Issue 9

Frattura ed Integrità Strutturale, 9 (2009) Notiziario IGF 162 - Mode II (Laminates and Structural Adhesive Joints): Bamber Blackman Bamber reviewed the protocol developed by TC4 to determine G IIC for composite laminates using a calibrated end-loaded split (C-ELS) test. This was a development of the original TC4 ELS test method and used an effective crack length approach to determine G . The first round-robin was complete and a second round robin was underway. Bamber reported that Graham Sims (NPL, UK) had submitted the 4-ENF test method to ISO as a new work item, and in discussions with Graham it had been agreed that the C-ELS protocol would also be submitted as an alternative document. Actions: Tests to be completed at Cranfield (Denis) and Empa (Andy) and results to be sent to Bamber. C-ELS test protocol to be sent to Graham Sims for presentation at the ISO meeting in Sept 2008 (Bamber). Peel of flexible laminates: Neal Murphy Neal presented the results of a detailed study into the results obtained by various workers using the TC4 peel protocol. Results were compared to values obtained from LEFM. A two part rejection criterion was proposed as an attempt to ensure invalid results were not obtained using the method. There was a discussion of the criteria proposed. Actions: Further consideration of the rejection criteria (Neal). Tony Kinloch (Imperial College) agreed to run a follow-on MSc project this year. Short fibre composites at 1m/s: Andrea Pavan A round-robin had been completed using the short fibre amendment to ISO-13586 (but without the size criteria) with testing at 1m/s. The main difficulty had been in the determination of crack initiation in the presence of pop-in effects. Andrea presented details of two requirements to formalise the identification. It was agreed that these should be added, and that the new text be proposed as an amendment to ISO-17281 (at 1m/s), which is now due for review. Actions: Andrea to prepare the text for the amendment to ISO-17281. Environmental stress cracking: Gordon Williams The possibility of the committee starting work in this area had been previously discussed. It was agreed that the procedure should be suitable for brittle polymers, probably in three point bending and in a water environment. A procedure will be written in time for the next meeting. Actions: An activity to be launched at the next meeting (Gordon). Labs to indicate their interest in participating to Gordon. Conference Assessment The committee reviewed the 5 th International TC4 Conference which had just taken place in the village and it was widely felt that this had been a great success. A detailed assessment of the conference was presented by committee members and this was to be passed to the conference organisers. The papers were to appear as a special issue of Engineering Fracture Mechanics, and the review procedures were discussed and agreed. Actions: Bamber to prepare the committee assessment and pass to Claire Norris at Elsevier. AOB Some dissatisfaction was expressed concerning the dates of the May meeting as they clash with the main European holiday. Bamber was in discussion with the hotel regarding possible alternative dates. Post meeting note , the date of the next meeting has been changed, see below. Dates of future meetings (all to be held at the Eurotel in Les Diablerets) are now confirmed as:  13 th -15 th May 2009 (Committee meeting)  30 th Sept-2 nd Oct 2009 (Committee meeting) ESIS - TC24 activity On 13-14 October 2008, Prof. Beretta hosted a TC24 workshop dedicated to the “Damage tolerance of railway axles”. The workshop was the opportunity to discuss some of the results obtained in different cooperative projects in Europe. The complete list of the presentations, that were delivered to an audience of 70 participants from different european countries, is: "Broken axles: moving to solutions of a long standing problem" R. Smith - Imperial College, UK “UK AXLE: Service loads in axles and their effects on the axle life” M. Beagles, DeltaRail, UK “Damage tolerance investigations on railway axles” U. Zerbst, M. Schodel – GKSS, Germany "DEUFRAKO: Crack propagation behavior on third- and full-scale railway axles" A. Esderts, K Lütkepoh - TU Clausthal, Germany