Computer-aided Engineering Environment Research Articles

Development of an algorithm-based approach for Computational Design Synthesis of individualized implants

The trend towards product individualization in medical technology, e.g., for implants, is based on the realization that taking patient-specific characteristics into account significantly influences the therapy of diseases. However, one problem in the individualization of implants is the inaccessible position in the body, which only permits computer-aided modeling of individual solutions. A promising solution is using a Computer-Aided Engineering Environment (CAEE), which enables an algorithm-based approach to implement tools based on Computational Design Synthesis (CDS) that can build design knowledge and robustly generate patient-specific variants. In this paper, a case study is used to demonstrate the development of an algorithm-based approach within the framework of the CDS in a CAEE that performs hip arthroplasty individualization. The functions, implemented in a CAEE, includes all process steps, from medical image processing of Computed Tomographic (CT) data to generating a patient-specific solution. Relevant research questions addressed here include the automated recognition of geometry information from initialized data, processing of these data in product models to derive solutions automatically and implementing optimization algorithms to maximize requirement satisfaction. The result of this work is a fully automated model generator for hip stem prosthesis that requires only a CT scan for its design synthesis and optimization.

Finite element model of fiber volume effect on the mechanical performance of additively manufactured carbon fiber reinforced plastic composites

Advancements in additively manufactured (AM) carbon-fiber-reinforced-plastic (CFRP) composites for structural applications require reliable tools to predict mechanical performance. Already, the composites are finding applications in wind turbines, Unmanned Aerial Vehicles (UAVs), space applications, etc., and are promising for more emerging needs. Fiber volume plays a huge role in influencing the mechanical performance of the composites. However, more understanding of their effects are still needed to better ascertain material performance, which can be achieved by applying simulation modeling. This study developed a micromechanical model from Python scripts for Abaqus command line within computer-aided engineering (CAE) environment to predict the composites’ structural stability and mechanical performance. The verification of the finite element model by experimental testing showed both the simulation and experimental results to match within an acceptable range. Tensile modulus increased with fiber volume while compressive modulus shows some decreased properties with fiber addition irrespective of fiber content for up to 25% CF volume. The overall results show a possible trade-off between the tensile and compressive properties of the composite, which should be carefully considered in material design for various AM applications.

Computer-Aided Engineering Environment for Designing Tailored Forming Components

The use of multi-material forming components makes it possible to produce components adapted to the respective requirements, which have advantages over mono-material components. The necessary consideration of an additional material increases the possible degrees of freedom in product and manufacturing process development. As a result, development becomes more complex and special expert knowledge is required. To counteract this, computer-aided engineering environments with knowledge-based tools are increasingly used. This article describes a computer-aided engineering environment (CAEE) that can be used to design hybrid forming components that are produced by tailored forming, a process chain developed in the Collaborative Research Center (CRC) 1153. The CAEE consists of a knowledge base, in which the knowledge necessary for the design of tailored forming parts, including manufacturer restrictions, is stored and made available. For the generation of rough and detailed design and for elaboration the following methods are used. The topology optimization method, Interfacial Zone Evolutionary Optimization (IZEO), which determines the material distribution. The design of optimized joining zone geometries, by robust design. The elaboration of the components by means of highly flexible computer-aided design (CAD) models, which are built according to the generative parametric design approach (GPDA).

Simulation-Based Engineering Approaches for Renewable Energy Conversion Systems

The article provides a brief overview of the existing simulation-based engineering approaches with main focus on applications in analysis and simulation of renewable energy conversion systems. Among available numerical simulation tools, the study focuses on finite element analysis and multibody dynamics simulation techniques that are currently attracting the major research attention. Any mechanical simulation task presupposes existence of a simulation model, commonly in a computer-aided design tool. Thus, the approach used to merge design data with other computer-aided engineering environment is discussed and elaborated. This approach is particularly beneficial for design optimization of wind and wave converters to be installed at harsh and unfriendly environment for testing physical prototypes.

