This review provides a comprehensive overview of experimental studies using the split Hopkinson pressure bar (SHPB) for evaluating the high strain rate properties of materials. It outlines key design guidelines and considerations for SHPB setups and describes data analysis methods across its four loading modes. Specialized versions of SHPB techniques and their novel applications are also introduced. A categorized summary of SHPB studies – organized by loading mode and material type – is presented in tabular form. Finally, the review discusses future developments and the potential for broad applications of SHPB techniques across various fields.

The photodegradation characteristics of polymer ceramic PSP (PC-PSP) and TLC-PSP were investigated. In the present experiment, a mixture of fluoropolymer powder (PTFE) and silicone resin was used as the polymeric ceramic of PC-PSP, and Ru(dpp)3 was used as the PSP dye. The PC-PSP was less susceptible to photodegradation than the TLC-PSP. This can be explained by the effect of PTFE and polymer resin. When we apply a polymer resin to the TLC plate, we could improve photodeterioration of that. The experimental results showed that the present PC-PSP and the TLC coated with polymer resin applied to polymer resin could suppress the photodegradation characteristics without losing the pressure sensitivity.

The purpose of this study is to reduce the dependence of wall shear stress measurements using the sublayer plate method on the flow angle. This is achieved by focusing on the leading-edge geometry of the sublayer plate. This is done in this study by focusing on the leading-edge geometry of the sublayer plate. A two-dimensional channel flow is used to investigate this issue. The bulk Reynolds number is between 10,000 and 22,000. The wall friction coefficient of this channel flow is verified using a previous study. A calibration curve that converts the pressure difference before and after the plate to wall shear stress is shown. It is confirmed that the same characteristics of the conventional sublayer plate method are maintained even when the leading-edge geometry is changed. The sensitivity of the measurement when the leading-edge geometry is changed is also investigated. The dependence of the wall shear stress values on the inflow angle is then shown. The dependence on the inflow angle depends on the leading-edge geometry and can be reduced by up to 20%.

The aim of this study is to investigate the efficiency of turbulence generation using turbulence grids, focusing on the cross-sectional shapes of the grid bars. Efficiency in this context refers to maintaining the intensity of velocity fluctuations in the generated turbulence while reducing the drag coefficient of the turbulence grid. Wind tunnel experiments were conducted using turbulence grids with three different cross-sectional shapes (circular, square, and rectangular), and the velocity fluctuation intensity and drag coefficient of the generating grids were measured. The results showed that the turbulence grid with square and rectangular cross sections produced higher velocity fluctuation intensities higher than those with circular cross sections, and the distributions of these intensities were consistent between the two shapes. In addition, the turbulence grid with a rectangular cross section had a drag coefficient about 10% lower than that of the square cross section. These results suggest that a rectangular turbulence grid may be more efficient at generating turbulence.

This paper proposes a data processing method for easily and efficiently determining strains near a crack from the displacement field data obtained using digital image correlation. The displacements within a strain window are approximated by polynomials and the strains are obtained as their derivatives. A crack is detected from the difference between the approximated and measured displacement distributions and the correlation coefficients obtained during the displacement measurement. The strains near the crack are obtained by ensuring that the data at the crack does not overlap with the strain window. The proposed method is applied to several displacement fields obtained using digital image correlation and demonstrates its effectiveness. This method makes it possible to easily obtain the strain distributions near a crack and is expected to be applied to various fracture mechanics studies.

This study demonstrates the first successful application of phase retrieval holography to microscopy. We developed a dual-camera phase retrieval holographic microscopy system that captures two in-line holograms at different axial positions. This system retrieves quantitative phase distributions through iterative reconstruction and mitigates the twin image problem inherent in conventional in-line holography. The relative error in measuring the volume of a 500µm-diameter ball lens was significantly reduced from 95% with the conventional method to 3.9% with the proposed method. These results confirm the feasibility and effectiveness of the proposed approach for precise, phase-based measurements in microscopic imaging.

Previous studies on the biomechanics of handrail use have primarily involved evaluation methods using sensors worn on the body (e.g., joint moments) and qualitative evaluations. If the load and grip strength acting on a handrail can be measured, then direct measurement would be possible without reliance on worn sensors or qualitative evaluations. In this study, we report the development of a system for measuring the mechanical loads on handrails and its use to clarify the trends in such loads during stair climbing. Mechanical loads on the handrail are measured using a 3-axis force sensor and two strain gauges. Subjects in the experiment were right-handed 10 healthy adults. The results showed that the grip duration on the handrail could vary by up to a factor of 2.6 depending on the subject. Also, the direction of the force acting on the handrail helped to elucidate the role of stair handrails. Future research will focus on moments around each axis to identify load application points, thereby further clarifying the role of stair handrails.

Polymers and their composites are widely used in aerospace, energy, and automotive industries due to their lightweight, manufacturability, and high impact resistance. Predicting the viscoelastic behavior of these materials is crucial for ensuring their reliability and durability. The Time-Temperature Superposition Principle (TTSP) is commonly used to predict long-term viscoelastic properties like creep and stress relaxation, but its molecular mechanisms are not fully understood. This study employs molecular dynamics simulations to investigate these mechanisms in polyethylene (PE), and polypropylene (PP) with methyl group. Creep analyses at various temperatures show that PP exhibits superior creep resistance compared to PE. Furthermore, the role of free volume was examined, showing that the methyl groups in PP contribute to more stable free volume changes. This study also shows the importance of torsion potential energy for TTSP and demonstrates that the presence of methyl groups primarily affects TTSP through bond and angle potential energies. This study clarified the effect of the presence or absence of methyl groups on TTSP.