Some comments on the Arcan mixed-mode (I/II) test specimen

Although the Arcan specimen has been used frequently for mixed-mode crack growth testing using single-axis servohydraulic test equipment, the specimen and its commonly-used fixturing have features and behaviors that have implications to the proper understanding of results garnered from their use. These implications extend to hardware issues as well, as the Arcan specimen (when mounted at off-axis angles) can generate significant and even potentially damaging side loads on the load frame actuator. This paper discusses a number of the issues associated with the Arcan specimen and Arcan testing.