Identification of Fatigue Damage of Metal Sheets Made of Material Dd11 From an Analysis of Vibration Signals

Abstract

This paper presents a method of identifying fatigue cracking of specimens made of material DD11 based on selected characteristics of the vibration signal. Acceleration of vibrations of the free end of a specimen was taken for an analysis of specimen properties during the process of fatigue cracking. Features which enable identification and monitoring of the process of specimen cross-section cracking were indicated for the diagnostic signal. The study was conducted on an original test stand in which the process of the destruction of material cross-section is caused by a specimen’s inertia force. The study results indicated that the presented method of identification of a specimen structure change can be applied to identify the technical condition of a structure in regard to a loss of continuity and structure properties (e.g., mechanical and fatigue cracking). The results of vibration analysis were verified by penetration methods and by microscopic observation.