No abstract

Additive manufacturing allows a direct fabrication of any sophisticated mechanism when the clearance of each joint is sufficiently large to compensate the fabrication error, which frees the designers of cumbersome assembly jobs. Clearance design for assembly mechanism whose parts are fabricated by subtractive manufacturing has been well defined. However, the related standard for parts fabricated by additive manufacturing is still under exploration due to the fabrication error and the diversity of printing materials. For saving time and materials in a design process, a designer may fabricate a series of small mechanisms to examine their functionality before the final fabrication of a large mechanism. As a mechanism is scaled, its joint clearances may be reduced, which affects the kinematics of the mechanisms. Maintaining certain clearance for the joints during the scaling process, especially for gear mechanisms, is an intricate problem involving the analysis of nonlinear systems. In this paper, we focus on the parametric design problem for the major types of joints, which allows the mechanisms to be scaled to an arbitrary level while maintaining their kinematics. Simulation and experimental results are present to validate our designs.

No abstract

No abstract

The aerodynamic performance of an automobile is affected by differing automobile tail shapes. Different simple automobile models were designed and analyzed with the FLUENT software; by using this research method, one can qualitatively analyze the automobile flow field, as well as the lift and drag coefficients in an accurate manner. The results from an analysis of different automobile tails indicate that the most improved automobile model tail shape resulted in a drag coefficient of 4.5% lower than the basic model, and a lift coefficient of 41.6% lower than the basic model. This design had the smallest drag coefficient, the smallest lift coefficient, and the best aerodynamic performance when simulated in the FLUENT Software, allowing the user access to a tangible reference basis for choosing an automobile model.