Showing papers by "Hamid Garmestani published in 1996"
TL;DR: In this article, an analytical solution for the stress analysis of superconducting solenoids is given which reflects the full spatial variation of Lorentz body forces and includes shear stress components.
Abstract: An analytical solution for the stress analysis of superconducting solenoids is given which reflects the full spatial variation of Lorentz body forces and includes shear stress components. The solution is based on power series expansions of the Lorentz body forces and the displacements which in turn gives the strains and stresses, including shear stress components. This solution is applicable to the windings and reinforcement layers of magnets and is compared to a finite element method using a 7 T sample magnet with reinforcement.
9 citations
TL;DR: In this article, the authors investigated the plastic behavior of a superconducting material and the corresponding elastoplastic formulation for the distribution of stress and strain in a solenoid magnet.
Abstract: The plastic behavior of a superconducting material is investigated and the corresponding elastoplastic formulation for the distribution of stress and strain in a superconducting solenoid magnet is presented. The analysis calculates stress and strain at the midsection, where tangential stress exhibits its maximum value and shear stress is negligible. The prediction of stress and strain is essential for both the mechanical and electrical design of high‐field superconducting magnets containing Nb3Sn superconductor. The concept of plasticity is introduced for the first time in the context of magnet design for Nb3Sn conductor and compared to alternative approaches using conventional elasticity theory. Individual coil sections of a superconducting magnet can be reinforced by an outer section of structural material, the effect of which is included in this formulation. The results show that the elasticity approach using the ‘‘secant modulus method’’ does not fully predict the strain distribution; however, it can be used to approximate the stresses. It is shown that for an accurate strain prediction the true nonlinear elastoplastic nature of the superconducting materials should be considered and proper yield criteria should be used. The inaccurate prediction of strains (tangential or radial) can affect critical current density and the evaluation of the reinforcements.
9 citations
4 citations
TL;DR: In this paper, texture analysis was conducted on gamma titanium aluminide (gamma)-TiAl strips produced using the recently developed plasma melt overflow process, and the results indicated that,, and texture components were all observed in the {alpha sub 2}-phase.
Abstract: Texture analyses have been conducted on gamma titanium aluminide ({gamma}-TiAl) strips produced using the recently developed plasma melt overflow process. The results indicated that , , and texture components were all observed in the {alpha}{sub 2}-phase. After annealing at 1,065 C/48 hrs., the {gamma}-phase textures did not change while the {alpha}{sub 2}-phase changed from a basal to a texture. It is suggested that the texture development in direct cast {gamma} strips produced using this technique are a direct result of lattice rotations and residual stresses caused by nonuniform cooling.