Digital Prototyping Research Articles

A comparison of methodologies for designing for human variability

In the design of artefacts that interact with people, the spatial dimensions of the user population are often used to size and engineer the artefact. The variability in anthropometry indicates the fixed allocation of space, adjustability requirements, or how many sizes are needed to accommodate the intended user population. Various tools are used to achieve this goal, including boundary manikins, digital human models, prototypes and population models, and hybrid methods that combine the approaches. The present work explores each of these and their relative strengths and weaknesses. This is done in the context of a univariate case study involving the adjustability requirements of a stationary bicycle. An experiment involving 51 individuals was conducted to obtain the data necessary for utilising and evaluating the methods.

Product data model of hull structures and digital prototyping system for basic structural design

This work describes a computer system developed for the fast parametric generation of a 3D model of ship hull structure. The system is intended to be used as a tool for generating an initial product model of the hull structures at the basic design stage. The model provides not only the geometry of the hull and the main structural systems but also data describing the arrangement of plates and stiffeners of the component panels, including scantlings, spacing and materials. The objective of the system is to generate and help to evaluate alternative structural configurations, producing information on total or partial weights and centres of gravity at different levels of detail. For the intended purpose, the ease and speed of generation of a model is much more relevant than a high geometric accuracy, and so it was adopted as a simplified geometric modelling, representing curved shapes with polygonal approximations. The modelling concepts and methodology are discussed and the architecture of the system is presented, describing the main components. Finally, some results are shown from the partial modelling of a real ship that was used for testing and validation of the system.

CAD/CAM bilateral ear prostheses construction for Treacher Collins syndrome patients using laser scanning and rapid prototyping

Ear defects in patients affected by Treacher Collins syndrome necessitate the replacement of the existing anatomic residuals of the ears with custom-made prostheses. This paper describes a multidisciplinary protocol involving both medicine and computer-aided design/computer-aided manufacturing for manufacturing ear prostheses. Using innovative prototyping technologies together with conventional silicone processing procedures, a step-by-step procedure is presented. The complete workflow includes laser scanning of the defective regions of a patient's face, the use of 3D anatomic models from an ear digital library and rapid prototyping of both substructures for bar anchoring and moulds for silicone processing.

The Question of Credibility

This article presents an overview of capabilities and applications of finite element analysis (FEA) in engineering analysis. FEA is useful wherever the risk of material failure or engineering error has serious consequences—any of the legal, regulatory, and bottom-line ramifications of product failure. They also point out that credibility lies at the heart of every simulation effort, FEA or otherwise. FEA software developers have made it easier to use their software via user-friendly graphical user interfaces. FEA is a uniquely powerful tool for prototyping, as well as reducing the traditional build-test-break cycle from months or even years of trial and error to weeks of digital calculations and validations. Digital prototyping also allows designers to quickly dig into more design options. Most complicated engineering analyses use nonlinear FEA for challenging problems. Nonlinear FEA includes elastic and plastic transformations; tension and compression; buckling; fixed and sliding contacts, fatigue, creep, large deflections and deformations; large strain; hyperelasticity, viscoelasticity, viscoplasticity, and many others. In the real world, each of the linear and nonlinear uses is problematical. Getting them right depends heavily on the analysts, so their skills should be also validated and verified.

Application development of rapid prototyping technology in orthopedics

Rapid prototyping technology, a kind of novel digital prototyping technology developed in mid-1980s based on a principle of discrete and accumulation, which fabricates a prototype by accurate accumulation of material according to the CAD models or CT data under the control of the computer without any other device. In recent years, it has shown a great application prospect in the field of orthopedics combined with three-dimensional image reconstruction of spiral CT and MRL In this article, review is given on the application development of rapid prototyping technology in orthopedics, such as organ model preparation and surgical planning, customized implant and bone tissue engineering porosity scaffold fabrication. Key words: Rapid prototyping; Tissue engineering; Surgical planning; Customized implant; Personal therapy

3D digital prototyping and usability enhancement of information appliances based on UsiXML

Recently, usability assessment of user interfaces (UIs) in the early design stage has become indispensable for the human-centered design of information appliances. Several digital prototyping tools of the UI software, in which the UI behavior can be simulated, have been developed so far. However, some problems can arise when using them for the usability assessment, such as: a lack of simulation fidelity, time-consuming modeling work, and lack of systematic usability assessment functions. To solve these problems, we developed a tool for virtual 3D prototyping and usability assessment of information appliances. First, we extended the specification of UsiXML (which is the XML-compliant UI description language) so that the static structure both of the logical elements displayed on the UI and of the physical elements placed on the housings can be modeled. Secondly, we developed 3D prototyping and simulation functions so that the extended UsiXML is combined with the 3D CAD models of the housings and where the interaction can be simulated based on the dynamic-behavior model of the UsiXML. Finally, we developed the automated user test and usability assessment functions which are connected to the models of the extended UsiXML. An example of the efficient usability assessment and the UI redesign using a 3D digital prototype of a digital camera is shown.

