Crashworthiness is a critical property that enables aerospace structures to minimise injuries and equipment damage during impact scenarios. This review examines the current state of crashworthiness research, with a focus on regulatory frameworks, experimental testing, and numerical modelling techniques. Stringent safety standards set by the Federal Aviation Administration (FAA) and the European Union Aviation Safety Agency (EASA) guide the design and certification protocols for aeronautical structures. Experimental crash testing, which includes both full-scale and subscale impact tests, provides essential data for validating material behaviour and energy absorption capabilities under both quasi-static and dynamic loading conditions. Advanced numerical modelling tools offer significant insights into crash behaviour, enabling optimisation of structural designs whilst reducing reliance on costly physical testing. This review highlights the integration of regulations, empirical data, and computational tools in advancing crashworthiness research, with an emphasis on developing safer, more efficient, and sustainable aerospace designs. Future directions should prioritise the use of sustainable materials and optimise crashworthy designs through artificial intelligence (AI) and advanced numerical models to enhance structural performance and safety.

Adhesively bonded joints are essential in the aeronautical industry, offering benefits such as weight reduction and enhanced sustainability. However, certifying these joints is challenging due to unreliable methods for assessing their strength and the development of predictive models for fatigue-driven disbonding remains an ongoing effort. This manuscript presents the implementation and validation of a cohesive zone model for studying high-cycle fatigue disbonding under Mode I and Mixed-Mode loading. The model was integrated into the commercial finite element analysis software Abaqus using user-defined material subroutine (UMAT). Two modelling approaches were investigated: one replacing the adhesive with a cohesive layer, and the other incorporating a cohesive layer at the adhesive’s mid-plane while modelling its entire thickness, using both 2D and 3D techniques. Validation was conducted against experimental data from the literature that examined the influence of adhesive thickness on fatigue behaviour in DCB and CLS tests. The findings of this study confirm that the model accurately predicts fatigue disbonding across all cases examined. Additionally, the analysis reveals that modelling adhesive thickness plays a critical role in the simulation’s outcomes. Variations in adhesive thickness can significantly alter the crack growth behaviour, highlighting the importance of carefully considering this parameter in future assessments and applications.

Adhesively bonded joints are crucial to the aeronautical industry, contributing to weight reduction and more sustainable flights. However, certifying these joints is still a topic of debate due to the lack of reliable inspection methods to determine their strength. Additionally, prediction models for crack growth under fatigue loading are still being developed. This manuscript describes the implementation and validation of a cohesive zone model to evaluate high cycle fatigue disbonding under mode I opening. This model was integrated into the commercial finite element analysis software Abaqus using user-defined subroutines, specifically a UMAT. The experimental data from the literature on the effect of adhesive thickness during fatigue loading of a double cantilever beam were used for model validation. Three modelling techniques were explored, including substitution of the adhesive with the cohesive zone (2D and 3D) and the addition of a cohesive layer in the mid-plane of the adhesive (2D only). The results have confirmed that the model is effective in accurately predicting fatigue crack growth in all the simulated cases. Additionally, it has been shown that the adhesive’s thickness has an impact on the simulation results, particularly with thicker bondlines and low strain energy release rates.

Delamination in fibre-reinforced polymer composites is a critical failure mechanism that can ultimately lead to a catastrophic failure. To characterise in-plane shear delamination (Mode II), several test setups have been proposed in the literature, with the End-Loaded Split (ELS) test being the most suitable for applications that require stable crack propagation (ISO 15114). This manuscript focuses on studying Mode II fatigue delamination in unidirectional carbon fibre-reinforced laminates using the ELS configuration. Experimental tests with varying displacement ratios and different initial energy levels were conducted to capture a wide range of stable crack propagation scenarios. To complement these experimental efforts, a numerical model based on cohesive zone models (CZM) was implemented in Abaqus, utilising a user-defined material subroutine (UMAT). The numerical results closely align with the experimental data, validating the model’s predictive capabilities. This combined approach deepens the understanding of Mode II fatigue delamination and provides a strong framework for designing and analysing composite structures.