Impact of adhesive layer properties on ceramic multi-layered ballistic armour systems: A review

The role of the adhesive layer in the ballistic performance of ceramic multi-layer armour system is complex and multi-faceted, often with trade-offs between single- and multi-hit performance. However, research focused on untangling the underlying impact of varying adhesive cohesive or adhesion properties is limited and sometimes appears to provide conflicting conclusions. Comparison between the available studies is also often difficult due to variations in armour systems or ballistic testing being conducted. This review scrutinises the available research, identifying six critical properties of an adhesive layer in determining ballistic performance: elastic modulus, fracture strain, acoustic impedance, tensile bond strength, shear bond strength, and thickness. The impact of each of these properties on ballistic performance is discussed in detail, with clear description of the underlying processes involved, allowing clear optimisation goals to be established depending on the ceramic armour specification.