Reconstruction of 3D Porous Geometry for Coupled FEM-CFD Simulation

Porous materials can be found in numerous areas of life (e. g., applied science, material science), however, the simulation of the fluid flow and transport phenomena through porous media is a significant challenge nowadays. Numerical simulations can help to analyze and understand physical processes and different phenomena in the porous structure, as well as to determine certain parameters that are difficult or impossible to measure directly or can only be determined by expensive and time-consuming experiments. The basic condition for the numerical simulations is the 3D geometric model of the porous material sample, which is the input parameter of the simulation. For this reason, geometry reconstruction is highly critical for pore-scale analysis. This paper introduces a complex process for the preparation of the microstructure's geometry in connection with a coupled FEM-CFD two-way fluid-structure interaction simulation. Micro-CT has been successfully applied to reconstruct both the fluid and solid phases of the used porous material.

3D survey and virtual reconstruction of heritage. The case study of the City Council and Lonja of Alcañiz

With current data acquisition techniques, exhaustive documentation of patrimonial goods is generated, which allows obtaining a 3D geometric model, on which data from research from research is generated. As in other fields of architecture, the latest graphic techniques and manipulation of the image, allow a working methodology other than the current one in the patrimonial field. The information systems have been evolving towards technologies developed with open source software, the use of standards, ontologies and the structuring of information and of the 3D model itself under a semantic hierarchy. Interoperability between databases is favored and the maintenance of applications is ensured. The purpose is to support decision-making related to the model and simultaneously, serve multiple purposes such as cataloging, protection, restoration, conservation, maintenance or dissemination, among others. The research carried out for the realization of the survey of the City Council and Lonja of Alcañiz (Teruel), has the aim of expanding the historical knowledge of the buildings and delimiting its possible constructive phases, in order to obtain the geometric reality of the buildings. In this way, provide greater instruments to carry out the drafting work of the set restoration project.

Systematic Enumeration and Identification of Unique Spatial Topologies of 3D Systems Using Spatial Graph Representations

Systematic enumeration and identification of unique 3D spatial topologies of complex engineering systems such as automotive cooling layouts, hybrid-electric power trains, and aero-engines are essential to search their exhaustive design spaces to identify spatial topologies that can satisfy challenging system requirements. However, efficient navigation through discrete 3D spatial topology options is a very challenging problem due to its combinatorial nature and can quickly exceed human cognitive abilities at even moderate complexity levels. Here we present a new, efficient, and generic design framework that utilizes mathematical spatial graph theory to represent, enumerate, and identify distinctive 3D topological classes for an abstract engineering system, given its system architecture (SA) — its components and interconnections. Spatial graph diagrams (SGDs) are generated for a given SA from zero to a specified maximum crossing number. Corresponding Yamada polynomials for all the planar SGDs are then generated. SGDs are categorized into topological classes, each of which shares a unique Yamada polynomial. Finally, for each topological class, one 3D geometric model is generated for an SGD with the fewest interconnect crossings. Several case studies are shown to illustrate the different features of our proposed framework. Design guidelines are also provided for practicing engineers to aid the utilization of this framework for application to different types of real-world problems.

Model-Based Manipulation of Linear Flexible Objects: Task Automation in Simulation and Real World

Manipulation of deformable objects is a desired skill in making robots ubiquitous in manufacturing, service, healthcare, and security. Common deformable objects (e.g., wires, clothes, bed sheets, etc.) are significantly more difficult to model than rigid objects. In this research, we contribute to the model-based manipulation of linear flexible objects such as cables. We propose a 3D geometric model of the linear flexible object that is subject to gravity and a physical model with multiple links connected by revolute joints and identified model parameters. These models enable task automation in manipulating linear flexible objects both in simulation and real world. To bridge the gap between simulation and real world and build a close-to-reality simulation of flexible objects, we propose a new strategy called Simulation-to-Real-to-Simulation (Sim2Real2Sim). We demonstrate the feasibility of our approach by completing the Plug Task used in the 2015 DARPA Robotics Challenge Finals both in simulation and real world, which involves unplugging a power cable from one socket and plugging it into another. Numerical experiments are implemented to validate our approach.

Strength Investigation of an Upholstered Furniture Frame with Side Plates of PB, OSB and PLY by Finite Element Method

Comparative analysis of the strength characteristics of one-seat upholstered furniture frame with rails of Pinus Sylvestris L. and side plates of PB, OSB and PLY boards was carried out. 3D geometric model of the upholstered furniture frame was created by Autodesk Inventor Pro®. Linear static analyses were carried out by the method of finite elements (FEM) simulating light-service loading. The orthotropic material characteristics of the used materials were considered in the analyses. Two variants of corner joints in the frame (model A – staples and PVAc; model B - staples, PVAc and strengthening elements under the rail of the seat) were considered. The laboratory established coefficients of rotational stiffness of used staple corner joints in the skeleton were considered in finite element analysis (FEA). As result, the distribution of the maximum and minimum principal stresses in the 3D model of upholstered furniture frame side plates were derived and analysed. The worst failure indexes according to Tsai-Wu failure criteria were calculated at heavy-service load. The study provided database of strength values that can help in the engineering of upholstered furniture frames with side plates of PB, OSB and PLY.

A Modeling Method of Human Knee Joint Based on Biomechanics

In order to establish an accurate model of human knee joint, which lays a foundation for the follow-up finite element analysis of knee joint and biomechanics analysis, the paper based on the theory of biomechanics and MRI, with the help of professional modeling software, provides a 3D geometric model modeling and materialization processing method of knee joint, and established a total knee joint model including femur, tibia, fibular, meniscus, cartilage, ligament and other related structures.

Finite element 3D numerical simulation study of car braking systems and brake disc/drum – pad/shoe friction couple materials

Our study uses the finite element method of modeling and analyzing the functioning of a braking system for a modern vehicle, in terms of stress ditributions, structural deformation, wear and thermal gradient of the brake disc and drum. The 3D geometric model of system brake is designed using Solidworks, and the coupled thermal and structural analysis is performed with the ANSYS Workbench R16 program. The brake was applied when the car was 85.7 km / h (ω = 125 rad · s-1), the duration of braking until the car stopped was t = 5 s. For the given example, the coefficient of average friction during braking, considering the pressure on the pad p = 7.5 MPa, is μ = 0.35. It was discovered that the relative deformations of the plate and disc are larger in the area of the outer diameter than that of the inner diameter. This is also outlined by the fact that the pressure is higher on the outer sides than on the inner sides of the plate, the highest value being in the central axis zone of the outer side. Knowing the thermophysical characteristics of the disc and the plate and the working conditions, it was possible to determine the temperature variation during braking. The results of the numerical research revealed that an increase of the contact pressure and / or the relative speed between the contact surfaces implies an increase of the amplitude of the stick-slip phenomenon.