Effect of helmet design on impact performance of industrial safety helmets

Lightweight detection model for safe wear at worksites using GPD-YOLOv8 algorithm

To address the significantly elevated safety risks associated with construction workers' improper use of helmets and reflective clothing, we propose an enhanced YOLOv8 model tailored for safety wear detection. Firstly, this study introduces the P2 detection layer within the YOLOv8 architecture, which substantially enriches semantic feature representation. Additionally, a lightweight Ghost module is integrated to replace the original backbone of YOLOv8, thereby reducing the parameter count and computational burden. Moreover, we incorporate a Dynamic Head (Dyhead) that employs an attention mechanism to effectively extract features and spatial location information critical for site safety wear detection. This adaptation significantly enhances the model's representational power without adding computational overhead. Furthermore, we adopt an Exponential Moving Average (EMA) SlideLoss function, which not only boosts accuracy but also ensures the stability of our safety wear detection model's performance. Comparative evaluation of the experimental results indicates that our proposed model achieves a 6.2% improvement in mean Average Precision (mAP) compared to the baseline YOLOv8 model, while also increasing the detection speed by 55.88% in terms of frames per second (FPS).

Effect of Structure and Wearing Modes on the Protective Performance of Industrial Safety Helmet

This study aims to explore the effects of helmet structure designs and wearing modes on the protective performance of safety helmets under the impact of falling objects. Four helmet types (no helmet, V-shaped, dome-shaped, and motorcycle helmets) and five wearing modes (left and right tilt by 5 deg, backward tilt by 15 deg, 0 deg without chin strap, 0 deg with chin strap) were included in this study. The axial impact of a concrete block under various impact velocities was simulated. The results indicate that the energy absorption and shock mitigation effects of the foam cushion are superior to those of the suspension system in traditional industrial safety helmets. The structure of the top of V-shaped helmets is designed to withstand greater impact. Regarding the wearing mode, the helmet strap's deflection angle increases stress in the brain tissue and skull, heightens intracranial pressure, and causes pressure diffusion toward the forehead.

Head kinematics of human subjects during laboratory-induced ladder falls to the ground

INTRODUCTION

Fall-induced traumatic brain injury (TBI) is considered one of the most serious occupational injuries in construction. Given the frequency of falls from ladders, knowledge of head kinematics during ladder falls to the ground may help inform any potential improvement to construction safety helmet design and improve their protection against head injury. Therefore, the goal of this descriptive study was to measure head kinematics during laboratory-induced ladder falls to the ground.

METHOD

Eighteen young adults wearing a hockey helmet simulated construction tasks that challenged their balance while standing on stepladders and an extension ladder with their feet at heights up to 1.8 m above padding covering the ground. Falls onto the padding occurred spontaneously or were induced by an investigator nudging the ladder to simulate ladder movement resulting from the ground shifting. Optoelectronic motion capture was used to capture head kinematics up to the instant immediately before head impact.

RESULTS

Of 115 total falls, 15 involved head impact with the padding and were analyzed. Head impact during all 15 of these falls occurred on the back of the head. Immediately before impact with the padding, head vertical velocity ranged from 0.42 to 3.88 m/s and head angular velocity about a medial-lateral axis ranged from 60.1 to 1215.5 deg/s.

CONCLUSIONS

These data can be used with computer simulations or headform impact testing to estimate true head impact kinematics, or to inform future versions of construction safety helmet testing standards.

PRACTICAL APPLICATIONS

This is the first study we are aware of to capture head kinematics of human subjects during ladder falls to the ground. These results have the potential to inform future versions of construction safety helmet testing standards and contribute to improved helmet design for protection against fall-induced head injury.

Development and Performance Evaluation of Hybrid Iono-organogels for Efficient Impact Mitigation

Dissipative materials are essential for mitigating impact in various automotive, aerospace, and sports equipment applications. This study investigates the efficiency of a novel hybrid iono-organogel in dissipating and absorbing impact energies. The gel consists of a covalently cross-linked poly(acrylic acid)-co-poly(zwitterionic (DMAPS)) in a hybrid solvent system composed of the ionic liquid [C2OHMIM][BF4] and the oligomer PEG200. The optimal solvent hybridization ratio for achieving the lowest deceleration during impact testing is 40 vol % of the ionic liquid and 60 vol % of PEG200. The gel exhibits efficient mechanical dissipative properties with a loss factor exceeding 0.5 when solicited under various dynamic conditions with this optimized ratio. Moreover, the gel demonstrates high strength and toughness, enabling it to withstand impacts without experiencing catastrophic failure. The developed gel presents stable mechanical properties over broad temperature (0-100 °C) and frequency (0.01-2000 Hz) ranges. It maintains its performance during successive impacts, thanks to its self-recovery abilities. The remarkable mechanical properties of the gel are attributed to the abundance of combined functional groups within the gel polymeric network. Indeed, reversible H-bonds, ion-dipole, and dipole-dipole interactions were observed in different studies to enhance mechanical performance. Their unique synergy effect in the developed hybrid gels held promise for better control of impact properties and durability in numerous dynamic applications.

