Digital Mock-up Research Articles

An algorithm for CAD tolerancing integration: Generation of assembly configurations according to dimensional and geometrical tolerances

For several years, Digital Mock-Up (DMU) has been improved by the integration of many tools as Finite Element (FE) Analysis, Computer Aided Manufacturing (CAM), and Computer Aided Tolerancing (CAT) in the Computer Aided Design (CAD) model. In the geometrical model, the tolerances, which specify the requirements for the proper functioning of mechanical systems, are formally represented. The nominal modeling of the parts and assemblies does not allow the prediction of the tolerance impacts on the simulation results as the optimization of mechanical system assemblability. So, improving the CAD model to be closer to the realistic model is a necessity to verify and validate the mechanical system assemblability. This paper proposes a new approach to integrate the tolerances in CAD model by the determination of the configurations with defects of a CAD part, used in a mechanical system. The realistic parts are computed according to the dimensional and geometrical tolerances. This approach provides an assembly result closer to the real assembly of the mechanical system. The Replacement of the nominal parts by the realistic ones requires the redefinition of the initially defined assembly mating constraints. The update of the mating constraints is performed by respecting an Objective Function of the Assembly (OFA). Integrating tolerances in CAD allows the visualization and simulation of the mechanical assemblies’ behavior in their real configuration and the detection of possible interference and collision effects between parts which are undetectable in the nominal state.

Simulation-based design process for the verification of ITER remote handling systems

The work behind this paper takes place in the EFDA's European Goal Oriented Training programme on Remote Handling (RH) “GOT-RH”. The programme aims to train engineers for activities supporting the ITER project and the long-term fusion programme. One of the projects of this programme focuses on the verification and validation (V&V) of ITER RH system requirements using digital mock-ups (DMU). The purpose of this project is to study and develop efficient approach of using DMUs in the V&V process of ITER RH system design utilizing a System Engineering (SE) framework. Complex engineering systems such as ITER facilities lead to substantial rise of cost while manufacturing the full-scale prototype. In the V&V process for ITER RH equipment, physical tests are a requirement to ensure the compliance of the system according to the required operation. Therefore it is essential to virtually verify the developed system before starting the prototype manufacturing phase. This paper gives an overview of the current trends in using digital mock-up within product design processes. It suggests a simulation-based process design centralized around a simulation lifecycle management system. The purpose of this paper is to describe possible improvements in the formalization of the ITER RH design process and V&V processes, in order to increase their cost efficiency and reliability.

Fuzzy grey relational analysis of design factors influencing on maintainability indices

Maintainability is a design attribute of a product, and its relationship with the design factors is complicated. In consideration of the fuzziness and uncertainty of design factors that influences the product's maintainability indices, we propose a method based on fuzzy grey relational analysis to determine their prioritization in this paper. First, the evaluation methods of various design factors and how these factors affect product maintainability indices are analyzed. Then, the fuzzy grey relational analysis model of the relationship between the design factors and maintainability indices is set up, and the prioritization of design factors to maintainability indices is achieved. Finally, the proposed methods are applied on a subsystem of a manned spacecraft, which indicates that the proposed method can quantitatively analyze the influencing degree of the design factors to maintainability indices. This information can be used to guide maintainability indices evaluation modeling based on digital mock-up in the design phase and help to catch the major influencing design factors in maintainability design.

The digital mock-up system to simulate and evaluate the dismantling scenarios for decommissioning of a NPP

This paper is to develop the digital mock-up system to simulate the dismantling scenarios for decommissioning of a NPP. Features of the digital mock-up system are kinematic simulation and human simulation of decommissioning scenarios of a NPP. The digital mock-up consists of major components, internals, support facilities, and equipments. The digital mock-up system could evaluate and optimize the decommissioning scenarios of a NPP.

