Innovative designs of an in-tank hydrogen valve towards direct metal laser sintering compatibility and fatigue life enhancement

in Structural and Multidisciplinary Optimization (2019)

Replacements of using fossil fuel by different types of renewable energy are the current development trend in the automotive industry towards sustainable vehicles. A hydrogen-powered car is a promising ... [more ▼]

Replacements of using fossil fuel by different types of renewable energy are the current development trend in the automotive industry towards sustainable vehicles. A hydrogen-powered car is a promising solution, in which the safe and smooth operation of the car is strongly depended on how an in-tank valve of a fuel-storage-system performs. The present paper introduces the investigations and innovations of structures of the mentioned valve, whose designs can be subjected to fabricate by direct metal laser sintering. Two parts of the valve were taken into considerations, including the largest female-thread and the body. While the threads were investigated in the proposed conditions via fatigue-life assessment, the bodies were only assessed after being built from the concepts, developed by structural optimisations and lattice implementation. The achieved results showed that within the same pre-treated conditions, the optimised valves have considerably higher fatigue life, but lower masses, than those of the original. It was also observed that the applications of pre-treatment by autofrettage could contribute significantly to life prolongation of the valves as compared to the non-treated ones. In addition, those essential features, such as powder-release channels, which make the developed valves compatible with DMLS, were implemented into the valve-designs to be able to ensure their successful prints. Finally, the results suggested that the second innovated structure of the lattice-valve is the best candidate, which could be additively produced for the upcoming experimental-validation phase of the demonstrated works. [less ▲]

NEW METHODOLOGY FOR DESIGNING DIRECT-LASER-SINTERED MOTORCYCLE FRAME BASED ON COMBINATION OF TOPOLOGY OPTIMIZATION AND LATTICE IMPLEMENTATION

in International Journal of Mechanical Engineering (2017), 6(3), 39-50

The use of direct laser sintering (DLS) has become more attractive recently since it offers a promising tool in fabricating complex components rapidly. Particularly, the technique is seen more powerful ... [more ▼]

The use of direct laser sintering (DLS) has become more attractive recently since it offers a promising tool in fabricating complex components rapidly. Particularly, the technique is seen more powerful when it is combined with computer-aid design and computational optimization. In spite of knowledge increment in the above areas presently, design method for sophisticated structures towards DLS is still far from being fully exploited. Therefore, this paper was issued to investigate a novel methodology of design, developed by combining topology optimization and lattice-beam implementation, for a blend-solid-lattice frame of a motorcycle. From the obtained results, it was recognized that the as-built tubular hybrid structure demonstrated comparable values of first resonant frequency and mass with respected to those of the original. Additionally, it was found that stiffness of the generated structures depended strongly on locations where lattice was substituted. In particular, less stressed frame’s components were evidenced as appropriate regions for the substitution. The achieved results also revealed estimated buckling load factors, being circa 18 times higher than applied bumping loads acted on the tubular-lattice structure. Finally, equivalent stress predicted in static analyses confirmed all designs working safely in nominated conditions. Based on these achievements, it is believed that the new method worked quite acceptably in designing direct-laser-sintered motorcycle frame, and it is very promising to further develop the method as well as extend it into different complex direct-laser-sintered elements designed for future applications. [less ▲]