Head Impact Location, Speed and Angle from Falls and Trips in the Workplace

Traumatic brain injury (TBI) is a common injury in the workplace. Trips and falls are the leading causes of TBI in the workplace. However, industrial safety helmets are not designed for protecting the head under these impact conditions. Instead, they are designed to pass the regulatory standards which test head protection against falling heavy and sharp objects. This is likely to be due to the limited understanding of head impact conditions from trips and falls in workplace. In this study, we used validated human multi-body models to predict the head impact location, speed and angle (measured from the ground) during trips, forward falls and backward falls. We studied the effects of worker size, initial posture, walking speed, width and height of the tripping barrier, bracing and falling height on the head impact conditions. Overall, we performed 1692 simulations. The head impact speed was over two folds larger in falls than trips, with backward falls producing highest impact speeds. However, the trips produced impacts with smaller impact angles to the ground. Increasing the walking speed increased the head impact speed but bracing reduced it. We found that 41% of backward falls and 19% of trips/forward falls produced head impacts located outside the region of helmet coverage. Next, we grouped all the data into three sub-groups based on the head impact angle: [0°, 30°], (30°, 60°] and (60°, 90°] and excluded groups with small number of cases. We found that most trips and forward falls lead to impact angles within the (30°, 60°] and (60°, 90°] groups while all backward falls produced impact angles within (60°, 90°] group. We therefore determined five representative head impact conditions from these groups by selecting the 75th percentile speed, mean value of angle intervals and median impact location (determined by elevation and azimuth angles) of each group. This led to two representative head impact conditions for trips: 2.7 m/s at 45° and 3.9 m/s at 75°, two for forward falls: 3.8 m/s at 45° and 5.5 m/s at 75° and one for backward falls: 9.4 m/s at 75°. These impact conditions can be used to improve industrial helmet standards.

A novel equestrian helmet testing method: helmet liner performance in highly realistic simulation

OBJECTIVE

Employ a novel testing method to assess Multi Directional Impact Protection System (MIPS) helmet technology on rotational velocity and acceleration during head impact.

METHODS

An optimization study was completed utilizing a 50th percentile male Hybrid III anthropomorphic test device (ATD). Helmets included expanded polystyrene foam (EPS) and two different MIPS helmets (MIPS 1, MIPS 2). A 24.38-m-long elevated track with rails and a motorized sled was utilized to replicate a fall from approximately 2.13 m. The sled was set to a speed of 20.92 kph, where a tripping mechanism induced rotation in the ATD from the sled and onto a sand surface. During impact of the ATD with the sand surface, head kinematics were measured using resultant acceleration (peak G's), duration of impact (ms), and rotational velocity (rad/s).

RESULTS

A total of three trials for each helmet did not demonstrate a significant difference between the EPS vs. MIPS 1 group with, peak (G's) for resultant acceleration (p = 0.100), duration (ms) for resultant acceleration, (p = 0.100), peak (G's) for rotational velocity, (p = 0.700), and duration (ms) for rotational velocity (p = 0.700). Similarly, the EPS vs. MIPS 2 testing demonstrated no significant differences between the MIPS 2 helmet compared to the EPS helmet, with resultant acceleration (p = 0.400), duration acceleration (p = 0.200), rotational velocity (p = 0.400) and duration velocity (p = 0.400). However, when the MIPS helmet data were pooled, and the EPS helmet data were compared, a statistically significant difference in the duration of acceleration was found (p = 0.048).

CONCLUSIONS

Current testing uses a helmeted head form which is dropped or rolled from a prescribed height. These methods discount the loading placed on the neck and head through the angular momentum of the body. Our novel testing method did not find significant differences between the helmet types in diminishing peak rotational forces to the brain; however, our data suggests that MIPS helmet liners may reduce duration of impact. The reduction of acceleration duration could indicate less rotation of the neck, due to the dampening of these forces by the MIPS liners.

Quantitative analysis of the protective performance of bicycle helmet with multi-direction impact protection system in oblique impact tests

PURPOSE

The current study aimed to assess the protective performance of helmets equipped with multi-directional impact protection system (MIPS) under various oblique impact loads.

