Fracture Analysis Of The Working Part Of An Impactor Based On A Three-Point-Bending Specimen Model

Impactor is widely used in mechanical engineering. Impacting is a process which receives an external force and transfers it to the objective structure in order to create an extrusion effect in a very short time. The objective may be moved, deformed even destroyed. This process may be repeated many times in reality. Because of the huge force and short time, the working part of an Impactor works with big deformation and big torsion, even with plastic deformation, frequently. Sometimes the Impactor was deformed or cracked even destroyed when it is still in its life length. The reason is the structure of the working part of an Impactor is not always continuity but possess many defects and cracks in itself. When the cracks grow even becomes instability by the external force, the Impactor may fractures.Because of the same mechanism of the crack growing and structure destroying, as well as the same condition of the external force, a3-Point Bending Specimen (3PB) model is one of the models which often used for simulating and studying an Impactor with cracks. In the past researching, people only focus on simple theoretical mathematics model with few experiments to compare. What’s more, those models don’t contain damping. In this paper, a3PB model with damping added was studied in order to improve the accuracy and reliability. And how damping affects the3PB model was considered. A mathematics model of the3PB model which adding the damping system is created and studied Then the Stress Intensity Factor was obtained in this method. Secondly, the3PB model was created in Finite Element Method with ABAQUS software contenting damping, and the Crack Mouse Opening Displacement as well as Stress Intensity Factor was obtained in this way. Thirdly, a3PB model impacting experiment was carried out in order to compare with the two models and prove their reliability. The basic data of the experiment as well as the displacement of the impacting hammer and Crack Mouth Opening Displacement (CMOD) was collected. The Crack Mouse Opening Displacement from the impacting experiment and ABAQUS were compared. Then the Stress Intensity Factor from mathematics model and ABAQUS were compared as well. The conclusion was made which contains how the damping affects the crack’s growing; the new method to calculate the Stress Intensity Factor and future research area. And according to the research of the3PB model, the conclusion which how to design the structure of the Impactor and how to choose the material of the Impactor was obtained.