Experimental investigation on the influence of crack front to fiber orientation on fatigue delamination growth rate under mode II

2006 ◽  
Vol 66 (2) ◽  
pp. 240-247 ◽  
Author(s):  
M. Beghini ◽  
L. Bertini ◽  
P. Forte
Keyword(s):  
Growth Rate ◽  
Experimental Investigation ◽  
Crack Front ◽  
Fiber Orientation ◽  
Mode Ii ◽  
Delamination Growth ◽  
Fatigue Delamination Growth Rate

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.

scholarly journals Thermal Delamination Modelling and Evaluation of Aluminium–Glass Fibre-Reinforced Polymer Hybrid

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 492
Author(s):  
Zhen Pei Chow ◽  
Zaini Ahmad ◽  
King Jye Wong ◽  
Seyed Saeid Rahimian Koloor ◽  
Michal Petrů
Keyword(s):  
Crack Front ◽  
Cohesive Zone ◽  
Experimental Tests ◽  
Mode I ◽  
Mode Ii ◽  
Cohesive Model ◽  
Reinforced Polymer ◽  
Glass Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced

This paper aims to propose a temperature-dependent cohesive model to predict the delamination of dissimilar metal–composite material hybrid under Mode-I and Mode-II delamination. Commercial nonlinear finite element (FE) code LS-DYNA was used to simulate the material and cohesive model of hybrid aluminium–glass fibre-reinforced polymer (GFRP) laminate. For an accurate representation of the Mode-I and Mode-II delamination between aluminium and GFRP laminates, cohesive zone modelling with bilinear traction separation law was implemented. Cohesive zone properties at different temperatures were obtained by applying trends of experimental results from double cantilever beam and end notched flexural tests. Results from experimental tests were compared with simulation results at 30, 70 and 110 °C to verify the validity of the model. Mode-I and Mode-II FE models compared to experimental tests show a good correlation of 5.73% and 7.26% discrepancy, respectively. Crack front stress distribution at 30 °C is characterised by a smooth gradual decrease in Mode-I stress from the centre to the edge of the specimen. At 70 °C, the entire crack front reaches the maximum Mode-I stress with the exception of much lower stress build-up at the specimen’s edge. On the other hand, the Mode-II stress increases progressively from the centre to the edge at 30 °C. At 70 °C, uniform low stress is built up along the crack front with the exception of significantly higher stress concentrated only at the free edge. At 110 °C, the stress distribution for both modes transforms back to the similar profile, as observed in the 30 °C case.

Trapezoidal traction–separation laws in mode II fracture in nano-composite and nano-adhesive joints

2018 ◽  
Vol 37 (11) ◽  
pp. 780-794 ◽  
Author(s):  
P Ghabezi ◽  
M Farahani
Keyword(s):  
Experimental Investigation ◽  
Data Reduction ◽  
Beam Theory ◽  
Calibration Method ◽  
Adhesive Joints ◽  
Nano Particles ◽  
Mode Ii ◽  
Nano Composite ◽  
Mode Ii Fracture ◽  
Beam Method

The main focus of this paper is on the experimental investigation and comparison between different bridging laws. For mode II fracture in the presence of nano-particles, these laws are calculated from three data reduction schemes for describing the bridging zone and trapezoidal traction–separation law parameters. For the calculation of the energy release rate in mode II fracture, three corresponding data reduction schemes, compliance calibration method, corrected beam theory and compliance-based beam method, have been utilized for different percentages of nano-particles in the adhesives and the adherents.

The Effect of Crack Growth Retardation when Comparing Constant Amplitude to Variable Amplitude Loading in an Aluminium Alloy

2014 ◽  
Vol 891-892 ◽  
pp. 948-954 ◽  
Author(s):  
Madeleine Burchill ◽  
Simon A. Barter ◽  
Michael Jones
Keyword(s):  
Growth Rate ◽  
Fatigue Life ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Growth Retardation ◽  
Crack Front ◽  
Constant Amplitude ◽  
Variable Amplitude ◽  
Growth Increments ◽  
Crack Growth Retardation

It has often been observed that the growth of short fatigue cracks under variable amplitude (VA) cyclic loading is not well predicted when utilising standard constant amplitude (CA) crack growth rate/stress intensity data (da/dN v DK). This paper outlines a coupon fatigue test program and analyses, investigating a possible cause of crack growth retardation from CA-only testing. Various test loading spectra were developed with sub-blocks of VA and CA cycles, then using quantitative fractography (QF) the sub-block crack growth increments were measured. Comparison of these results found that, after establishing a consistent uniform crack front using a VA load sequence, the average crack growth rate then progressively slowed down with the number of subsequent CA load cycles applied. Further fractographic investigation of the fracture surface at the end of each CA and VA sub-block crack growth, identified significant crack front morphology differences. Thus it is postulated that a variation or deviation from an efficient crack path is a driver of local retardation in short crack growth during CA loading. This may be a source of error in analytical predictions of crack growth under VA spectra loading that may need to be considered in addition to other potential effects such asless closure whilst cracks are small. For aircraft designers, using solely CA data for fatigue life predictions this may result in non-conservative estimates of total crack fatigue life, producing unexpected failures or an increased maintenance burden.

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