A 3D printable strain sensor developed by University of Michigan engineers could provide the U.S. Navy and commercial shippers with a more accurate, less expensive way to assess damage to their vessels, helping to keep sailors safe in the aftermath of an attack or storm. Called the Strain Application Sensor (SAS), the new device detects tiny flexing movements in the metal parts of ships -movements that can alert crews to damage before cracks or other visual signs can be seen by the naked eye. This can be vital information when a ship has been damaged and crews need to quickly determine what to do next. The SAS sensor can precisely measure strain without the need for power or data connections. Made of 3D-printed plastic at a cost of a few dollars each, the sensors can be attached quickly with magnets. Mark Groden, the sensor's inventor and a graduate researcher at the U-M college of Naval Architecture & Marine Engineering, predicts they'll be in use within the next year.