An analysis is given for determining G for removing a thin layer using a we
dge. Corrections are described for both friction and the plastic bending of
the layer. Experimental results are analysed for adhesive joints and for c
utting tests on polymers and biological materials. In all of these the frac
ture toughness could be found. Some general observations on schemes for ana
lysing these tests are given. (C) 1998 Kluwer Academic Publishers.