A tapered bondline thickness double cantilever beam (DCB) specimen geometry for combinatorial fracture studies of adhesive bonds

The characterization of fracture energy (GIc) of an adhesive joint as a function of bondline thickness requires multiple specimens covering a range of bondline thicknesses. In this work, DCB specimens with linearly increasing or decreasing bondline thickness were studied for their feasibility to determine fracture energy as a function of bondline thickness. In a combinatorial characterization sense, this approach explores the possibility to characterize the effect of bondline thickness on fracture energy through fewer tests than those required for a “one at a time” characterization approach, thus offering a significant reduction in characterization times. Fracture energies were characterized under mode I loading conditions using corrected beam theory. The results obtained from linearly increasing or decreasing bondline thickness specimens showed good agreement with those obtained from specimens with a range of constant bondline thicknesses.