United Kingdom Overview

Presentation Abstracts

November 9, 2011
External Keynote:
Designing Your Way Out of Recession Sir Richard Needham, Director for International and Commercial Affairs, Dyson Presentation Abstract: Richard will talk about how design and innovation have been the building blocks of success both in his ministerial and business careers. From the redesigning of Belfast in the late 80’s and early 90’s, being with James Dyson for over 16 years, to the transformation of the Avon Rubber Company Richard will explain how every nook and cranny of a company's entity needs design and innovation to succeed and prosper.
Mechanical Stream
High Performance Computing Simon Cross and Mark Keating, ANSYS UK Ltd
Modelling Delamination Damage in Pin-loaded Composite Lamites Akin Atas, University of Sheffield Presentation Abstract: Delamination is one of the main failure modes in laminated composite materials and it has a significant effect on the strength of the mechanical joints. A 3D FE model is created with cohesive elements to simulate a mechanically fastened cross-ply pin-loaded joint in a composite laminate. The model incorporates fully integrated solid elements in the pin-loaded area to accurately capture the high stress gradients. Results from the FE model show that delamination damage initiated at the point of maximum average shear stress at the 0°/90° interface. It is shown that delaminated area develops an elliptical shape which grows in a non-self similar manner with increasing pin displacement.
Transient Simulation of the Closing of a MEMS Switch with Air Gap Modelled by FLUID136 Elements Lorphelin Nicolas, Delfmems Presentation Abstract: This paper presents an utilization of new capabilities of FLUID136 squeeze film fluid element since ANSYSv12. This element is very useful in MEMS (Micro Electro Mechanical Systems) modelling, where lateral dimensions of the squeeze film are often very large compared to the fluid gap. Since ANSYS v12 release it is possible to perform coupled fluid-structure simulations where the displacement of a membrane changes the fluid gap and therefore the fluid pressure, which has effects on the membrane behaviour. However the transient simulation of pull-in, where the membrane goes to touch the substrate under electrostatic actuation, remains very challenging for two reasons. The first one is that near the pull-in state the electrostatic gap becomes low thus the electrostatic force modelled by TRANS126 elements becomes very high whereas the high velocity and the very low air gap induce high pressure in fluid film and thus high reaction force on the membrane. The problem is solved by imposing implicit treatment of cross-coupling terms (KEYOPT(3)=2) and using the compressible nonlinear Reynolds equation (KEYOPT(4)=1), which is the most adapted for large displacement and large pressure change. Moreover the time increment has to be decreased around the contact time in order to improve the convergence. The second reason is the difficulty to model the closing of the switch. The FLUID136 element has two options to manage the thin film when the gap becomes lower than a defined minimum gap: The first one (KEYOPT(5)=2) is to declare the element “dead” from a fluid standpoint. The “fluid element death” induces an abrupt change from very high pressure to zero pressure, which is not relevant physically. Moreover the behaviour of the structure is dependant from the arbitrary choice of the fluid minimum gap. The second option is to reset the gaps lower than the fluid minimum gap to the said fluid minimum gap, which is equivalent to model a very thin film which remains under the membrane and enables the air to escape and the pressure to decrease progressively. This solution does not seem relevant but the results are similar to those obtained by simulating a membrane with roughness on its lower face, which keeps small air gaps even at pull-in state. Moreover, the simulation of the rough membrane enables to set up the suitable value the fluid minimum gap for a simulation on a “flat” membrane. These simulations have been validated by the measurement of the displacements of the membrane during the switching of the component.
