One of the major factors in road-induced noise in a vehicle is the vibration characteristics of its tires. The effects of tire cavity resonance are clarified in this paper by a mathematical approach to the excitation and by road tests. Peaks of road noise due to cavity resonance in automobile tires exist at frequencies between 230 and 300 Hz. The major peak is at the first mode of cavity resonance in the circumferential direction and is not affected by the cross-sectional shape of the tire. The noise is affected by only the first mode of cavity resonance. Therefore, by using countermeasures to this resonance, the road noise can be reduced.
The basic part of the vertical form, fill and seal packaging machine is the forming collar. The forming collar provides the shape over which packaging film is smoothly formed at high speed into a cylindrical shape. Describing the forming collar geometry and hence its design is, however, remarkably difficult. This paper presents, for the first time, a flexible methodology for calculating the complete geometry of the film rather than the usually non-complete collar over which the film is formed. That is, a methodology to calculate the film geometry over the collar including the seam along which the film is longitudinally sealed. The film geometry is calculated such that it has minimum deformation energy. Advantages of the proposed methodology include its great flexibility to generate collars with different configurations for different needs. Among the collar generation methods reviewed, the proposed methodology is the first that can systematically consider all collar configuration parameters such as the seam configuration, general package cross-section, flat or straight part of the collar, collar back angle, etc. A means for obtaining the exact collar geometry is also demonstrated. This enables right-first-time and repeatable collar production and reduces the time and cost for producing next generation packaging machines.
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