Steven De Candia

Image Steven Candia

 

Date commenced:

09/06/2015

Full name:         

Steven De Candia

Study/Department Area:

Mechanical Engineering

Profile Type:

PhD Candidate

Qualifications:

Bachelor of Mechanical Engineering (Honours) at RMIT University

History

 

I graduated RMIT University in the Bachelor of Degree of Mechanical Engineering with 1st Class Honours. Throughout my degree I had a wide exposure to working in different industries from the local transport industry, focusing on quality management of train and tram components, to large international industry, working with Robert Bosch GmbH in Germany on the structural analysis of fuel injectors.

My studies brought me to the Maritime Division at the Defence Science and Technology Group looking at the structural response of warships and the equipment response on submarines to underwater explosions. This unique and challenging field combined my interests and strengths in fluid dynamics, solid mechanics and finite element analysis, which motivated me to move further in this area.

Expanding on my work I opted to take on further study through this PhD candidature, looking into the effects of underwater explosions on submarine platforms and mounted equipment.

 

Research Project/s summary/description

Modern navy vessels and their on-board equipment are required to undergo an exhaustive structural assessment process in order to ensure they are robust enough to survive underwater explosive (UNDEX) loads. Current assessment techniques use a simplified approach to assess equipment but in some cases, such as a torpedo tube which is operates in dry and flooded configurations and has a complex dynamic response due to its interaction with surrounding/internal fluid and the distribution of mass along its length, there is uncertainty as to how accurate and efficient these assessment methods are.

The UNDEX loading is complex due to multiple loading mechanisms occurring over a comparatively long duration for an explosive event. The shock wave impact is substantially affected by the surrounding environment over a very large range due to the high speed of sound and near incompressibility of water. Reflected shock waves from surfaces, walls and the sea floor all contribute to the loading profile. Additionally the presence of the remaining explosive material introduces a pulsating gas bubble phenomenon that continues to load the target structure well after detonation. The bubble itself has a complex response that can be coupled to the response of the structure if the interaction is close enough. This Fluid Structure Interaction (FSI) between the bubble-water-target can initiate a global bending response in the target vessel known as “whipping”, while this is well understood in surface ships, it has not been significantly explored for submarines.

The substantial increase in power and availability computers makes numerical analysis of these complex systems a viable alternative to traditional assessment methodology and offers the chance to improve accuracy and efficiency in designs. My research project aims to develop and validate a numerical model for predicting the response of submarine platforms and equipment to UNDEX loads and use this to improve future design and assessment techniques.

PhD Thesis Title

(if applicable)

Application of Fluid Structure Interaction Modelling for Underwater Shock to Future Submarines

Research Supervisors:

Dr. Roberto Ojeda, Assoc. Prof. Jonathan Binns, Adj. Prof. Stuart Cannon

Associated Researchers:

Dr. Roberto Ojeda, Adj. Prof. Stuart Cannon, Dr. Max Ratcliffe, Mr. Warren Reid, Dr. Craig Flockhart

Research Interests:

Underwater Shock Analysis

Fluid Structure Interaction

Structural Analysis

Dynamic Response

Teaching Interests / Subjects:

Finite Element Analysis

Published Research:

De Candia, S., Flockhart, C. and Cannon, S. M. (2014) Whipping assessment of a scale warship structure. In: Australasian Congress on Applied Mechanics (ACAM) 8 Melbourne, Institution of Engineers Australia

De Candia, S. and Flockhart, C. (2015) Modelling the response of platforms resiliently mounted with rubber isolators to shock loads. In: 86th Shock and Vibration Symposium, Orlando FL, USA, Shock and Vibration Exchange