David cracks under the stress

US researchers have developed a way to predict the fracturing that is commonplace in old statues.

For statues, stress injuries come from standing in place for hundreds of years. Using a novel technique, researchers have now developed a way to predict such fracturing, applying the procedure to Michelangelo’s famous statue David in an analysis that proved simpler, faster and more accurate than previous methods.

In their analysis of Michelangelo’s David, engineering researchers from UW-Madison and Florida International University were able to predict the stresses that the statue endures on a daily basis.

The analysis matched well with the statue’s known crack damage, indicating that the method could help archivists by serving as a predictor for what areas of an ancient artefact may need to be bolstered to prevent damage, even if the statue has not yet shown fatigue.

In applying the technique to other objects – including human bones – the researchers are also gaining new perspective on how these structures are likely to fail.

‘This research is a breakthrough technology for performing direct engineering analysis on physical artefacts in situ,’ said University of Wisconsin-Madison mechanical engineering Prof Vadim Shapiro.

The so-called ‘Scan and Solve’ technique takes 3D sampled or scanned data of an object and calculates where points of weakness occur and how the points will be affected by forces acting on them, such as gravity in the case of David, or activity in the case of a human bone.

‘These calculations are simple and painless, allowing for the exploration of many potential solutions for fixes in areas where fractures might occur,’ said Shapiro.

‘Unlike existing analysis techniques that can be error prone and require models that take far longer to create, Scan and Solve compresses the entire analysis into a series of automated, efficient steps,’ added UW-Madison engineering graduate student Michael Freytag, whose doctoral thesis detailed the Scan and Solve approach.