This study reviews the assumption that the lightweight design of commercial vehicles is significant from the aspect of the anticipated fuel consumption and environmental regulations that are consequently applicable to those vehicles. Generally speaking, it is noted that among the numerous trailer components, a stub axle, which is designed to independently operate as an integral part of trailer’s suspension, can play an important role in increasing the shipping capacity of a box trailer. For this reason, because each stub axle is comparatively a heavy unit in itself, and a total of six stub axles are mounted in a box trailer, the lightweight design of a stub-axle is noted as an essential factor to reduce the whole weight of a trailer. For a finite element analysis, an original CAD model is modified through removing a chamber, airbag, axle drum, bearing and pivot on a vehicle. In addition, the loading conditions are imposed considering three extreme driving conditions and the effects are studied when in the event of review of a fully loaded in a box trailer. A topology optimization is conducted to determine a lightweight design for minimizing compliance under these boundary conditions.

The central seam, the vertical ‘line’ between doors, in the front view of a refrigerator must have its gap and flush within certain ranges to meet functional and aesthetic requirements. The conventional criteria for gap and flush control in the industry are to keep the gap and flush within certain ranges at each of various points along the seam. For aesthetics, however, the uniformity of the gap is also as important because a ‘tapered’ seam is negatively perceived by human eyes. This paper shows a case study of tolerance design for a refrigerator door system. It presents a step-by-step procedure, which consists of datum flow chain analysis, identification of assembly features, computer modeling of feature tolerances, assembly operations and measurements, tolerance simulation, and tolerance adjustments based on the simulation results. It is found that extra care may need to be used to satisfy the aesthetical criterion for gap uniformity.