Fracture properties of an acrylic bone cement.

This study investigated experimentally the fracture properties, i.e., the fatigue strength, the resistance to crack propagation and the fracture toughness, of an acrylic bone cement (Cemex RX). The mean endurance limit was determined following the staircase method. The endurance limit was estimated at 9.2 MPa. The fatigue crack propagation rate was measured according to the ASTM E647 standard. The equation of the line fitting the crack growth per cycle (da/dN) versus the stress-intensity factor range (delta K), in a log-log graph, was used to calculate the empirical constants of Paris' law for the selected bone cement: da/dN (m/cycle) = 3.56 x 10(-7) x delta K (MPa x m1/2)5.79. This power-law relationship described well (R2 = 0.96) the growth rate in the stable crack growth region, i.e., in the mid delta K range. The fracture toughness K(IC) of the bone cement was determined according to the ASTM E399 standard. The K(IC) mean value was 1.38 MPa x m1/2. These experimental results provide the set of necessary inputs for numerical studies aimed to investigate the damage accumulation process in the mantle fixing cemented prostheses.