Loading Jig Manufacture to Apply Mixed-Mode Loading to Bonded Structures

A simple loading jig has been designed and manufactured. The purpose of the loading jig is to facilitate mixed-mode fracture testing of adhesively bonded Double Cantilever Beam (DCB) joint specimens over a wide range of mode mixities from pure mode I to pure mode II. The loading jig is statically determinate. The specimen loads F1 and F2 (loads applied to lower and upper substrate respectively) have been calculated based on conditions of mechanical equilibrium, neglecting shear deformation and assuming that the adhesive layer of the test specimen is very thin. Finite Element Analysis (FEA) has been used to optimise the design. The results for loads acting on upper and lower substrates due to applied load from external source, obtained using established analytical methods and Finite Element Methods (FEM), agree very well over the range of loadings applied by the jig. Same load ratios are obtainable using different supports and point of external force within the jig. Therefore, the jig provides the self verification method as well.