The use of metallic foams as a filler in thin-walled structures can enhance their crashworthiness characteristics. It is believed that, tailoring the properties of the foam filler would enhance the effectiveness of these characteristics. This view is also supported by recent works in the literature. It is the objective of this study to examine the crush behaviour of functionally graded foam-filled tubes and evaluate the effect of discretely graded density upon the specific energy absorbed. Nonlinear parametric finite element simulations of the foam-filled tube were developed to estimate the most favourable foam density gradient in the lateral and axial directions. The effect of various design parameters such as density grading, number of grading layers, and thickness of the interactive layer upon the resulting specific energy absorption was investigated. The results show that the specific energy absorption of a tube filled with functionally graded foam is better than uniform density foam.

This project sets as its goal the development of an Intelligent Design paradigm that makes falsifiable predictions. According to Karl Popper, such falsifiability is a key component of scientific theories. To accomplish this, two hypothetical historical narratives are first outlined based on guided processes and the design points they predict. A biochemical approach to characterizing organisms then defines a protein's global functional limits as determining the set of amino acids that allow it to successfully perform its functions in any situation. The local functional limits restrict this potential substitution set to only those proteins viable within an individual genetic background. Proteins are referred to as the first-order of specified complexity because a protein's gene is the fundamental unit of inheritance. Other orders of specified complexity are described culminating in the organism level, which is the fundamental unit of selection. Each phylogenetic tree within the two intelligent design scenarios is founded by an original group or archetype. The descendants of this archetype are known as the archetype's genus. Speciation events within the genus are brought about by a slow process called co-adapted drift that creates distinct species through functional incompatibilities. A theory of natural selection is developed that attempts to characterize the relationship between the gene and the organism. Natural selection in this sense is described as a preservation mechanism that selects against deleterious phenotypes instead of selecting for beneficial ones. Finally, a practical methodology is developed that begins by determining the history of a gene in a given species by the symmetrical causal relationships of the alleles and the species allelic distribution. The original alleles in this species and their local functional limits are then compared with those of analogous genes in similar species to determine if these species were functionally compatible at that time. The two Intelligent Design paradigms predict patterns of incompatibilities, or design points, where guided actions were involved. This is a falsifiable prediction that raises the status of these paradigms in a Popperian sense.

Thesis (Ph.D.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references (ℓ. 156-163)

Thesis (Ph.D.) -- University of Rhode Island, 2005. / Typescript. Includes bibliographical references (leaves 201-207).

Thesis (M.S.)--Washington State University, December 2005. / Includes bibliographical references.

Thesis (Ph.D.) -- University of Rhode Island, 2009. / Typescript. Includes bibliographical references (leaves 171-177).

Thesis (M.S.) in Mechanical Engineering--University of Maine, 2005. / Includes vita. Includes bibliographical references (leaves 148-154).

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published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy