Microcrack accumulation at different intervals during fatigue testing of compact bone

Variability and anisotropy of mechanical behavior of cortical bone in tension and compression

“…With micro-crack initiated at low stress levels (O'Brien et al, 2003), damage could start well before the material yields. At the same time, stiffness reduction was suppressed at compressive conditions due to the closing of cracks (Kasiri et al, 2010).…”

Distribution of microcrack lengths in bone in vivo and in vitro

“…We collected data on the lengths of individual microcracks, using results obtained previously from our research group, consisting of in vivo ovine bone data [15], bovine bone data from work published previously [16] and bovine bone data obtained from new tests as described below. We also contacted other researchers, who had published work in this field [17,18], who kindly agreed to provide us with their original crack length measurements which had not appeared in their publications.…”

“…In this work we used the same protocol as described previously [16], the only difference being the stress level. Ten cylindrical samples of bovine bone were obtained using a coring device, the longitudinal axis of the sample corresponding to the bone's axis.…”

“…in vivo cracks); after 50,000 cycles and after fracture or one million cycles, whichever happened first. The reason for selecting 50,000 cycles for the second dye was to detect microcracks which formed after a relatively small number of cycles, compared to the number of cycles to failure, since it has previously been observed that significant numbers of cracks form in this early stage [16].…”

“…For the Weibull distribution the form is: Figure 5 shows an example of the data analysis, in this case for data relating to the in vivo cracks found in bovine tibiae as reported in [16]. The data are plotted on two probability density plots, in one plot the axes are chosen such that the data should lie on a straight line if they conform to a normal (i.e.…”