A review of shape memory alloy research, applications and opportunities

Blast exposure is associated with traumatic brain injury (TBI), neuropsychiatric symptoms, and long-term cognitive disability. We examined a case series of postmortem brains from U.S. military veterans exposed to blast and/or concussive injury. We found evidence of chronic traumatic encephalopathy (CTE), a tau protein–linked neurodegenerative disease, that was similar to the CTE neuropathology observed in young amateur American football players and a professional wrestler with histories of concussive injuries. We developed a blast neurotrauma mouse model that recapitulated CTE-linked neuropathology in wild-type C57BL/6 mice 2 weeks after exposure to a single blast. Blast-exposed mice demonstrated phosphorylated tauopathy, myelinated axonopathy, microvasculopathy, chronic neuroinflammation, and neurodegeneration in the absence of macroscopic tissue damage or hemorrhage. Blast exposure induced persistent hippocampal-dependent learning and memory deficits that persisted for at least 1 month and correlated with impaired axonal conduction and defective activity-dependent long-term potentiation of synaptic transmission. Intracerebral pressure recordings demonstrated that shock waves traversed the mouse brain with minimal change and without thoracic contributions. Kinematic analysis revealed blast-induced head oscillation at accelerations sufficient to cause brain injury. Head immobilization during blast exposure prevented blast-induced learning and memory deficits. The contribution of blast wind to injurious head acceleration may be a primary injury mechanism leading to blast-related TBI and CTE. These results identify common pathogenic determinants leading to CTE in blast-exposed military veterans and head-injured athletes and additionally provide mechanistic evidence linking blast exposure to persistent impairments in neurophysiological function, learning, and memory.

Chronic traumatic encephalopathy in blast-exposed military veterans and a blast neurotrauma mouse model.

Magnesium casting technology for structural applications

Characterization of polymeric structural foams under compressive impact loading by means of energy-absorption diagram

The paper reviews the roots, the state-of-the-art and perspectives of multibody system dynamics. Some historical remarks show that multibody system dynamics is based on classical mechanics and its engineering applications ranging from mechanisms, gyroscopes, satellites and robots to biomechanics. The state-of-the-art in rigid multibody systems is presented with reference to textbooks and proceedings. Multibody system dynamics is characterized by algorithms or formalisms, respectively, ready for computer implementation. As a result simulation and animation are most important. The state-of-the-art in flexible multibody systems is considered in a companion review by Shabana.

https://hosting.umons.ac.be/html/mecara/grasmech/PaperSchiehlen.pdf

Multibody System Dynamics: Roots and Perspectives

Numerical analyses frequently accompany experimental investigations that study injury biomechanics and improvements in automotive safety. Limited by computational speed, earlier mathematical models tended to simplify the system under study so that a set of differential equations could be written and solved. Advances in computing technology and analysis software have enabled the development of many sophisticated models that have the potential to provide a more comprehensive understanding of human impact response, injury mechanisms, and tolerance. In this article, 50 years of publications on numerical modeling published in the Stapp Car Crash Conference Proceedings and Journal were reviewed. These models were based on: (a) author-developed equations and software, (b) public and commercially available programs to solve rigid body dynamic models (such as MVMA2D, CAL3D or ATB, and MADYMO), and (c) finite element models. A clear trend that can be observed is the increasing use of the finite element method for model development. A review of these modeling papers clearly indicates the progression of the state-of-the-art in computational methods and technologies in injury biomechanics.

Development of numerical models for injury biomechanics research: a review of 50 years of publications in the Stapp Car Crash Conference.

Mathematical modelling, simulation and experimental testing of biomechanical system crash response.

An energy absorbing vehicle door includes an inner panel, an outer panel joined to the inner panel, a door trim panel mounted on the inner panel, and energy absorbing bolsters protracting through the door trim panel for movement independently into an occupant compartment of the vehicle during a side collision type impact of the vehicle door.

Energy absorbing vehicle door and side panels

A rollover sensing system ( 12 ) that may be used in the determination of when to deploy restraints in the vehicle. The rollover sensing system ( 12 ) may include lateral acceleration sensors ( 32 ), a roll rate sensor ( 18 ) and a roll angle detector ( 20 ). A control circuit ( 16 ) determines a predetermined rollover threshold in response to the roll rate and roll angle detector ( 20 ) and calculates an adjusted threshold as a function of the predetermined rollover threshold and the lateral acceleration. The control circuit ( 16 ) generates a control signal in response to the adjusted threshold.

Method and apparatus for detecting rollover of an automotive vehicle

An improved structure is provided for supporting pillars of automotive vehicles which provides energy absorption through provision of three stamped metallic panels (24, 26, 28) defining first and second energy absorbing chambers (56, 58) therebetween and an interior trim cover (30) joined to all the panels and defining a third chamber (62) between it and the interior of the three panels and selected energy absorbing media carried between the trim cover and the interior of the panels. Generally C-shaped spring structures (74) and plastic honeycomb structures (68) are preferred for the energy absorbing media.

Clifford C. Chou

Papers

Development of numerical models for injury biomechanics research: a review of 50 years of publications in the Stapp Car Crash Conference.

Mathematical modelling, simulation and experimental testing of biomechanical system crash response.

Energy absorbing vehicle door and side panels

Method and apparatus for detecting rollover of an automotive vehicle

Energy absorbing vehicle pillar structure