Bending beam strain gauging method and test setup for carrying out such a strain gauging method

摘要

The invention relates to a strain measurement method for determining the stretchability of thin layers of a wall paint (20) or a multilayer wall coating system (25), and comprises the following steps: - providing a bending beam (1) made of an absorbent material with a beam length (L); - Arranging a notch (2) on a broad side (11) in the middle (L / 2) of the bending beam (1); alternatively - applying a wall paint (20) on the smooth broad side (12) opposite the notched broad side (11); or - applying a multi-layer wall coating system (25) on the notched broad side (11) of the bending beam (1); and further - arranging measuring points (M) on the applied wall paint (20) or wall coating system (25); - Recording at least one initial length (L0) between measuring points (M) on the undeformed bending beam (1); - performing a three-point bending test with a test device; - Recording the bending deformation of the bending beam (1) with an industrial camera (7); - Stop the three-point bending test as soon as there is cracking with hairline cracks; - Determining the change in length ΔL of the wall coating (20) or wall coating system (25) applied to the bending beam (1).