Failure Analysis of Helicopter Windshield

Cracking frequently occurs to the windshields of a type of helicopters, more commonly in winter. A typical helicopter windshield with cracks was selected for study. Macroscopic and microcosmic examination on the cracking fracture shows that the windshield edge is rough; fatigue load and stress corrosion are main reasons for cracking. Stress analysis was carried out on the windshield under the condition of temperature difference, flying and assembly stress load. It is found that there exists greater stress by temperature difference at the bonding area of the edge, and there are greater cycle work stress under the given temperature load spectrum. Combined with macroscopic and microcosmic examination and strength analysis results, it is found that there exists greater stress by temperature difference at the bonding area of the edge, and the windshield edge is rough and thus has larger stress concentration, decreasing the windshield bearing capacity and causing cracking.