Effect of Bird Yaw/Pitch Angles on Soft Impact Damage of a Fan Assembly

Abstract

This paper presents a numerical investigation of bird attitude angles affecting the soft-impact damage of a full fan assembly. Firstly, considering the geometry of a mallard, a real bird model is established by the Smoothed Particle Hydrodynamics (SPH) method and calibrated with available test data. Then, complying with airworthiness requirements, simulations of a full-bladed fan assembly subjected to a real bird were conducted to determine the critical ingestion parameters (CIP). Furthermore, a real bird with different attitude angles aimed at a full fan assembly was simulated. Results show that attitude angles of the bird produce a significant impact on the effect of the bird strike on rotating blades and would increase the possibility of blade failures, especially for the yaw angle of -45° and the pitch angle of −60°. It is invaluable for commercial airlines and engine manufactures to provide safe flight and landing by adopting the real bird model with critical yaw and pitch angles in the design for resistance to bird ingestion.

Multiple-Bird-Strike Probability Model and Dynamic Response of Engine Fan Blades

“…This material model effectively captures the relationship between impact load and structural response and is a commonly utilized approach in numerical simulations of bird strike scenarios. In the Johnson-Cook material model, the flow stress can be expressed as [29] σ ε ε In the event of a bird strike on an engine, the fan blades can experience deformation or even failure due to the high-speed impact. To address this, the Johnson-Cook material model is employed, which comprehensively considers the interplay between flow stress, strain, strain rate, and temperature.…”

“…This material model effectively captures the relationship between impact load and structural response and is a commonly utilized approach in numerical simulations of bird strike scenarios. In the Johnson-Cook material model, the flow stress can be expressed as [29]…”

“…ε * is a unitless rate which can be obtained by dividing the effective plastic strain rate by the quasi-static threshold rate; and T * = T−T r T m −T r is the homologous temperature, where T is the current temperature, T m is the melt temperature of the material, and T r is the room temperature. In the Johnson-Cook material model, the strain at fracture is given by [29]…”