Yinfei Yang

A gun drill mechanics model analysis based on 15-5PH solid solution stainless steel

Abstract Referencing special energy model, a new gun drill mechanics model was established and the influence of the cutting parameters on axial force and torque was based on 15-5PH solid solution stainless steel through theoretical analysis and cutting tests. On the basis of the existing model, the model coefficients were modified under various cutting conditions and the integral area of the cutting edge was enlarged. The eccentricity at the bottom of the drill groove was taken into account in the integral area of the cutting edge. In the meanwhile, the torque calculation was simplified reasonably according to the theoretical analysis. The feasibility of the model was verified by experiments and the influence of cutting parameters on the axial force and torque was analyzed. The experiment data had shown that the relative error between the calculated values and the experimental values were within the acceptable range. The axial force and torque increased with the increase in cutting speed and feed rate.

Residual Stress Calculation by Measuring Deformation After a Diagonal Cut

A new straightforward method for residual stress measurement is presented. A specimen is cut in half along its diagonal by using electric discharge machining, and the deformation benchmarks are measured to determine the displacements caused by release of the residual stresses. Analytically, to verify calculation accuracy of the new method, the known stresses are applied in finite element model as an initial condition. By using the series expansion approach, the inverse calculation based on displacements gives the original longitudinal residual stress of the specimen. This “wedge method” is more straightforward than other relaxation methods because it measures fewer data. Its data processing is simpler, yet its result is found to be in good agreement with other methods. The new method is first outlined for a three-dimensional (3-D) body and the accuracy of the methodology is demonstrated for a representative case using a numerical experiment. Then measurements are performed on a block specimen of AA6061-T6 to show that the approach is valid under real experimental conditions.