Evaluation of the head protection effectiveness of cyclist helmets using full-scale computational biomechanics modelling of cycling accidents

Fang Wang; Junzhi Wu; Lin Hu; Chao Yu; Bingyu Wang; Xiaoqun Huang; Karol Miller; Adam Wittek

doi:10.1016/j.jsr.2021.11.005

Evaluation of the head protection effectiveness of cyclist helmets using full-scale computational biomechanics modelling of cycling accidents

J Safety Res. 2022 Feb:80:109-134. doi: 10.1016/j.jsr.2021.11.005. Epub 2021 Dec 1.

Authors

Fang Wang¹, Junzhi Wu², Lin Hu³, Chao Yu², Bingyu Wang², Xiaoqun Huang², Karol Miller⁴, Adam Wittek⁵

Affiliations

¹ School of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha 410015, Hunan, China. Electronic address: wangfang@csust.edu.cn.
² School of Mechanical and Automotive Engineering, Xiamen University of Technology, Xiamen 361024, Fujian, China.
³ School of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha 410015, Hunan, China. Electronic address: hulin888@sohu.com.
⁴ Intelligent System for Medicine Laboratory, Department of Mechanical Engineering, The University of Western Australia, Perth 6009, Western Australia, Australia; Harvard Medical School, Boston 02115, MA, USA.
⁵ Intelligent System for Medicine Laboratory, Department of Mechanical Engineering, The University of Western Australia, Perth 6009, Western Australia, Australia.

PMID: 35249593
DOI: 10.1016/j.jsr.2021.11.005

Abstract

Introduction: Cycling is a popular choice for urban transportation. Helmets are important and the most popular means of head protection for cyclists. However, a debate about the effectiveness of helmets in protecting a cyclist's head from injury continues.

Method: We employed computational biomechanics methods to analyze the head protection effectiveness of nine off-the-shelf-helmets for two typical impact scenarios that occur in cycling accidents: cyclist's head impacting a kerb (kerb-impact) and cyclist skidding (skidding impact) on the road surface. We conducted drop tests for all nine analyzed helmets, and used the test data for validation of the corresponding helmet finite element (FE) models created in this study. The validated helmet models were then used in the full-scale computer simulations (FE analysis for the skull, brain and helmet, and multibody dynamics for the remaining segments of the cyclist's body) of the cycling accidents for cyclists wearing a helmet and without a helmet.

Results: The results indicate that helmets can reduce both the peak linear acceleration of the cyclist head center of gravity (COG) and the risk of cyclist skull fracture. However, higher rotational acceleration of the head COG was predicted for cyclists wearing helmets. The results obtained using the injury criteria that rely on the brain deformations (maximum shear strain MPS and cumulative strain damage measure CSDM) suggest that helmets may offer protection in all the analyzed cyclist impact scenarios. However, the predicted level of protection varies for different helmets and impact scenarios with appreciable variations in the predictions obtained using different injury criteria. Reduction in the maximum principal strain (MPS_0.98) for helmeted cyclists was predicted for both impact scenarios. In contrast, wearing the helmet reduced the CSDM only for the skidding impact scenario. For the kerb-impact scenario, no clear influence of the helmet on the predicted CSDM was observed.

Keywords: Computational biomechanics model; Cyclist helmet; Finite element model; Head/brain injury; Multibody model.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Acceleration
Accidents, Traffic / prevention & control
Bicycling / injuries
Biomechanical Phenomena
Craniocerebral Trauma* / prevention & control
Head Protective Devices*
Humans