Fatigue crack growth analysis of 2024 T3 aluminium specimens under aircraft service spectra

Abstract

The fatigue crack growth behaviour of 2024 T3 aluminium was investigated experimentally. The fatigue experiments were performed under constant stress amplitude, constant amplitude with single and multiple overloads and aircraft service spectra. The fatigue spectra used correspond to the air‐to‐air, air‐to‐ground and instrumentation and navigation flight phases. They were applied for different stress levels. In total 11 different random flight service spectra were examined. The retardation effects caused by the overloads on the fatigue crack growth behaviour and the fatigue crack growth under aircraft service spectra were predicted using an in‐house‐developed code. The code makes use of the strip plastic zone approximation to account for material hardening effects along the path of prospective crack growth. Crack growth is treated incrementally and corresponds to failure of material elements ahead of an existing crack after a certain critical number of fatigue cycles. For the simulation of irregular service spectra by equivalent sequences of distinguished stress cycles a modified rainflow counting method is utilized. Spectrum simulation accounts also for non‐linearity in fatigue damage accumulation and load sequence effects. The computed fatigue curves fit well with the experimental results.

Fatigue assessment of refill friction stir spot weld in AA 2024‐T3 similar joints

“…In terms of safety, fatigue is the main damage mechanism in an aeronautical structure, and a typical fatigue failure occurs unexpectedly. Furthermore, the airframe design is closely correlated with interactions between cracks and fastened components . The extensive use of structural welded joints represents an important challenge considering the damage tolerance design, where a full comprehension of the crack initiation and crack growth is mandatory for applying these solid‐state processes in the aerospace industry …”

“…Furthermore, the airframe design is closely correlated with interactions between cracks and fastened components. [8][9][10][11] The extensive use of structural welded joints represents an important challenge considering the damage tolerance design, where a full comprehension of the crack initiation and crack growth is mandatory for applying these solid-state processes in the aerospace industry. 12 Although the fatigue test conditions are carefully controlled, it is common to observe considerable scatter in the fatigue data results at the same stress level.…”

Monotonic and low cycle fatigue behaviour of 2024‐T3 aluminium alloy between room temperature and 300 °C for designing VAWT components

“…Fatigue behaviour of various aluminium alloys and their different chemical compositions have been studied extensively. Studies mainly focused on the different fatigue behaviour of different aluminium alloys, while few of them focused on specimens under low cycle fatigue and high cycle fatigue . Numerous studies regarding the fatigue life of various aluminium alloys under different temperatures have been conducted.…”

Interactive creep–fatigue crack growth of 2024‐T3 Al sheets: selective transitional functions

“…The explicit solutions from fracture mechanics are preferentially adopted in the research of interactive creep–fatigue phenomenon. Extensive efforts have been initiated to focus on the aspect of fatigue under various conditions . Creep effects are considered under certain circumstances, such as high‐temperature environment.…”

“…Extensive efforts have been initiated to focus on the aspect of fatigue under various conditions. [8][9][10][11] Creep effects are considered under certain circumstances, such as high-temperature environment. It should be emphasised that creep and fatigue are de facto coexisting inherently in the process of material and structural degradation.…”