The invention provides an
internal stress measuring method of an opening plate, belonging to the technical field of measurement. An opening plate is evenly
cut into strips via marking benchmark straight lines on the opening plate for releasing the
internal stress; the bending deformation of the benchmark straight line, corresponding to each measuring strip, is measured; the
internal stress before releasing the stress is calculated according to the bending deformation of each measuring strip, so that the internal
stress distribution of the whole opening plate is obtained. Advantageously, under the
precondition of satisfying the internal
stress measurement precision of the opening plate,
sample preparation and measurement can be performed by common workers with conventional
cutting tools, ordinary rulers and tapered rulers; and the internal stress of the opening plate is obtained fast by a
mathematical model built by the invention. The method of the invention is used in the works of the
process optimization of hot-rolling ship plates and opening
process optimization of
chip plates, and respectively used for measuring the internal stresses of D36 and D32 levels of ship plate opening plates which are 2000 mm in length and 2000 mm in width, so that the internal
stress distribution of the ship plate opening plate is obtained accurately, and reliable reference data is provided for the optimization of production process.