Proto-TAI: Quick Design Prototyping Using Tangible Assisted Interfaces

In the real world, we use our innate manual dexterity to create and manipulate 3D objects. Conventional virtual design tools largely neglect this skill by imposing non-intuitive 2D control mechanisms for interacting with 3D design models. Their usage is thus cumbersome, time consuming and requires training. We propose a novel design paradigm that combines users’ manual dexterity with the physical affordances of non-instrumented and ordinary objects to support virtual 3D design constructions. We demonstrate this paradigm through Proto-TAI, a quick prototyping application where 2D shapes are assembled into 3D representations of ideated design concepts. Here, users can create 2D shapes in a pen-based sketch medium and use expressive handheld movements of a planar proxy to configure the shapes in 3D space. The proxy provides a metaphorical means for possessing and controlling the shapes. Here, a depth sensor and computer vision algorithms track the proxy’s spatial movement. The 3D design prototype constructed in our system can be fabricated using a laser cutter and physically assembled on-the-fly. Our system has vast implications in many design and assembly contexts, and we demonstrate its usability and efficacy through user studies and evaluations.

Concept for an Integrated Workflow Planning of Dental Products Based on Federative Data Management

Workflows to produce dental products by using CAD/CAM technology are very complex. Each patient needs an individual restoration. The challenge is to provide a patient individual production aiming at a price of mass production. But every single job has to run through an individual development as well manufacturing process. Typically, three stakeholders are involved in the workflow. The dentist performs the treatment and defines requirements for restoration. The dental laboratory plans the workflow and designs the reconstruction by using a dental CAD system. Subsequently, a milling center produces the restoration. Because of these highly heterogeneous workflows, diverse data streams and incompatibilities result. Often improper partners and resources are involved in the workflow. This fact is a significant source for errors. An additional complication is that errors are often discovered in late phases of the workflow. To avoid high costs and unacceptable delivery times, the aim is to develop a new concept for integrated workflow planning. The concept depends on three parts: Federative dental data management (FDDM) as a basic approach, including anticipated logic and structured activities. The federative data management provides a loosely coupling of heterogeneous systems crossing enterprise borders by using web technology. The FDDM service depends on APP technology. Each participant applies its specialized APP: FDDMz (dentist), FDDMd (dental laboratory) and FDDMf (milling center). FDDM services enable a continuously integrated workflow throughout the whole process of a patient individual production. Each participating enterprise is able to register its available processes and resources. Information about resources like 3D dental scanner or milling machines are able to add, according to a global data model schema. This schema depends on an integrated information model with eight partial models: Collaboration, resource, process, workflow, requirements, product, work preparation and production model. This integrated information model provides dental information including interlinked objects. Through a proper anticipation logic, conclusions about later phases can be anticipated already at early phases. The last conceptual part is workflow management on frame of structured activities. By combining the information network with the anticipation logic, filtering of appropriate partners, processes, resources and sequences is supported. Next, a prototypical implementation is demonstrated exemplarily. This concept delivers an important contribution to increase process reliability and quality as well as to reduce delivery times and costs for digital dental workflows.

Experimental Study of an Airplane Accident Evacuation/Rescue Simulation Using 3D Kinematic Digital Human Models

The 3D mass evacuation simulation of an airplane accident is experimentally verified. Evacuee motion has been experimentally investigated by building a test field that emulates the interior of an actual regional airliner with a capacity of approximately 100 passengers. The experiment results indicate that the evacuation time tends to be affected by the number of passengers and the evacuee guidance at the emergency exit. The results also indicate that any evacuation delay in exiting by individual passengers only slightly affects the total evacuation time because of evacuee congestion in the aisles. Moreover, the importance of evacuation guidance notification was investigated based on the evacuation-order variance. Finally, the experimental results were compared to the corresponding simulation results. Simulations using appropriate evacuee walking speeds can provide valid evacuation times, which are the most important factor in designing evacuation drills. Consequently, these results should be applied to existing 3D simulations using precise KDH models for more accurate mass evacuation/rescue simulations.

Towards a Computational Multiphysics Framework for Modeling Antibiofouling Processes

Biofouling is a process of major concern on naval vessels because it considerably affects their performance, maintenance and operational costs due to the fact that induces an increased hydrodynamic drag that leads to higher fuel consumption that in turn demands expensive cleaning procedures. A possible antibiofouling system can be designed by enhancing an existing impressed current cathodic protection system and taking advantage of the chlorine oxidants produced during its operation. In this work we present a design methodology for such a system, together with the associated multiphysics formulation framework based on a coupled chemical reactions — electric currents, species mass transport and electromigration model. This framework predicts the spatio-temporal distributions of the Chlorine species concentration that tend to inhibit the biofouling formations. We also demonstrate the applicability of the computational framework on a number of platforms ranging from simple panels up to a full scale boat. The computational results are compared with the actual field experiments.

