A MULTILEVEL PRODUCT MODEL FOR SIMULATION-BASED DESIGN OF MECHANICAL SYSTEMS

This paper presents a multilevel product model that supports Simulatio n-Based Design (SBD) of mechanical systems, from preliminary to detail ed design stages. The primary goal of the SBD is to achieve product de signs featuring better performance and greater durability and reliabil ity through computer-based modeling. engineering analysis, and design trade-off. A Computer-Aided Design (CAD) model combined with engineeri ng parameters and mathematical equations that simulate physical behavi or of the mechanical system constitute its product model for SBD. For preliminary design, improvement of system performance. including dynam ics and human factors, is usually the primary feats. A CAD model with reasonably accurate physical parameters, such as mass properties of ma jor components or assemblies, is defined as the base definition of the product model for SBD. A number of simulation models are derived from the base definition to support simulation of the mechanical system pe rformance. A parametric study can be conducted to search for design al ternatives using dimension parameters created in the parameterized CAD model. The CAD model and base definition are then refined from the pr eliminary design stage to support intermediate designs. Intermediate d esigns will primarily focus on product subsystem performance. A produc t model is evolved by refining geometric representation of mechanical components in CAD, and expanding product assembly into parts and subas semblies for further engineering analysis. Component designs for perfo rmance, such as fatigue, mechanical reliability, and structural perfor mance, as well as maintainability are the primary focus in the detaile d design stage. A detailed product model evolved from that of the prev ious design is needed. in the detailed design stage. a systematic desi gn trade-off method supports design improvement. A High Mobility Multi -Purpose Wheeled Vehicle (HMMWV) is employed to illustrate and demonst rate the proposed product model.