Abstract:
High-velocity impact loads pose significant challenges due to their potential to generate
dynamic responses in structures, which can cause severe damage. Structural engineers face an
evolving challenge in designing structures that can effectively resist impact and blast loads.
Active and passive mitigation systems are two different categories of mitigation systems.
Active mitigation systems are based on detection and reaction systems, while passive
mitigation systems use energy absorption and wave propagation characteristics to mitigate the
effects of high-velocity impacts and shockwaves. This study investigates nature-inspired
solutions to minimise damages from high-velocity impact loads on structures. By analysing the
basic elements of several existing biological systems and their contribution towards the
structural integrity of these systems, key potential characteristics that can be translated into
impact-resisting structures have been identified. The primary focus centres on the mantis
shrimp arm, drawing insights from its remarkable mechanical properties and translating them
into structural engineering applications. In the present study, a solution that is inspired by the
mantis shrimp arm has been developed as such, a multilayered structure was designed using
metallic materials that use the mantis shrimp arm’s concept of elastic modulus gradient
variation. The study pursues three objectives: to identify the mechanisms employed by
biological systems for impact resistance, to investigate effective and efficient systems
considering the impact resistance using theoretical analysis and numerical simulations, and to
propose feasible combinations of the system to resist impact loads for enhanced impact load
mitigation. Based on a theoretical analysis involving shock wave propagation, this system
demonstrated the potential to reduce the magnitude of the stress waves during an impactloading
event. Further numerical analysis of this system was carried out using the nonlinear
finite element software ABAQUS, where the impact of a metallic flyer at a known velocity on
a target of the multilayered structure was simulated. The magnitude of the incident stress wave
of the final material in the target was obtained to evaluate the performance of this system. The
results demonstrated that the proposed multilayered system has the potential to reduce the
magnitude of the incident stress waves in the system when compared to the monolithic system
with no variation of the elastic modulus. The arrangement of gradient variation of elastic
modulus results in a pressure reduction of approximately 66% and 58% in theoretical and
numerical analyses, 41% and 33% in stepwise periodic variation, and 80% and 67% in
combined gradient and periodic variations. The study reveals that incorporating materials with
gradient variations in elastic modulus in the layered structure can effectively reduce pressure
waves than the monolithic structure. The combined arrangement of gradient and periodic
structures can potentially improve mitigation performance. The findings suggest further
research on microstructural aspects, comparison with different biological systems,
experimental studies, and deeper design and optimisation of combined arrangements. These
findings contribute to developing innovative engineering solutions and paving the way for
structures that can withstand high-velocity impact loads effectively.