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Full-Text Articles in Mechanical Engineering
On The Effective Elastic Properties Of Macroscopically Isotropic Media Containing Randomly Dispersed Spherical Particles, D. Cojocaru, Anette M. Karlsson
On The Effective Elastic Properties Of Macroscopically Isotropic Media Containing Randomly Dispersed Spherical Particles, D. Cojocaru, Anette M. Karlsson
Mechanical Engineering Faculty Publications
computational scheme for estimating the effective elastic properties of a particle reinforced matrix is investigated. The randomly distributed same-sized spherical particles are assumed to result in a composite material that is macroscopically isotropic. The scheme results in a computational efficient method to establish the correct bulk and shear moduli by representing the three-dimensional (3D) structure in a two-dimensional configuration. To this end, the statistically equivalent area fraction is defined in this work, which depends on two parameters: the particle volume fraction and the number of particles in the 3D volume element. We suggest that using the statistically equivalent area fraction,introduced …
Determining Equi-Biaxial Residual Stress And Mechanical Properties From The Force-Displacement Curves Of Conical Microindentation, J. Yan, X. Chen, Anette M. Karlsson
Determining Equi-Biaxial Residual Stress And Mechanical Properties From The Force-Displacement Curves Of Conical Microindentation, J. Yan, X. Chen, Anette M. Karlsson
Mechanical Engineering Faculty Publications
An alternative, improved method to determine mechanical properties from indentation testing is presented. This method can determine the elastic modulus, yield strength and equi-biaxial residual stress from one simple test. Furthermore,the technique does not require the knowledge of the contact area during indentation, a parameter that is hard to determine for highly elastic material. The evaluation technique is based on finite element analyses, where explicit formulations are established to correlate the parameter groups governing indentation on stressed specimens.
Stresses In Proton Exchange Membranes Due To Hygro-Thermal Loading, Yaliang Tang, Michael H. Santare, Anette M. Karlsson, Simon Cleghorn, William B. Johnson
Stresses In Proton Exchange Membranes Due To Hygro-Thermal Loading, Yaliang Tang, Michael H. Santare, Anette M. Karlsson, Simon Cleghorn, William B. Johnson
Mechanical Engineering Faculty Publications
Durability of the proton exchange membrane (PEM) is a major technical barrier to the commercial viability of polymer electrolyte membrane fuel cells (PEMFC) for stationary and transportation applications. In order to reach Department of Energy objectives for automotive PEMFCs, an operating design lifetime of at least 5000 h over a broad temperature range is required. Reaching these lifetimes is an extremely difficult technical challenge. Though good progress has been made in recent years, there are still issues that need to be addressed to assure successful, economically viable, long-term operation of PEM fuel cells. Fuel cell lifetime is currently limited by …