Biomechanics of the Upper Extremity in Response to Dynamic Impact Loading Indicative of a Forward Fall: An Experimental and Numerical Investigation.
Date of Award
Industrial and Manufacturing Systems Engineering
Andrews, David (Industrial and Manufacturing Systems Engineering)
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The distal radius is one of the most common fracture sites in humans, often resulting from a forward fall with more than 60 % of all fractures to the wrist requiring some form of surgical intervention. Although there is a general consensus regarding the risk factors for distal radius fractures resulting from forward falling, prevention of these injuries requires a more thorough understanding of the injury mechanisms. Therefore the overall purpose of this dissertation was to assess the response of the upper extremity to impact loading to improve the understanding of distal radius fracture mechanisms and the effectiveness of joint kinematic strategies for reducing the impact effects. Three main studies were conducted that utilized in vivo, in vitro and numerical techniques. In vitro impact testing of the distal radius revealed that fracture will occur at a mean (SD) resultant impact force and velocity of 2142.1(1228.7) N and 3.4 (0.7) m/s, respectively. Based on the failure data, multi-variate injury criteria models were produced, highlighting the dynamic and multidirectional nature of distal radius fractures The in vitro investigation was also used to develop and validate a finite element model of the distal radius. Dynamic impacts were simulated in LS-DYNA and the resulting z-axis force validation metrics (0.23-0.54) suggest that this is a valid model. A comparison of the experimental fracture patterns to those predicted numerically (i.e. von-Mises stress criteria) shows the finite element model is capable of accurately predicting bone failure.
Burkhart, Timothy, "Biomechanics of the Upper Extremity in Response to Dynamic Impact Loading Indicative of a Forward Fall: An Experimental and Numerical Investigation." (2011). Electronic Theses and Dissertations. 451.