Scientists are cracking a 100-year-old puzzle
A husband and wife team at Strathclyde University are experts in cracks ... and the duo claim their peridynamic discoveries could have prevented the sinking of the Titanic
ASCOTTISH university has created what is understood to be the world’s first centre for the “science of cracks”. Formally known as the Peridynamics Research Centre, the purpose is to determine the health of all types of structures such as planes, ships and buildings to make sure they are safe.
It is a science that could have prevented the sinking of the Titanic and could now be used to make sure modern ships can safely sail the new routes that are opening up due to the effects of global warming on Arctic ice.
While peridynamics (PD) is being embraced in the US and China it is still in its infancy in the UK.
However the husband and wife team running the Strathclyde centre are aiming to spread understanding about their computational technology which can predict and track cracks of any size and in any materials.
“We are like doctors of structures,” said the centre’s vice director Dr Selda Oterkus. “Just as the human body can crack under stress so can structures if they are subject to high levels of external loading.”
Director Dr Erkan Oterkus added: “What we do here in the centre are computer solutions to find out how cracks occur, how they will evolve or even if they will evolve.
“Through the simulations we are trying to understand if certain cracks are really critical for the safety of a structure.”
He pointed out that cracks are not always bad. For example, if we want to eat a large walnut without choking we will have to bite it to make it into smaller pieces, therefore creating cracks.
“Sometimes we want to create cracks and sometimes we want to prevent them,” said Erkan.
Peridynamics is an improvement on traditional methods of testing the safety of structures because it is better able to assess the impact of multiple cracks rather than just one.
It can more accurately predict how each crack will evolve under stress and is much more comprehensive than traditional methods because it can be applied to tiny structures as well as large ones like buildings.
The method is also not limited to structural analysis but can be used in many different areas including fluid and thermal flow analysis. The results of being able to predict how cracks will begin and how, or if, they will develop can save lives.
“Just one small crack can mean you lose your aeroplane,” pointed out Selda. “The implications are massive. With PD, we look at under what conditions this crack will propagate so we can have a full understanding of whether it will cause a problem or not, or whether you can safely ignore it, or prevent it getting worse.”
The importance of the work can be viewed in the light of Arctic ice melt due to climate change. While this is bad news in terms of global warming it is opening up more shipping channels – although the melting ice remains a hazard.
“There may not be a huge amount of ice but even small pieces can cause damage to ships,” said Erkan.
“PD can be used to not only assess potential damage to the ship but to the ice as well, which is also fracturing when it hits the structure.
“It’s important to know how it does this so you can make a better prediction of its effect on both sides and ultimately design ships which can withstand collisions which could cause significant damage, even sinking the ship.
“The obvious one here is of course the Titanic.”
The centre has already worked with electronics giant Samsung on a project aimed at mitigating the effect of moisture on polymer components in their products. During storage and shipping these components absorb moisture,” explained Selda.
“Then during the soldering process, when you want to combine the electronic components together, the temperature rises and it creates vapour pressure - it creates a crack.”
From her research, Selda was able to develop a peridynamic model which couples moisture, temperature and structural fields with failure prediction capability.
Other ways the methodology can be used is to predict the effects of underwater explosions from mines or the damage caused by missiles.
As well as saving lives, the technique has the potential to save businesses a lot of money by predicting the amount and strength of building materials, for example, or by predicting the effects of corrosion on a structure.
“The UK is still hesitant about using this computational technique and so there are funding challenges but the applications of PD are enormous,” said Selda.
Added Erkan: “Our main goal is to extend understanding of the methodology so that companies will start utilising it in their design environment.
“We are hoping that in the very near future there will be a commercial software based on it.
“I think that would really help in terms of usage.”
“YOU CAN DESIGN SHIPS WHICH CAN WITHSTAND COLLISIONS AND AVOID SIGNIFICANT DAMAGE