METHOD AND APPARATUS FOR PREVENTING OR ARRESTING CRACK DEVELOPMENT AND PROPAGATION

摘要

A method and surface treatment apparatus for preventing or arresting the development and propagation of cracks in the material surrounding a fastener. The method includes introducing compressive residual stresses in the material surrounding the fastener. The compressive residual stresses offset the high residual tensile and applied stresses which the material may be subjected to in operation and thereby prevent or arrest the development of cracks. The surface treatment apparatus comprises a compression tool, positioning device and at least one sensor for determining the location of a fastener on the surface being treated. Using the output of the sensor, the surface treatment apparatus is positioned relative to a fastener. The compression tool is impinged against the surface of the material adjacent to the fastener and rotated around the perimeter of the fastener thereby inducing a zone of compressive residual stress.