A toughness test device with opposite roller loading

Bars loaded by opposite concentrated forces via rollers are appropriate tes t specimens for the determination of the fracture toughness K-lc, and the c rack resistance curve (R-curve). In this paper, stress solutions fur the pr oposed specimens are provided. For the fracture mechanics specimens contain ing edge cracks, stress intensity factor solutions are given in form of fig ures and tables. As practical applications, R-curves are determined for an unpoled soft lead zirconate titanate (PZT) ceramic and an alumina with 4% g lass content. (C) 2000 Elsevier Science Ltd. All rights reserved.