Estimation of the kinetic energy dissipation in fall-arrest system and manikin during fall impact

Abstract

Fall-arrest systems (FASs) have been widely applied to provide a safe stop during fall incidents for occupational activities. The mechanical interaction and kinetic energy exchange between the human body and the fall-arrest system during fall impact is one of the most important factors in FAS ergonomic design. In the current study, we developed a systematic approach to evaluate the energy dissipated in the energy absorbing lanyard (EAL) and in the harness/manikin during fall impact. The kinematics of the manikin and EAL during the impact were derived using the arrest-force time histories that were measured experimentally. We applied the proposed method to analyse the experimental data of drop tests at heights of 1.83 and 3.35 m. Our preliminary results indicate that approximately 84–92% of the kinetic energy is dissipated in the EAL system and the remainder is dissipated in the harness/manikin during fall impact. The proposed approach would be useful for the ergonomic design and performance evaluation of an FAS.

Statement of Relevance: Mechanical interaction, especially kinetic energy exchange, between the human body and the fall-arrest system during fall impact is one of the most important factors in the ergonomic design of a fall-arrest system. In the current study, we propose an approach to quantify the kinetic energy dissipated in the energy absorbing lanyard and in the harness/body system during fall impact.

Keywords:

• fall-arrest equipment
• energy
• impact
• drop test
• lanyard

Acknowledgements

We would like to acknowledge the contributions of SkyJack Inc., which provided the study with the use of a new scissor lift and other critical technical and design data. We are grateful to MSA, who generously provided the study with the use of new harnesses/lanyards. We acknowledge the International Safety Equipment Association for their constructive comments at various stages of this study. We want also to express our gratitude to Randall Wingfield and Gravitec Inc., who generously provided constructive comments concerning the drop tests. Finally, special appreciation is extended to Doug Cantis and Bradley Newbraugh (NIOSH) for their valuable assistance in data collection.