We are both delighted and excited that this is the fourth time Defence Technology has published scientific papers presented at an International Symposium on Ballistics (ISB). This particular issue publishes papers presented at the 31st ISB, co-chaired by Dr VK Saraswat, Member NITI Aayog, Government of India and Dr G.Satheesh Reddy, Secretary, Department of Defence (R&D) &Chairman DRDO, Government of India, and supported by the Aeronautical Society of India, Hyderabad Branch, and Cyberabad Convention Center Private Limited under the auspices of the International Ballistics Society (IBS, www.ballistics.org). This is the first time the ISB has been held in India and only the second time in Asia.

The ISB provides an opportunity for ballistics scientists, engineers,and others to report,share and discuss current research and advances in ballistics and their visions for the future. The symposium allows exposure to the most current state-of-the-art technology in ballistics, provides opportunities for interactions with some of the world's leading experts in the field of ballistics technology, and offers the chance to present, exhibit, and share scientific research and development with an international group of professionals.

The Society encourages the presentation of a wide range of papers at the ISB, from work in progress through to high quality scientific papers. Issue 5 of the journal includes 19 of these scientific papers, which have been rigorously peer-reviewed and approved according to the practises of the journal.

These papers comprise an extensive range of ballistic science areas covered by the symposium; interior ballistics, launch dynamics, exterior ballistics, explosion mechanics, vulnerability and survivability, and terminal ballistics and impact physics.

The Special Issues were enabled by the good cooperation between the IBS and the Defence Technology journal, and we would like to thank the China Ordnance Society, and the Editorial Office,Ms.LI Ying,Ms.MA Xin,Ms.LI Liu,Ms.BU Min and Ms.WU Miao for their dedicated,hard and expeditious work in producing this issue.

We hope you will find these papers stimulating and very interesting. Defence Technology provides an opportunity to develop an understanding of the entire realm of ballistic science outside of the reader's specialist area. We therefore highly commend this issue of the journal to you.

Clive Woodley, Executive Editor-in-Chief & Board Member, International Ballistics Society

Baoming Li, Executive Editor-in-Chief & Board Member, International Ballistics Society

Previously published scientific volumes from the International

Symposia on Ballistics:

26th ISB, Beijing, China J. Appl. Mechanics, 77 (2010)5, September 2010

26th ISB, Miami, FL, USA J. Appl. Mechanics, 78 (2011)5, September 2011

27th ISB, Freiburg i. B.,J. Appl. Mechanics, 80 (2010)3, May 2013

Germany

28 ISB, Atlanta, GA, USA Defence Technology, 10 (2014)2, June 2014

29 ISB, Edinburgh, Scotland,Defence Technology, 12 (2016)2, April 2016 UK

30 ISB, Long Beach, USA Defence Technology, 13 (2017)3 & 4, June &August 2017