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This study presents the results of indentation tests on the superior vertebral endplate of the 4th lumbar vertebra (L4) of eleven male cadaveric subjects (65 +/- 7 years). Three locations on the superior endplate surface were loaded with a 7.9 mm spherical indentor at either a low (1 mm/s) or high (1000 mm/s) rate. Anterior midline and posterior right and left indentation locations were chosen to prevent local deformations and fractures from influencing the results of subsequent and preceding tests. Peak forces were higher in the dynamic tests (498 +/- 261 N) than in the quasi-static tests (451 +/- 256 N) on the posterior side, although the difference was not significant (p = 0.139). However, the peak forces in the anterior tests (304 +/-166 N) were significantly lower (p =0.0157) than in the posterior tests with the same loading rate. The variation in failure forces in the current study correlates with the variation in thickness of endplate cortical bone (between specimens and between anterior and posterior locations on the same specimen) as measured from small field of view computed tomography scans.

The purpose of this study was to investigate the response and failure properties of the transverse and spinous vertebral processes under cantilever bending. Twelve human third lumbar vertebrae (L3) were harvested from donors aged 56-79 years, and the processes were loaded in either dynamic (1000 mm/s) or quasi-static (1 mm/s) cantilever bending. All of the spinous processes were loaded dynamically, and transverse process loading was alternated between dynamic and quasi-static and between right and left. Peak forces measured for the transverse processes were 252 +/- 77 N and 234 +/- 50 N in the dynamic and quasi-static tests, respectively, which corresponded to lack of rate sensitivity in the transverse process peak force for the range of loading rates considered (p=0.6). Peak forces measured for the spinous processes were 1179.6 +/- 587.1 N, and both subject mass (p=0.038) and subject age (p=0.006) were found to be significant predictors of peak force.

The purpose of this study was to investigate the magnitude of bending moment that results in fracture of the pedicles when lumbar vertebrae are loaded in four-point bending. Nine human second lumbar vertebrae (L2) were harvested from donors aged 59-75 years. The specimens were potted and then subjected to quasi-static sagittal-plane four-point bending, which allowed for a constant bending moment applied over a 3.8 cm span centered on the vertebral pedicles until fracture. The failure bending moment calculated for the pedicles varied widely (30.7 +/- 12.3 Nm) and was poorly correlated with subject age (y = -0.91x + 91.5, R(2) = -0.27). With increasing displacement, the bending moment applied to the pedicles increased, first linearly, followed by a non-linear portion, prior to specimen fracture. In general, the specimens failed at the interface of the pedicles and vertebral bodies, but failures were observed elsewhere as well. These data provide sufficient response and boundary condition information for finite element modeling and model validation.

The goal of this study was to investigate the response and failure properties of the human sternum under bending loading. Nine sternum specimens from post mortem human surrogates (n=7 male, n=2 female, age: 62.7 +/- 10.9 years) were extracted and potted in a three point bending test setup. Specimens were loaded to failure at their center points in bending at 1100 mm/s, with some specimens previously loaded in a non-failure quasi-static loading test. In two cases, the non-failure test was repeated to show that specimens were not damaged during non-failure testing. The sternum specimens were found generally to be unable to support shear forces in the anterior-posterior direction and as a result had relatively low failure moments (24.1 Nm +/- 20.1 Nm). While two of the specimens did fail in bending, the remaining specimens failed as a result of the high tensile forces introduced by the bending loads. These specimens first experienced compressive loads, and then, as the potted ends continued to rotate, tensile loads, which resulted in failure of the specimens (400-800 N).

Three-dimensional kinematics of body targets are frequently tracked during vehicle impact tests using instrumented cubes. While the components of linear acceleration and angular velocity are recorded in a cube local coordinate system, transformation to a global coordinate system is required to reconstruct the whole body motions. This paper presents a methodology for local-to-global kinematic transformations using a finite element cube model mounted on heads with local measurements. This methodology was used to reconstruct the head kinematics during occupant and pedestrian impact tests and shown to produce similar displacement, velocity, and acceleration results to those obtained by the Euler parameter method. In addition, the possible measurement errors of the local frame orientation were simulated and the proportional displacements and velocities were observed in simulation outputs: the maximum differences are 6.5 % of a global displacement and 9.1 % of a global velocity at applying a 10 degree rotated measurement error in the initial local frame.