Mechanical response of avian skeletal muscle under quasi-static and dynamic uniaxial compression

Mitigating aeroengine damage from bird-aircraft collisions is crucial to prevent economic losses and even loss of human lives. Because engine testing and validation is often expensive, aircraft engineers depend on computational simulations to maximize engine component protection against high-speed bird-strike events at reduced cost. Since the bulk of a bird's mass is comprised of skeletal muscle, developing an insight into this mechanical behavior is crucial for understanding the muscle tissue's loading, recovery, and breakup behavior within the engines. In this work, we aim to quantify the compressive mechanical response of avian skeletal muscle tissue. Experimental sample preparation protocols and testing procedures were first established to ensure consistent conditions that aim to reproduce the behavior of a live avian muscle specimen subjected to external loads. The samples were then tested in directions parallel and perpendicular to the muscle fibers, and under uniaxial quasi-static and dynamic compression across various strain rates. Avian skeletal muscle was generally observed to be strain-rate dependent for both compression directions. The samples further demonstrated an anisotropic mechanical response under compressive loading, where samples compressed perpendicular to the direction of muscle fibers exhibited markedly stiffer behavior than their parallel counterparts. The current work provides an initial understanding of the avian skeletal muscle mechanical behavior, which can potentially be developed for high-fidelity computational simulations and experiments at relevant engine operational conditions.