Non-destructive determination of local mechanical properties employs inductive determination of indenter velocity before and after impact, determining e.g. stiffness and damping characteristics.

摘要

The surface is indented, during which a magnetic field is applied to the indenter. A magnitude of the magnetic field characterizing motion of the indenter is determined directly or indirectly. From measured magnitudes characterizing this motion, local mechanical properties of the component are determined. An Independent claim is included for corresponding apparatus. Preferred features: The surface is indented. The pulse resulting, and indenter motion to and from the surface, describe the indentation process. Indentation takes place repeatedly. Apparatus influences magnetic field characteristics; the indenter falls vertically under gravity. Induced voltage alters magnetic field characteristics, and is measured during indentation. A number characteristic of object (i.e. of the test area) stiffness is determined from the indenter mass and damping behavior of the material. Damping is deduced from accelerations and speeds measured during indentation. Comparative on-line testing of samples against reference data, is described. Values determined include impact speed, maximum impact force, rebound (restitution) velocity. An equation is specified to calculate hardness. The testing process is carried out essentially as described, and the mechanical values are determined. The following magnitudes related to electrical potential are determined. Uo proportional to impact velocity Vo, Umax proportional to the maximum rebound velocity Vmax and dU/dtmax proportional to indenter speed. Features of the apparatus noted, include the body holding the indenter, the assembly being accelerated magnetically.