On the residual stress measurement for non-conductive species by modified contour method

Sintered silicate ceramics have traditionally been difficult to measure for residual stress due to their inhomogeneous microstructure and non-conductive nature, making the state-of-the-art traditional contour method ineffective. To address this issue, a self-invented Double Three-point Bending Moment Delocalization technique was developed to "cut" the ceramics and obtain the necessary sections. By modifying the filtering algorithm for the smoothing program and establishing an automatic reliability parameter for the normalization procedure, the contour method was successfully modified, eliminating errors introduced by manual normalization and the inhomogeneous microstructure. The traditional contour method yielded a residual stress value between - 75 and 117 MPa, whereas the modified contour method resulted in a value of - 12 to 12 MPa. The modified contour method was validated by the mature Hole Drilling Strain-Gage Method, which demonstrated its success in measuring residual stress in non-conductive ceramics. This work highlights the potential of the modified contour method for measuring residual stress in non-conductive ceramics.