This study reviewed types and dynamic behavior characteristics of shock-absorbing materials used in spent nuclear fuel transport containers. Among various shock-absorbing materials, wood, honeycomb, and foam materials were the most commonly used. Redwood and balsa wood are sustainable materials with excellent energy absorption properties and natural decomposition, but vulnerable to temperature and humidity. Although honeycomb materials have better mechanical strength than other materials, they only support unidirectional loads. Urethane foam and Fenosol foam materials have lower mechanical strength and lower shock absorption than others, but have higher lightness and fire resistance. They also allow users to control density and produce them. Due to their isotropic characteristics and ease of increasing or decreasing strength by adjusting density, foam materials are better for design and manufacturability than others. Shock-absorbing materials show more complex behavior characteristics than general steel materials. For shock absorption, large deformations are considered up to sections that greatly exceed the elastic region, inevitably increasing the complexity of behavior simulation. During design, to accurately simulate large deformation behavior, it is important to select an appropriate analysis property card and determine major influencing factors. An analysis-based review was additionally conducted for property cards typically applied to foam materials.

In this study, focusing on reducing a load in forming helical gears, the extrusion using two-step processes for manufacturing helical gear is proposed. The process is composed of the extrusion step in which spur gear to be used as a preform in next step is formed, and the torsion step in which the preform of spur gear is formed to helical gear. Upper-bound theory for the two-step process is applied and compared with the results of experiment. The result of upper-bound solution has a good agreement with that of the experiment and the FE analysis. The newly proposed method can be used as an advanced forming technique to remarkably reduce a forming load, to prolong a tool life, and to replace the conventional forming process of helical gears. Results obtained from the extrusion using two-step processes enable the designer and manufacturer of helical gear to be more efficient in this field.

A gerotor pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. Especially the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobes with circular shape, while the inner rotor profile is determined as conjugate to the other. For this reason the first topic presented here is the definition of the geometry of the rotors starting from the design parameters. The choice of these parameters is subject to some limitations in oder to limit the pressure angle between the rotors. Now we will consider the design optimization. The first step is the determination of the instantaneous flow rate as a function of the design parameter. This allows us to calculate three performance indexes commonly used for the study of positive displacement pumps: the flow rate irregularity, the specific flow rate, and the specific slipping. These indexes are used to optimize the design of the pump and to obtain the sets of optimum design parameter.
Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field, and the system could serve as a valuable one for experts and as a dependable training aid for beginners.