METHODS

Initially, a finite element model of a bicycle helmet with MIPS was developed based on the scanned geometric parameters of an actual bicycle helmet. Subsequently, the validity of model was confirmed using the KASK WG11 oblique impact test method. Three different impact angles (30°, 45°, and 60°) and 2 varying impact speeds (5 m/s and 8 m/s) were employed in oblique tests to evaluate protective performance of MIPS in helmets, focusing on injury assessment parameters such as peak linear acceleration (PLA) and peak angular acceleration (PAA) of the head.

RESULTS

The results demonstrated that in all impact simulations, both assessment parameters were lower during impact for helmets equipped with MIPS compared to those without. The PAA was consistently lower in the MIPS helmet group, whereas the difference in PLA was not significant in the no-MIPS helmet group. For instance, at an impact velocity of 8 m/s and a 30° inclined anvil, the MIPS helmet group exhibited a PAA of 3225 rad/s2 and a PLA of 281 g. In contrast, the no-MIPS helmet group displayed a PAA of 8243 rad/s2 and a PLA of 292 g. Generally, both PAA and PLA parameters decreased with the increase of anvil angles. At a 60° anvil angles, PAA and PLA values were 664 rad/s2 and 20.7 g, respectively, reaching their minimum.

CONCLUSION

The findings indicated that helmets incorporating MIPS offer enhanced protection against various oblique impact loads. When assessing helmets for oblique impacts, the utilization of larger angle anvils and rear impacts might not adequately evaluate protective performance during an impact event. These findings will guide advancements in helmet design and the refinement of oblique impact test protocols.

Correlation between Malocclusion and Mandibular Fractures: An Experimental Study Comparing Dynamic Finite Element Models and Clinical Case Studies

Mandibular fractures are very common in maxillofacial trauma surgery. While previous studies have focused on possible risk factors related to post-operative complications, none have tried to identify pre-existing conditions that may increase the risk of mandibular fractures. We hypothesized, through clinical observation, that anatomical conditions involving poor dental contacts, such as malocclusions, may increase the risk of mandibular fractures. This work was subdivided into two parts. In the first part, Digital Imaging and Communications in Medicine (DICOM) data of four healthy patients characterized by different dentoskeletal occlusions (class I, class II, class III, and anterior open bite) have been used to develop four finite element models (FEMs) that accurately reproduce human bone structure. A vertical and lateral impact have been simulated at increasing speed on each model, analyzing the force distribution within the mandibular bone. Both vertical and lateral impact showed higher level of stress at the impact point and in the condylar area in models characterized by malocclusion. Specifically, the class III and the open bite models, at the same speed of impact, had higher values for a longer period, reaching critical stress levels that are correlated with mandibular fracture, while normal occlusion seems to be a protective condition. In the second part of this study, the engineering results were validated through the comparison with a sample of patients previously treated for mandibular fracture. Data from 223 mandibular fractures, due to low-energy injuries, were retrospectively collected to evaluate a possible correlation between pre-existing malocclusion and fracture patterns, considering grade of displacement, numbers of foci, and associated CFI score. Patients were classified, according to their occlusion, into Class I, Class II, Class III, and anterior open bite or poor occlusal contact (POC). Class I patients showed lower frequencies of fracture than class II, III, and open bite or POC patients. Class I was associated with displaced fractures in 16.1% of cases, class II in 47.1%, class III in 48.8% and open bite/POC in 65.2% of cases (p-value < 0.0001). In class I patients we observed a single non-displaced fracture in 51.6% of cases, compared to 12.9% of Class II, 19.5% of Class III and 22.7% of the open bite/POC group. Our analysis shows that class I appears to better dissipate forces applied on the mandible in low-energy injuries. A higher number of dental contacts showed a lower rate of multifocal and displaced fractures, mitigating the effect of direct forces onto the bone. The correlation between clinical data and virtual simulation on FEM models seems to point out that virtual simulation successfully predicts fracture patterns and risk of association with different type of occlusion. Better knowledge of biomechanics and force dissipation on the human body may lead to the development of more effective safety devices, and help select patients to plan medical, orthodontic/dental, and/or surgical intervention to prevent injuries.

Neurotrauma Prevention Review: Improving Helmet Design and Implementation

Neurotrauma continues to contribute to significant mortality and disability. The need for better protective equipment is apparent. This review focuses on improved helmet design and the necessity for continued research. We start by highlighting current innovations in helmet design for sport and subsequent utilization in the lay community for construction. The current standards by sport and organization are summarized. We then address current standards within the military environment. The pathophysiology is discussed with emphasis on how helmets provide protection. As innovative designs emerge, protection against secondary injury becomes apparent. Much research is needed, but this focused paper is intended to serve as a catalyst for improvement in helmet design and implementation to provide more efficient and reliable neuroprotection across broad arenas.