Critical assessment of the mandrel peel test for fiber reinforced thermoplastic laminates

The applicability of the mandrel peel test for thermoplastic composites was investigated experimentally by comparing the fracture toughness to the values obtained by the double cantilever beam (DCB) and end loaded split (ELS) beam test. Two laminates were considered: a unidirectionally carbon-PPS laminate and a carbon-PPS hybrid laminate, in which the interface consisted of a woven fabric and a unidirectionally reinforced ply. The mandrel peel results on the unidirectionally reinforced laminate compared well with the DCB and ELS test results. The fracture toughness of the hybrid interface could not be quantified by the DCB or ELS test, whereas this was possible using the mandrel peel test.

► We critically assess the mandrel peel test for thermoplastic composite laminates. ► Two interfaces are considered: a UD–UD and a hybrid, i.e. fabric–UD, interface. ► The peel fracture toughness is compared to values obtained by DCB and ELS tests. ► The experiments on the UD laminate showed good comparison between the tests. ► The hybrid interface could only be quantified using the mandrel peel test.