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Finite element (FE) analysis of the tensile test of TWB-HPF 22MnB5 steel was performed and compared with the experimental results. To improve the accuracy of the simulation, the damage theory of FLD and ductile damage theory were used in 2D and 3D simulations. The tensile strength of 22MnB5 steel was determined under various welding heat inputs for FE simulation. Crack propagation of the welded region indicated that the fracture was observed in the base metal under normal welding conditions. Also, the crack propagated along the HAZ region due to higher heat input of the welding, and lead fractures have been highlighted as a potential complication. [ABSTRACT FROM AUTHOR]

This study is about fear of crime, which is one of the most important topics in the criminological research.The study tested an integrated model in structural equation modeling method by using both SPSS and AMOS. Those who perceive higher levels of incivility were found to be more fearful of crime. Policies to reduce fear of crime and implications for future research were discussed based on the findings.

Using a tailor-welded blank (TWB) and hot-press forming (HPF), a 22MnB5 blank was surface-treated under four conditions. The penetration rates of the FexAly compounds under the four surface-treatment conditions were investigated, and the hardness values were measured. A finite element (FE) simulation was performed for the characteristics of the heat-affected zone (HAZ), using the hardness value and results of previous researchers. In particular, the mechanical property settings of the mesh were designed to realize the conditions for the FexAly compounds in the HAZ. Fine meshing was performed by partitioning the HAZ sections. For the mechanical properties of the HAZ with the FexAly compounds, the strength was predicted from the hardness value, and the elongation values investigated by other researchers were used. The forming limit diagram, which was proportional to the elongation, was predicted. Specific elements were defined as the areas with FexAly compounds, which played the same role as impurities. Tensile TWB–HPF specimens with different HAZ characteristics under four surface-treatment conditions were fabricated. Experiments and FE simulations were performed and compared. Details are as follows: For loads, a minimum error rate of 3% and a maximum error rate of 6% were obtained. For displacement, a minimum error rate of 9% and a maximum error of 25% were obtained. The feasibility of the simulation was verified by comparing the simulation and experimental results. A match of more than 75% was obtained. [ABSTRACT FROM AUTHOR]

The present article describes the tribological properties of Mg-based hybrid composites reinforced with graphite nanofiber (GNF) and alumina short fiber (Al2O3sf) that were investigated. The Mg/GNF/Al2O3sf hybrid composites with varying volume fraction of fiber (10 vol.%, 15 vol.%, 20 vol.%) were developed. SEM observations indicate that the GNF cluster distributions within the array of the Al2O3sf network are found to be relatively good. The Taguchi design of the experiment has been applied to conduct the wear test, and the statistical analysis of variance (ANOVA) has been used to evaluate the influence of wear test parameters on the wear loss and coefficient of friction (COF) of the composites. The influence of wear test parameters such as volume fraction of fiber (VF), applied load (AL), sliding distance (SD), and sliding speed (SP) on the wear loss and COF of composites was analyzed under dry sliding conditions. The results of ANOVA indicate that the sliding distance was found to be the prominent factor affecting wear loss, and the applied load influenced the COF most significantly. Furthermore, the composites with 20 vol.% of fiber had lower wear loss than those with 10 vol.% and 15 vol.% of fiber. The COF of composites with 15 vol.% of fiber was found to be slightly lower compared to the 10 vol.% and 20 vol.% of fiber cases. The results imply that the hybridization of GNFs and Al2O3sf, as well as the formation of Mg17Al12 and Al2MgC2 precipitates enhanced the tribological properties of the Mg hybrid composites. [ABSTRACT FROM AUTHOR]

As the crashworthiness and weights of parts in vehicles are both directly influenced by the thickness of the corresponding materials, a reasonable compromise is required for the optimal design. In this study, an innovative crashworthiness diagram was proposed for optimizing the multiple collision characteristics of automobile components with respect to thickness. The crashworthiness diagram was designed to consider multiple collision characteristics, such as the impulse, energy absorption, and anti-intrusion displacement, based on a crashworthiness index (CI). The respective CI values were assessed both analytically and numerically to determine the optimal thickness of an alternative material. The use of aluminum alloys was investigated, aiming to improve the collision resistance while ensuring lightness. Based on the crashworthiness diagram, an Al7075-T6 bumper beam with a thickness of 2.5 mm was used to replace a 22MnB5 (HPF) bumper beam with a thickness of 1.4 mm. An experimental validation of the Al7075-T6 bumper beam through a drop-weight test confirmed that the proposed crashworthiness diagram is a feasible and reliable guide to determine alternative material with target collision resistance [ABSTRACT FROM AUTHOR]

Hot press formed parts in a fully martensitic structure limit its application in the centre pillar, which requires high collision resistance. In this study, the combined effect of the patchwork and partial softening on the collision characteristics of the centre pillar, such as impulse, absorbed energy, and intrusion displacement, were investigated both experimentally and numerically. The partial softening process was used to provide ductility, while the patchwork was attached to improve the stiffness during impact loading. The energy absorption was assessed by integrating unit element deformation during impact. When patchwork and partial softening were applied to the centre pillar simultaneously, the anti-intrusion and absorbed energy were improved remarkably by 20.0% and 20.3%, respectively. The combined application of patchwork and partial softening is a feasible alternative for enhancing the collision resistance of the centre pillar with high degree of reliability. [ABSTRACT FROM AUTHOR]