Using Digital Mock-Ups Within Simulation Lifecycle Environment for the Verification of ITER Remote Handling Systems Design

This paper is part of the EFDAs European goal oriented training program on remote handling (RH) GOT-RH. The program aims to train engineers for activities supporting the ITER project and the long-term fusion program. This paper is written based on the results of a project verification and validation (V&V) of ITER RH system using digital mock-ups (DMUs). The purpose of this project is to study an efficient approach of using DMU for the V&V of the ITER RH system design using a system engineering framework. This paper gives an overview of the current trends in product and simulation lifecycle management (PLM/SLM) in the industry. This paper suggests a design verification process centralized around a collaboration platform. The purpose of this paper aims at improving and formalizing the ITER RH design process together with the V&V process. The objective of the suggested process is to improve the cost efficiency and reliability of ITER RH systems.

An extension of the core product model for the maturity management of the digital mock up: use of graph and knowledge to describe mechanical parts

Reverse engineering (RE) of mechanical parts consists in creating a 3D virtual model using data that are often gathered by 3D measurement systems like laser scanners. The resulting point cloud is then transformed into a geometrical model. The purpose of RE activity is to make maintenance or redesign operations easier. The boundary of the literature is the component, isolated from its product assembly. Because of unreported on-field maintenance, a long time running in-use product may not reflect its digital mock-up (DMU) anymore. In order to maintain an efficient lifecycle, the changes made have to be considered. This paper focuses on the development of a knowledge-based RE methodology to support the DMU maturity management: to identify the maturity defaults, which correspond to unreported changes, in the CAD assembly model in order to make it matching the real product. That approach is supported by a core product model data model extension.

Assessing the Ability of a VR-Based Assembly Task Simulation to Evaluate PhysicalRisk Factors

Nowadays the process of workstation design tends to include assessment steps in a virtual environment (VE) to evaluate the ergonomic features. These approaches are cost-effective and convenient since working directly on the digital mock-up in a VE is preferable to constructing a real physical mock-up in a real environment (RE). This study aimed at understanding the ability of a VR-based assembly tasks simulator to evaluate physical risk factors in ergonomics. Sixteen subjects performed simplified assembly tasks in RE and VE. Motion of the upper body and five muscle electromyographic activities were recorded to compute normalized and averaged objective indicators of discomfort, that is, rapid upper limb assessment score, averaged muscle activations, and total task time. Rated perceived exertion (RPE) and a questionnaire were used as subjective indicators of discomfort. The timing regime and complexity of the assembly tasks were investigated as within-subject factors. The results revealed significant differences between measured indicators in RE and VE. While objective measures indicated lower activity and exposure in VE, the subjects experienced more discomfort than in RE. Fairly good correlation levels were found between RE and VE for six of the objective indicators. This study clearly demonstrates that ergonomic studies of assembly tasks using VR are still challenging. Indeed, objective and subjective measurements of discomfort that are usually used in ergonomics to minimize the risks of work-related musculoskeletal disorders development exhibit opposite trends in RE and VE. Nevertheless, the high level of correlation found during this study indicates that the VR-based simulator can be used for such assessments.

Designing and evaluating a workstation in real and virtual environment: toward virtual reality based ergonomic design sessions

This paper adresses the issue of properly designing a digital mock-up (DMU) to be used in an experiment comparing simulated assembly tasks in both real and virtual environments. Motivations and specifications relative to the experiment are reported, and the design process of the DMU is described and illustrated. Recommendations are proposed with a particular focus on specificities relative to the use of a DMU as a support for both manufacturing and virtual reality—3D visualisation and interaction. A subjective evaluation of Real (RE), Virtual (VE), and Virtual with Force Feedback (VEF) environments is provided. Results indicate a real sensory and difficulty gap between RE and VEF, whereas a smaller difference was observed between RE and VE. In further improvements of scale-1 (where the objects in VE have the same size as in the real environment), co-localized simulation using haptic devices are warranted to fill in this gap. Results also highlight the impact of cognition and sensory feedback on user’s feeling and presence sensation. Applications of such numerical designs are presented in the last section, especially focusing on collaborative design sessions. Virtual Reality based evaluation of newly designed workstations will be a way in the future to improve design and user learning processes.

