Failure of elastomeric sealants under tension and shear: Experiments and analysis

The mechanical behaviour of two elastomeric fuel tank sealants was investigated. Laboratory tests were conducted on two sealants, an epoxy cured polythioether and a manganese cured polysulfide. Tensile, planar tension and torsion tests were performed to characterize and understand the response of the sealants under quasi-static loading. Single lap joint tests in tension were also carried out using four different sealant layer thicknesses and two types of adherend (aluminium and steel). The adherends were either primed with an epoxy primer or otherwise conventionally treated (e.g. grit blasted). Experimental results showed a decrease in joint strength with increasing sealant layer thickness. Emphasis was given to the understanding of the failure and the prediction of the strength of the single lap joints. Predicted failure loads were derived by analytical calculations and finite element simulation of the joints.