Method and appliance for determining strain and/or stress of tyre use Shearing interferometer with time or phase shift

摘要

The method is based on so called 3D phase measurement using a Shearing interferometer (6) with a time or phase shift. The surface (7) of the tyre (8) is radiated with two coherent beams (3,4), preferably from a laser source, having different angles of incidence. The light reflected from the tyre is picked up and evaluated by the interferometer