Impact dynamics of mechanical systems and structures, and applications in crash energy management, impulse mitigation, and impact injury biomechanics
Abstract
Among the different load conditions on a mechanical system, impact loading and its
contribution to the design process require special consideration. The static methods of stress,
strain, and deflection analyses are not applicable under impact conditions. The main goal of this
study is to address the fundamental aspects of impact and to examine its applications for
different design requirements. First, different approaches to the impact phenomena, namely
stereomechanics, contact mechanics, stress wave propagation, finite element method, and energy
method are investigated in this dissertation. The advantages and disadvantages of each method
are pointed out, and the areas of application of each method and the degree of accuracy are
examined. Quantification of energy absorption during impact is the most complicated part of
impact modeling and is one of the topics of interest addressed in this dissertation.
Application of the impact analysis methodologies in vehicular accidents and protection of
occupants are the eventual goals of this research, demonstrated using some case studies and
applicable examples. Because occupant safety is a major concern in the automobile and
aerospace industries, a crashworthy design must be able to dissipate the kinetic energy of impact
in a controlled manner. Four test cases or applications related to impact energy management or
dissipation, impulse mitigation, and impact injury biodynamics are thus presented. The
application examples include the design of a truck side guard and quantification of its effects on
reducing occupant injury in the collison of a small car with a truck; lumbar load attenuation for
seated occupants of a rotorcraft; injuries to pedestrians impacted by a sport or utility vehicle
equipped with a frontal guard; and investigation of a motorcyclist impact with roadside barriers.
For each case, an analysis methodolgy is developed, and from the modeling and simulations,
impact design issues are addressed.
Description
Thesis (Ph.D.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering