Strain and temperature dependences in anisotropic constitutive equations for metal plasticity

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Personal computer controlled combined stress testing machine was developed in 1991. For investigation into anisotropic elastic-viscoplastic behavior of metals at high temperature, an electric furnace attachable to this testing machine and temperature controller were designed and developed. Rods for combined axial and torsional loading with water-cooler were also designed and developed. The expense for developments of these apparata was supported by this grant. The change in outer diameter and gauge length and torsional deformation of specimen are transmitted to outside of the furnace. Since the apparatus for measuring outer diameter is fixed to the wall of furnace, anvils slip on the surface of the specimen. The noise caused by slip is smoothed out by data processing. The change in diameter is detected by strain gauges on thin plates. The measuring apparatus for combined axial and torsional deformation must be attached to specimen without constraint to the deformation of the specimen. … More But usual protrusion is not adequate for thin-walled specimen. To cope with this problem, smooth specimen was adopted and a device with link and weight was designed. In the designed measuring apparatus, the axial and torsional deformation is separated and detected by differential transformer. The expense for four sets of transformer and connecting cable and braket was supported by this grant. The multi-displacement meter for these transformers was an another outlay. But the designed apparatus could not be developed because of shortage of expense.Relating to this project, a software for room temperature experiments of bilinear plastic strain path and determination of subsequent yield surface was developed. Furthermore, a study on expression of strain history dependent elastic-plastic constitutive relation with a truss lattice model was presented at JSME Kansai branch meeting held on Nov.1992. Strain-rate and temperature dependency of the deformation behavior of a superplastic material was investigated in 1993. Results will be presented in near future. Less