Tough–brittle transition in unidirectional composites with fibre breakage and fibre–matrix interfacial failure

2022 ◽  
Author(s):  
Sivasambu Mahesh
Keyword(s):  
Interfacial Failure ◽  
Unidirectional Composites ◽  
Fibre Breakage ◽  
Brittle Transition ◽  
Fibre Matrix

Low Velocity Impact Studies on a 4-Ply Knitted Kevlar Fabric Reinforced Epoxy Composite

2002 ◽  
Vol 21 (2) ◽  
pp. 121-138 ◽  
Author(s):  
C. T. Lim ◽  
V. B. C. Tan ◽  
S. Ramakrishna ◽  
J. B. K. Lee
Keyword(s):  
Epoxy Composite ◽  
Impact Resistance ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Normal Impact ◽  
Low Velocity ◽  
Fibre Breakage ◽  
Significant Difference ◽  
Impact Energies ◽  
Fibre Matrix

Four-ply knitted Kevlar fabric reinforced epoxy composites with three different stacking sequences were subjected to normal impact of up to 10 J using a hemispherical steel impactor. Similar modes of damage were observed from impacts on all three different stacking sequences where damage progressed from matrix cracking and fibre/matrix debonding at low impact energies to fibre breakage and eventual through-thickness cracks at higher impact energies. A critical mode of damage occurred at about 4.5 J where there was a sudden deterioration of impact resistance due to fibre breakage at the top and bottom plys. The only significant difference among composites of different stacking sequences subjected to low velocity impacts of similar magnitude was the propagation of through-thickness cracks at impact energy larger than 5 J.

scholarly journals Routine evaluation of Interfacial Adhesion in Fibre Reinforced Plastics

1994 ◽  
Vol 3 (6) ◽  
pp. 096369359400300
Author(s):  
E.U. Okoroafor ◽  
A–M. Priston ◽  
R. Hill
Keyword(s):  
Interfacial Adhesion ◽  
Strain Range ◽  
Relative Number ◽  
Stress And Strain ◽  
Matrix Interface ◽  
Interfacial Failure ◽  
Reinforced Plastics ◽  
Transverse Tension ◽  
Damage Process ◽  
Fibre Matrix

The predominant damage process occurring, when unidirectional composites are subjected to transverse tension, is interfacial failure events which are detected as acoustic emission(AE) by a transducer in contact with the test piece. The stress and strain range over which these AE events occur determine the strength of the fibre—matrix interface, while the relative number of recorded events give indication as to the interfacial failure mode.

scholarly journals Fibre break failure processes in unidirectional composites: evaluation of critical damage states

2016 ◽  
Vol 374 (2071) ◽  
pp. 20150270 ◽  
Author(s):  
A. Thionnet ◽  
A. R. Bunsell
Keyword(s):  
Structural Integrity ◽  
Critical Density ◽  
Tensile Loading ◽  
Unidirectional Composites ◽  
Fibre Breakage ◽  
Fibre Break ◽  
Sustained Loading ◽  
Damage States ◽  
Large Clusters ◽  
Kinetics Of

Earlier work which successfully modelled the kinetics of fibre breakage in unidirectional composites under monotonic tensile loading has been extended to quantify the kinetics of fibre failure during both monotonic and sustained tensile loading. In both cases, failure was seen to occur when a critical density of large clusters (more than 16 fibres are broken within the representative volume element) of fibre breaks developed. However, in monotonic loading failure occurred very quickly after the first development of these large clusters, whereas under sustained loading the composite could accommodate greater levels of large clusters because of the lower applied load. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’.

Real-time cryo-deformation of polypropylene and impact-modified polypropylene in the transmission electron microscope

1993 ◽  
Vol 51 ◽  
pp. 892-893
Author(s):  
Robert C. Cieslinski ◽  
H. Craig Silvis ◽  
Daniel J. Murray
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Failure Mechanisms ◽  
Brittle Transition ◽  
Molded Part ◽  
Transmission Electron ◽  
Solvent Cast ◽  
The Impact ◽  
Annealed Copper ◽  
Dynamic Plane

An understanding of the mechanical behavior polymers in the ductile-brittle transition region will result in materials with improved properties. A technique has been developed that allows the realtime observation of dynamic plane stress failure mechanisms in the transmission electron microscope. With the addition of a cryo-tensile stage, this technique has been extented to -173°C, allowing the observation of deformation during the ductile-brittle transition.The technique makes use of an annealed copper cartridge in which a thin section of bulk polymer specimen is bonded and plastically deformed in tension in the TEM using a screw-driven tensile stage. In contrast to previous deformation studies on solvent-cast films, this technique can examine the frozen-in morphology of a molded part.The deformation behavior of polypropylene and polypropylene impact modified with EPDM (ethylene-propylene diene modified) and PE (polyethylene) rubbers were investigated as function of temperature and the molecular weight of the impact modifier.

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