This was the 6th International Conference in the series organised by the European Structural Integrity Society - Technical Committee 4 on Fracture Mechanics related to Polymers, Polymeric Composites and Adhesives.

Important dates and deadlines

• 15th November 2010 – deadline for the submission of abstracts
• 14th January 2011 – author notification deadline
• 25th February 2011 – Author registration deadline
• 3rd June 2011 – One page abstract submission deadline
• 15th October 2011 – Full paper submission deadline

The 5th ESIS TC4 International Conference on the Fracture of Polymers, Composites and Adhesives took place in 2008 in Les Diablerets, Switzerland. Selected papers from this conference have been published as a special edition of Engineering Fracture Mechanics, 76 (18) December 2009. ‘Call for papers’ for the 6th International Conference on the Fracture of Polymers, Composites and Adhesives is now open. Deadline is 5th November 2010.

NEW: INSTRUCTIONS FOR POSTER AUTHORS

Active work areas

The following are active work areas, in which the technical committee are developing ESIS TC4 test protocols with the aim that these will become full ISO standards in due course. Anyone wishing to get involved in these exciting work areas should either contact the work area co-ordinator (see below) or the committee technical secretary, Bamber Blackman) for further details.

1. Polymers

Following the successful development of standards for slow rate Kc and Gc determination in polymers (ISO 13586-1) and in short fibre composites (ISO 13586-2) and of the development of a test standard for these properties at high rates of loading (ISO 17281) and under tension-tension fatigue loading (ISO 15850), the committee is currently developing test protocols in the following areas:

1.1 Work area: Jc testing; Co-ordinator: Francesco Baldi
The committee aims to develop a test protocol to characterise toughness in polymers which fail the LEFM validity criteria for Kc and Gc. A protocol was developed by the committee members Hale and Ramsteiner, based upon a multi-specimen technique (ESIS Publication 28, Chapter 2, Fracture Mechanics Testing Methods for Polymers Adhesives and Composites, Elsevier 2001)). The major limiting factor has proved to be the difficulty to accurately measure the crack growth in the test. Development of the test method is still underway within the committee, with modified test and analysis schemes under consideration.

1.2 Work area: Essential work of fracture; Co-ordinator: Marta Rink
The committee aims to develop a plane stress fracture test for polymeric films. A version of the protocol was published in 2001 (ESIS Publication 28, Chapter 2, Fracture Mechanics Testing Methods for Polymers Adhesives and Composites, Elsevier 2001) but in the view of the committee, the results produced by this method are currently insufficiently reproducible to warrant standardisation within ISO. The committee is investigating the origins of the poor reproducibility in the results via round-robin studies and additional experimental and theoretical contributions.

1.3 Work area: Determination of Gc via Cutting; Co-ordinator: Gordon Williams
The committee aims to develop an alternative technique for the determination of Gc in tough, ductile polymers using a cutting technique. A test protocol has been developed in which a tool is used to remove a thin layer of polymer from a specimen via orthogonal cutting at a constant speed (Eng Fract Mech 76, (18) p.2711-2730, 2009). Gc is determined by measuring forces in two directions, in the direction of cutting and transverse to this direction. One round-robin has been completed and a second is now underway within the committee.

1.4 Work area: Environmental stress cracking; Co-ordinator: Leonardo Castellani
The committee aims to develop a test protocol to determine the sensitivity of different polymers to stress cracking in various hostile environments. The activity started in 2010. The test adopted will follow a fracture mechanics approach and will permit different test environments to be studied. An initial ESIS TC4 Protocol has been development, and round-robin testing is due to commence.

2. Composites

Following the successful development of standards for slow rate Kc and Gc determination in short fibre composites (ISO 13586-2) and for delamination resistance of unidirectional laminates in mode I (ISO 15024: 2000), the committee is currently developing test protocols in the following areas:

2.1 Work area: Short fibre composites at high loading rates; Co-ordinator: Andrea Pavan
The committee aims to extend the techniques developed to determine Kc and Gc of short fibre composites at slow rate (ISO 13586-2) to faster rates (circa 1m/s). Such development will build upon the tecniques developed by the committee for determining Kc and Gc in bulk polymers at higher rates (ISO 17281). Technical issues being addressed include the identification and treatment of ‘pop-in’ failure, the mitigation of dynamic effects and specimen manufacture and fibre orientation effects.

2.2 Work area: Delamination of UD and cross-ply laminates; Co-ordinator: Andy Brunner
The committee aims to extend the techniques developed to determine GIc via delamination in UD composites to engineering laminates where other fibre orientations are typically used. These can include cross-ply layups, woven fabrics and through-thickness (3D) reinforcements. Round-robins on various different composites have been completed.

2.3 Work area: Delamination of UD laminates at high rates, Co-ordinator: Ian Horsfall
The committee aims to extend the test developed for the determination of delamination resistance at quasi-static test rates (ISO 15024) to higher rates (circa 1m/s). The challenges include the mitigation of dynamic effects, the measurement of accurate and reliable test data and the treatment of kinetic energy effects. A protocol was drafted by Bamber Blackman and a round-robin using a UD carbon fibre PEEK composite has been completed. A second round robin is planned in the near future.

2.4 Work area: Delamination fatigue in UD laminates; Co-ordinator: Gerald Pinter
The committee aims to develop a test protocol to measure the fatigue resistance of composites to failure by delamination fatigue. The quasi-static test protocol (ISO 15024) has been modified for fatigue loading at constant applied crack opening displacement. A first round robin using a carbon fibre reinforced composite has been completed, and a second round robin is now underway.

3. Adhesives

3.1 Work area: Fracture of structural adhesive joints; Co-ordinator: Bamber Blackman
The committee aims to develop linear elastic fracture mechanics (LEFM) test standards for the determination of Gc in structural adhesive joints under modes I, II and mixed I/II loading regimes. The development of the test protocol for mode I fracture is now complete following the publication of a British Standard in 2001 (BS 7991:2001) and an ISO standard in 2009 (ISO 25217: 2009). The current round robin activities in the committee are directed towards the development of a mode II test using the calibrated end-loaded split (C-ELS) test and in mixed-mode using the fixed-ratio mixed-mode (FRMM) test. There is a future goal to extend the LEFM tests to high rates and to fatigue loading conditions.

3.2 Work area: Peel testing of flexible laminates; Co-ordinator: Neal Murphy
The committee aims to develop test protocols to determine the adhesive fracture toughness, Ga, for the debonding of a flexible layer by peeling. The central goal has been to develop geometry independent tests where a measurement is made of ‘how well a substrate is bonded’ as opposed to the much more commonly measured peel strength, i.e. ‘how difficult it is to peel the substrate.’ Initial round robins focused on the measurement of adhesion between layers in packaging laminates and more recent activity has been directed towards the peeling of metallic layers bonded by structural adhesives. The major challenge here is to accurately account for the energy dissipated plastically in the peel arm. An ESIS Test Protocol is available ESIS Publication 28, Chapter 3, Fracture Mechanics Testing Methods for Polymers Adhesives and Composites, Elsevier 2001, and a more fully developed version of this is currently being prepared for submission to ISO.