# Evaluation of Snowboarding Helmets in Mitigation of the Biomechanical Responses of Head Surrogate
## 5 Conclusions  
This work investigated the performance of snowboarding helmets in mitigating the biomechanical response (i.e., head kinematics, brain simulant pressure, equivalent stress, MPS) of a head surrogate with different helmet technologies (conventional, MIPS, WaveCel, and silica pad) against blunt impact. The front and side orientations were considered. The key findings of this work are as follows:  
1. The kinematic and kinetic responses of the head surrogate were dominated by the design aspects of the helmets (conventional, anti-rotational, and types of liners). 2. The peak angular kinematics of the head surrogate were reduced significantly using the anti-rotational helmets compared to the conventional helmet. 3. Compared to conventional helmet, a significant reduction in the peak linear accelerations and peak coup pressures was seen in the WaveCel and silica pad helmets. Changes in peak linear acceleration and peak coup pressure between the conventional and MIPS helmet were marginal for the front orientation. For all helmet configurations, insignificant changes in contrecoup pressures were observed. 4. In the absence of a comfort liner, MIPS and WaveCel helmets increased peak angular kinematics by up to 60%, whereas peak linear acceleration was significantly increased for the WaveCel helmet by 45%. 5. The brain responses (brain simulant pressure, equivalent stress, and MPS) were computed from the concurrent simulation using the head model. Reasonably good agreement was seen between the experimental brain simulant pressure and brain simulant pressure obtained from the simulation. Peak values of equivalent stress and MPS were reduced by 50-60% using the MIPS, WaveCel, and silica pad helmets compared to conventional helmets. Taken together, our results underscore the design-specific response of the helmet in mitigating blunt impact. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app142311460/s1](https://www.mdpi.com/article/10.3390/app142311460/s1)]([https://www.mdpi.com/article/10.3390/app142311460/s1](https://www.mdpi.com/article/10.3390/app142311460/s1)), Figure S1: (a-d) represents the photographs of head surrogate equipped with conventional, MIPS, WaveCel, silica pad helmets, respectively, subjected to blunt impact (front orientation); (e-h) represents the photographs of head surrogate equipped with conventional, MIPS, WaveCel, silica pad helmets, respectively, subjected to blunt impact (side orientation); Figure S2: Coup and contrecoup pressures in the head surrogate for various configurations (experimentally measured and computed from simulation). (a) front orientation (b) side orientation; Figure S3: Comparison of brain simulant pressures of head surrogate against intracranial pressure measured in PMHS ([PERSON] et al. [46]) (a blunt impact on the head surrogate with impact energy of 50 \(\pm\) 3 J) was compared against PMHS experiment no. 48 (corresponding energy 48 J) of [PERSON] et al. [46] (b) blunt impact on the head surrogate with impact energy of 255 \(\pm\) 15 J was compared against PMHS experiment no. 37 (corresponding energy 276 J) of [PERSON] et al. [46]. For experiments on head surrogate, five repetitions (N = 5) were considered for each energy level. The presented pressure-time histories of current work are based on the average of five repetitions. **Author Contributions:** Conceptualization, S.G.G. ; Methodology, A.H. and S.G.G. ; Formal analysis, A.H.; Investigation, A.H.; Resources, S.G.G. ; Writing--original draft, A.H.; Writing--review & editing, S.G.G. ; Supervision, S.G.G. ; Project administration, S.G.G. ; Funding acquisition, S.G.G. All authors have read and agreed to the published version of the manuscript. **Funding:** This research received funding from the project, \"iHUB DivyaSampark, IIT Roorkee, under grant iHUB-2122-MID\". **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable.