A two-dimensional analysis of the biomechanics of frontal and occipital head impact injuries

Gilchrist, Michael D.; O’Donoghue, D.; Horgan, TJ

doi:10.1533/cras.2001.0176

Cited by 35 publications

(19 citation statements)

References 12 publications

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“…The STI rather than the energy absorption, gravity centre acceleration and HIC, may reflect these phenomena effectively. These findings conform to the general concepts regarding the head injury, i.e., 'the risk of injury is related to the energy delivered to the body by the impacting object as well as the object's shape' and 'the rate of loading and thus the strain rate is also an important factor in causing injury since biological tissues are viscoelastic [11][12][13][14].…”

Section: Introductionsupporting

confidence: 85%

Effects of head size and morphology on dynamic responses to impact loading

Wang

Lee

2007

Med Bio Eng Comput

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Head responses subjected to impact loading are studied using the finite element method. The dynamic responses of the stress, strain, strain energy density and the intracranial pressure govern the intracranial tissues and skull material failures, and therefore, the traumatic injuries. The objectivity and consistency of the prevailing head traumatic injury criteria, i.e., the energy absorption, the gravity centre acceleration and the head injury criterion (HIC), are examined with regard to the head dynamic responses. In particular, the structural intensity (STI) (the vector representation of energy flow rate) is calculated and discussed. From the simulations, the STI, instead of the gravity centre acceleration, the HIC and the energy absorption criteria, is found to be consistent with the dynamic response quantities. The different local skull curvatures at impact have a marginal effect whereas the locations of the impact loadings have significant effects on the dynamics responses or the head injury. The STI also shows the failure patterns.

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Section: Introductionsupporting

confidence: 85%

Effects of head size and morphology on dynamic responses to impact loading

Wang

Lee

2007

Med Bio Eng Comput

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“…Impact- and/or acceleration-induced brain traumatic injuries have already been the focus of many cellular and macroscopical studies through in vivo [3, 4, 5, 6, 7, 8, 9, 10], ex vivo [11, 12], in vitro [13, 14, 15, 16, 17], medical postanalysis [18, 19, 20] or modeling approaches [21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34]. However the specific effects of a blast—a pressure wave of finite amplitude generated by a rapid release of energy [35]—on the brain is still widely unkown.…”

Section: Introductionmentioning

confidence: 99%

Continuum modeling of a neuronal cell under blast loading

Jérusalem

Dao

2012

Acta Biomaterialia

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Traumatic brain injuries have recently been put under the spotlight as one of the most important causes of accidental brain dysfunctions. Significant experimental and modeling efforts are thus ongoing to study the associated biological, mechanical and physical mechanisms. In the field of cell mechanics, progresses are also being made at the experimental and modeling levels to better characterize many of the cell functions such as differentiation, growth, migration and death, among others. The work presented here aims at bridging both efforts by proposing a continuum model of neuronal cell submitted to blast loading. In this approach, cytoplasm, nucleus and membrane (plus cortex) are differentiated in a representative cell geometry, and different material constitutive models are adequately chosen for each one. The material parameters are calibrated against published experimental work of cell nanoindentation at multiple rates. The final cell model is ultimately subjected to blast loading within a complete fluid-structure interaction computational framework. The results are compared to the nanoindentation simulation and the specific effects of the blast wave on the pressure and shear levels at the interfaces are identified. As a conclusion, the presented model successfully captures some of the intrinsic intracellular phenomena occurring during its deformation under blast loading and potentially leading to cell damage. It suggests more particularly the localization of damage at the nucleus membrane similarly to what has already been observed at the overall cell membrane. This degree of damage is additionally predicted to be worsened by a longer blast positive phase duration. As a conclusion, the proposed model ultimately provides a new three dimensional computational tool to evaluate intracellular damage during blast loading.

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“…In overarm attacks, the knife speed upon entry is approximately 10 m/s while for underarm attacks it is closer to 7 m/s. Injuries to the human head including scalp laceration and skull fracture, by contrast, can occur from impact against blunt objects at linear velocities in the order of 4 m/s [16][17][18] whereas impacts against sharp objects at even slower speeds can also lead to soft tissue cranial injuries [19,20]. It is reasonable to assume that slow or walk-on stab speeds would occur at velocities in the order of 1.0 m/s, i.e., speeds comparable to typical walking speeds.…”

Section: Introductionmentioning

confidence: 99%

Measuring knife stab penetration into skin simulant using a novel biaxial tension device

Gilchrist

Keenan

Curtis³

et al. 2008

Forensic Science International

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This paper describes the development and use of a biaxial measurement device to analyse the mechanics of knife stabbings. In medicolegal situations it is typical to describe the consequences of a stabbing incident in relative terms that are qualitative and descriptive without being numerically quantitative. Here, the mechanical variables involved in the possible range of knife-tissue penetration events are considered so as to determine the necessary parameters that would need to be controlled in a measurement device. These include knife geometry, in-plane mechanical stress state of skin, angle and speed of knife penetration, and underlying fascia such as muscle or cartilage. Four commonly available household knives with different geometries were used: the blade tips in all cases were single-edged, double-sided and without serrations. Appropriate synthetic materials were used to simulate the response of skin, fat and cartilage, namely polyurethane, compliant foam and ballistic soap, respectively. The force and energy applied by the blade of the knife and the out of plane displacement of the skin were all used successfully to identify the occurrence of skin penetration. The skin tension is shown to have a direct effect on both the force and energy for knife penetration and the depth of out of plane displacement of the skin simulant prior to penetration: larger levels of in-plane tension in the skin are associated with lower penetration forces, energies and displacements. Less force and energy are also required to puncture the skin when the plane of the blade is parallel to a direction of greater skin tension than when perpendicular. This is consistent with the observed behaviour when cutting biological skin: less force is required to cut parallel to the Langer lines than perpendicularly and less force is required to cut when the skin is under a greater level of tension. Finally, and perhaps somewhat surprisingly, evidence is shown to suggest that the quality control processes used to manufacture knives fail to produce consistently uniform blade points in knives that are nominally identical. The consequences of this are that the penetration forces associated with nominally identical knives can vary by as much as 100%.

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A two-dimensional analysis of the biomechanics of frontal and occipital head impact injuries

Cited by 35 publications

References 12 publications

Effects of head size and morphology on dynamic responses to impact loading

Effects of head size and morphology on dynamic responses to impact loading

Continuum modeling of a neuronal cell under blast loading

Measuring knife stab penetration into skin simulant using a novel biaxial tension device

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