Espiによる局所熱変形挙動の可視化

This pape discusses feasibility of a non-destructive residual stress analysis method through visualization of local thermal deformation behavior. Reversible and localized thermal deformation in the range from room temperature to about +10°C was applied using an infared spot laser to an aluminum alloy specimen, and the thermal deformation behavior was visualized using an 2-D electronic speckle pattern interferometer. External tensile stress was applied to the specimen to simulate residual stress. The effect of external stress on the local thermal deformation behavior was investigated. The results showed that the thermal contraction in and around the heated area varied depending on the external stress. The strain rate of the heated area within 1s after the heating increased with an increase in external stress. Strain relaxation due to the thermal expansion of the heated part occurs at the surrunding part, and the changes of strain increases with the increase in external stress. Therefore, the resulst indicate the feasibility of the residual stress analysis by visualizing the local thermal deformation behavior.