Improving the Reliability in the Next Generation of US Army Platforms through Physics of Failure Analysis

Published studies and audits have documented that a significant number of U.S. Army systems are failing to demonstrate established reliability requirements. In order to address this issue, the Army developed a new reliability policy in December 2007 which encourages use of cost-effective reliability best practices. The intent of this policy is to improve reliability of Army systems and material, which in turn will have a significant positive impact on mission effectiveness, logistics effectiveness and life-cycle costs. Under this policy, the Army strongly encourages the use of Physics of Failure (PoF) analysis on mechanical and electronics systems. At the US Army Materiel Systems Analysis Activity, PoF analyses are conducted to support contractors, program managers and engineers on systems in all stages of acquisition from design, to test and evaluation (T&E) and fielded systems. This article discusses using the PoF approach to improve reliability of military products. PoF is a science-based approach to reliability that uses modeling and simulation to eliminate failures early in the design process by addressing root-cause failure mechanisms in a computer-aided engineering environment. The PoF approach involves modeling the root causes of failure such as fatigue, fracture, wear, and corrosion. Computer-aided design tools have been developed to address various loads, stresses, failure mechanisms, and failure sites. This paper focuses on understanding the cause and effect of physical processes and mechanisms that cause degradation and failure of materials and components. A reliability assessment case study of circuit cards consisting of dense circuitry is discussed. System level dynamics models, component finite element models and fatigue-life models were used to reveal the underlying physics of the hardware in its mission environment. Outputs of these analyses included forces acting on the system, displacements of components, accelerations, stress levels, weak points in the design and probable component life. This information may be used during the design process to make design changes early in the acquisition process when changes are easier to make and are much more cost effective. Design decisions and corrective actions made early in the acquisition phase leads to improved efficiency and effectiveness of the T&E process. The intent is to make fixes prior to T&E which will reduce test time and cost, allow more information to be obtained from test and improve test focus. PoF analyses may be conducted for failures occurring during test to better understand the underlying physics of the problem and identify the root cause of failures which may lead to better fixes for problems discovered, reduced test-fix-test iterations and reduced decision risk. The same analyses and benefits mentioned above may be applied to systems which are exhibiting failures in the field.

Method, Models and Tools for CAD-CAE Integration

Computer Aided Design (CAD) and Computer Aided Engineering (CAE) are two significantly different disciplines, and hence they require different shape models representations. As a result, models generated by CAD systems often need to be submitted to shape transformations for Finite Element Analysis (FEA). In this paper, a new approach is proposed to ease integration between CAD and CAE also outlining some patents. It is based on new shape representation called 'mixed shape representation' that supports simultaneously a B-Rep (manifold and non-manifold) and a polyhedral representation to create a robust link between the CAD and CAE environments. Both representations are maintained through the same topology description called the High Level Topology (HLT), which represents a common requirement for simulation model preparation. An innovative approach to FE model preparation based on the mixed representation is presented in this paper. Thus a set of necessary tools is associated to the mixed shape representation, which contributes to reduce, as much as possible, the time of a model preparation process.

Reflecting communication: a key factor for successful collaboration between embodiment design and simulation

The need for integration of computer-aided design and computer-aided engineering environments stems from the business priority to reduce product cycle times. It is exacerbated by the coexistence of two different paradigms: a topological one in embodiment design and a functional one in simulation. This dualism places increasing demands on human communication between design and simulation engineers. This paper claims that reflecting communication is a key factor for successful collaboration. Reflection is used in both senses of the Latin word ‘reflectare’: to trigger active thinking about and consideration of communication, as well as to mirror perceptions of a given situation by people collaborating. The paper reports on the development and application of a maturity-grid approach to diagnose the current and desired states of communication between design engineers and simulation engineers in the car body development of a German automotive manufacturer. Results include three themes: one, the importance of understanding of the collaborators’ information needs; two, the importance of orientation, e.g., indicated by the engineers’ overview of sequence of tasks in the design process; and three, the importance of reflection.

A component framework for reusing a proprietary computer-aided engineering environment

Nowadays, it is becoming more frequent for engineers to deal with problems and situations that require specific software and the commercially available applications may not result adequate. Because of this, the reuse of software components is becoming a normal practice for improving the productivity of the software programmers, and the quality of the products that they develop. The employment of reusable components presents a number of advantages, such as the reduction in time necessary to develop new software, or the simplification of many computational tasks. There are some proprietary software environments in the engineering domain that are practically de facto standards, since they offer a broad functionality, robustness and constant updating. Therefore, those environments could be ideal candidates to be reusable components when developing new software. An example of this is Matlab, which can be encapsulated, in order to use it as a true reusable component. This will provide the user with efficient tools for designing his/her own applications. Moreover, there is an increasing importance for any software to offer distributed services. To perform this task, it is fundamental to have at one’s disposal reusable components that support Internet-based distributed applications and services development. In the present work, a software component framework that effectively encapsulates Matlab is described. This software allows developers the reuse of Matlab, for both local and distributed applications. To address those issues the .NET technology was employed. The component framework developed can be integrated in the toolbars of software development environments supporting the .NET framework. This facilitates the construction of applications that can reuse the components, since the software developers can use and test them and change their properties in design-time.

