio ◽  
Hybrid Procedure ◽  
Random Loading ◽  
Degradation Model ◽  
Damage Prediction ◽  
Space State

In this document, a hybrid procedure is constructed in order to predict the damage of a composite unidirectional laminate under random loading. This procedure is based on two pillars: a stiffness degradation model (SD-M) combined with an energy approach taking into account the effect of load ratio in addition to a system of equations generated by SSDQM method (Space State Differential Quadrature Method) which we have solved with a novel technic. The outputs of SSDQM method, previously serving for free vibration behavior analysis of composite structures, are used with those of SD-M model to predict damage failure of a composite laminate subjected to spectra loading. The results obtained correlate very well with experimental ones and an extensive comparison with other models validate the accuracy and convergence characteristics of this hybrid procedure.

Hybrid Damage Prediction Procedure for Composite Laminates Submitted to Spectra Loading

2021 ◽  
Vol 15 ◽  
pp. 206-213
Author(s):  
Mohammed Bousfia ◽  
Mohammed Aboussaleh ◽  
Brahim Ouhbi
Keyword(s):  
Composite Laminates ◽  
Composite Structures ◽  
Composite Laminate ◽  
Differential Quadrature Method ◽  
Load Ratio ◽  
Hybrid Procedure ◽  
Random Loading ◽  
Degradation Model ◽  
Damage Prediction ◽  
Space State

In this document, a hybrid procedure is constructed in order to predict the damage of a composite unidirectional laminate under random loading. This procedure is based on two pillars: a stiffness degradation model (SD-M) combined with an energy approach taking into account the effect of load ratio in addition to a system of equations generated by SSDQM method (Space State Differential Quadrature Method) which we have solved with a novel technic. The outputs of SSDQM method, previously serving for free vibration behavior analysis of composite structures, are used with those of SD-M model to predict damage failure of a composite laminate subjected to spectra loading. The results obtained correlate very well with experimental ones and an extensive comparison with other models validate the accuracy and convergence characteristics of this hybrid procedure.

Analysis of reinforced concrete beams strengthened in flexure with composite laminates

1999 ◽  
Vol 26 (5) ◽  
pp. 646-654 ◽  
Author(s):  
C Nitereka ◽  
K W Neale
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Composite Laminates ◽  
Composite Structures ◽  
Composite Laminate ◽  
Concrete Beams ◽  
Steel Reinforcement ◽  
Nonlinear Finite Element ◽  
Reinforced Concrete Beams ◽  
Reinforced Composite

The structural behaviour of reinforced concrete beams strengthened in flexure by means of externally bonded fibre reinforced composite laminates is simulated numerically using a nonlinear finite element layered model. The full-bond assumption between the composite laminate, steel reinforcement, and the concrete is assumed, and shear deformations are neglected. Interlayer compatibility is achieved by imposing the same displacements at the interfaces of adjacent layers. The concrete is assumed to be nonlinear in compression and to exhibit a post-cracking tension-stiffening behaviour in tension. The behaviour of the steel reinforcement is modelled as elastic-plastic, while that for the composite laminate is linear elastic using an equivalent elastic modulus obtained from the so-called "classical lamination theory" of composite structures. An incremental, iterative displacement-control numerical analysis is developed. The finite element code is validated using published test results for conventional reinforced concrete beams, as well as for beams strengthened with composite laminates. A comparison of the numerical and experimental curves shows very good agreement. The effects of various parameters on the behaviour of composite-strengthened concrete beams are examined.Key words: reinforced concrete beams, fibre reinforced composite strengthening, nonlinear finite element analysis.

Numerical Simulation of Unidirectional Hoop Composite Laminates under Flexural Loads

2007 ◽  
Vol 334-335 ◽  
pp. 217-220
Author(s):  
Li Li Tong ◽  
Zhen Qing Wang ◽  
Bao Hua Sun
Keyword(s):  
Numerical Simulation ◽  
Composite Laminates ◽  
Calculated Result ◽  
Composite Laminate ◽  
Stiffness Degradation ◽  
Test Results ◽  
Degradation Model ◽  
Compressive Stresses

Numerical simulation for unidirectional hoop composite laminates under flexural loads was finished. The change of tensile and compressive stresses, the position of local crush and delamination and stiffness degradation were analyzed with parametric program compiled by APDL language in ANSYS. The results showed that composite laminate could bear the load continually after local crush and delamination. Displacements of calculated result with stiffness degradation model matched test results well.

