Design And Fabrication Of A Tropical Motorcycle Helmet

The present work is devoted to the design and evaluation of a new crashworthy motorcycle helmet taking into consideration the tropical climate of Malaysia. A multidiscipline literature review on the design problems of motorcycle helmet was carried out and current problems were formulated. Based on the literature review findings, a new shell and liner designs were then proposed to overcome or eliminate these problems. The shell design improvements consisted of developing hybrid natural fiber composite (NFC) shells which were fabricated and evaluated by the standard dynamic penetration test. The results of the new design were found to be satisfactory according to the related helmet standards. Three additional methods have been developed to assess the new shells performance in a more quantified manner. These tests are the helmet quasi-static penetration, the helmet rigidity, and the helmet crushing. All these tests were performed and the results confirmed the superior performance of the new natural fiber shell helmets as compared to the market dominant ABS shell helmets. Other factors also supported this design improvement such as cost, and the utilization of environmental friendly material. In the liner design improvement, the shell was kept to the current ABS shell and the EPP foam as a liner. A 3D finite element algorithm has been developed using LSDYNA- 3D software. Based on the simulation results, the helmet with EPP foam liner was found to be satisfactory according to the related helmet standards. A parametric study of the helmet design was performed using the Response Surface Methodology in the Design of Experiment (DOE) statistical method. From this parametric study, the foam thickness and the foam density were found to have more significant effect on the helmet energy absorption than the she]] effects. Design optimizations were also conducted and optimum design was obtained. Finally, thermal analysis for commercially available helmet without ventilation system and the new helmet design with ventilation system were made. from which it was found that helmet ventilation is essential to avoid possible health problems. A design chart for helmet with ventilation system to obtain the minimum cross sectional area required for ventilation nozzles has been developed. This chart is suitable for a wide span of amounts of heat generated from the motorcyclist head. The effect of adding the ventilation system to the helmet has been structurally investigated by the finite element simulation and found to positively improve the energy absorption performance of the helmet

Drop Weight Testing Rig Analysis and Design

Crashworthiness studies are becoming increasingly important in mechanical design, particularly with the new advancement of the computer simulation codes. These studies generally require material and prototype testing for both modelling and validation. Large percentages of these studies lie on the limits of medium strain rate, which could be achieved by a drop weight test rig. Therefore, the drop weight test rig becomes an essential tool for such research activities besides the universal quasi-static testing machines. This paper is devoted to the analysis and design of the drop weight impact-testing rig. First, the different aspects of the mechanical design such as the propulsion, guidance, and frame layout, foundation and energy aspects are presented and discussed. Then, the basic types of data retrieval and analysis systems applicable for drop weight impact testing machines are presented and discussed. Data retrieval components considered in this study include the sensors for load, acceleration, and velocity measurements, image acquisition including high-speed cameras and PC-based image acquisition system, and data acquisition including oscilloscope or PC-based data acquisition system which utilizes an AID card and application software for visualizing and analyzing of the results. At the end of this article the designed and constructed test machine is presented as a case study

Comfortable motorcycle helmet.

The present invention is to provide a helmet having satisfactory compatibility between its shock absorbing capacity, comfortable and satisfying users demand in view of the cost. The invention consist of a motocycle helmet, which uses resilient polymer foam such as expanded polypropylene (EPP). This type of foam recovers its shapes after first impact; therefore provide a protection of head against multi impact hits usually encountered in motocycle crashes. The density configuration to enhance ventilation. The new design shell, which may be of the conventional type or of a new bio-composite material. The said bio-composite shell can be made of reinforced natural fibers such as oil palm, or coca nut, or a combination of one of these fibers with common fibers such as glass, carbon, or polypropylene or the like. The said fiber are impregnanted in either thermoplastics such as polyester or thermoset such as epoxy resins. Therefore this invention relates to a new design of safety helmet, particularly to the one with suitable multi-impact protection, enhanced air ventilation, good fitness, and with an environmental friendly shell material

Motorcycle Helmet Part II. Materials and Design Issues.

The main objective of this paper is to formulate a methodology, which could be used for material selection and basic design of motorcycle helmets. The importance of simplified solutions to motorcycle helmet material selection and design are first highlighted. Two methods are presented. The first approach is based on energy absorption theory for packaging design and also was used for bicycle helmets design with some adjustments. This method is reviewed and modified to cope with the motorcycle helmet design requirements. The second approach is also base on energy absorption principle. This method was developed for packaging design but the same principle could be employed to the motorcycle helmet problem. It was found that the two approaches have the same energy absorption principles but differ in the way of formulation and utilization. These differences could have significance effect on the results particularly the energy per unit volume calculation. However, both procedures could be used as useful tool for the helmet foam material selection and helmet preliminary analysis and design. Using these energy approaches together with advanced computational techniques could reduce the lead-time of helmet design and manufacture

Motorcycle Helmet Part I. Biomechanics and Computational Issues.

This paper is devoted to review the current status related to motorcycle helmet crash studies from biomechanics and computational point of view. The importance of motorcycle helmet performance on statistical background was reviewed. The paper is divided into two main sections: in the first section, the biomechanics issues are highlighted and the head injury classifications are presented. The injury mechanisms for different injury types are analyzed and the related helmeted-head impacts were indentified. The injury tolerances for the head main components presented with an insight into the current controversies among the different limits particularly rotational acceleration effects on the brain and the DAI brain damage type. In the second section, insights into the computational techniques used are also reviewed. Finally, directions for future research are also highlighted