The use of dynamic mechanical analysis to assess the viscoelastic properties of human cortical bone

Abstract

The purpose of this study was to examine the use of a dynamic mechanical analyzer (DMA) system to study the viscoelastic nature of bone. Cortical bone specimens from human femora were tested isothermally for 150 min at 37 degrees C and the loss factor (tan delta) and storage modulus (E') were measured. To explore the effects of test conditions on tan delta and E', different levels of applied stress, two specimen sizes, and two hydration conditions (wet and vacuum-dried) were evaluated. Finally, nonisothermal tests were performed, wherein specimens were heated up to 70 degrees C at different heating rates: 1 degrees C/min, 3 degrees C/min, and 5 degrees C/min. The results indicated that a threshold level of minimum applied stress was required to obtain repeatable and relatively constant values of tan delta. Specimen size did not significantly affect tan delta although it influenced E'. Moisture content had a significant effect on tan delta; vacuum-dried specimens exhibited a lower tan delta compared to wet specimens. Lastly, heating rates influenced tan delta values with lower rates producing more consistent results. The study demonstrated that DMA can be used as an effective tool to test bone.

Analysis of anisotropic viscoelastoplastic properties of cortical bone tissues

“…This conclusion is consistent with the results of another study that showed the specimen-size effect on the storage modulus (Yamashita, 2001). Though DMA underestimated the values of elastic moduli, the anisotropic ratios for two directions for all positions were practically in the same range as those obtained from the quasi-static results -1.2 -1.8.…”

“…To achieve those functions, the skeleton system should have adequate mechanical properties such as strength, stiffness, and fracture toughness (Yamashita et al, 2001). Due to age-based properties deterioration together with an increased fracture susceptibility as an outcome of structural changes, various experimental studies investigating the effect of structural properties of the cortical bone and its mechanical properties have been conducted (Zioupos and Curry, 1998;Zioupos et al, 1999;Wachter et al, 2002;Curry, 2004;Augat and Schorlemmer, 2006).…”

Orientation Dependent Compressive Response of Human Femoral Cortical Bone as a Function of Strain Rate

“…The overall stress-strain trends of cortical bone measured in this study agree with bovine and equine studies in that the mechanical properties of the bone were anisotropic. Unfortunately, some investigators used dry bones for their studies, making it impractical to draw comparisons of the mechanical response to wet bones because of the significant effect of hydration of collagen on the mechanical behavior [14,15]. …”

“…This drying process has been shown to alter the mechanical response of bone due to the hydration-dependent behavior of bone collagen [14,15]. Katsamanis et al [16] studied the effect of loading rate on the elastic modulus and Poisson's ratio of human femoral cortical bone using one-dimensional wave theory and strain gages bonded to the surface of the bone in two directions at multiple locations.…”

Instructive composites for bone regeneration

“…This observation clashes with the fact that M50 has high storage modulus. [338] (F n physiologica 02, [339,340] valu n tangent ma of the compo ure 7), [338] thu eeded for load that water ca cally bind the ave already s ains through th nic acid. [332] In ndence of me ticles also affe higher apatite line solution ( .…”