Biomechanical Analysis of Wrist Impact Loading During Fall Arrests: Experimental and Computer Simulation Study

This dissertation research focuses on comprehensive analyses of the wrist impact loading during fall arrests through experimental measurement and computer simulation. Two experiments are conducted for measurement of the impact loading profiles during simulated falls and for identification of the roles of wrist protectors in reducing the impact loading. Finite element modal analysis and transient dynamic analysis are performed using 3D human forearm models reconstructed from the Visible Human Project® (VHP) datasets. The objectives of this computer simulation research are to develop anatomically based finite element (FE) models of the human forearm, to clarify the effect of the loading rates on the distal radius during fall arrests, and to provide helpful information in designing wrist protectors.

In this research, impact loading on the wrist during fall arrests is to be measured in a simulated fall experiment. Several biomechanical param eters are to be extracted from the force profiles, and the statistical assessm ent are to be made to understand the effects of different fall directions, wrist guard usage, and landing conditions.

In this study, a new efficient image segmentation technique is proposed to extract boundary curves from series of 2D color images from VHP dataset. A method to avoid skewed surfaces during 3D reconstruction process is also developed to get more accurate geometric models of the forearm complex.

Using the geometric models FE modal analyses are conducted to calibrate the mechanical properties of the parts of each forearm bone. Natural frequencies and their mode shapes of the ulna and radius are estimated. With the experimentally measured force profiles, FE transient analyses of the forearm complex are conducted to investigate the effects of the loading rate on the distal radius.

Based on the results of the transient analysis, another impact experiment is conducted to identify the roles of palmar splint of wrist guards in reducing the impact loading and to improve the efficacy of the wrist guards.

Year	Entry
1980	Nagurka ML, Hayes WC. An interactive graphics package for calculating cross-sectional properties of complex shapes. J Biomech. 1980;13(1):59-64.
1999	Ulrich D, van Rietbergen B, Laib A, Rüegsegger P. Load transfer analysis of the distal radius from in-vivo high-resolution CT-imaging. J Biomech. August 1999;32(8):821-828.
1993	Keyak JH, Fourkas MG, Meagher JM, Skinner HB. Validation of an automated method of three-dimensional finite element modelling of bone. J Biomed Eng. November 1993;15(6):505-509.
1995	Tran NT, Watson NA, Tencer AF, Ching RP, Anderson PA. Mechanism of the burst fracture in the thoracolumbar spine: the effect of loading rate. Spine. September 15, 1995;20(18):1984-1988.
2001	van Rietbergen B, Huiskes R. Elastic constants of cancellous bone. In: Cowin SC, ed. Bone Mechanics Handbook. 2nd ed. Boca Raton, FL: CRC Press; 2001:chap 15.
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Year

Entry

1980

Nagurka ML, Hayes WC. An interactive graphics package for calculating cross-sectional properties of complex shapes. J Biomech. 1980;13(1):59-64.

1999

Ulrich D, van Rietbergen B, Laib A, Rüegsegger P. Load transfer analysis of the distal radius from in-vivo high-resolution CT-imaging. J Biomech. August 1999;32(8):821-828.

1993

Keyak JH, Fourkas MG, Meagher JM, Skinner HB. Validation of an automated method of three-dimensional finite element modelling of bone. J Biomed Eng. November 1993;15(6):505-509.

1995

Tran NT, Watson NA, Tencer AF, Ching RP, Anderson PA. Mechanism of the burst fracture in the thoracolumbar spine: the effect of loading rate. Spine. September 15, 1995;20(18):1984-1988.

2001

van Rietbergen B, Huiskes R. Elastic constants of cancellous bone. In: Cowin SC, ed. Bone Mechanics Handbook. 2nd ed. Boca Raton, FL: CRC Press; 2001:chap 15.