EDITORIAL

Strain has changed a lot over the last 7 years. I was invited onto the Editorial Board during late 1999, when Janice Barton took over as Editor in Chief. In those days, Strain was the ‘house journal’ of BSSM and was published at the University of Southampton. We had Editorial meetings before each issue, and paper flow was a major preoccupation. The front cover was redesigned at the beginning of 2000, with a different front cover photo for each issue, in order to update the image of the journal. The next step in the development of the journal came in 2001, when Janice Barton negotiated with a number of publishing houses to publish Strain. This development had to be supported by the National Council of BSSM. The first issue of Strain printed by Blackwell Publishing was in February 2002. In 2003, we had a Themed Issue on Optical Metrology (edited by Jon Petzing and Stephen James). Later that year, Blackwells applied for an impact factor for the journal, which eventually came out in June 2006. I was honoured to be asked to become Editor in Chief in 2003, and my first issue was the February 2004 one. 2004 was an interesting year. We looked back over the last 40 years of BSSM and Strain. A review of papers published in Strain over the last 40 years was written by Peter Stanley (Vol. 40, No. 3), and it is interesting to note that the Editorial issues are the same today as they were 40 years ago! We also looked forward with a special issue on Biomechanics (edited by Elizabeth Tanner and John Orr) in November 2004. Along with this, negotiations were initiated by Janice Barton and Emmanuel Gdoutos to make Strain the official Journal of EURASEM. The parties involved were the National Council of BSSM, the membership of BSSM, Blackwell Publishing and the Permanent Committee of EURASEM. The negotiations took place throughout 2004/2005 so that each party was satisfied with the new arrangements. Contracts were drawn up and signed in September 2005 after the final proposal was ratified at the BSSM Annual General Meeting. The result was that the February 2006 issue was the first EURASEM issue with a new front cover. At the beginning of 2006, there was a joint meeting between the Strain Editorial Board and the EURASEM PC in Rome, and I decided to stand down as Editor in Chief from the end of this year. There was a nominations process, and Emmanuel Gdoutos was selected to be the next Editor in Chief. In Rome, it was also decided to have an Editorial Council, to further drive the growth of Strain. Further highlights of 2006 have been a technical note from NASA on the Columbia Shuttle Disaster in the August issue, the high profile of Strain at the ECF16 conference in Greece in July and the selection of six plenary papers from ECF16 for publication in future issues of Strain. We also gained our first ISI impact factor of 0.465. We have a special issue on Photomechanics coming out next year, and a special issue with selected papers from ICEM13 in 2008. I would like to thank all the Editorial Board Members who have worked with me. We have a system in Strain where the Editor in Chief gives papers for review to Editorial Board members, who then arrange and progress reviews. Hence, their involvement in the review process is extensive. I would also like to thank Blackwell Publishing for their support as publishers. Finally, I would like to thank Janice Barton for her constant support and ideas during my tenure as Editor in Chief. I believe that Strain is now well placed to grow further as an international journal for Experimental Mechanics, and I commend the journal to the New Editor in Chief, Emmanuel Gdoutos, and wish him all the best for the future. My next duty is the review the papers in this issue. The first paper by Ritchie, Nalla, Kruzic, Ager III, Balooch and Kinney concerns the application of fracture mechanics to quantify the ageing of bone. This paper is an expanded version of a plenary lecture from ECF16 at Alexandroupolis, Greece last July. Bone has a complex, hierarchical, material structure that gives complex micromechanics of failure. The fracture behaviour of bone from a 34-year-old person is compared with that from a 85-year old, and it is concluded that the reduction in toughness with age can be quantified but that the micromechanics of fracture in bone are still not fully understood. This paper is an illustration of the application of classical experimental mechanics to new materials, and Strain welcomes the submission of further biomaterial-based papers. The next paper is an invited and substantial review article from Grediac, Pierron, Avril and Toussaint on full field measurements for extracting constitutive parameters. A number of geometries are studied, namely a ring subject to in-plane compression, a shear (Iosipescu) specimen, a rectangular plate and a tensile specimen. These are simple geometries in which strain fields are well defined, so giving good comparison with full-field measurements. The full field measurements are achieved using the grid method, in which a grid pattern is deposited onto the surface of the specimen with resolution 100 μm The images of the deformed and undeformed gratings are then digitised. The authors conclude that the experimental technique is a powerful tool for understanding heterogeneous strain fields. The next series of papers cover optical techniques. The third paper, by Kihara, concerns the tradition optical technique of polarised light and its application to strain measurement in a compressed disc. The innovation here is the automatic measurement of the principal axis and the total relative phase retardation, which have not been addressed in the literature. Moreover, the author proposes to use the technique for dynamic measurements, using incident light of multiple wavelengths. The fourth paper, by Andrianopoulos, continues the theme of optical techniques. In this, a combined experimental and numerical technique for the determination of strain fields on the surface of a deformable solid is proposed using the speckled grid method. The method does have some inaccuracy, but also has certain advantages, such as measuring crack tip fields and the effects of irregular boundaries. The fifth paper, by Grewal, Dubey and Claremont, also addresses data reduction techniques in which a cost-effective approach, to demodulate isochromatic fringes using a flat bed scanner, is proposed. They consider flat geometries of a bending beam and a disc under compression. The technique is especially useful for educational purposes. The final paper in this series is by Badalouka and Papadopoulos, and they address the optical method of caustics, as applied to the classical problem of a hole in a finite sheet subject to tension. The next two papers consider the hyperelastic and deformation behaviour of rubber. Giton, Caro-Bretelle and Ienny discuss the tear test in silicon rubber. They quantify parameters of viscosity and strain softening, and the hyperelastic parameters are identified using tear tests. The parameters are then put into a finite element code to analyse deformation in the tear test. Feichter, Major and Lang look at strain distributions at the notch tip in a rubber planar specimen with a view to quantifying fatigue behaviour of rubber components. They started with the Mooney Rivlin formulation, but found that a third-order Ogden or Yeoh model is required. As a researcher who has recently completed some work on rubber tyre fragments hitting aircraft, I can appreciate the power of the Mooney Rivlin rubber model. Moreover, I believe that the constitutive large strain behaviour of rubber materials is worthy of general study as the field contains classical and elegant work from the giants of the mechanics researchers of the past. The final paper is from my colleagues in Liverpool, namely Dave Moreton and Doug Moffat (with Lee and Bouchard). It is worth noting that they have consistently supported Strain over many years. They first published in Strain in the early 1970s and Doug Moffat actually attended the inaugural meeting of BSSM and Strain back in 1964. Their efforts have been recognised, as they have been awarded Strain best paper prizes four times over the past years. This paper concerns post-yield behaviour of an internally pressurised cylinder. Both experimental and theoretical results are presented. They use strain gauges and finite element analysis to investigate fatigue crack growth and burst pressure in gas-filled steel pipelines. From the above papers, the reader can appreciate the wide-ranging nature of the papers published in Strain. I think that this is a good thing, given that many journals these days are very focussed and have a specialised readership. This broad view allows Strain (An International Journal for Experimental Mechanics) to change with new science and technology, and to appeal to a large research community.