Three point bending Hopkinson bar for fracture toughness measurement: A new approach for interface analysis

Abstract

The arrangement of the three‐point‐bending (3PB) Hopkinson bar has been adopted as a convenient means for measuring the dynamic fracture toughness of materials. Some researchers have used this method to evaluate that property which has become an important dynamic fracture mechanics parameter. In this work, an insight of this arrangement is presented through a finite element method (FEM) analysis. A number of important aspects are approached. Among them, the history of the force conveyed to the specimen and the evolution of the dynamic stress intensity factor (SIF) during tests. A new approach, allowing estimating a more accurate effect on the specimen and also an eventual loss of contact with the incident and transmitter bars is described and explained: instead of obtaining the force, the velocity on the incident bar tip is extracted to feed the finite element model.