The airbag is a widely accepted device for occupant protection in the automotive industry. As the injuries induced by airbag deployment have become a critical issue, revisions to Federal Motor Vehicle Safety Standard (FMVSS) 208 were required to create advanced airbags that can protect occupants of varying statures. In this paper, we developed a new low-risk deployment passenger airbag by adding the Passenger Protection Wrap (PPW). The PPW reduces the cushion impact force to the occupant in order to ensure pressure dispersion. A series of tests were conducted by using FMVSS 208 test procedures to demonstrate the proposed system. It was found that the system not only satisfied the injury criteria of FMVSS 208 but was also effective for protecting passengers of all sizes (male, small female, 3-year-old, 6-year-old).
Ti alloys are extensively used in high-technology application because of their strength, oxidation resistance at high temperature. However, Ti alloys tend to be classified very difficult to cut material. In this paper, The powder synthesis, spark plasma sintering (SPS), bulk material properties such as electrical conductivity and thermal conductivity are systematically examined on Ti2AlN and Ti2AlC materials having most light-weight and oxidation resistance among the MAX phases. The bulk samples mainly consisted of Ti2AlN and Ti2AlC materials with density close to theoretical value were synthesized by a SPS method. Machining characteristics such as machining time, surface quality are analyzed with measurement of voltage and current waveform according to machining condition of micro-electrical discharge machining with micro-channel shape.
An FFD(flexible fine die) is an embossed mold that consists of a thin plate ranging from 0.6 to 3 mm in thickness. FFDs are primarily used for cutting LCD films and F-PCB sheets. In the high-speed micro-milling process of flexible fine dies, the lubrication and cooling of the cutting edges is very important from the aspect of eco machining and cutting performance. In this paper, a comparative study of tool wear and surface roughness between cutting fluid and hybrid lubrication for eco-machining of FFD was conducted for processes of high-speed machining of highly hardened material (STC5, HRC52). Especially, the incorporated fluid method for eco machining, in which the cutting performances can be simultaneously measured, was introduced. The machining results show that hybrid lubrication, instead of conventional cutting fluid, leads to excellent tool wear and surface roughness and represents the proper conditions for eco micro-machining of flexible fine dies.
Thin sheets of lightweight aluminum alloys, which are increasingly used in automotive, aerospace, and electronics industries to reduce the weight of parts, are difficult to weld. When applying micro-friction stir welding (μ-FSW) to thin plates, the heat input to the base materials is considerably important to counter the heat loss to the jig and/or backing plate. In this study, three different backing-plate materials—cordierite ceramic, titanium alloy, and copper alloy—were used to evaluate the effect of heat loss on weldability in the μ-FSW process. One millimeter thick AA6061-T6 and AA5052-H32 dissimilar aluminum alloy plates were micro-friction stir welded by a butt joint. The tensile test, hardness, and microstructure of the welded joints using a tool rotational speed of 9000 rpm, a welding speed of 300 mm/min, and a tool tilting angle of 0° were evaluated. The heat loss was highly dependent on the thermal conductivity of the backing plate material, resulting in variations in the tensile strength and hardness distribution of the joints prepared using different backing plates. Consequently, the cordierite backing plate exhibited the highest tensile strength of 222.63 MPa and an elongation of 10.37%, corresponding to 86.7% and 58.4%, respectively, of those of the AA5052-H32 base metal.
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