Research Article

Characteristic Evaluation on Bolt Stress by Ultrasonic Nondestructive Methods

Table 4

Matlab least squares fit of the stress measurement coefficients, and .

MaterialCoefficient
0–100 MPa100–360 MPa or 100–260 MPa

A2-703.7835 × 10161.1885 × 10172.813 × 10158.7741 × 1015
4.85.5036 × 10161.7992 × 10174.2938 × 10151.396 × 1016
8.83.3484 × 10161.0982 × 10173.543 × 10151.1544 × 1016