Method and device for determining the tensile or compressive stress in a ferro-magnetic member such as a prestressing, tension or compression organ used in civil engineering

摘要

The present invention relates to a method for determining the tensile or compressive stress in a ferro-magnetic member such as a prestressing, tension or compression organ used in civil engineering. This method comprises measuring directly or indirectly the following parameters in at least one given point of the magnetisation curve of the ferro-magnetic member: the intensity (H) of the magnetic field for a predetermined value of the magnetic flow (B) and/or the dependence of the magnetic flow (B) relative to the stress for a predetermined value of the magnetic field intensity (H) and/or the rise in the magnetisation curve for a predetermined value of the magnetic flow (B) or intensity (H) of the magnetic field. A calibration procedure is carried out for the material and/or the type of ferro-magnetic member which comprises calculating for the above-mentioned point(s) the dependence of the measured values relative to the stress for the respective and predetermined value of the magnetic flow (B) or intensity (H) of the magnetic field. The value of the tensile or compressive stress in the ferro-magnetic member or the modification thereof are calculated by comparing the value of the detected ranges with the assigned calibration dependence. This invention also relates to a device for realising this method.