Mechanics of arterial subfailure with increasing loading rate

Area of Science:

• Biomedical Engineering
• Biomechanics
• Trauma Research

Background:

• Arterial subfailure, particularly in the thoracic aorta and carotid arteries, results in significant morbidity and mortality.
• Previous research on arterial injuries primarily focused on quasi-static loading conditions, not high-velocity impacts typical of automotive collisions.

Purpose of the Study:

• To investigate the mechanical response of aortic segments under varying loading rates.
• To quantify the effects of loading rate on elastic, subfailure, and ultimate vessel mechanics.
• To assess the implications for arterial injury risk in high-velocity impact scenarios.

Main Methods:

• Sixty-two aortic specimens were subjected to axial distraction at increasing loading rates.
• Mechanical properties, including stress and strain at initial subfailure and ultimate failure, were measured.
• Statistical analysis was performed to determine the relationship between loading rate and mechanical response.

Main Results:

• Over 92% of specimens exhibited subfailure before ultimate failure.
• Increasing the loading rate significantly increased stress at both initial and ultimate failure.
• Conversely, increasing the loading rate significantly decreased strain at both initial and ultimate failure.

Conclusions:

• Higher loading rates increase arterial susceptibility to subfailure and dissection.
• Automotive occupants face elevated risk of arterial injury during high-velocity impacts due to reduced strain tolerance and increased body segment motion.