Tensile shear test on overlapping bonds

Including high-resolution measurement of the shear path

For a shear tensile test, two wood samples were glued together. A clamp-on extensometer was used for the most precise displacement measurement

Shear tensile test: Wood bonding - micropath measurement

By using a clamp-on extensometer, the finest displacement of the glued wooden surfaces can be measured.

A unique feature of this experiment is the use of an additional adhesive to compensate for thickness differences in an adapter piece. This setup allows the use of a conventional clamp-on extensometer for measuring the minute displacement of the bonded surfaces. This extensometer has a measuring resolution of 0,000.1 mm.

In order to make the results comparable, the area of the bond is measured before the test (sample width and length of the overlap). The determined maximum test force is divided by this area to determine a shear stress.

Since the test pieces are relatively stiff, the clamping device must be offset to prevent any bending effect on the adhesive joint. This was achieved using a special clamping device . With this device, a center offset between the upper and lower clamping planes can be achieved by manually adjusting the left clamping surface.