Parallelization of the multibody simulation package FEDEM

This paper presents the conceptual and functional design of a novel hybrid leg-wheel-track ground mobile robot for surveillance and inspection, named WheTLHLoc (Wheel-Track-Leg Hybrid Locomotion). The aim of the work is the development of a general-purpose platform capable of combining tracked locomotion on irregular and yielding terrains, wheeled locomotion with high energy efficiency on flat and compact grounds, and stair climbing/descent ability. The architecture of the hybrid locomotion system is firstly outlined, then the validation of its stair climbing maneuver capabilities by means of multibody simulation is presented. The embodiment design and the internal mechanical layout are then discussed.

Download Full-text

New developments in the GDIS simulation package: Integration of VASP and USPEX

Journal of Computational Chemistry ◽

10.1002/jcc.26697 ◽

2021 ◽

Author(s):

Hubert Okadome Valencia ◽

Busheng Wang ◽

Gilles Frapper ◽

Andrew Lloyd Rohl

Keyword(s):

New Developments ◽

Simulation Package

Download Full-text

Localization of Scattering Objects Using Neural Networks

Sensors ◽

10.3390/s21010011 ◽

2020 ◽

Vol 21 (1) ◽

pp. 11

Author(s):

Domonkos Haffner ◽

Ferenc Izsák

Keyword(s):

Neural Networks ◽

Plane Waves ◽

Measurement Data ◽

Scattered Wave ◽

Training Data ◽

Data Set ◽

Main Compound ◽

Incident Plane ◽

The Neural Networks ◽

Simulation Package

The localization of multiple scattering objects is performed while using scattered waves. An up-to-date approach: neural networks are used to estimate the corresponding locations. In the scattering phenomenon under investigation, we assume known incident plane waves, fully reflecting balls with known diameters and measurement data of the scattered wave on one fixed segment. The training data are constructed while using the simulation package μ-diff in Matlab. The structure of the neural networks, which are widely used for similar purposes, is further developed. A complex locally connected layer is the main compound of the proposed setup. With this and an appropriate preprocessing of the training data set, the number of parameters can be kept at a relatively low level. As a result, using a relatively large training data set, the unknown locations of the objects can be estimated effectively.

Download Full-text

Design for X Approach to Optimise a Formula SAE Car

Volume 2 ◽

10.1115/esda2004-58491 ◽

2004 ◽

Author(s):

Renzo Capitani ◽

Tommaso Iacomelli ◽

Daniele G. Rosti ◽

Pierluigi Tozzi

Keyword(s):

Experimental Data ◽

Integrated Approach ◽

Design For Manufacturing ◽

Cnc Machining ◽

Recursive Method ◽

Multibody Simulation ◽

Design For X ◽

Formula Sae ◽

Class 1

The Universita` degli Studi di Firenze joined the Formula Student competition (organised by SAE and IMechE) in 2002 competing in Class 3, the following year the first car was ready to compete in Class 1. In order to build this car, an integrated approach was adopted to obtain the best solution in every aspect. The purpose of the design was to optimise the car handling, fulfilling the Formula SAE rules. All the design phases were based on the Design for X approach, with the aim to optimise all the aspects of the Formula SAE project, like performance, design and cost. A Design for Manufacturing approach was added to the FEA to design all the components, like uprights and wheel spindles, in order to simplify the CNC machining. The suspensions layout was defined using a recursive method based on the Multibody Simulation and the components design. Some experimentations were conducted to verify the simulations. The experimental data were used to start the redesign, to improve the performance of the new car that will compete in the 2004 events.

Download Full-text

The Dependence of Tensile Ductility on Investment Casting Parameters in Gamma Titanium Aluminides

MRS Proceedings ◽

10.1557/proc-552-kk2.1.1 ◽

1998 ◽

Vol 552 ◽

Author(s):

R. Raban ◽

L. L. ◽

T. M.

Keyword(s):

Titanium Aluminide ◽

Titanium Aluminides ◽

Tensile Ductility ◽

Gamma Titanium Aluminide ◽

Cooling Rates ◽

Gamma Titanium ◽

Investment Cast ◽

Thermal Data ◽

Titanium Aluminide Alloys ◽

Simulation Package

ABSTRACTPlates of three gamma titanium aluminide alloys have been investment cast with a wide variety of casting conditions designed to influence cooling rates. These alloys include Ti-48Al-2Cr-2Nb, Ti- 47Al-2Cr-2Nb+0.5at%B and Ti-45Al-2Cr-2Nb+0.9at%B. Cooling rates have been estimated with the use of thermal data from casting experiments, along with the UES ProCAST simulation package. Variations in cooling rate significantly influenced the microstructure and tensile properties of all three alloys.

Download Full-text

Efficient Simulation of Gear Contacts Including Transient Elastohydrodynamic Effects

Journal of Tribology ◽

10.1115/1.4024212 ◽

2013 ◽

Vol 135 (3) ◽

Cited By ~ 6

Author(s):

Peter Fietkau ◽

Bernd Bertsche

Keyword(s):

Three Dimensional ◽

Direct Determination ◽

Simulation Method ◽

Elastic Half Space ◽

Operating Conditions ◽

Multibody Simulation ◽

Multibody Model ◽

Gear Contact ◽

Oil Films ◽

Lubrication Conditions

This paper describes an efficient transient elastohydrodynamic simulation method for gear contacts. The model uses oil films and elastic deformations directly in the multibody simulation, and is based on the Reynolds equation including squeeze and wedge terms as well as an elastic half-space. Two transient solutions to this problem, an analytical and a numerical one, were developed. The analytical solution is accomplished using assumptions for the gap shape and the pressure in the middle of the gap. The numerical problem is solved using multilevel multi-integration algorithms. With this approach, tooth impacts during gear rattling as well as highly loaded power-transmitting gear contacts can be investigated and lubrication conditions like gap heights or type of friction may be determined. The method was implemented in the multibody simulation environment SIMPACK. Therefore it is easy to transfer the developed element to other models and use it for a multitude of different engineering problems. A detailed three-dimensional elastic multibody model of an experimental transmission is used to validate the developed method. Important values of the gear contact like normal and tangential forces, proportion of dry friction, and minimum gap heights are calculated and studied for different conditions. In addition, pressure distributions on tooth flanks as well as gap forms are determined based on the numerical solution method. Finally, the simulation approach is validated with measurements and shows good consistency. The simulation model is therefore capable of predicting transient gear contact under different operating conditions such as load vibrations or gear rattling. Simulations of complete transmissions are possible and therefore a direct determination of transmission vibration behavior and structure-borne noise as well as of forces and lubrication conditions can be done.

Download Full-text