Immediate facial rehabilitation in cancer patients using CAD–CAM and rapid prototyping technology: a pilot study

This study describes the workflow in a procedure to create a provisional facial prosthesis for cancer patients using digital and rapid prototyping technologies without the need for supporting craniofacial implants. An integrated workflow procedure aimed at the construction of provisional silicone prosthesis was used to rehabilitate a facial disfigurement in a patient who had undergone ablative surgery of the midface. A laser scan of the defect was obtained, and a digital model of the patient's face was constructed using virtual mirroring of the healthy side and referencing the "Nose Digital Library." The missing volume of the face was reconstructed, and a rapid-prototyped mold was devised to process the silicone prosthesis. A provisional eyeglasses-supported prosthesis designed with a CAD/CAM-projected titanium substructure was connected using the micro-components of implant prosthetic devices. The workflow described herein offers a viable procedure for quickly restoring facial defects by means of provisional prosthetic rehabilitation.

Digital libraries in China: progress and prospects

PurposeThe aim of this paper is to provide an overview of Chinese digital library (DL) projects via the corresponding web sites, It also seeks to illustrate the current situation of DLs in China by offering insights into the digitization of resources, technologies and services.Design/methodology/approachA questionnaire was designed on the basis of the definition and features of digital libraries, together with the relevant library homepages and services. Overall, ten comprehensive universities and their library web sites, five public libraries and one science library were selected for comparison and analysis focusing on the content set‐up, digital resources, navigation systems, mainstream modes, home‐grown databases construction, user instruction training programs etc. Other issues including the virtual reference, service (VRS), academic information resource portal and integrated searching system or platform, personalized service, logon and authentication are also discussed.FindingsAll the selected libraries are operational digital libraries or prototypes. The electronic or digital resources are made up of two parts and the mainstream modes are service‐oriented. Most have their own library information portals and provided integrated searching. However, there are some defects in term unification on some home pages, unified retrieval platform selection among various databases, and navigation system construction.Practical implicationsThis paper presents a perspective of how DLs in China have been developing in the past few years. It also indicates the existing problems and difficulties and suggests the practical ways to optimize the application, standards, laws and rules, personal information environment, logon and authentication based on encryption. In addition, Open Access resources' utilization, conflict between copyright protection and resources sharing, and user interface customizing are addressed.Originality/valueThis paper describes the general status of Chinese digital library construction. It provides relevance for researchers and the public in China as well as other countries on the DL construction experiences, efforts and achievements. It also highlights the importance and value of sharing experience in DL construction.

Rapid Prototyping of a Double-Layer Polyurethane–Collagen Conduit for Peripheral Nerve Regeneration

A new technique for preparing double-layer polyurethane (PU)-collagen nerve conduits for peripheral nerve repair via a double-nozzle, low-temperature, deposition manufacturing (DLDM) system has been developed. The DLDM system is based on a digital prototyping approach, and uses a combination of thermally induced phase separation and freeze-drying. With this system, two kinds of biomaterials with different properties can be combined to produce scaffold structures with good biocompatibility in the inner layer and with the desired mechanical strength protruded by the outer. The forming precision is high, the wall thickness can be controlled, and a tight connection between the two layers can be achieved. The effects of changing the processing parameters and the material temperature on the structure of the scaffolds have been investigated. Additionally, the effect of material concentration on the mechanical strength and hydrophilic properties of the scaffolds has also been studied. Ideal peripheral nerve repair conduits, comprising an outer microporous layer of PU and internal oriented filaments of collagen, have been manufactured through optimizing the processing parameters and the biomaterial concentrations.

Development and design optimization of water hydraulic manipulator for ITER

This paper describes one of the research projects carried out in The Preparation of Remote Handling Engineers for ITER (PREFIT) program within the European Fusion Training Scheme (EFTS). This research project is focusing on the design and optimization of water hydraulic manipulators used to test several remote handling tasks of ITER at Divertor Test Platform 2 (DTP2), Tampere, Finland, and later in ITER. In this project, a water hydraulic manipulator designed and build by Department of Intelligent Hydraulics and Automation in Tampere University of Technology, Finland (TUT/IHA) is further optimized as a case study for a given manipulator requirement specification in order to illustrate and verify developed comprehensive design guidelines and performance metrics. Without meaningful manipulator performance parameters, the evaluation of alternative robot manipulators designs remains ad hoc at best. Therefore, more comprehensive design guidelines and performance metrics are needed for comparing and improving different existing manipulators versus task requirements or for comparing different digital prototypes at early design phase of manipulators. In this paper the description of the project, its background and developments are presented and discussed.

