A new kind of electronic speckle pattern interferometer (ESPI) was developed by the authors' group using conical mirrors to measure the radial in-plane displacement component. True radial in-plane sensitivity is achieved by double illumination. This device is used in the present work to measure residual stresses in combination with the indentation method. A semi-empirical mathematical model is developed to quantify the residual stresses. Several tests were made on a specimen with different levels of stress imposed by mechanical loading. Empirical constants were computed from these tests and are used in combination with the developed model to predict the residual stress levels. The tests presented here are preliminary as they are restricted to only one material, a uniaxial stress state, one geometry of the indentation tip, and only one value of indentation force. In these conditions the results are very encouraging, a typical measurement error of about 5 per cent being found for the principal residual stress.
This paper presents a combined system based on digital speckle pattern interferometry and laser annealing to determine residual stresses in ductile materials. The system allows the measurement of the radial in-plane displacement field generated when a specimen subjected to residual stresses is locally heated. This novel approach for measuring residual stresses has the advantage of being nondestructive and can be easily applied to in situ tests. The description of the combined system is followed by the presentation of preliminary results which illustrate the ability of both techniques to identify residual stress fields and also to determine their principal directions.
This paper presents a combined system based on digital speckle pattern interferometry and laser annealing to determine residual stresses in ductile materials. The system allows the measurement of the radial in-plane displacement field generated when a specimen subjected to residual stresses is locally heated. This novel approach for measuring residual stresses has the advantage of being nondestructive and can be easily applied to in situ tests. The description of the combined system is followed by the presentation of preliminary results which illustrate the ability of both techniques to identify residual stress fields and also to determine their principal directions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.