Delamination Fatigue Properties of Z-Pinned Composites

2014 ◽  
Vol 891-892 ◽  
pp. 197-201
Author(s):  
Khomkrit Pingkarawat ◽  
Adrian P. Mouritz
Keyword(s):  
Growth Rate ◽  
Experimental Investigation ◽  
Carbon Fibre ◽  
Fatigue Resistance ◽  
Volume Content ◽  
Fatigue Properties ◽  
Mode I ◽  
Thickness Direction ◽  
Toughening Mechanisms ◽  
Delamination Growth

This paper presents an experimental investigation into the mode I interlaminar fatigue resistance of carbon fibre-epoxy laminate reinforced in the through-thickness direction with z-pins. The effects of the volume content, diameter and length of z-pins on the interlaminar toughness, fatigue resistance and crack bridging toughening mechanisms are determined. The delamination growth rate also slowed when the volume content or length of the z-pins was increased or the z-pin diameter was reduced.

Fatigue Properties of Aerospace Z-Pinned Composites

2016 ◽  
Vol 828 ◽  
pp. 67-75
Author(s):  
Adrian P. Mouritz ◽  
Fabio Pegorin ◽  
Mohd Dali Isa ◽  
Khomkrit Pingkarawat
Keyword(s):  
Volume Content ◽  
Composite Structures ◽  
Large Scale ◽  
Fatigue Properties ◽  
Mode I ◽  
Scale Bridging ◽  
Microstructural Damage ◽  
Out Of Plane ◽  
Cycles To Failure ◽  
Properties Of Composites

This paper presents an experimental study into the effect of through-thickness z-pin reinforcement on the in-plane and out-of-plane (delamination) fatigue properties of carbon-epoxy composites used in aerospace structures. The in-plane fatigue strength and fatigue life (load cycles-to-failure) of aerospace composite materials are reduced by z-pins. The in-plane compressive fatigue properties decrease when the volume content of z-pins is increased. Reductions to the in-plane fatigue properties are due to microstructural damage caused by the z-pins. However, the out-of-plane (delamination) fatigue properties of composites are increased greatly by z-pins. The mode I, mode II and mixed mode I/II delamination fatigue properties increase rapidly with increasing volume content of z-pins. The improvement is due to the z-pins forming a large-scale bridging zone along the delamination which resists fatigue crack growth. The work clearly reveals that a trade-off exists between the in-plane and out-of-plane fatigue properties of z-pinned composites. Improvements to the delamination fatigue properties come at the expense of lower in-plane fatigue performance, and this is a key consideration for the design of z-pinned aerospace composite structures.

A mesh-free simulation of mode I delamination of composite structures

2014 ◽  
Vol 21 (1) ◽  
pp. 137-149
Author(s):  
Goudarz Ghanizadeh Hesar ◽  
Yeliz Pekbey ◽  
Hasan Yildiz ◽  
Farshid Khosravi Maleiki
Keyword(s):  
Experimental Investigation ◽  
Composite Laminates ◽  
Composite Structures ◽  
Degrees Of Freedom ◽  
Meshfree Method ◽  
Iterative Solution ◽  
Mode I ◽  
Delamination Growth ◽  
Mode I Loading ◽  
Mode I Delamination

AbstractA numerical and experimental investigation for the analysis of delamination problem under mode I loading in composite material is presented. Firstly, the simulation of the delamination under mode I loading and failure of composite materials based on the cohesive segments model is investigated by using the meshfree method. With the partition of unity of moving least-squares shape functions, the discontinuities at the cohesive segments are approximated with additional degrees of freedom at the nodes. An iterative solution scheme between the continuous and discontinuous fields is presented to solve mode I delamination growth. Secondly, to verify the meshfree method’s results, an experimental investigation and the finite element method were used for the simulation of delamination. The experimental study used a double-cantilever beam made of carbon/epoxy laminate (AS4/3501-6) which consists of 10 plies in [0]10 and [0/90/0/90/0]s layup with delamination inserted in the middle of the laminate. The critical fracture force, which can be experimentally measured, was used to calculate the mode I delamination fracture toughness of the carbon/epoxy laminate. Results obtained from the meshfree method showed very good agreement with experimental data for single-mode delamination under mode I loading. The meshfree method could also be used effectively to produce delamination growth in composite laminates and is especially suitable for the simulation of complex delamination patterns that are difficult to model using traditional numerical methods.

Interlaminar crack initiation and growth rate in a carbon-fibre epoxy composite under mode-I fatigue loading

2008 ◽  
Vol 68 (12) ◽  
pp. 2325-2331 ◽  
Author(s):  
A. Argüelles ◽  
J. Viña ◽  
A.F. Canteli ◽  
M.A. Castrillo ◽  
J. Bonhomme
Keyword(s):  
Growth Rate ◽  
Crack Initiation ◽  
Carbon Fibre ◽  
Epoxy Composite ◽  
Fatigue Loading ◽  
Mode I ◽  
Interlaminar Crack

scholarly journals Comparative study of elastic properties and mode I fracture energy of carbon nanotube/epoxy and carbon fibre/epoxy laminated composites

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Jyotikalpa Bora ◽  
Sushen Kirtania
Keyword(s):  
Carbon Nanotube ◽  
Carbon Fibre ◽  
Fracture Energy ◽  
Elastic Properties ◽  
Volume Fraction ◽  
Laminated Composites ◽  
Laminated Composite ◽  
Fe Analysis ◽  
Mode I ◽  
Mode I Fracture

Abstract A comparative study of elastic properties and mode I fracture energy has been presented between conventional carbon fibre (CF)/epoxy and advanced carbon nanotube (CNT)/epoxy laminated composite materials. The volume fraction of CNT fibres has been considered as 15%, 30%, and 60% whereas; the volume fraction of CF has been kept constant at 60%. Three stacking sequences of the laminates viz.[0/0/0/0], [0/90/0/90] and [0/30/–30/90] have been considered in the present analysis. Periodic microstructure model has been used to calculate the elastic properties of the laminated composites. It has been observed analytically that the addition of only 15% CNT in epoxy will give almost the same value of longitudinal Young’s modulus as compared to the addition of 60% CF in epoxy. Finite element (FE) analysis of double cantilever beam specimens made from laminated composite has also been performed. It has been observed from FE analysis that the addition of 15% CNT in epoxy will also give almost the same value of mode I fracture energy as compared to the addition of 60% CF in epoxy. The value of mode I fracture energy for [0/0/0/0] laminated composite is two times higher than the other two types of laminated composites.

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