Maintaining consistency between CAD elements in collaborative design using association management and propagation

The complete definition of a product often requires the collaboration of various partners. Data sharing and exchange between partners has thus become an important task throughout a product's entire life cycle. Even while subsets of the product definition are exchanged (as work packages) and modified by various partners, the global product definition must remain consistent. This paper focuses on maintaining consistency between Computer-Aided Design (CAD) work packages and the global product Digital Mock-Up (DMU). The approach is designed to ensure better management of the associations between objects when a work package is extracted from the global DMU, modified by a partner, sent back to the originator and then re-inserted into the global DMU, which must be modified in turn so as to maintain consistency. To this end, we propose an association management model for the digital mock-up (Digital Mock-up Association Management Model, DMU-AMM) that transposes the associations that exist between a DMU and a work package, including package extraction and modifications, to ultimately guide the evolution of the DMU so as to reconcile the associations between a modified DMU and the modified work package and there by maintain consistency.

The Method of Equipment Maintenance Accessibility Evaluation Based on Index Correlation Degree

Aiming at the disadvantage of existing equipment maintenance accessibility evaluation method, this paper studied the project of equipment maintenance accessibility evaluation. a method of equipment maintenance accessibility evaluation in the virtual environment is put forward based on Matrices Permanent and index correlation degree , at last an example is given. It is significant for developing maintainability verification and increasing Equipment Maintainability in the course of equipment digital mock-up designing.

Equipment MTTR Demonstration Method Based on Virtual Simulation

Aiming at the disadvantage of existing equipment MTTR demonstration method, this paper studied the project of equipment maintainability demonstration Based on Virtual Simulation, and put forward a method of equipment MTTR demonstration in the virtual environment, at last power system of equipment is verified as an example. It is significant for developing maintainability demonstration and increasing Equipment maintainability in the course of equipment digital mock-up designing.

Middle Managers' Sensemaking and Interorganizational Change Initiation: Translation Spaces and Editing Practices

In fast changing environments, middle managers regularly have to participate in interorganizational sensemaking work in order to deal with issues of industry-wide significance. The research is grounded on an empirical study of a cross-sector study group, bringing together middle managers from five large French public works and civil engineering firms who are examining issues related to the adoption of a shared digital mock-up that will reconfigure the sector. The article identifies four translation spaces in which these middle managers make sense of this design technology through a set of editing practices. The article ends by discussing the dynamic of these translation spaces and the need to better understand middle managers' editing practices when they are making sense of change across organizational boundaries.

Communication through Digital Engineering Processes in an Aircraft Program

An aircraft is a complex, inherently multidisciplinary product that requires real time global collaboration for Design, Manufacture and Service. Digital engineering processes play an intelligent role inproduct and process design from concept to retirement, which is around 70 years. The entire engineering data is hierarchically structured and traced throughout the lifecycleunder strict Configuration Control (CC). This requires an accurate, easily communicable Digital Mock-Up(DMU)as a Virtual 3D-static and dynamic platform for, real-time concurrent engineeringthrough wide collaboration, a sample of which is presented herein. Holistically, this requires a networked Product Lifecycle Management (PLM) system as an Integrated Digital Environment (IDE) for engineering (primary and continuous improvement) for life cycle of the aircraft. The latest feature in PLM is the use of ModelBased Engineering.

Improving concept design of divertor support system for FAST tokamak using TRIZ theory and AHP approach

The paper focuses on the application of the Theory of Inventive Problem Solving (TRIZ) to divertor Remote Handling (RH) issues in Fusion Advanced Studies Torus (FAST), a satellite tokamak acting as a test bed for the study and the development of innovative technologies oriented to ITER and DEMO programs. The objective of this study consists in generating concepts or solutions able to overcome design and technical weak points in the current maintenance procedure. Two different concepts are designed with the help of a parametric CAD software, CATIA V5, using a top-down modeling approach; kinematic simulations of the remote handling system are performed using Digital Mock-Up (DMU) capabilities of the software. The evaluation of the concepts is carried out involving a group of experts in a participative design approach using virtual reality, classifying the concepts with the help of the Analytical Hierarchy Process (AHP).

