Abstract: In this paper, an analytical study is made for the dynamic behavior of human brain tissue under transient loading. In this analytical model the Mooney-Rivlin constitutive law is coupled with visco-elastic constitutive equations to take into account both the nonlinear and time-dependent mechanical behavior of brain tissue. Five ordinary differential equations representing the relationships of five main parameters (radial stress, circumferential stress, radial strain, circumferential strain, and particle velocity) are obtained by using the characteristic method to transform five partial differential equations (two continuity equations, one motion equation, and two constitutive equations). Analytical expressions of the attenuation properties for spherical wave in brain tissue are analytically derived. Numerical results are obtained based on the five ordinary differential equations. The mechanical responses (particle velocity and stress) of brain are compared at different radii including 5, 6, 10, 15 and 25 mm under four different input conditions. The results illustrate that loading curves types of the particle velocity significantly influences the stress in brain tissue. The understanding of the influence by the input loading cures can be used to reduce the potentially injury to brain under head impact by designing protective structures to control the loading curves types.
Abstract: For the last decade, statistics show traumatic brain
injury (TBI) is a growing concern in our legal system. In an effort to
obtain data regarding the influence of neuropsychological expert
witness testimony in a criminal case, this study tested three
hypotheses. H1: The majority of jurors will vote not guilty, due to
mild head injury. H2: The jurors will give more credence to the
testimony of the neuropsychologist rather than the psychiatrist. H3:
The jurors will be more lenient in their sentencing, given the
testimony of the neuropsychologist-s testimony. The criterion for
inclusion in the study as a participant is identical to those used for
inclusion in the eligibility for jury duty in the United States. A chisquared
test was performed to analyze the data for the three
hypotheses. The results supported all of the hypotheses; however
statistical significance was seen in H1 and H2 only.