• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.3
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• pp.41-48
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• 2019

The industrial safety helmets are personal protective equipment (PPE), used to protect the head against falls from a height. This study indicated the necessity of wearing a safety helmet while working at heights below 4 m, through analysis of fall accidents occurring in the industrial field. The stress, displacement, and strain of the safety helmet shell structure have been analyzed using the finite element method with various thicknesses, engineering plastics, and designs. It was preferred that the safety helmet shell structure had a reinforcement frame of uniform thickness in terms of increased impact strength and strain energy absorption rate. The thickness can be reduced to lighten the total weight for workers wearing safety helmets.

• Journal of the Korean Institute of Gas
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• v.13 no.4
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• pp.27-32
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• 2009

This paper presents the stress and deformation behaviors using the finite element method as a function of the thickness of the helmets without the bead frames on the top of the shell structure. The helmet that would provide head and neck protections without causing discomfort to the user when it was worn for long periods of time should be manufactured for increasing the safety and impact energy absorption. The FEM computed results show that when the impulsive force is applied on the top surface of a helmet, the maximum stress and strain have been occurred around the position of an applied impact force, which may lead to the initial failure on the top surface of the helmet shell. As the helmet thickness is decreased from 4mm to 2mm, the impact energy absorbing rate is radically increased, and the maximum stress of the helmet is increased over the tensile strength, 54.3MPa of the thermoplastic material. Thus, the top surface of the helmet should be supported by a bead frame and increased thickness of the shell structure.

• Fire Science and Engineering
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• v.5 no.3
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• pp.5-14
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• 1991

Now a days, according that the occurrence of industrial disaster is on the increase, the necessity of protective goods is increasing. Specially estimate of safety helmet for protect of head is very important. On this, in this paper, amplification ratio and natural frequencies of fire safety helmet and general safety helmet are estimated by falling impect test and frequency analysis. Also. trend of damping is estimated by using these test results. And we know that the fire safety helmet is more safe than general safety helmet for protect of head.

• Journal of the Korean Society of Safety
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• v.28 no.5
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• pp.83-89
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• 2013

Occupational Safety and Health Act provides that industrial safety helmets are personal protective equipment(PPE) to protect heads against falls from a height. Relevant domestic regulations are distinguished and different from other countries' cases. This study investigated industrial safety helmet's protective purposes and characteristics related to falls and the notion of fall prevention. A comparative analysis of regulations on safety helmets and fall prevention as well as standards on safety helmet's impact test requirements is followed by a literature review. It is also suggested that the term "fall" related to safety helmets should be changed to "impact on the upper part of head" in domestic regulations and standards.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.2
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• pp.82-89
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• 2023

Due to the characteristics of ship structure, the compartment structure is complicated and narrow, so safety accidents frequently occur during the work process. The main causes of accidents include structural collisions, falling objects, toxic substance leaks, fires, explosions, asphyxiation, and more. Understanding the on-site conditions of workers during accidents is crucial for mitigating damages. In order to ensure safety, the on-site situation is monitored using CCTV in the ship, but it is difficult to prevent accidents with the existing method. To address this issue, a smart safety helmet equipped with location identification and voice/video communication capabilities is being developed as a safety technology. Additionally, the smart safety helmet incorporates environmental sensors for temperature, humidity, vibration, noise, tilt (gyro sensor), and gas detection within the work area. These sensors can notify workers wearing the smart safety helmet of hazardous situations. By utilizing the smart safety helmet and environmental sensors, the safety of workers aboard ships can be enhanced.

