TC01 Update 2005

Notes from the ESIS TC1 and TC8 Joint Meeting held at GKSS, Germany, 09/10 December 2003

ESIS technical committees TC1 (Elastic Plastic Fracture Mechanics) and TC8 (Numerical Methods) held a joint meeting 09/10th December at GKSS, Geesthacht, Germany. Approximately 30 engineers and scientists attended the 2 day meeting kindly hosted by Prof K-H Schwalbe. Nine technical presentations were made over the two days in addition to the plenary sessions of both committees. The themes of the meeting were; Changes in fracture toughness testing and analysis procedures; Review of numerical methods & Round-Robin studies; Advances in elastic-plastic fracture toughness methodologies. In addition to the formal presentations there were two main topics tabled for discussion in the TC1 session (i) the current status of the ESIS P2 document (Prof K-H Schwalbe) and (ii) sub/miniature sized specimen fracture toughness testing (Dr G Wardle). The main discussion topic within TC8 related to the ESIS P9-02D guideline document, and the follow up to the 3rd Phase of the micromechanical numerical Round Robin (Dr C St-Catherine).

ESIS P2 document on fracture toughness testing procedures

The latest version of the updated ESIS P2 document had been sent out for comment early in 2003, and Prof Schwalbe along with Drs Wardle and Pisarski held a TC1.4 meeting in July to revise the document on the basis of their comments received. It was proposed that this document be given a new P3 number. This procedure, for normal quasi-static fracture mechanics testing, is now the most up to date procedure, and covers tests on: compact C(T), single edge notched bend SE(B), and low constraint mid-cracked tension M(T) test geometry's. The procedure includes the fracture toughness determination of welded joints as well as homogenous material. Fracture toughness parameters covered in this document relate to standard J-integral, CTOD, CMOD measurements but additionally includes Crack Tip Opening Angle CTOA, and crack tip displacement 5, parameters. Dissipated energy measurements are now also standardized. Prof Schwalbe stated that his intention was to have the new document ready for distribution to the ESIS committees for comment early in 2004. The document would then be peer reviewed by the committee and ratified prior to formal issue of the document.

Test procedures for small/ miniature fracture toughness specimens

There was world-wide interest in the use of miniature specimens for obtaining realistic fracture toughness values from limited amounts of material that may be obtained from operating plant, without compromising its integrity, or from surveillance, or archive, materials. There was an activity within ISO TC164-TC4 (Dr Wardle) to look at the requirements for a new standard, or Appendix to current standards, dealing with the small specimen issue. (Within ESIS this topic is related to TC1.3 activities). However, following discussion it was concluded there was an overlap between experimental and numerical methods /damage mechanics approaches in this study area. The consensus view was that there should be a joint TC1/TC8 activity in this area. This work also meshed closely with the work of Professor Kuma on small punch testing/ damage mechanics and fracture toughness specimen behavior. It was agreed that Dr Wardle and Prof Kuma would jointly put together a plan of action. This would be distributed to ESIS committee members, and would, over the next few months, suggest a program of activities that would bring together: small specimen testing; numerical methods and damage mechanics modeling. The aim would be to link these activities to the transferability of small specimen testing to structural components.

Follow up to the 3rd Phase of the micromechanical numerical Round Robin

Dr St-Catherine presented the Results of the ESIS TC 8 - Numerical Round Robin on Micro-Mechanical Models: Phase III for the Simulation of the Brittle to Ductile Transition Curve (see TC8).