Semantic-driven grid-enabled computer-aided engineering of aperture-antenna arrays

In this paper, we propose a novel architecture for computer-aided engineering (CAE) of rectangular aperture arrays that takes advantage of semantic grid computing technologies. This allows the implementation of the CAE environment in a service-oriented framework, where CAE applications are built up at run time, by exploiting remote services through the grid. The identification and localization of remote services and their orchestration is simplified by semantic facilities, centered around a CAE ontology. This provides a structured, conceptual representation of hardware and software resources, including CAE services, which is understandable both by humans and software agents. The implemented prototype demonstrates how semantic grids satisfy the strong need for cooperation tools in the CAE of microwave circuits and antennas, and represents an effective pathway towards the automatic generation of design tools, attained by integrating electromagnetic software available through the Web.

An integrated CAE environment for simulation-based durability and reliability design

This paper introduces a flexible, general purpose, integrated Computer-Aided Engineering (CAE) system, called Durability and Reliability Analysis Workspace. It carries out the simulation-based spectral fatigue damage and failure probability analysis of mechanical components. In this environment, a hybrid quasi-static method for computing dynamic stress time history has been introduced, a critical plane method for predicting multiaxial fatigue crack initiation life have been used. Also, a new methodology for assessing component reliability based on fatigue failure mode has been proposed. The corresponding CAE tools for the purpose of aiding engineers in the durability and reliability analysis have been developed and implemented in the system. The system also provides a graphical, menu-driven user interface for quick and easy interaction with these tools. Advanced Computer Integrated Technology is utilized to integrate CAE tools bound into a system with automatic control, coordinate, and communicate. This paper explains the methodologies and treatment in the implementation of the CAE system. The objective of this research is to provide a layer of network computational services for reliable remote computations and data transfers between an engineering workstation and a computation server on a high-speed computer. It incorporates methods of both engineering and computer science to allow the engineer to solve engineering problems through automation and reliability, utilizing high-speed procedures.

Development of SDAI-Based Common Access Interface for Object-Oriented DBMS

The objective of this research is to construct a data access implementation at the database level using the specifications de fined in the ISO 10303 Standard Data Access Interface (SDAI). This paper documents the process of implementing the SDAI on a specific object-oriented database management system (OODBMS), called Web-based Object Oriented-DataBase (WOO-DB). WOO-DB is devel oped by the Institute for Information Industry and uses a proprietary object definition language (ODL) and object manipulation language (OML) to describe and manipulate data. The implementation is achieved by mapping the functions and schemata between the SDAI data model and WOO-DB ODL and OML. This research concludes a number of basic features that an OODBMS should support when con structing the SDAI access mechanism. Once the data access interface is independent of data storage technologies, the integration of ap plications in a computer-aided Concurrent Engineering environment can be achieved under a common data accessing protocol.

Ginger2: an environment for computer-aided empirical software engineering

Empirical software engineering can be viewed as a series of actions to obtain knowledge and a better understanding about some aspects of software development, given a set of problem statements in the form of issues, questions or hypotheses. Experience has made us aware of the criticality of integrating the various types of data that are collected and analyzed as well as the criticality of integrating the various types of activities that take place, such as experiment design and the experiment itself. This has led us to develop a Computer-Aided Empirical Software Engineering (CAESE) framework to support the empirical software engineering lifecycle. The paper first presents the CAESE framework that consists of three elements: (1) a process model for the lifecycle of empirical software engineering studies, including needs analysis, experiment design, actual experimentation, and analyzing and packaging results; (2) a model that helps empirical software engineers decide how to look at the world to be studied in a coherent manner; (3) an architecture, based on which CAESE environments can be built, consisting of tool sets for each phase of the process model, a process management mechanism, and the two types of integration mechanism that are vital for handling multiple types of data: data integration and control integration. Next, the paper describes the Ginger2 environment as an instantiation of our framework. It concludes with reports on case studies using Ginger2, which dealt with a variety of empirical data types including mouse and keystrokes, eye traces, 3D movement, skin resistance level, and videotaped data.

A New Approach to Generating Finite-State Control Programs for Hybrid Systems

We provide an abstract of a new approach for generating finite-state control programs for hybrid systems. We illustrate these ideas in the context of a cost-based Computer-Aided Control Engineering (CACE) environment. We discuss our methodology for ensuring that the environment should support automatic generation of automata which simultaneously comply with logic and evolution constraints. We argue that a declarative, hybrid systems approach to off-line design and online generation of reactive control automata is needed for achieving synchronization, scalability, integration, and incremental construction of large-scale, computer-controlled systems. The methodology supports a multiple-game strategy for distributed systems optimization whereby different components of the systems can employ different local optimization strategies. We conclude by comparing this constructive approach for on-line selection of actions that are near-optimal with respect to economic cost to the simulation-based approach for heuristic and exhaustive trade-off analysis.

