ISSN:
1741-2765
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Couple-stress effects in materials have received much theoretical consideration recently but little or no experimental verification. The first part of this paper deals with a simplified elastic analysis for thin plates with couple stress which should provide a simple experimental approach to the determination of the order of magnitude of these effects. Classical concepts were utilized where applicable and many existing solutions can be modified by the present analysis to include couple stress. In the second part, experiments approximating cylindrical bending were carried out on plates of commercial-grade low-carbon steel and high-purity aluminum in the annealed and wrought conditions in order to establish the order of magnitude of the couple stress constantl as found in a simple couple-stress theory. Results were compared with classical theory and other experimental data correlated by the Neuber method to determine whether or not the couple-stress effect as predicted by a simple couple-stress theory could account for the reduction in the stress concentration found for small-radius notches and holes. It was found that the order of magnitude ofl was not greater than 0.002 in. rather than 0.02 in. as would be required to explain the above-mentioned reduction in stress concentration. Since the grain size of those materials was also ≅0.002 in., it was concluded that: (a) Couple-stress effects predicted by a simple theory were not significant enough to account for the reduction of stress concentration noted above for the material tested. (b) Due to the fact thatl was the same or likely smaller than the order of magnitude of the grain size, it would appear that theoretical foundations other than the isotropic, homogeneous, continuum simple-theory description employed here would be necessary to pursue the problem in further detail.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02326308
Permalink