Experimental Validation of the Calibration Function of the Hole-Drilling-Method and Ring-Core-Method for Residual Stress Measurement

摘要

Residual stresses (RS) in mechanical components can result in both detrimental but also beneficial effects on the strength and lifetime of the components. Two commonly used mechanical methods for determination of residual stresses are the hole-drilling-method and the ring-core-method which can be regarded as semi-destructive. Often these methods are divided into the groups of nondestructive and destructive methods. With a specific theory and a calibration for each method the RS are calculated. This issue will validate the calibration functions experimentally for residual stress measurements of the HDM and RCM. These functions are used for RS analyses using the differential method. With a four-point-bending testing machine, a defined stress can be triggered between the middle bearings. The strain in this area can be measured with strain gauges, so the stress is well-known. In this defined loading area, the strains in two load cases with the HDMconfiguration and RCM configuration were measured using strain-gauge-rosettes. With these measured strains and the actually known stresses, the specific calibration functions are to be calculated and presented together with the numerical ones.