Interactive-adaptive geometrically nonlinear analysis of shell structures

This paper presents an investigation of interactive-adaptive techniques for nonlinear finite element structural analysis. In particular, effective methods leading to reliable automated, finite element solutions of nonlinear shell problems are of primary interest here. This includes automated adaptive nonlinear solution procedures based on error estimation and adaptive step length control, reliable finite elements that account for finite deformations and finite rotations, three-dimensional finite element modeling, and an easy-to-use, easy-to-learn graphical user interface with three-dimensional graphics. A computational environment, which interactively couples a comprehensive geometric modeler, an automatic three-dimensional mesh generator and an advanced nonlinear finite element analysis program with real-time computer graphics and animation tools, is presented. Three examples illustrate the merit and potential of the approaches adopted here and confirm the feasibility of developing fully automated computer aided engineering environments.

A hybrid systems approach to computer-aided control engineering

In this article we provide a tutorial-style overview of ideas for a new computer-aided control engineering (CACE) environment. We discuss these ideas through repetition of two themes. The first theme is that the CACE environments should support a thread from requirements development to implementation. While some CACE environments come close to this today, none provides the end-to-end thread we envision. The second theme is that the environment should support automatic generation of automata that simultaneously comply with discrete and continuous constraints. Success in this theme would reduce the need to conduct extensive simulations and build prototypes in order to deliver and incrementally change computer-controlled systems. An example shows how such an environment can assist in addressing a recurring problem in manufacturing systems: repair of production schedules required by changes in logical or continuum constraints on factory operation. We argue that a declarative, hybrid-systems approach to off-line design and online generation of reactive control is needed for achieving synchronization, scalability, integration, and incremental construction of large-scale, computer-controlled systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The ANDECS CACE framework

Computer-aided control engineering (CACE) environments, in order to be reusable in a broad spectrum of applications, have to be based on an open software framework that provides seven classes of services: database services; model-definition services; algorithmic services; tool-control services; task-control services; user-interaction services; and process-communication services. This is detailed herein with the available CACE framework for the application system ANDECS. >

Maintainability Analysis in Concurrent Engineering of Mechanical Systems

Maintainability of the mechanical system should be considered from early stages of the design process to reduce its total life-cycle cost A computer-aided engineering environment that supports maintainability analysis of an evolving mechanical system design in a concurrent engineering environment is presented Its communication with the underlying concurrent engineering environment and capabilities to evaluate maintainability of the mechanical system are described and illustrated

248 A requirements analysis of future environments for computer-aided control engineering: H.A. Barker, C.P. Jobling, O. Ravn, M. Szymkat, pp 1201–1204

248 A requirements analysis of future environments for computer-aided control engineering: H.A. Barker, C.P. Jobling, O. Ravn, M. Szymkat, pp 1201–1204

Configuring problem-solving methods: a CAKE perspective

Over the past few years a certain amount of research has been done on ways of configuring problem-solving methods from smaller-grained components. Although frameworks for method configuration have been explored in previous studies, ways of developing and maintaining a library of reusable knowledge have not been fully integrated into the frameworks. The purpose of this paper is to provide a view of bridging the architecture of component assembling and the knowledge contents, on the basis of our experiences in the area of scheduling problems. First, existing component-oriented approaches are briefly reviewed. We then introduce the concept of a computer-aided knowledge engineering (CAKE) environment, which consists of not only processes for constructing knowledge systems, but also processes for developing knowledge libraries to be reused for the prospective systems. The content issues in a class of scheduling problems are pursued in terms of the representation primitives of the task and method, the task-specific components to be configured into problem-solving methods, and the process of obtaining those components. Taking account of the knowledge contents, we explore the architectural issues related to our development environment, and give running examples for the task analysis, component retrieval and component configuration. Finally, we compare related studies on reuse-oriented development environments.

The Beacon Block-diagram Environment

BEACON is a Computer Aided Engineering environment which allows the user to graphically design a real time control system as a series of hierarchical block diagrams. The diagrams constitute a complete documentation of the designed system. These diagrams can thereafter be used to automatically generate both simulation and real-time computer code. BEACON has been used within the General Electric Company to generate production code since the first quarter of 1992. This paper will present the BEACON block-diagram editor, its graphical user interface, and its different modes of operation. The extensive hierarchical modeling capabilities of BEACON will be discussed.