Most people find the sounds of steel creaking to be highly irritating. However, for mechanical engineer Prof Anriëtte “Annie" Bekker, that's what life is all about. She leads a research programme at Stellenbosch University that examines every vibration, movement and wave that hits South Africa's polar research ship, the SA Agulhas II.
Bekker will present a lecture on her research work to the Stellenbosch Forum on 26 September 2019, at the US Museum in Ryneveldt Street between 13:00 and 14:00.
The SA Agulhas II regularly ferries researchers and technicians to South Africa's research bases in Antarctica and on islands in the Southern Ocean.
"Our work is to find out what impact ice and rough seas have on the ship's shafts and propellers, and how comfortable passengers are on board depending on the impact of waves slamming against the hull, the engine's vibrations and the movement of the ship," explains Prof Bekker, since 2012 director of the Sound and Vibration Group SU Department of Mechanical and Mechatronic Engineering. "Ultimately, we hope our research contributes to better ship designs and digital services for the SA Agulhas II and the shipping industry in general."
One of her students is currently working on a scale model of the vessel that can be evaluated in the Department of Mechanical and Mechatronic Engineering's towing tank. Other students are developing the building blocks to create so-called “digital twin" models of passengers on board. This will hopefully give captains an informed idea of how passengers and crew experience specific weather and ice conditions encountered on route. Such a virtual tool will allow captains to know how uncomfortable or seasick their passengers possibly are, and whether they are capable of still performing their tasks under severe conditions. It will allow them to make informed decisions on whether they should change the speed or direction of the vessel, in an effort to ensure the comfort of the people on board and to ensure that the research objectives of each cruise can be carried out. According to Prof Bekker, the general shipping industry will be able to use such “digital twins" to help improve crew safety, and to better plan for comfortable voyages on cruise ships.
Anything that vibrates
Bekker's research group does not focus solely on ships. They have previously collaborated with the Ford Motor Company to select the most comfortable seat from a vibration perspective. Research has been done on the sound quality inside the cabin of electric cars, and how people experience the “symphony of new sounds" on these "quieter" vehicles.
Her research group has been working with mining companies to measure the extent to which drivers of heavy vehicles are exposed to vibration. The effect of such long-term exposure is researched, among other things, in the Faculty of Engineering's Structural Laboratory, where a vibrating platform is in place to perform man-rated tests.
"The constant vibration and shocks to which a driver of a giant construction vehicle is exposed can eventually lead to injury," explains Bekker.
“We can technically research anything that vibrates. Mechanical systems, music, electrical stimuli and weather data all produce signals that oscillate. Vibration-based techniques basically enable us to gather important characteristics or features from oscillating data," explains Bekker, who has made the Mail & Guardian's list of top 200 young South Africans.
Becker grew up in Benoni in a home of self-proclaimed car fanatics. She says her interest in engineering is a natural result of her love for math, creativity and problem solving.
She obtained the BEng degree in mechanical engineering from Stellenbosch University in 2001, and a MEng degree cum laude in 2004. Her doctorate followed at the University of Cape Town in 2008, with a study on how injuries can be reduced in vehicles operating in landmine areas.
She cut her teeth in the field of vibration and sound as member of South Africa's Optimal Energy team that designed the Joule electric vehicle. Five Joule prototypes were built, but the project ended due to budget cuts.
Fortunately, that was not the end of Bekker's career. She joined SU in July 2011. Shortly thereafter, a Finnish contact reached out to hear if the University wanted to collaborate on a research project involving the SA Agulhas II. At the time, it was being built for the South African Department of Environmental Affairs to replace the outdated SA Agulhas I polar ship.
The first trials to ascertain the ship's ability as an icebreaker were scheduled for March 2012, in Bothnia Bay in the Baltic Sea near Finland.
With sensing equipment as part of her luggage, she travelled to Finland for five days of testing. Thus, Stellenbosch University, together with, among others, the University of Aalto in Finland, became important partners in the study of the SA Agulhas II as an ice-going ship.
"Once you get on board, and see the environment in which you work, it becomes a compelling and addictive environment," she explains why she is intrigued by the subject.
Many of her students have since made their way in the direction of Antarctica. A measurement system of 200 sensors (including 32 accelerometers), monitors the movement and bending of the ship structure during such voyages. Sound recordings are also done in a cabin with a doll named Mike, that has microphones in his “ears".
"We are very proud of the 32-sensor acceleration system that was developed at Stellenbosch University. It allows researchers to detect the displacement and deformation of the ship's structure as it travels through ice and massive waves," explains Bekker, who acknowledges that she can't do without the Latex program which creates written documents, and Matlab which plots graphs of the data collected.
When her students return to Stellenbosch from their icy adventures, she enjoys listening to their stories, and hearing what insights about themselves they have discovered in the process.
At the end of last year, Bekker turned off her computer, packed enough food in the freezer and left her young family at home to board the SA Agulhas II again and to experience Antarctica for the first time. She was part of an international research team that travelled to the infamous Weddell Sea of Ernest Shackleton-and-the-Endurance fame. They were the first to do so since 2002. In the process she experienced first hand how traveling through stormy, polar waters can make a person's stomach turn.
“Nothing can prepare you for the immense experience of Antarctica. Except for the sounds of the ship's machinery, everything is quiet. There is tranquillity and peace, and even the shadows that the clouds make create features on the white landscape. Because it never really got dark when I was there, I even lost my sense of night or day. It is an environment where prestige does not count, and where the lack of the internet and an existing culture tests you in who and what you are. There's no place to hide. The result was a surprising sense of freedom, even exuberance, that I had never experienced before."
Thanks to their studies about the SA Agulhas II, two of Bekker's students have already obtained their doctorates, and six their master's degrees in engineering. Two students now work for space agencies - one in Germany and the other in Pakistan. A third student is involved in vibration testing and design in the German automotive industry.
Bekker cherishes the days on which her students defend their theses: "I stand amazed at how students develop and how their ingenuity amidst challenges often exceeds your expectations."
“The best part of my job is to open doors for students who are inquisitive and have potential. It's inspiring to see how they leave you full of life and with the will to succeed," she explains. “It energizes me to watch how purposefully, resourcefully and creatively they defeat challenging problems."