Contact identification for assembly-disassembly simulation with a haptic device

Assembly/Disassembly (A/D) simulations using haptic devices are facing difficulties while simulating insertion/extraction operations such as removing cylinders from holes. In order to address this configuration as well as others, an approach based on contact identification between components is presented in this paper. This approach can efficiently contribute either to a new A/D simulation preparation process relying on two types of shape representations (mesh and CAD NURBS models), or directly to the real time simulation process when it is performed with 6D haptic devices. The model processing pipeline is described and illustrated to show how information can be propagated and used for contact detection. Then, the contact identification process is introduced and illustrated through an exampl

Rapid model-guided design of organ-scale synthetic vasculature for biomanufacturing

Our ability to produce human-scale bio-manufactured organs is critically limited by the need for vascularization and perfusion. For tissues of variable size and shape, including arbitrarily complex geometries, designing and printing vasculature capable of adequate perfusion has posed a major hurdle. Here, we introduce a model-driven design pipeline combining accelerated optimization methods for fast synthetic vascular tree generation and computational hemodynamics models. We demonstrate rapid generation, simulation, and 3D printing of synthetic vasculature in complex geometries, from small tissue constructs to organ scale networks. We introduce key algorithmic advances that all together accelerate synthetic vascular generation by more than 230-fold compared to standard methods and enable their use in arbitrarily complex shapes through localized implicit functions. Furthermore, we provide techniques for joining vascular trees into watertight networks suitable for hemodynamic CFD and 3D fabrication. We demonstrate that organ-scale vascular network models can be generated in silico within minutes and can be used to perfuse engineered and anatomic models including a bioreactor, annulus, bi-ventricular heart, and gyrus. We further show that this flexible pipeline can be applied to two common modes of bioprinting with free-form reversible embedding of suspended hydrogels and writing into soft matter. Our synthetic vascular tree generation pipeline enables rapid, scalable vascular model generation and fluid analysis for bio-manufactured tissues necessary for future scale up and production.Comment: 58 pages (19 main and 39 supplement pages), 4 main figures, 9 supplement figure

Developing a systematic approach to investigate interoperability issues between Building Information Modeling (BIM) tools and Building Energy Modeling (BEM) tools

Integrated building design necessitates the Architecture-Engineering-Construction-Owner-Operator (AECOO) Industry’s participants to collaborate efficiently with each other through the different phases of a building. Nevertheless, to reduce the energy consumption and CO2 emissions of a building, the emphasis is on the early design phases, since if accurate energy calculations and strategies are developed in an early design stage, the sustainable footprint of the building will be significantly reduced. That said, Building Information Modelling (BIM) promotes collaboration among the stakeholders by allowing them to design and store and access the data related to a project into one building information model. Furthermore, this model can be used for energy analysis through Building Energy Modelling (BEM) tools in the early design stages of the project, and through the whole life-cycle. For this, BIM and BEM tools must be able to communicate and exchange information with one another, seamlessly. This means that these tools should be interoperable. However, currently, there are some issues in the BIM to BEM exchange process, which obliges the user to check for the interoperability issues and fix them manually. Therefore, as a result of these interoperability issues, the BIM to BEM process in not automated, and creating an accurate BIM-based BEM is quite time-consuming, laborious and prone to human-made errors. Hence, this thesis aims to systematically investigate the interoperability issues and the state of automated data exchange between BIM and BEM tools, based on the Industry Foundation Class (IFC) exchange data schema. For this, Revit and IDA-ICE are used as BIM, and BEM tools, respectively. The outcome is the presentation of a set of interoperability issues that were found based on the investigation of 19 case studies, with some suggestions for Revit and IDA-ICE developers and future researchers in the end

Integration of TLS-derived Bridge Information Modeling (BrIM) with a Decision Support System (DSS) for digital twinning and asset management of bridge infrastructures