• Structural Engineering and Mechanics
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• v.48 no.5
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• pp.661-679
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• 2013

In this work, the safety performance of a commercial motorcycle helmet already placed on the market is assessed. The assessed motorcycle helmet is currently homologated by several relevant motorcycle standards. Impacts including translational and rotational motions are accurately simulated through a finite element numerical framework. The developed model was validated against experimental results: firstly, a validation concerning the constitutive model for the expanded polystyrene, the material responsible for energy absorption during impact; secondly, a validation regarding the acceleration measured at the headform's centre of gravity during the linear impacts defined in the ECE R22.05 standard. Both were successfully validated. After model validation, an oblique impact was simulated and the results were compared against head injury thresholds in order to predict the resultant head injuries. From this comparison, it was concluded that brain injuries such as concussion and diffuse axonal injury may occur even with a helmet certified by the majority of the motorcycle helmet standards. Unfortunately, these standards currently do not contemplate rotational components of acceleration. Conclusion points out to a strong recommendation on the necessity of including rotational motion in forthcoming motorcycle helmet standards and improving the current test procedures and head injury criteria used by the standards, to improve the safety between the motorcyclists.

• Journal of the Korean Institute of Gas
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• v.13 no.4
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• pp.22-26
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• 2009

In this paper, the displacement behavior and strain energy density characteristics of a safety helmet with various corrugation dampers has been analyzed based on the finite element analysis. The safety helmet is to protect impact forces and to absorb the impact energy. Three different helmet models with a corrugation damper have been compared as functions of the displacement and strain energy density characteristics when the maximum external impulsive force is imposed on the summit of the helmet. The computed FEM results show that the extruded corrugation damper is very useful to increase the damping effect of the helmet. This study indicates that the round corrugation damper may absorb the transferred impact energy successfully. Thus, this paper recommends round and long corrugation damper on the lower part of the helmet as a new design element.

• Journal of the Korean Institute of Gas
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• v.12 no.3
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• pp.31-37
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• 2008

In this paper, the strength analysis has been presented for the stress and strain by using the finite element method for various shell models of the helmets. The advanced helmet that would provide head protection without causing discomfort to the user when it was worn for long periods of time should be manufactured for increasing the safety and workability of the workers. We need a safe, comfortable and light weight of the helmet shell structure. Thus, the helmets had to stand up to the most rigorous conditions encountered for the fire and gas explosion. The FEM computed results show that when the impulsive force is applied on the summit area of a helmet shell structure, the maximum stress and strain have been occurred around the position of an applied impact force, which may lead to the initial failure on the summit of the helmet shell. Thus, the summit area of the helmet shell should be supported by a bead frame and increased thickness of the bead. But the overall thickness of the helmet is to decrease for the light weight of a helmet.

• Journal of the Korean Institute of Gas
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• v.17 no.5
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• pp.37-41
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• 2013

This paper presents the strength safety of stress and deformation behaviors using the finite element method as a function of the thickness of the protective helmets with and without an extruder on the top of the shell structure. The helmet that would provide head and neck protections without causing discomfort to the user when it was worn for long periods of time should be manufactured for increasing the safety and impact energy absorption. The stress analyzed results show that when the impulsive force of 4,540N is applied on the top surface of a helmet, the safe thickness is 3.7mm for the conventional helmet and 3.2mm for the modified new helmet. Based on the deformation analysis, the FEM results recommend that the safe thickness is 3.2mm for the conventional helmet and 2.0mm for the modified new helmet. Thus, it may be more safe design of the helmet, which has an extruded structure on the summit surface of the helmet.

• Journal of the Korea Safety Management & Science
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• v.4 no.2
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• pp.1-10
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• 2002

In order to protect the head, baseball helmet must to have proper strength and to absorb the kinetic energy. The purposes of this study are to validate whether the helmet have the protecting ability or not. We performed three kinds of experiment to know about the this ability. To find out the limit of displacement at 4 points(front, rear, right side, and left side), the static load by magnetic dial gauges were used, and to validate the ability of absorption, drop tests were peformed from 0.5 and 1.0 meter. Futhermore, we calculated natural frequency of the helmets by the principle of Lissajous Diagram and we performed FEM(Finite Element Method) analysis. From the results of these experiments, we found that the displacement of helmet was largest at rear point and it was smallest at left-side point(ear-covered part). The ability of absorption was better at the left-side point than the other points.