Fall from height in a stairwell--mechanics and simulation analysis.
The range of problems considered in the biomechanical analysis of a fall from height has been presented. A complicated case of a fall in a stairwell was investigated, the analysis of which demonstrates the research scale and aspect multitude. The scope of the article was restricted to the analysis of biomechanical problems and the simulation analysis of the event. A virtual 3D model of the stairwell was built using sketches, photographs and photogrammetric techniques. A dummy created according to the victim's data was parameterised. Using the PC-Crash biomechanical module a series of several hundred simulations were run following the adopted research plan, allowing for pre-formulated boundary conditions. The region of the stairwell where the accident was likely to originate and the victim's initial configuration were identified. It was proved that biomechanical simulation can bring invaluable benefits in exposing the mechanism of an event and verification of various hypotheses. Despite general similarities, each fall has its own specificity, which, making the use of methodological generalisations difficult, increases the significance of casuistry. The presented analysis can prove very useful in providing guidelines on investigating other cases.
Horizontal Distance and Height Determining Falling Pattern
Falling from a height, usually from a building, occurs ordinarily in suicide, in some accidents, and sometimes as an act of homicide. The point of trajectory, the horizontal distance and the impact point are closely related to the initial velocity, angle and height. This study examines the falling pattern in order to determine the mental status of the jumper as well as the manner of death. Initial velocity is found using horizontal movement and height. A serial study of athletes performing both the running jump (long jump) and standing jump (swimmer's start jump) via biomechanical methods is described. The initial velocity of the running jump and standing jump in normal athletics is 9.15 and 2.70 m/s with initial jumping angles of 21 and 38 deg, respectively. The maximal horizontal velocity of 9.15 m/s is closely related to maximal strength of initial velocity, angle of engaged force, and height. Theoretical estimation of the initial velocity between 2.70 and 9.15 m/s is correlative with the unique initial velocity and running jump to fall from a height that is closely related to the voluntary and attempted jump. Hence, the jumping victim with an initial velocity higher than 2.70 m/s implies suicide. These results indicate that horizontal distance and height are legitimate measures to use in speculating on the falling pattern and the manner of death. A unique case of suicide involving a run and jump with initial velocity greater than 2.70 m/s is illustrated.
An Optimization Approach to Occupant Safety and Fuel Economy in Vehicle Design
1. Abstract A major challenge in automotive design is the creation of safe vehicles with minimal environmental impact. This study presents a modeling framework for evaluating and optimizing body designs for improved occupant safety and fuel efficiency. Vehicle body mass is considered as the main link between safety and sustainability. The modeling framework includes frontal crash energy absorption, restraint system design and fuel economy. Preliminary results indicate a Pareto-optimal curve between safety and sustainability may exist when other factors are not taken into account. A more complete modeling framework that includes more sophisticated sustainability and safety metrics, cost and other market considerations, is suggested in order to support better design and regulatory decisions. 2. Keywords: Automotive body structures, fuel economy, occupant safety, optimal vehicle design, restraint systems