Conservative Surgical Treatment for Osteoarthritis: A Finite Element Study Diagarajen Carpanen & Franziska Reisse, Anglia Ruskin University Presentation Abstract: Osteoarthritis (OA) is a degenerative disease of all tissues in the di-arthrodial joints, leading to limited mobility and joint deformation (Coggon, et al., 2000). Lower extremity malalignment (Andriacchi, et al., 2000) and meniscal injuries (Englund, et al., 2003) have been associated with knee OA. High tibial osteotomy (HTO) is a realignment surgery, while partial meniscectomy is a surgical practice for treating torn menisci. Both techniques aim at restoring high-level knee function. However, the effect of HTO and resecting specific sizes and locations of meniscus on knee joint contact pressure is not clear. Therefore, the aim of this study is to determine how knee realignment and meniscal resection may affect joint contract pressure by finite element (FE) method. FE models of the healthy aligned knee joint were created from computer tomography and magnetic resonance images, using Mimics v14 (Materialise, Belgium). Following image registration, these 3D models were exported to the FE package Ansys 13.0 to investigate stress distribution in the tibio-femoral compartments of the knee joint. Boundary conditions, simulating physiological conditions during the stance phase of the gait cycle, were applied. The peak compressive stress is 60% higher in a malaligned knee than in a well aligned knee. The peak stresses were twice as high in the simulated knee without menisci compared to the intact knee. Results of the study show that malaligned and meniscectomised knees are subjected to high stress levels which may promote the development of OA. Therefore, further work in this area is warranted to bring understanding to the effects of HTO and partial meniscectomy techniques on the knee joint contact stresses and help improve conservative surgical treatments for OA.
Fluid Stream
The Role of the Analysis in the DECODE System: A Decision Environment for Complex Design Evaluation Erika Quaranta, Southampton University Presentation Abstract: Every value driven design process needs strong support from the analysis, which effectively provides the values to judge the design itself. The DECODE project is aimed to explore a Decision Environment for Complex Design Evaluation, specifically applied to developing a maritime surveillance UAV for search and rescue missions. In order to take fully advantage of the more and more increasing computational resources available nowadays, an efficient, rapid and automatic CFD workflow was implemented internally to the design optimization loop, as core part of the software decision environment. The challenge was to include the high fidelity drag and stall analysis into the optimization loop at the conceptual design stage, that is, starting from the geometry and weight specifications, the software has to manage the entire workflow automatically to provide the aerodynamic results for the full aircraft, including the calculation of the trimmed configuration. The workflow was developed using Ansys Workbench, because it is a fully comprehensive tools, which allows to cover the entire process from the geometry to the aerodynamic results, and it is broadly scriptable. Using this technique, few UAV configurations has been compared and the resulting design values analysed.
Robust Design Optimisation TBC, ANSYS
Analyses and Explorations of Ducted Marine Turbines Thomas Clark, Green-Tide Turbines Presentation Abstract: At Green-Tide Turbines Ltd., we had a problem: for early stage design there are multiple mechanical performance indices for ducted turbines. Moreover, efficiency values can be misleading and poorly bounded (depending on the denominator of the performance metric). In order to create a concrete performance index, G-TT integrated cost and geometric models of a ducted turbine in order to improve the economic performance of the system. This presentation looks at the system used to achieve this optimisation, from creation of a fully parameterised geometry interface (with SolidWorks TM), analysis in ANSYS CFX to investigation and optimisation using ANSYS Design Explorer. The aim of this talk is to highlight the potential for effective use of ANSYS tools in an early-stage design process. In this case, that usage allowed optimisation of a product beyond just the mechanical performance - minimising the cost per unit energy (£/kWh).
Efficient Plume Dispersion Analysis for Large Scale Installations Victoria Arthur, Senior Engineer Prospect The presentation will cover some of the tools and techniques that Prospect uses when modeling gas dispersion along with some example cases.
Electromagnetics Stream
Electromagnetic Force Coupling in Electric Machines Vincent Delafosse, ANSYS
Using HFSS for design at 77GHz Kate Moore, Roke Manor Research Ltd Presentation Abstract: Designing at mm wave frequencies is challenging and expensive to prototype. As with all RF design, using HFSS reduces prototype iterations and lets you optimise the design but there are several pitfalls to avoid. This presentation will highlight some of the problem areas and what extra considerations are needed for work at high frequencies.
*EKM and You* Mike Slack, ANSYS Presentation Abstract: Update yourself on the latest ANSYS EKM simulation environment. Four years after the first release of EKM more and more customers are starting to experience the benefits of the ANSYS simulation management tool. Attend this session to learn more about this collaborative environment and how it can enable teams to link, automate and deploy simulation processes in a web based environment.
Value-adding Services Greg Fairlie, ANSYS