Synthesis of consolidated data schema for engineering analysis from multiple STEP application protocols J. Liang a , J.J. Shah a, * , R. D’Souza a , S.D. Urban b , K. Ayyaswamy b , E. Harter c , T. Bluhm c a Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, AZ 85287, USA b Department of Computer Science and Engineering, Arizona State University, Tempe, AZ 85287, USA c Boeing Phantom Works, Seattle, WA, USA Received 7 August 1998; received in revised form 15 March 1999; accepted 19 March 1999 Abstract This paper addresses the data modeling aspect of an integrated product data-sharing environment (IPDE) based on the international standard STEP. The IPDE involves multiple design and analysis applications that require data from several STEP Application Protocols (AP203, 209, 214, 224) and integrated resources from different parts of STEP. Issues that were addressed include data granularity, interoperability of STEP-AP’s, partitioning the AP’s into units of functionality (UoF), and resolving inter-object references among UoFs. The consolidated data model used for progressive implementation of several prototypes is presented in this paper. Because of limitations of STEP, extensions beyond STEP were necessary for data related to aerodynamic analysis, parametric geometry and constraints. The latter were imported from the ENGEN (ENGEN is a DARPA supported collaborative project managed by PDES, Inc.) Data Model and a new STEP-compliant model was created for CFD. This paper may be regarded as a study of issues related to the synthesis of an integrated data schema from multiple independent topical models.  1999 Elsevier Science Ltd. All rights reserved. Keywords: Data modeling; Engineering data management; STEP; Data exchange standards 1. Introduction The aim of Boeing’s Integrated Product Design Environ- ment (IPDE) is to allow CAD/CAM/FEA programs from different vendors to share data dynamically. Fig. 1 shows the three principal components, an Integrated Product Data- base (IPDB), Shared Design Manager (SDM), and a set of Data Access Interfaces (DAI) for each application type which is included in the environment. The Integrated Product Database (IPDB) is designed to house the complete product/process definition in integrated form. The contents of the IPDB include product geometry, dimensions and tolerances, finite element analysis grids and results, features data, manufacturing process plans, and so on. The IPDB schema embodies the data required to support both the product/process definition and the suite of analyses that must be applied to evaluate that definition. For this reason, STEP was used in the design of the schema. The role of the SDM is to manage the semantics amongst various elements of IPDB. The SDM also controls access to the IPDB through Data Access Interfaces (DAI) by supplying tool-type inter- face definitions. The IPDB schema needs to be in a standard form to make it possible for different vendor applications to read and write to it. The development of the integrated database schema (meta-data) based on STEP is the focus of this paper. Rationale for the IPDE architecture and details of the workings of the SDM are not discussed here; the reader may refer to other documents [1,2]. This paper describes the schema design for a prototype IPDB to support a selected sub-set of applications used in airframe design: Lofting (external surface geometric design), CFD for aerodynamic analysis, FEA for structural analysis, Dimension and Tolerance specification, Feature recognition, Manufacturability evaluation, and PDM to manage product data. The meta-data describes the seman- tics of the database (IPDB) and includes a description of the application and physical level database schemes, and the mappings between these schemes. Dimension and Toler- ance specifies geometric variations permitted by design. Computational Fluid Dynamics (CFD) is a set of computa- tional aerodynamic codes which have been developed for numerical flow simulation to calculate the flow fields, pres- sures with streamline traces and velocity. Finite Element Structural Analysis (FEA) is a computational method, which can determine deflections, strains and stress on a Computer-Aided Design 31 (1999) 429–447 COMPUTER-AIDED DESIGN 0010-4485/99/$ - see front matter  1999 Elsevier Science Ltd. All rights reserved. PII: S0010-4485(99)00041-X www.elsevier.com/locate/cad * Corresponding author. Tel.: + 602-965-3291; fax: + 602-965-2412. E-mail address: jami.shah@asu.edu (J.J. Shah)