Resources Contact Us Home
Nondestructive fatigue test method for ferromagnetic construction materials

Image Number 3 for United States Patent #6345534.

A nondestructive test method determines fatigue of a test ferromagnetic construction material by quantifying a change in effective stress due to aging of the test material, in which the magnetic susceptibility (.chi..sub.c) of the test material is measured in its aged state under a magnetic field having a specified intensity (H) according to a relation as expressed by a first equation: c=.chi..sub.c H.sup.3. The magnetic susceptibility (.chi..sub.c) so measured and the magnetic field intensity (H) are put into the first equation, to obtain a susceptibility coefficient (c) of the test material. The susceptibility coefficient (c) so obtained is put into a second equation: .sigma.={log (c)-a}/b, where a and b are known constants determined by an internal structure of the test material, to obtain a current tensile stress (.sigma.) of the test material. The current tensile stress (.sigma.) of the test material so obtained is compared with a known, initial tensile stress (.sigma..sub.0) of the same test material, to determine a change in effective tensile stress of the test material.

  Recently Added Patents
Vehicle motion control device
System and method for multi-threaded MIMO OFDM channel equalizer
Pyrrolidine-1,2-dicarboxamide derivatives
Method and system for processing dictated information
Aggregating completion messages in a sideband interface
Battery cell separator
Method of making a CIG target by spray forming
  Randomly Featured Patents
Modular interconnect system
Time out stool
Devices for cleaning heating batteries
Apparatus and method for scanning a key matrix
Shake-proof camera
Press roller
Method and apparatus for dynamic contrast improvement in video pictures
Substituted guanidines having high binding to the sigma receptor and the use thereof
Bi-directional regulator/converter with buck/boost by fuzzy logic control
Look-up table using multi-level decode