Load-displacement measurement and work determination in three-point bend tests of notched or precracked specimens

Suggestions for testing of notched or cracked three-point bend specimens are presented that (1) correct displacement measurement errors resulting from misalignment between the load applicator and specimen; (2) account for coincidental strains not associated with the work of crack extension; (3) simplify record analysis and processing; and (4) extend displacement gage range without sacrifice of sensitivity or accuracy. These testing details are particularly applicable to procedures in which the crack extension force J(I) is determined from the work done on the specimen.