New material options for FDM direct digital manufacturing and rapid prototyping machines

New material options for FDM direct digital manufacturing and rapid prototyping machines

Digital Prototypes Assist Development

Digital Prototypes Assist Development

Sustaining Engineering Informatics: Toward Methods and Metrics for Digital Curation

Ensuring the long-term usability of engineering informatics (EI) artifacts is a challenge, particularly for products with longer lifecycles than the computing hardware and software used for their design and manufacture. Addressing this challenge requires characterizing the nature of EI, defining metrics for EI sustainability, and developing methods for long-term EI curation. In this paper we highlight various issues related to long-term archival of EI and describe the work towards methods and metrics for sustaining EI. We propose an approach to enhance the Open Archival Information System (OAIS) functional model to incorporate EI sustainability criteria, Digital Object Prototypes (DOPs), and end user access requirements. We discuss the end user’s requirements from the point of view of reference, reuse and rationale – the “3Rs” – to better understand the level of granularity and abstractions required in the definition of engineering digital objects. Finally we present a proposed case study and experiment.

The contributions and consequences of simulation tools and digital mock-ups on design and production as applied to the automobile and aeronautics industries

In order to reduce costs and deadlines while increasing product differentiation and variety, companies make use of Digital Mock-Ups (DMUs) and rapid prototyping (virtual and physical models). These allow them to anticipate (a long way upstream) questions which may arise later. The considerable development of simulation tools and prototyping has transformed the way in which products are developed. Thus, the use of a digital chain of information that goes from the expression of a product idea right through to recycling, passing through the phases of conception, production and commercialisation (Product Life Cycle Management (PLM)), has become a priority. This involves removing the separation between the world of planning and the world of production. It permits a shared nomenclature, better access to information, better anticipation and, hence, simulation at the earliest possible stage. Having said that, the approach is relatively new and using Information and Communication Technology (ICT) in design and production is full of hurdles and setbacks. Finally, the experience feedback of the new usages of DMUs, virtual platforms and collaborative work highlights the importance of the strategic, organisational, cultural and human dimensions that are associated with technological innovation. The deployment of Information Technology (IT) has completely changed work practices.

Applications of Digital Prototyping to Operational Simulation and Usability Assessment of Information Appliances

Applications of Digital Prototyping to Operational Simulation and Usability Assessment of Information Appliances

A VHDL Holistic Modeling Approach and FPGA Implementation of a Digital Sensorless Induction Motor Control Scheme

This paper presents a sensorless neural-network-based induction motor control scheme, developed by following a holistic approach to electronic system modeling and controller design. The method uses very-high-speed integrated circuits hardware description language (VHDL), allowing the engineering system's functional description to be combined with a detailed digital controller design, which is then implemented into a field- programmable gate array (FPGA). The VHDL description of the hardware-implemented neural networks is automatically generated by C++ programs, in an adaptable architecture, appropriate to low-dynamic systems such as fans and pumps. The complete system performance is investigated by simulation and validated experimentally. This approach provides advantages such as a unique modeling and evaluation environment for complete power electronic systems, the same environment is used for the digital controller design and compact FPGA rapid prototyping, fast design development, short time to market, a CAD platform independent model, and reusability of the model/design

Digital design of a combine harvester using virtual prototyping

A parametric feature-based modeling was used to model the parts of a combine harvester. The digital virtual prototyping of the harvester was completed by virtual assembly. The finite element analysis of the vehicle frame was made and the result satisfied the requirements. The vibration sieve, which is a key part of the combine harvester, was simulated and optimized. The excellent parameters of the vibration were gained by optimization. The grain passed through the sieve easily after the optimization and reduced the loss rate and impurity rate in theory.

Optimization-Based Layout Design

The layout problem is of importance to ergonomists, vehicle/cockpit packaging engineers, designers of manufacturing assembly lines, designers concerned with the placement of levers, knobs, controls, etc. in the reachable workspace of a human, and also to users of digital human modeling code, where digital prototyping has become a valuable tool. This paper proposes a hybrid optimization method (gradient-based optimization and simulated annealing) to obtain the layout design. We implemented the proposed algorithm for a project at Oral-B Laboratories, where a manufacturing cell involves an operator who handles three objects, some with the left hand, others with the right hand.

デジタル家電向けSTEPベースの形状・挙動モデル連携シミュレーションシステムの開発(J20-2 デジタルエンジニアリングによる製品開発革新(2),J20 デジタルエンジニアリングによる製品開発革新)

デジタル家電向けSTEPベースの形状・挙動モデル連携シミュレーションシステムの開発(J20-2 デジタルエンジニアリングによる製品開発革新(2),J20 デジタルエンジニアリングによる製品開発革新)

A layer-based virtual prototyping system for product development

This paper proposes a layer-based virtual prototyping (VP) system, which builds virtual or digital prototypes to facilitate product development. The approach resembles the physical fabrication process of laminated sheet-based rapid prototyping (RP) systems. It simulates such an RP process to create a virtual prototype of a product design. Thus, the designer can perform design validation and accuracy analysis easily in a virtual environment as if using a physical prototype. In addition to numeric quantification of the RP process, the system provides vivid visualizations of the prototype for studying its characteristics. The prototype may also be superimposed on the original model, and the areas with dimensional errors beyond the design limits may be clearly highlighted for subsequent improvement. Hence, the designer can analyze and compare the surface texture point-by-point of the prototype with the product design. Furthermore, the virtual prototypes can also be transmitted via the Internet to customers to facilitate global manufacturing. As a result, both the lead-time and product development cost can be significantly reduced.