In the current modern era of information and technology, the concept of Building Information Modeling (BIM), has made revolutionary changes in different aspects of engineering design, construction, monitoring, and management of infrastructure assets, especially bridges. In the field of bridge engineering, Bridge Information Modeling (BrIM), as a specific form of BIM, includes digital twinning of bridge assets associated with geometrical information and non-geometrical inspection data. BrIM has demonstrated tremendous potential in substituting traditional paper-based documentation and handwritten reports with digital bridge documentation/trans-formation, allowing professionals and managers to execute bridge management more efficiently and effectively. However, concerns remain about the quality of the acquired data in BrIM development, as well as lack of research on utilizing these information for remedial actions/decisions in a reliable Bridge Management System (BMS), which are mainly reliant on the knowledge and experience of the involved inspectors, or asset managers, and are susceptible to a certain degree of subjectivity. To address these concerns, this research paper presents a comprehensive methodology as an advanced asset management system that employs BrIM data to improve and facilitate the BMS. This innovative BMS is comprised of a precise Terrestrial Laser Scan (TLS)-derived BrIM as a qualitative digital replica of the existing bridge, incorporating geometrical and non-geometrical information of the bridge elements, and equipped with a requirement-driven framework in a redeveloped condition assessment model for priority ranking of bridge elements based on their health condition. In another step ahead, the proposed BMS integrates a Decision Support System (DSS) to score the feasible remedial strategies and provide more objective decisions for optimal budget allocation and remedial planning. This methodology was further implemented via a developed BrIM-oriented BMS plugin and validated through a real case study on the Werrington Bridge, a cable-stayed bridge in New South Wales, Australia. The finding of this research confirms the reliability of BrIM-oriented BMS implementation and the integration of proposed DSS for priority ranking of bridge elements that require more attention based on their structural importance and material vulnerability, as well as optimizing remedial actions in a practical way while preserving the bridge in a safe and healthy condition

Numerical studies of flow in porous media using an unstructured approach

Flow and transport in porous media is relevant to many areas of engineering and science including groundwater hydrology and the recovery of oil and gas. Porous materials are characterized by the unique shape and connectivity of the internal void structures which give rise to a large range in macroscopic transport properties. Historically an inability to accurately describe the internal pore-structure has prevented detailed study of the role of pore structure on transport. In recent decades however, the combination of high resolution imaging technologies with computational modeling has seen the development of fundamental pore-scale techniques for studying flow in porous media. Image-based pore-scale modeling of transport phenomena has become an important tool for understanding the complicated relationships between pore structure and measurable macroscopic properties, including permeability and formation factor. This has commonly been achieved by a network-based approach where the pore space is idealized as a series of pores connected by throats, or by a grid-based approach where the voxels of a 3D image represent structured quadrilateral elements or nodal locations. In this work however, image-based unstructured meshing techniques are used to represent voxelised pore spaces by grids comprising entirely of tetrahedral elements. These unstructured tetrahedral grids are used in finite element models to calculate permeability and formation factor. Solutions to the Stokes equations governing creeping, or Darcy flow, are used to validate the finite element approach employed in this work, and to assess the impact of different image-based unstructured meshing strategies on predicted permeability. Testing shows that solutions to the Stokes equations by a P2P1 tetrahedral element are significantly more accurate than solutions based on a P1P1 element, while permeability is shown to be sensitive to structural changes to the pore space induced by different meshing approaches. The modeling approach is also used to investigate the relationship of an electric and hydraulic definition of tortuosity to the Carman-Kozeny equation. The results of simulations using a number of computer generated porous structures indicate that an electrical tortuosity based on computed formation factor is well correlated with the tortuosity suggested by the Carman-Kozeny equation

A hybrid method for haptic feedback to support manual virtual product assembly

The purpose of this research is to develop methods to support manual virtual assembly using haptic (force) feedback in a virtual environment. The results of this research will be used in an engineering framework for assembly simulation, training, and maintenance. The key research challenge is to advance the ability of users to assemble complex, low clearance CAD parts as they exist digitally without the need to create expensive physical prototypes. The proposed method consists of a Virtual Reality (VR) system that combines voxel collision detection and boundary representation methods into a hybrid algorithm containing the necessary information for both force feedback and constraint recognition. The key to this approach will be successfully developing the data structure and logic needed to switch between collision detection and constraint recognition while maintaining a haptic refresh rate of 1000 Hz. VR is a set of unique technologies that support human-centered computer interaction. Experience with current VR systems that simulate low clearance assembly operations with haptic feedback indicate that such systems are highly desirable tools in the evaluation of preliminary designs, as well as virtual training and maintenance processes. This work will result in a novel interface for assembly methods prototyping, and an interface that will allow intuitive interaction with parts based on a powerful combination of analytical, visual and haptic tools

A NOVEL PROJECTION ALGORITHM FOR PRODUCTION LAYOUT EXTRACTION FROM POINT CLOUDS

The paper is focused on point cloud data processing obtained by 3D laser scanning. The scanning devices are at a very advanced level and after reaching their possible maximum scanning speeds, manufacturers are now more focused on a minimization of the devices. However, there is still a lack of software solutions for a simple and successful model creation from point cloud data or data evaluation. This paper briefly describes the laser scanning principle and the process of production floor layout capturing. Furthermore, a newly developed algorithm for an extraction of specific areas of point cloud is introduced. The algorithm was tested and compared with other solutions for a production layout development. After testing, the standalone software application called CloudSlicer™ was programed and the user interface is also presented