Experimental and Numerical Assessment of Fibre Bridging Toughening Effects on the Compressive Behaviour of Delaminated Composite Plates

Riccio, Aniello; Russo, Angela; Sellitto, Andrea; Toscano, Cinzia; Alfano, Davide; Zarrelli, Mauro

doi:10.3390/polym12030554

Cited by 26 publications

(16 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Compared with bolted connection, the new connection method can reduce stress concentration and fiber damage. Riccio [35] studied the effect of delamination on the compressive mechanical properties of composite laminate through experiments and simulations. Studies show that fiber bridging phenomenon is a natural toughening mechanism that can improve the interlayer strength of composite laminates.…”

Section: Research Backgroundmentioning

confidence: 99%

Effect of Gap and Shims on the Strain and Stress State of the Composite-Aluminum Hybrid Bolted Structure

Yue

et al. 2020

International Journal of Aerospace Engineering

View full text Add to dashboard Cite

The composite-aluminum hybrid bolted structures are widely used in aircraft. Due to low molding accuracy of composite components, gaps always occur between components during assembly. In this case, the bolt connection can cause a complex strain and stress state of component. It may adversely affect the mechanical properties or cause local damage of the structure. A simplified model of the composite-aluminum assembly structure was established in this paper. Then, the influence of forced assembly, liquid shim, and peelable fiberglass shim on the strain and stress state of the composite-aluminum hybrid bolted structure was studied. A bolt connection experimental device was designed to apply a preload to the specimen. The strain field on the specimen surface was measured using the 3D-DIC strain measurement system. The finite element model was established to study the interlaminar stress and damage state of composite laminates. It is found that the strain of specimen in the X -direction is mainly affected by the bending deformation, while the strain in the Y -direction is mainly affected by the compression of bolt head. For composite laminates, the strain value in the X -direction can be reduced by 8.31%-70.97% with shims. As for the strain value in the Y -direction, the liquid shim can only reduce it up to 23.93%when the gap is large. In addition, the liquid shim and peelable fiberglass shim cannot reduce the stress value of all interlaminar elements, but it can make the stress distribution more uniform and improve the stress state of the interlaminar element when the shim was more than 0.8 mm.

show abstract

Section: Research Backgroundmentioning

confidence: 99%

Effect of Gap and Shims on the Strain and Stress State of the Composite-Aluminum Hybrid Bolted Structure

Yue

et al. 2020

International Journal of Aerospace Engineering

View full text Add to dashboard Cite

show abstract

“…They concluded that it is possible to predict the Mode II interlaminar fracture toughness by using the formula

where B is a coefficient that takes into account the additional shear stress contribution. Considering the loading conditions found in impact events, the main cause of failure within the composite structure can be related to the shear stress [ 41 , 42 , 43 ] localised within a structure during the dynamic loading. Consequently, it is possible to assume that Mode II failure is dominant and high dependency from the ply angle is expected for the G c value in this loading condition.…”

Section: Functionally Graded Pitch (Fgp) Laminatesmentioning

confidence: 99%

Bioinspired Helicoidal Composite Structure Featuring Functionally Graded Variable Ply Pitch

et al. 2021

View full text Add to dashboard Cite

Composite laminated materials have been largely implemented in advanced applications due to the high tailorability of their mechanical performance and low weight. However, due to their low resistance against out-of-plane loading, they are prone to generate damage as a consequence of an impact event, leading to the loss of mechanical properties and eventually to the catastrophic failure of the entire structure. In order to overcome this issue, the high tailorability can be exploited to replicate complex biological structures that are naturally optimised to withstand extreme impact loading. Bioinspired helicoidal laminates have been already studied in-depth with good results; however, they have been manufactured by applying a constant pitch rotation between each consecutive ply. This is in contrast to that observed in biological structures where the pitch rotation is not constant along the thickness, but gradually increases from the outer shell to the inner core in order to optimise energy absorption and stress distribution. Based on this concept, Functionally Graded Pitch (FGP) laminated composites were designed and manufactured in order to improve the impact resistance relative to a benchmark laminate, exploiting the tough nature of helicoidal structures with variable rotation angles. To the authors’ knowledge, this is one of the first attempts to fully reproduce the helicoidal arrangement found in nature using a mathematically scaled form of the triangular sequence to define the lamination layup. Samples were subject to three-point bending and tested under Low Velocity Impact (LVI) conditions at 15 J and 25 J impact energies and ultrasonic testing was used to evaluate the damaged area. Flexural After Impact (FAI) tests were used to evaluate the post-impact residual energy to confirm the superior impact resistance offered by these bioinspired structures. Vast improvements in impact behaviour were observed in the FGP laminates over the benchmark, with an average reduction of 41% of the damaged area and an increase in post-impact residual energy of 111%. The absorbed energy was similarly reduced (−44%), and greater mechanical strength (+21%) and elastic energy capacity (+78%) were demonstrated in the three-point bending test.

show abstract

“…After being toughened, the resistance to the interlaminar crack growth is significantly improved; typically, the mode I (G IC ) and mode II (G IIC ) interlaminar fracture toughness of the composites will be greatly improved [18,19]. The increase in energy dissipation can be attributed to several mechanisms, such as the bridging caused by nanofillers and fibers, the increase in matrix viscoelasticity, and the deflection of the crack path [20,21].…”

Section: Introductionmentioning

confidence: 99%

Enhancing the Interlaminar Fracture Toughness and AO Resistance of CFRPs by Using Phosphorus-Containing Polymer/PEC-K Bifunctional Film

Guo

2021

Aerospace

View full text Add to dashboard Cite

A new attempt to use a bifunctional interleaf for developing a novel structure–function-integrated composite with simultaneously improved interlaminar fracture toughness and atomic oxygen resistance was studied. The toughening mechanism and the atomic oxygen erosion property of the delaminated surfaces of the composites were examined. The bifunctional interleaf was prepared by blending a phosphorus-containing polymer and a thermoplastic polymer. After being interleaved, the mode I and mode II fracture toughness increased by 8.2% and 23.7% compared to the control sample, respectively. The toughness gains are much smaller than that of the only thermoplastic film-toughened composite because of the relative brittleness of the blend film. The atomic oxygen erosion rates of the mode I and mode II delamination surfaces decreased by 45.3% and 31.3% compared with the control, respectively. The carbon fibers on the irradiation surfaces are protected by a layer of phosphine oxide to prevent further erosion, and they were much less eroded, particularly for the mode I surface. In comparison, the erosion rates of the mode I and mode II surfaces of the toughened-only composite significantly increased by 83.6% and 107.2%, respectively, and the carbon fibers are seriously eroded.

show abstract

Experimental and Numerical Assessment of Fibre Bridging Toughening Effects on the Compressive Behaviour of Delaminated Composite Plates

Cited by 26 publications

References 35 publications

Effect of Gap and Shims on the Strain and Stress State of the Composite-Aluminum Hybrid Bolted Structure

Effect of Gap and Shims on the Strain and Stress State of the Composite-Aluminum Hybrid Bolted Structure

Bioinspired Helicoidal Composite Structure Featuring Functionally Graded Variable Ply Pitch

Enhancing the Interlaminar Fracture Toughness and AO Resistance of CFRPs by Using Phosphorus-Containing Polymer/PEC-K Bifunctional Film

Contact Info

Product

Resources

About