For many mechanicians and materials scientists one of the most confounding things (in the ever increasing literature on carbon nanotubes) is the reported theoretical value of the nanotube elastic modulus. Depending upon the specific paper at hand, the reported numerical values range from 1 -6 TPa!
Initially posted on Applied Mechanics News on 28 April 2007.
Hot rolling from ingot is the dominant fabrication method of producing plate, sheet, and foil aluminum products. It is a striking fact that the total rolling-plant recovery of aluminum process from ingot to final products is typically about 50%. This recovery loss causes enormous amount of energy waste both as remelt energy and energy to process material that is just recycled. Assuming the annual US domestic net shipments of sheet and plate products being 10,500 million lb, 10% improvement of the hot rolling recovery will result annual savings of $126 million per year for the US domestic aluminum industry. The annual domestic energy savings would be 2.54 trillion Btu. The environmental benefits include annual reduction of 2.32 million lb SOx , 1.01 million lb NOx, 303.2 million lb CO2, 0.67 million lb of particulate, and 11000 lb VOCsd .
The fundamental inability to reduce or eliminate these recovery losses is “lack of the integrated models that relate structural properties to manufacturing processes”. Currently, processing parameters are determined by trial and error and largely based on experience. This makes it difficult to optimize the process even on the macroscale level, and almost impossible from microstructure level. Research in the following areas are desirable:
The number of registered iMechanicians has just passed 1000 today. iMechanica went "officially" online on 9 September 2006. See other numbers of iMechanica recorded today, and our evolving history.
This blog focuses on the behaviors of energetic materials (such as solid rocket propellants, high explosives), shock waves, and explosions. And also on the protections, from the design of protecting materials and structures.
Lecture notes:
The following is a link to a FEMA course
The following are links to the FEMA (Federal Emergency Management Agency) documents:
Mitigating the threat of terrorist attacks against high occupancy buildings is a challenging task.
Chapter 1: ASSET VALUE, THREAT/HAZARD, VULNERABILITY, AND RISK
This chapter presents several methodologies for architects and engineers to quantify risk and to identify the most effective mitigation measures to achieve a desired level of protection against terrorist attacks at an acceptable cost.
16.223 Mechanics of Heterogeneous Materials
Course Description: Mechanical behavior of heterogeneous materials such as thin-film microelectromechanical systems (MEMS) materials and advanced filamentary composites, with particular emphasis on laminated structural configurations. Anisotropic and crystallographic elasticity formulations. Structure, properties and mechanics of constituents such as films, substrates, active materials, fibers, and matrices including nano- and micro-scale constituents. Effective properties from constituent properties. Classical laminated plate theory for modeling structural behavior including extrinsic and intrinsic strains and stresses such as environmental effects. Introduction to buckling of plates and nonlinear (deformations) plate theory. Other issues in modeling heterogeneous materials such as fracture/failure of laminated structures.
