CHALLENGES IN DEVELOPMENT OF EASY-TO-USE TORSION TEST METHOD FOR BIOCERAMICS - TOWARD ISO STANDARD PROPOSAL

摘要

This paper deals with challenges in development of easy-to-use torsion test method for bioceramics. The development contains several improvements for specimen geometry and grip jig mechanism. The specimen shape is set to be dog-bone type; however, its gage is changed from 20mm to 10mm, and also gage diameter is changed from Φ8 mmto Φ6mm in the improvements. The grip jig is upgraded by adding a cylindrical plastic sleeve guide to prevent bending moment and axial loading during applying torque by hand. The grip jig (lower side) is fixed to an opening torque tester for PET botdes, and one end of specimen is inserted into a square hole in the grip jig. The other end of specimen is also inserted in the other grip jig (upper side). The upper grip jig is rotated by hand to apply torque until me specimen is fractured in torsion, and the torsion strength is calculated from the maximum torque and gage diameter of the specimen. In the developments, a blackboard chalk and 5 types of bioceramics were tested, and reasonable torsion strength data were obtained.