The vibration of the tubes in steam generators (SG) causes fretting-wear, especially in the tubes bended parts near anti-vibration bars (AVB). Similar degradations, with more unpredictable shapes, can also be caused by foreign objects, like a welding rod located in the secondary area of the SG for example. This joint study between CEA LIST and IRSN aims at efficiently simulating eddy current testing (ECT) signals due to fretting-wears. For this purpose new advanced geometric tools feed the 3D models developed by the CEA LIST allowing to quantify the influence of the various geometric parameters of the configuration. In particular, we want to verify the ability of usual simplified geometric representations to approximate these signatures (typically with a rectangular notch in a straight tube to represent the wear under AVB). This numerical study is accompanied by numerous experimental acquisitions on machined tubes, with and without external object.