Hydrogen production using water electrolysis is generally a well-known phenomenon. Hydrogen produced using the water electrolysis method is an environment-friendly energy source called ‘green hydrogen’ that does not emit any environmental pollutants when using renewable energy as an energy source. This study aims to improve the efficiency of hydrogen production by using the ion transportation effect induced by a rotating magnetic force. For this purpose, the experimental conditions for ion transport were determined through an experiment using a copper wire and the rotating magnetic force for water electrolysis was applied using an alkali aqueous solution. Based on the results, an increase in the number of bubbles generated by the rotating magnetic force increased was observed. It is assumed that the efficiency of hydrogen production using water electrolysis can be improved by the rotating magnetic force.

The photovoltaic power generation facility is usually installed outdoors and is extensively impacted by snow and wind power as well as external contact friction caused by snow and rain. In particular, since there is a markedly high possibility of damage from devastating wind power such as a typhoon, an overall safety evaluation is essential. However, most studies are conducted using cell-level stress analysis rather than cluster-wide stress analysis. Thus, in this study, a finite element analysis was performed on the entire support structure of the photovoltaic power generation facility, wherein the wind load was applied, and the portion wherein extensive stress was generated was identified. The results of the analysis showed that the stress in the rear side was relatively higher than in the front side of the support structure for the horizontal wind. Additionally, it was confirmed that a relatively high stress occurs in the lower side than the upper side of the support structure.

Seismic load induces a reverse cyclic load that alternately applies a tensile and a compressive load to a structure. For nuclear piping material, safety is assessed in terms of fracture toughness. However, test results using a quasi-static load can’t guarantee safety if there is a seismic load. In this paper, the fracture toughness of SA312 TP304 stainless steel, which is used as the safety injection pipe of a nuclear power plant, was estimated by using reverse cyclic loads with different ratios of tensile load to compressive load. The test results using a load ratio of -1 (compressive load / tensile load) show that fracture toughness decreases to approximately 10% against a load ratio of zero. These test results show that the reverse cyclic load must be considered in planning for the safety of nuclear power plants under seismic loads.

Recently, carbon fiber reinforced plastic(CFRP) composite materials have been widely used in various fields of engineering because of its advanced properties. Also, CFRP composite materials offer new design flexibilities, corrosion and wear resistance, low thermal conductivity and increased fatigue life. However CFRP composite materials are susceptible to impact damage due to their lack of through-thickness reinforcement and it causes large drops in the load-carrying capacity of a structure. Therefore, the impact damage behavior and subsequently load-carrying capacity of impacted composite materials deserve careful investigation. In this study, the residual strength and impact characteristics of plain-woven CFRP composites with impact damage are investigated under axial tensile test. By using obtained residual strength and Tan-Cheng failure criterion, residual strength of CFRP laminate with arbitrary fiber angle were evaluated.

A straight pipe is used after complicated bending work in a mechanical system. In this work process, the plastic deformation of the pipe produces residual stress in the pipe. This residual stress significantly affects the behavior of pipe fracture. For this reason, residual stress must be evaluated. Measuring the residual stress of a U-shaped pipe is difficult with existing destructive and nondestructive measurement methods. In this paper, the residual stress of a U-shaped aluminum pipe (99.7% pure aluminum) was evaluated from the Raman shift by Raman spectroscopy and FEM(Finite Element Method, FEM) analysis. The results of the stiffness test by FEM analysis are compared with those by experiments. The analyzed results of the Raman spectra showed a similar tendency with the results of the FEM analysis with respect to the residual stress distributions in U-shaped pipes. Also, the results of the bending tests showed resemblance to each other.