Sander's Theory Research Articles

Elasto/visco-plastic deformation of multi-layered shells of revolution.

This paper is concerned with an analytical formulation and a numerical solution of the elasto/visco-plastic problems of multi-layered shells of revolution under asymmetrical loads with application to a cylindrical shell. The analytical formulation is developed by extending the Sanders theory on elastic shells. It is assumed that the total strain rates are composed of an elastic part and a part due to visco-plasticity. The elastic strains are proportional to the stresses by Hooke's law. The visco-plastic strain rates are related to the stresses by Perzyna's equation. As a numerical example, the elasto/visco-plastic deformation of a two-layered cylindrical shell composed of a titanium and a mild steel layer subjected to locally distributed loads is analyzed. Numerical computations have been carried out for three cases of the ratio of the thickness of the titanium layer to the shell thickness. It is found from the computations that the stress distributions and the deformation are significantly varied depending on the ratio.

Computer evaluation of primary deposited energy profiles in ion-implanted silicon under channeling conditions

Primary deposited energy profiles produced by 40-keV P ions channeled along the [110] direction in silicon are computed. The model takes into account impact-parameter-dependent electronic energy loss and dechanneling mechanisms, such as thermal vibrations, electronic scattering, and a surface oxide layer. The deposited energy is converted to damage by using Kinchin and Pease's model and distributed along the range of primary recoils or dechanneled ions in two ways: either uniformly or localized at the average damage depth, evaluated using Winterbon, Sigmund, and Sanders's theory. The model is tested for the random case with experiments available. When no dechanneling mechanism is present, radiation damage is reduced by a factor of 10 compared to the random case. Thermal vibrations increase damage almost uniformly along all the channeled path, while the oxide layer increases the damage mostly at the surface. The combined effect of these mechanisms gives a reduction of radiation damage of only a factor of [inverted lazy s]2 compared to the random case. The results show also that damage is mostly concentrated at the surface: about 85% in the first 2000 Å compared to a maximum penetration of 7600 Å.

Linear structures and their relation to movement in the Caledonides of Scandinavia and Scotland

Summary The author considers that, although Dr. D. B. McIntyre's geometrical reconstruction of the structures observed in mid-Strathspey (1951, Q.J.G.S. 107 , 1–22) may be essentially correct, his kinematic interpretation of the structures is open to question. Dr. Mclntyre's evidence is discussed briefly. Sander's evidence for his theory of the relation of plane of symmetry to direction of movement is also reviewed. Structures in the Caledonides of Norway cannot be brought into agreement with Sander's theory, and it is concluded that the theory needs modification. A plane of symmetry may be formed at right angles to a lineation which is parallel to the direction of movement. Linear structures reflect local conditions of deformation and may under certain conditions be formed at any angle with the principal direction of movement. Brief remarks are given on the formation of a lineation and on the general picture of linear structures in the Caledonides. Comments are made on the occurrence of minor linear structures in the Scottish Highlands, and their importance. Variation in trend of linear structures in the Highlands is briefly discussed. It is suggested that when the linear structures of the Highlands are more completely known it may be possible to explain all structures as having been formed during the Caledonian orogeny. The Moinian and the Dalradian may both be Caledonian geosynclinal sediments, corresponding to the Norwegian Sparagmite Formation and Soros Group respectively.