Hole-Drilling Method in Residual Stress Diagnostics

In all industrialized countries, research of residual stresses and their effect on the strength of materials and structures is actively underway. The need for such studies is largely due to the fact that many technical failures and man-made disasters occur due to a high level of residual technological stresses. Various physical and mechanical methods are used to diagnose residual stresses. Methods based on different physical principles do not affect the strength of the measuring object, i.e., can be considered nondestructive if you do not take into account the change in the state of the surface of the object during preparation for measurements. But between the measured values and the desired stresses, there are complex relations with parameters which often depend on a number of factors that are difficult to take into account. Mechanical methods are destructive or partially destructive. Residual stresses are calculated from deformations or displacements arising from the unloading of an object or its parts using the equations of the theory of elasticity; only the basic mechanical properties of the material are required to process the measurements. Among the mechanical methods, the hole method is the most widely used: it is not very damaging, it is quite universal-the shape and material of objects can be very different, it is methodically and materially provided-and measurement standards have been approved, equipment, measurement technology and a method for processing results have been developed. The article presents the history of the development of the hole method, the contribution of domestic and foreign scientists to its formation, and gives examples of specific measurements of residual stresses using this method in laboratory and production conditions with an emphasis on domestic measurement technology.