Finite element method-based analysis of human arm bruise tolerance in blunt impact scenarios of human-robot interaction

摘要

• Bruise tolerance thresholds were estimated using finite element analysis. • A strain threshold was derived from reconstruction simulations of porcine experiments. • The threshold was applied to a FE human arm model to estimate bruise tolerance. • Identified loading conditions contribute to human-robot interaction safety. • The method can be extended to different body regions. With the increasing integration of robots in daily life, ensuring safe human-robot interactions is crucial to minimize injury risks. Bruising is a commonly observed minor injury resulting from blunt impacts; however, its tolerance threshold for the human body has not been fully elucidated. Understanding bruise tolerance is essential for establishing safety requirements for human-robot interactions, particularly in collaborative environments where unintended physical contact may occur. This study aimed to estimate the bruise tolerance thresholds for the human upper arm using finite element analysis. Blunt impact experiments on living porcine thighs were reconstructed with a finite element (FE) porcine thigh model to analyze the relationship between soft tissue strain and bruising occurrence. A strain-based bruise tolerance threshold in soft tissue was then derived and applied to an FE human upper arm model to estimate external loading conditions that may lead to bruising in the human upper arm. The results identified external loading conditions that exceed the strain-based threshold of 0.314 (the maximum principal strain) in soft tissue layers and presented them in terms of the relationship between impact velocities and impactor masses. These findings contribute to the development of safety requirements for human-robot interactions, providing acceptable mechanical inputs. The proposed methodology allows for the extension of bruise tolerance estimation to different body regions, facilitating a more comprehensive understanding of human bruise tolerance across various anatomical sites, impactor types, and loading conditions.