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Cleveland State University

Durability

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Full-Text Articles in Mechanical Engineering

High Strength And Light-Weight Materials Inspired By The Exoskeleton Of Arthropods, Anette M. Karlsson May 2010

High Strength And Light-Weight Materials Inspired By The Exoskeleton Of Arthropods, Anette M. Karlsson

Mechanical Engineering Faculty Publications

This work investigates the multiscaled structure and the constitutive behavior of the exoskeleton of arthropods (Japanese beetle) along with the response of biomimicked structures. Image analysis (SEM and TEM) revealed three load-bearing regions comprised of chitin-protein fiber layers orientated parallel to the cuticle surface. The chitin fibers in the exocuticle and mesocuticle are organized in a helicoidal structure (layers stacked with a small rotational angle relative to their adjacent layers). The endocuticle has a distinct pseudo-orthogonal pattern, characterized by a thin transitional helicoidal region inserted between two orthogonal layers. Idealized mechanics based models showed that the pseudo-orthogonal structure redistributes the …


Numerical Investigation Of Mechanical Durability In Polymer Electrolyte Membrane Fuel Cells, Ahmet Kusoglu, Michael H. Santare, Anette M. Karlsson, Simon Cleghorn, William B. Johnson Jan 2010

Numerical Investigation Of Mechanical Durability In Polymer Electrolyte Membrane Fuel Cells, Ahmet Kusoglu, Michael H. Santare, Anette M. Karlsson, Simon Cleghorn, William B. Johnson

Mechanical Engineering Faculty Publications

The relationship between the mechanical behavior and water transport in the membrane electrode assembly (MEA) is numerically investigated. Swelling plays a key role in the mechanical response of the MEA during fuel cell operation because swelling can be directly linked to the development of stresses. Thus, in the model introduced here, the stresses and the water distribution are coupled. Two membranes are studied: unreinforced perfluorosulfonic acid (PFSA) and an experimental reinforced composite membrane. The results suggest that open-circuit voltage operations lead to a uniform distribution of stresses and plastic deformation, whereas under current-load operation, the stresses and the plastic deformation …