Modular Distributed Models of Engineering Structures

Approaches to engineering design and manufacturing such as integrated design and manufacture and just in time fabrication depend on interaction with and among component supply companies that most often use very diverse technologies. The Internet Engineering Design Agents (i-EDA) software system uses a distributed, component-based, agent methodology that is realized following a strong black box approach to modeling. An individual Design Agent (DA) is a virtual product capable of encapsulating both descriptive and model based information about the product it represents. Hierarchically recursive agents for sub-systems and/or components are linked via a communications network to form larger integrated model systems. A two dimensional bridge system structural model is used as an example to illustrate the distributed assembly of structural models from components registered as DA’s on a communications network. Modular Distributed Modeling (MDM) of engineering structures performs static deflection analysis using traditional, fixed causality, structural stiffness models. This paper presents the methodology required to assemble traditional structural stiffness models provided by internet agents representing structural components. The methodology discussed assembles these component models into the structural stiffness model of an assembly distributed by an agents represent that physical assembly of components. Using this modular distributed modeling method; models of complex assemblies can be built and distributed while hiding the topology and characteristics of their structural subassemblies. The automated, modular, assembly of structural stiffness models will be derived for discrete physical connections. Discrete connections are important to the assembly of components such as truss and shaft structures where the relationship between component displacements involve discrete, matching, degrees of freedom on components to be assembled. Specific examples of discrete assembly of truss bridge component models will be presented. Internet connection permitting, real-time, automated assembly of models and deflection analysis will be performed. INTRODUCTION Modular Distributed Modeling (MDM) is a novel Internetbased architecture enabling cooperative engineering design, distributed black-box modeling of engineered products, and open and competitive e-commerce in producer/assembler chains (Radcliffe and Sticklen, 2001). The motivation for modular distributed modeling lies in the realization that today’s engineering and manufacturing communities have been fundamentally altered by two important factors: (a) the development on non-captive suppliers for large manufacturing firms who largely act as assemblers and (b) the development of reliable, high speed electronic connectivity (the Internet). The automobile industry is prototypical of both the old and new manufacturing organizational structure. Formerly, large manufacturing/assembler firms typically had a captive supply chain of smaller companies. The smaller companies produced parts only for their captor firm. Today the situation has changed dramatically; the automotive companies act as assemblers of components produced by a global, non-captive, supplier network. In today’s typical engineering and manufacturing environments, supplier companies are not captive to any single firm, but rather sell their goods as dictated by the marketplace. On the surface, this change should result in more competition and hence lower pricing and more innovative products. But in order to protect intellectual property, suppliers are very reluctant to share with “window shoppers” the designs of their products without strong and enforceable legal agreements. Putting in place such legal agreements (typically proprietary information agreements) requires both money and, more importantly time. This time lengthens time-to-market, and requires agreements be in place long before sales agreements are considered. The effect is that although on the surface assembler/supplier chains are open, in effect there is a web of legal agreements that bind specific assemblers to specific