Suchinthana Dissanayaka



Date commenced:


Full name:         

Suchinthana Pragathi Dissanayaka

Study/Department Area:

Department of Mechanical, Materials and Mechatronics Engineering

Profile Type: (Please highlight all that are relevant)

PhD candidate


Bachelor of Science of Engineering (Hons)



I graduated 2007 with an honours degree in Mechanical Engineering from University of Peradeniya, Sri Lanka. Soon after graduation, I joined Colombo Dockyard PLC, a leading ship building and ship repairing company in Sri Lanka as a Trainee Engineer and later got promoted to Ship Repair Engineer. During my employment I was part of several ship building projects, which involved being in charge of the project management and execution of the hull construction for three major ship building projects.

I moved to Australia in 2011 and started working as a Workshop Engineering Coordinator for Mainteck Pty Ltd, a steel fabrication and construction company. During these three years of industrial experience in Australia, I developed an interest to build up my knowledge and skills in welding. This lead to my desire to do a higher research degree, on weldability, which will provide me with important knowledge for my future career and advance my personal development.



Research Project/s summary/description


I am working on a joint project with DST-G, ASC and UOW, dealing with the effect of multiple repair welds on the mechanical properties of high strength submarine steel. This 690 MPa quenched and tempered steel has been extensively used in the fabrication of Australia’s Collins class submarines. In practice, these submarines undergo maintenance and repairs in regular intervals which commonly involve weld-repairing of degraded parent material and re-welding the Hull. It is a common practice to cut the hull along existing welding seams to enable access to internal machineries. Thus, these seams have to be re-welded once the maintenance is completed.

Weldability of 690 MPa quenched and tempered steels has been studied extensively and, effective and safe welding procedures have been developed. However, the effect of multiple repair welding on the properties of these materials has not been studied.

The experimental plan involves two phases. In the first phase, multiple repair welds will be carried out on steel samples with approved welding procedures. Metallurgical analysis and mechanical testing will be carried out on these samples. The second phase of the experiment is to simulate the thermal effect of multiple repair welding on the material on a Gleeble thermo-mechanical simulator. It is envisaged that the combination of methods will be used to identify the effect of multiple repair welds on the properties of the parent material.

The objectives of this project are to identify the effect of multiple repair welds on the properties of the parent metal and to provide quantitative guidelines for improving repair and re-welding procedures in order to maintain the structural integrity of the pressure hull.

PhD Thesis Title

Effect of multiple repairs on the mechanical properties of 690 MPa steel

Research Supervisors:

Prof. Huijun Li, Dr. Stephen Van Duin, Dr. Kristin Carpenter

Research Interests:

Welding metallurgy, Welding processes

Teaching Interests / Subjects:

Materials Engineering, Fluid Mechanics, Mechanics of Materials