Graph Based Representation and Analyses for Conceptual Stages

What is the fundamental similarity between investing in stock of a company, because you like the products of this company, and selecting a design concept, because you have been impressed by the esthetic quality of the presentation made by the team developing the concept? Except that both decisions are based on a surface analysis of the situations, they both reflect a fundamental human’s cognitive feature. Human brain is profoundly trying to minimize the efforts required to solve a cognitive task and is using when possible an automatic mode relying on recognition, memory, and causality. This mode is even used in some occasion without the engineer being conscious of it. Such type of tendencies are naturally pushing engineers to rush into known solutions, to avoid analyzing the context of a design problem, to avoid modelling design problems and to take decision based on isolated evidences. Those behaviors are familiar to experience teachers and engineers. This tendency is magnified by the time pressure imposed to the engineering design process. Early phases in particular have to be kept short despite the large impact of decisions taken at this stage. Few support tools are capable of supporting a deep analysis of the early design conditions and problems regarding the fuzziness and complexity of the early stage. The present article is hypothesizing that the natural ability of humans to deal with cause-effects relations push toward the massive usage of causal graphs analysis during the design process and specifically during the early phases. A global framework based on graphs is presented in this paper to efficiently support the early stages. The approach used to generate graphs, to analyze them and to support creativity based on the analysis is forming the central contribution of this paper.

A Framework of CAD/CAE Integration System and its Implementation for Container Crane

A framework of CAD/CAE integration system and its implementation for dockside container crane are proposed in this paper. First, the system framework based on web technology, software design pattern and service-oriented architecture (SOA) is introduced. Then, requirement input interfaces of Customer-Designer-Interaction (CDI) module are built based on ASP.NET multiple-layer Browser/Server (B/S) architecture, core design patterns and .NET WCF Services, and customers can provide specifications of the cranes to designers. Next, CAD and CAE modules are accomplished using multiple-layer architecture, and designers can parametrically create 3D models of the crane structures and conduct explicit dynamic Finite Element Analysis (FEA) on the designed crane structures. SOA based Design-Analysis-Integration (DAI) is developed to maintain consistence between CAD and CAE models by using .Net WCF Service. Last, system management functions such as user interaction, user account and file management are described. Since all the operations are conducted in Web and SOA context, customers and designers are able to participate in the design process at different geographical locations.

Multi-Physics Simulation Based Design and Analysis of a High Speed Aerostatic Spindle and its Performance Assessment

High speed aerostatic spindles operating at a speed up to 200,000 r/min are a complex product with a multi-physics nature resulted from embedded mechanical-thermal-fluidic-electromagnetic fields. It is much needed to have a comprehensive analysis on the multi-physic interactions within a high speed aerostatic spindle, which is essential for design of the spindles working at much higher speeds and accuracy in various increasingly stringent engineering conditions. This paper presents a multi-physics integrated modelling approach for design and analysis of the high speed aerostatic spindle, including thermal, electromagnetic, mechanical and fluidic analysis models. The heat source, heat transfer mechanism and heat sinks of the spindle system are comprehensively investigated. Furthermore, air film pressure distribution is studied to lead to optimal design and analysis of loading capacity and stiffness of the aerostatic bearings. The multi-physics modelling is implemented using the CFD-FEA integrated approach and validated experimentally. It is shown that the multi-physics integrated modelling is able to simulate the performance characteristics of the spindle system accurately.

Geons and Non-Accidental Relations in 2D Shape Abstraction: A BCI Study

Simple line drawings and 2D sketches are commonly used by humans to convey their ideas about a particular shape or shapes in an image. These approximations of shapes are effective means for visual communication and artistic practices. The idea of shape abstraction can be derived from such approximations of shapes, which considers their most important and salient features. The key idea behind shape abstraction is to extract a simplified version of a shape that preserves the salient characteristics of the input shape. In this paper, we introduce and analyze a slightly different and novel facet of abstraction, which we call “partial to full shape recognition” of two dimensional shapes (line drawing and sketches). The key idea is recognizing partial 2D shapes that leads to recognition of full shape utilizing the theory of recognition-by-components (RBC) and geons (human shape perception). We segment the 2D shapes according to the non-accidental relations provided by RBC and analyze the electroencephalogram (EEG) brain activity of subjects using a brain computer interface (BCI) to gain knowledge of human understanding of such relations pertaining to specific partial to full shape correspondence.

Reduced Material Model of Composite Laminates for 3D Finite Element Analysis

Laminate composites are widely used in automotive, aerospace, medical, and increasingly in consumer industries, due to their reduced weight, superior structural properties and cost-effectiveness. However, structural analysis of complex laminate structures remains challenging. 2D finite element methods based on plate and shell theories may be accurate and efficient, but they generally do not apply to the whole structure, and require identification and preprocessing (dimensional reduction) of the regions where the underlying assumptions hold. Differences in and limitations of theories for thin/thick plates and shells further complicate modeling and simulation of composites. Fully automated structural analysis using 3D elements with sufficiently high order basis functions is possible in principle, but is rarely practiced due to the significant increase in computational integration cost in the presence of a large number of laminate plies. We propose to replace the actual layup of the laminate structure by a simplified material model, allowing for a substantial reduction of the computational cost of 3D FEA. The reduced model, under the usual assumptions made in lamination theory, has the same constitutive relationship as the corresponding 2D plate model of the original laminate, but requires only a small fraction of computational integration costs in 3D FEA. We describe implementation of 3D FEA using the reduced material model in a meshfree system using second order B-spline basis functions. Finally, we demonstrate its validity by showing agreement between computed and known results for standard problems.