Critical buckling load of composite laminates containing delamination using differential quadrature method and ABAQUS finite element

2021 ◽  
pp. 030932472199657
Author(s):  
Hamed Edalati ◽  
Vahid Daghigh ◽  
Kamran Nikbin
Keyword(s):  
Finite Element ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Differential Quadrature Method ◽  
Compressive Load ◽  
Differential Quadrature ◽  
Buckling Load ◽  
Quadrature Method ◽  
Critical Buckling Load ◽  
Finite Element Package

Differential quadrature method (DQM) was used to compute the critical buckling load (CBL) of composite laminates containing complex delamination shapes. The composite laminate was initially flat; however, it buckled under a compressive load due to weak adhesive between the outer ply and the whole composite laminate. Previous data obtained for composite laminates containing circular or elliptical delaminations by finite element and the Rayleigh-Ritz methods as well as DQM available in the literature were used to validate the accuracy of the approach. A good agreement between the results was observed. To show the ability of this approach for calculating the CBL of a composite laminate containing complex delamination shape, a crescent-shaped delamination was considered. The CBLs for various stacking sequences of such a composite laminate were then calculated and discussed. The commercial finite element package, ABAQUS was used to validate the DQM results for crescent delamination.

Optimizations of Flame Spraying Aluminum Thickness and Laminate Plies for Composite Lightning Protection

2014 ◽  
Vol 915-916 ◽  
pp. 698-703
Author(s):  
Zhi Qiang Liu ◽  
Zhu Feng Yue ◽  
Fu Sheng Wang ◽  
Yao Yao Ji
Keyword(s):  
Composite Laminates ◽  
Composite Structures ◽  
Composite Laminate ◽  
Analysis Procedure ◽  
Flame Spraying ◽  
Lightning Strike ◽  
Lightning Protection ◽  
Direct Effects ◽  
Aluminum Layer ◽  
Design Optimum

Anti-lightning strike protection for composite structures is catching great attention to design optimum lightning protection solution. Based on lightning direct effect, optimizations of flame spraying aluminum thickness and composite laminate plies were conducted by combining electrical-thermal analysis procedure and corresponding optimization programs. Optimized thickness was acquired for flame spraying aluminum layer. Meanwhile, non-uniform thick plies and optimized stacking angles were given for anti-lightning strike composite laminate. Comparisons were conducted to investigate changes of lightning direct effects on composite laminates fore and after optimization. Synergetic protections of flame spraying aluminum and laminate plies design were listed. The conclusions can be used as suggestions for lightning strike protection of advanced aircraft.

scholarly journals Wave Propagation Analysis in Composite Laminates Containing a Delamination Using a Three-Dimensional Spectral Element Method

2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Fucai Li ◽  
Haikuo Peng ◽  
Xuewei Sun ◽  
Jinfu Wang ◽  
Guang Meng
Keyword(s):  
Wave Propagation ◽  
Lamb Wave ◽  
Composite Laminates ◽  
Composite Structures ◽  
Spectral Element Method ◽  
Three Dimensional ◽  
Spectral Element ◽  
Wave Mode ◽  
Diagonal Form ◽  
Element Method

A three-dimensional spectral element method (SEM) was developed for analysis of Lamb wave propagation in composite laminates containing a delamination. SEM is more efficient in simulating wave propagation in structures than conventional finite element method (FEM) because of its unique diagonal form of the mass matrix. Three types of composite laminates, namely, unidirectional-ply laminates, cross-ply laminates, and angle-ply laminates are modeled using three-dimensional spectral finite elements. Wave propagation characteristics in intact composite laminates are investigated, and the effectiveness of the method is validated by comparison of the simulation results with analytical solutions based on transfer matrix method. Different Lamb wave mode interactions with delamination are evaluated, and it is demonstrated that symmetric Lamb wave mode may be insensitive to delamination at certain interfaces of laminates while the antisymmetric mode is more suited for identification of delamination in composite structures.

scholarly journals The Effect of High Glass Fiber Content and Reinforcement Combination on Pulse-Echo Ultrasonic Measurement of Composite Ship Structures

2021 ◽  
Vol 9 (4) ◽  
pp. 379
Author(s):  
Sang-Gyu Lee ◽  
Daekyun Oh ◽  
Jong Hun Woo
Keyword(s):  
Glass Fiber ◽  
Composite Laminates ◽  
Composite Structures ◽  
Ultrasonic Waves ◽  
Ship Structures ◽  
Glass Fiber Reinforced ◽  
Gfrp Composite ◽  
Chopped Strand Mat ◽  
Composite Ship ◽  
Pulse Echo

