This paper presents a numerical study of specimen geometry and load frame/s
pecimen interaction of a four-point-bend mixed mode fracture specimen. The
aspect ratio of the specimen, the stick/slip condition between the loading
pin and specimen, and the lateral and rotational restraint of the load trai
n all have a potentially significant effect on the mode I and mode II crack
tip fields in the specimen. These effects are illustrated by the dependenc
e of the uncracked stress fields, mode I and mode II stress intensity facto
rs, and crack opening and sliding displacements on geometric parameters and
load train restraint conditions. (C) 2001 Elsevier Science Ltd. All rights
reserved.