Photoelasticity is a technique that has been used for decades in industry. It looks at the patterns of coloured light reflected from the surface of an object to gain a detailed understanding of the stresses on that object. In its most modern incarnation photoelectric stress analysis uses high tech light sources and computer analysis to get an even more precise understanding of the stresses involved. However it is all very well mounting a piece of machinery on a test rig to perform these tests but how would one use it to understand the stress on a part of the human body when the human is still using it? Now researchers at the University of Warwick's Warwick Manufacturing Group working with a surgeon in London have found a way to do just that.
Initially the surgeon had tried placing mechanical strain gauges on an aortic aneurysm as they manipulated it but found that the gauges themselves placed an unwelcome additional physical strain on the aortic aneurysm. The surgeon turned to researchers at the University of Warwick led by Geoff Calvert who had an idea that would combine photoelastic stress analysis with the technology of rapid prototyping to solve the problem. The University of Warwick and surgeons in London took a 3D scan of the patient's actual aortic aneurysm and used rapid prototyping technology to produce an exact latex duplicate of the aneurysm. They then covered the duplicate with a reflective coating and used photoelastic stress analysis to examine the stress on the model aneurysm as the surgeon manipulated it.