Special Issue on Pressure Vessels Technology Applied to Gun Tubes

Abstract

The last open conference with a focus on large caliber gun tube design took place in 1983; since then there have been significant technological and strategic developments. The GT2002 conference at Keble College, Oxford, England, September 2002 focussed upon such developments and future requirements. Technical papers from the conference are included in this special issue. The 21st Century will require rapid reaction, mobility and technological effectiveness. This implies weight reduction and more extreme firing environments, including operating pressures, temperatures and chemistry. Specific issues relating to material behavior include experimental testing of current and candidate gun steels with particular emphasis upon the Bauschinger effect. The autofrettage process is analyzed in depth. The impact of the Bauschinger effect upon residual stress fields is the subject of several papers, while other authors address the use of autofrettage for quality control and the determination of stress intensity factors for cracks in complex autofrettage residual stress fields, including those due to a curved crack-front and material removal following autofrettage. Several authors address the measurement and numerical prediction of residual stress and of crack tip stress intensity. Experimental methods include neutron diffraction and Sachs’ material removal method. Numerical solutions encompass finite elements, boundary methods, nonlinear “Hencky” formulations and weight (Green’s) functions. Fatigue lifetime depends crucially upon near-bore thermal damage arising from initial firings. A keynote paper emphasizes the fundamental importance of environmental (hydrogen) cracking driven by near-bore residual tensile stresses and the use of laser pulse heating techniques to simulate firing. Related work addresses bore erosion and the use of additives to reduce thermal effects. In a review paper it is argued that the concept of yield-before-break may be more appropriate than leak-before-break for high-strength gun steels. Novel design issues are addressed via papers including an autofrettage case study, optimal combinations of shrink-fitting and autofrettage and hydraulic assembly of compound tubes. The GT 2002 conference was organized by the Royal Military College of Science, Cranfield University, UK and sponsored by the US Army European Research Office; the US Army TACOM-ARDEC-Benét Laboratories; ASME Pressure Vessels and Piping Division and the Institution of Mechanical Engineers, UK. We extend special thanks to all the authors, to Professor M. Perl, Dr. S. Sampath and Dr. A. Hameed who created a successful and enjoyable conference and to Professor S. Zamrik, Professor M. Perl and Ms. D. Bierly who made possible this special journal issue. John G. Hetherington RMCS, University of Cranfield, UK, Anthony P. Parker RMCS, University of Cranfield, UK, John H. Underwood, US Army TACOM-ARDEC-Benét Laboratories