Chapter 1 Effect of Specimen Holder on Static and Fatigue Tests on Titanium/Cement Interfaces S. Riahinezhad, Y. Li, and M. Khandaker Abstract A tension or compression load was applied onto the Ti rod to test the fracture strength and fatigue life of Ti-cement interface under static and fatigue loadings, respectively. These tests are referred as static and fatigue in this study. A customized holder for the cement is required for the static and fatigue experiments, since the typical wedge, pneumatic, or hydraulic gripper are not suitable for static and fatigue tests on the fracture tests of bi-material samples. The objectives of this study are (1) to evaluate the effect of cement thickness on the fracture strength and fatigue life on Ti-cement union by finite element analysis; (2) to evaluate the effect of plastic cement holder and aluminum cement holder on fracture strength and fatigue life on Ti-cement union by experiment and finite element analysis. Ti-cement union model with 0.22 and 0.11 in. cement, Ti-cement-holder union with plastic and aluminum holders were created and validated using ANSYS in this study to develop a suitable specimen holder for static and fatigue tests. Experimental static tests of Ti-cement with both plastic and aluminum specimen holders were conducted as well. The result clearly showed that both plastic and aluminum holders can be used for static test whereas aluminum holder required much larger fracture load compared to the fracture load on plastic holder. Plastic holder is not suitable for fatigue test, because fatigue test required a stronger and more rigid holder such as aluminum. Keywords Titanium • Cement • Interface • PMMA • Polycaprolactone • Fracture strength • Implant 1.1 Background The bond of an ideal implant with surrounding tissue must maintain certain fracture strength, σ f , due to static loads (e.g. body weight, carry weight) as well as fatigue life, N, due to cyclic loads (e.g. walking, running) [1]. Accordingly setup for fracture strength and fatigue life test, especially the specimen holder, was needed in this research. To the author’s best understanding, there were no static and fatigue test gripper for bi-material samples that can be suitable for Test Resources Machines (UTM). Finite element analysis on customized specimen holder for static and fatigue tests were executed in this study to validate the application of the holder for these tests. Cement holder material is one of the main factors to consider before the cement holder design. The elastic properties of cement holder material may affect the fracture of Ti-cement interface under the static tests. If the cement holder is not strong enough, the damage will occur on the cement holder other than the Ti-cement interface. Cement thickness is also an important factor that affects Ti-cement interface. Fisher et al. [2] found out increasing cement mantle thickness caused substantial strain reductions in the distal cement which may eventually increase the fatigue life of a bone-implant system. In this study, effects of the cement holder material and cement thickness on the fracture of Ti-cement interface were investigated to determine a suitable cement holder design for the static and fatigue test of Ti-cement interface. The objectives are (1) to evaluate the effect of cement thickness on the static and fatigue tests on Ti-cement union by finite element analysis; (2) to evaluate the effect of plastic cement holder and aluminum cement holder on static and fatigue tests on Ti-cement union by experiment and finite element analysis. The scope of work for this study was: (1) to conduct static experiment test of Ti-cement with plastic holder and aluminum holder; (2) to determine the frictional coefficient of Ti-cement interface and cement-aluminum holder interface based on the experiment result; (3) to determine the cement thickness by comparing the deformation of Ti at Z axis, Von-Mises stress of S. Riahinezhad • Y. Li • M. Khandaker (*) Department of Engineering and Physics, University of Central Oklahoma, Edmond, OK 73034, USA e-mail: mkhandaker@uco.edu # The Society for Experimental Mechanics, Inc. 2017 Y. Zhu, A.T. Zehnder (eds.), Experimental and Applied Mechanics, Volume 4, Conference Proceedings of the Society for Experimental Mechanics Series, DOI 10.1007/978-3-319-42028-8_1 1