Measurement of surface flatness for pressure surfaces used in concrete compression tests, in which measurements at mesh intersection points on measured surface are compared with similar points on reference surface

摘要

In the fifth stage and for each mesh intersection point (Xi,Yi), a calculated surface fault (Zi) is subtracted. The flatness fault of the reference surface (11) is obtained by replacing the measured surface by a non fault flat surface and by previous execution of the first 5 stages. Displacement sensors (20a,20b) are used as differential transformers. An Independent Claim is included for the measuring device. Method for measuring faults in a flat surface, which includes the following stages: (a) 1. place a reference surface (11) with respect to the surface (21) to be measured and parallel to it; 2. displace a carriage (18) on which are mounted two head to toe displacement sensors (20a,20b) which indicate their to and fro displacement along an axis (X) and step by step along an axis (Y) perpendicular to the axis (X) in an intermediary plane (X0Y) between the surfaces. One of the sensors (20a) touches the reference surface and the other (20b) the measured surface perpendicular to the plane (X0Y); 3. the sensor measurements are taken at points of intersection (X,Y) of a mesh and the coordinates 9Xi,Yi) of the points of intersection; 4. the measurements at each mesh intersection point are converted into displacement values (z1,z2); for each mesh intersection point (Xi,Yi) is subtracted the displacement values (z-10,z20) from a point of origin respectively for the displacement values (z1,z2) so as to produce displacement differences ( DELTA z1, DELTA z2) for each sensor with respect to the reference surface, and; 5. for each mesh intersection point (Xi,Yi) the differences are added so as to produce a measure of the flatness faults (Zi) of the measured surface at the intersection points (Xi,Yi) with respect to the reference surface, and; 6. a fault map is produced of the measured surface.