ISO 22841:2021 Composites and reinforcements fibres — Carbon fibre reinforced plastics(CFRPs) and metal assemblies — Determination of the tensile lap-shear strength.
7 Preparation of test panels
Cut the metal and CFRP to suitable sizes and assemble in a group of two sheets, taking one from each material.
Prepare the adhesive in accordance with the procedure specified by the manufacturer of the adhesive.
The surface to be bonded may or may not he abraded, as agreed between the interested parties. Apply the adhesive to the metal or CFRP as specified by the manufacturer of the adhesive. After the specified time has elapsed, assemble the metal and CFRP into two-ply panels as described in Clause 6. Then press the panel under the specified conditions. Cure time and conditions shall be those specified by the manufacturer of the adhesive or as agreed between client and testing agency and have to be recorded.
8 Conditioning of test panels
The specimens shall be conditioned and tested in one of the standard conditioning atmospheres specified in Iso 291 or as agreed between client and testing agency.
9 Preparation of test specimens
Cut the test specimens as shown in Figure 1, taking care that a margin to exclude manufacturing edge effects is removed first. This is accomplished by first cutting the notches to the proper width, depth and location in the test panel, using a hollow-ground grooving saw or any other method that will give equally satisfactory results. Notch the specimens as shown in Figures 1 and 2. The notch of the two-layer specimen shall go as far as the adhesive line and care shall he taken that the ply is cut completely. When the panel has been notched, cut the individual specimens from the panel. Number them consecutively from one end of the panel to the other and identify them with regard to their origin in the panel. Select the specimens to be tested so that an even and equal number of specimens is taken from each test panel. The dimensions of the adhesive shear area as machined shall be reported.
Place the test specimen in the jaws of the grips in the test machine so that the notches are approximately 5 mm from the end of the jaws. The specimen shall be perfectly aligned, and the pairs of jaws shall be directly above each other and in such a position that an imaginary straight vertical line would pass through the centre of the core ply and through the points of suspension of the grips. Test the specimens from each panel in numbered sequence and place them in the jaws alternately so that in one case the upper notch is to the left and in the other case to the right. The rate of separation of the jaws shall be such that the failure occurs within (60 ± 20) s, unless other speeds are agreed upon. The rate of separation shall be reported in the test report.
11 Precision data
Precision data are not available at the time of publication.ISO 22841 pdf download.