Study On Online Measurement Of Blank Inner Stress Field Using ESPI

The release of internal stress in the blank causes serious deformationafter machining, which restricts the production of aerospace structures andmechanical parts. Therefore, studying the measurement method of innerstress is important to control the machining deformation. According to theproblems existed in inner stress measurement for monolithic componentusing hole-drilling method, the paper proposes a new measurement idea anda construction method. How to improve the efficiency of stressmeasurement for monolithic component is mainly discussed. The majorresearch works are lists as follows:1. According to the problems of the depth of hole-drilling method andthe calculation of the stress in component which can’t be measured, a newmeasurement method for uneven distributed stress is proposed. Theoperations of measurement are inserted into the rough machining process.The2D stress is retrieved by interpolation algorithms, and then the stress innon-measured component can be calculated by building a self-balancingmodel of3D stress filed. 2. In order to improve the efficiency of the inner stress measurementfor monolithic component by hole-drilling method, a new inner stressmeasurement method combining electronic speckle pattern interferometertechnology (ESPI) and hole-drilling method is developed. The traditionalESPI optical path is improved. Overall structure of stress onlinemeasurement system is designed and measurement process is planned.3. The measurement device developed for uneven distributed stressfiled as well as the image acquisition and processing system speciallydesigned lay hardware basis and software basis for the stress automaticmeasurement. A series of verification tests are made to prove the probabilityof this method and the effectiveness of this system.