Ship structures made of glass fiber-reinforced polymer (GFRP) composite laminates are considerably thicker than aircraft and automobile structures and more likely to contain voids. The production characteristics of such composite laminates were investigated in this study by ultrasonic nondestructive evaluation (NDE). The laminate samples were produced from E-glass chopped strand mat (CSM) and woven roving (WR) fabrics with different glass fiber contents of 30–70%. Approximately 300 pulse-echo ultrasonic A-scans were performed on each sample. The laminate samples produced from only CSM tended to contain more voids compared with those produced from a combination of CSM and WR, resulting in the relative density of the former being lower than the design value, particularly for high glass fiber contents of ≥50%. The velocity of the ultrasonic waves through the CSM-only laminates was also lower for higher glass fiber contents, whereas it steadily increased for combined CSM–WR laminates. Burn-off tests of the laminates further revealed that the fabric configuration of the combined CSM–WR laminates was of higher quality, prevented the formation of voids, and improved inter-layer bonding. These findings indicate that combined CSM–WR laminates should be used to achieve more accurate ultrasonic NDE of GFRP composite structures.

SELF-HEALING OF WOVEN COMPOSITE LAMINATES VIA IN SITU THERMAL REMENDING

2021 ◽  
Author(s):  
ALEXANDER D. SNYDER ◽  
ZACHARY J. PHILLIPS ◽  
JASON F. PATRICK
Keyword(s):  
Composite Laminates ◽  
Composite Laminate ◽  
Laminated Composites ◽  
Reaction Times ◽  
Carbon Fiber Composites ◽  
Self Healing ◽  
Damage Mode ◽  
Woven Composite ◽  
Internal Damage

Fiber-reinforced polymer composites are attractive structural materials due to their high specific strength/stiffness and excellent corrosion resistance. However, the lack of through-thickness reinforcement in laminated composites creates inherent susceptibility to fiber-matrix debonding, i.e., interlaminar delamination. This internal damage mode has proven difficult to detect and nearly impossible to repair via conventional methods, and therefore, remains a significant factor limiting the reliability of composite laminates in lightweight structures. Thus, novel approaches for mitigation (e.g., self-healing) of this incessant damage mode are of tremendous interest. Self-healing strategies involving sequestration of reactive liquids, i.e. microcapsule and microvascular systems, show promise for the extending service- life of laminated composites. However, limited heal cycles, long reaction times (hours/days), and variable stability of chemical agents under changing environmental conditions remain formidable research challenges. Intrinsic self- healing approaches that utilize reversible bonds in the host material circumvent many of these limitations and offer the potential for unlimited heal cycles. Here we detail the development of an intrinsic self-healing woven composite laminate based on thermally-induced dynamic bond re-association of 3D-printed polymer interlayers. In contrast to prior work, self-repair of the laminate occurs in situ and below the glass-transition temperature of the epoxy matrix, and maintains >85% of the elastic modulus during healing. This new platform has been deployed in both glass and carbon-fiber composites, demonstrating application versatility. Remarkably, up to 20 rapid (minute-scale) self-healing cycles have been achieved with healing efficiencies hovering 100% of the interlayer toughened (4-5x) composite laminate. This latest self-healing advancement exhibits unprecedented potential for perpetual in-service repair along with material multi-functionality (e.g., deicing ability) to meet modern application demands.

Damage Control in Composite Laminates

2001 ◽  
Author(s):  
Alexander P. Suvorov ◽  
George J. Dvorak
Keyword(s):  
Composite Laminates ◽  
Composite Laminate ◽  
Damage Control ◽  
Thermomechanical Loading ◽  
Interlaminar Stresses ◽  
Damage Resistance ◽  
Viscoelastic Composite ◽  
Mechanical Loads ◽  
Composite Damage ◽  
The Matrix

Abstract Several effects that fiber prestress may have on stress redistribution in the plies of composite laminates and in the phases of individual plies are illustrated. These include improvement of composite damage resistance under tensile mechanical loads, reduction/cancelation of interlaminar stresses at free edges of composite laminate subjected to thermomechanical loading, and stress relaxation in the matrix phase of viscoelastic composite laminates. Specific results are found for quasi-isotropic and cross-ply symmetric S-glass/epoxy and carbon/epoxy AS4/EPON 828 laminates.

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