Research on the Method of Materiel Maintainability Qualitative Requirement Demonstration Based on Virtual Simulation

Aiming at the disadvantage of existing materiel maintainability quantitative requirements demonstration method, this paper studied the project of the materiel maintainability qualitative requirement demonstration Based on virtual simulation, in order to determine the materiel maintainability qualitative requirement, the accessibility and visibility as an example to illustrate the virtual demonstration method. It is significant for developing maintainability demonstration and increasing materiel maintainability in the course of materiel digital mock-up designing.

HYBRID REPRESENTATION OF DIGITAL MOCKUP FOR HERITAGE BUILDINGS MANAGEMENT

Abstract. This article deals with the implementation of tool allowing the portability of the digital mock-up for architectural projects on the building renovation place and the use of representation layers giving functions adapted to the different workers open to work in this place. Our test case is applied to renovation works on old windows in an ancient abbey where it is necessary to improve the thermal efficiency.

FROM POINT CLOUD TO BIM: A SURVEY OF EXISTING APPROACHES

Abstract. In order to handle more efficiently projects of restoration, documentation and maintenance of historical buildings, it is essential to rely on a 3D enriched model for the building. Today, the concept of Building Information Modelling (BIM) is widely adopted for the semantization of digital mockups and few research focused on the value of this concept in the field of cultural heritage. In addition historical buildings are already built, so it is necessary to develop a performing approach, based on a first step of building survey, to develop a semantically enriched digital model. For these reasons, this paper focuses on this chain starting with a point cloud and leading to the well-structured final BIM; and proposes an analysis and a survey of existing approaches on the topics of: acquisition, segmentation and BIM creation. It also, presents a critical analysis on the application of this chain in the field of cultural heritage.

Integrating Physical and Digital Assemblies

Computer-based tools have changed the focus and modes of design thinking in architecture. While often criticized for its overemphasis on formal expressions and its pursuit of the spectacular, digital creativity has begun to take into account a multiplicity of design factors that define architecture. These factors relate to performance simulation and analysis, constructability, and building information modeling (BIM). This paper discusses the use of physical and digital mock-ups in the context of building technology courses. It uses these mock-ups as an important vehicle that provides students with a feedback mechanism regarding often digitally idealized creative thinking.

Enhancement of the use of digital mock-ups in the verification and validation process for ITER remote handling systems

The paper is part of the EFDA's programme of European Goal Oriented Training programme on remote handling (RH) “GOT-RH”. The programme aims to train engineers for activities supporting the ITER project and the long-term fusion programme. This paper is written based on the results of a project “verification and validation (V&V) of ITER RH system using digital mock-ups (DMUs)”. The purpose of this project is to study efficient approach of using DMU for the V&V of the ITER RH system design utilizing a system engineering (SE) framework. This paper reviews the definitions of DMU and virtual prototype and overviews the current trends of using virtual prototyping in the industry during the early design phase. Based on the survey of best industrial practices, this paper proposes ways to improve the V&V process for ITER RH system utilizing DMUs.

A modular architecture for a driving simulator based on the FDMU approach

The present paper describes the development of a modular and easily configurable simulation platform for ground vehicles. This platform should be usable for the implementation of driving simulators employed both in training purposes and in vehicle components testing. In particular, the paper presents a first architectural model for the implementation of a simulation platform based on the Functional Digital Mock-Up approach. This platform will allow engineers to implement different kinds of simulators that integrate both physical and virtual components, thus achieving the possibility to quickly reconfigure the architecture depending on the hardware and software used and on specific test case needs. The platform has been tested by developing a case study that integrates a motion platform, some I/O devices and a simple dynamic ground vehicle model implemented in OpenModelica.