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Vampire Advanced Tutorial Guides

We are pleased to provide advanced tutorial guides on the following topics. These guides provide practical instruction on modelling complex elements; making full best use of Vampire's features; and more. In the sections below, you can find the list of topics, synopses of each guide, and links to the member area to download the full guide. All guides are available in the Members Area.

3 Piece Truck Modelling

Alan Minnis, Principal Consultant, AtkinsRéalis

This tutorial guide describes the modelling of a generic three-piece truck or bogie. This design remains the truck of choice for essentially all freight cars in North America and is used commonly around the world for freight wagons. The three-piece truck is a friction damped freight truck, it consists of one bolster, two side frames and two wheelsets.

In this guide, a description of the key features of the three-piece truck is given together with one simplified example of how it can be modelled. The advice contained in this guide will enable the reader to construct a basic model of a three-piece truck from which more sophisticated variations can be developed for specific applications and analyses. The guide includes a sample model of a three-piece truck in Interactive Vehicle Builder (IVB) format.

To download the guide please click here.

Airspring Modelling

Owen Evans, Principal Engineer, AtkinsRéalis

This tutorial guide describes the 'airspring' vehicle model element in Vampire. At its simplest, an airspring is a rubber membrane containing pressurised air, which is used to support a load. If it is compressed, the air pressure increases, thus providing a reaction force. As we shall see, the stiffness increases with the pressure, so an airspring is ‘load conscious’, such that the natural bounce frequency of the suspended load is fairly constant. This is a useful property in a vehicle suspension system.

This guide introduces how airsprings work, including discussion of airspring coupling; failure modes; shear charactistics of airsprings; and the evolution of airspring design. We proceed to introducing the formulae for vertical behaviour, before presenting details for using the built-in Vampire vehicle model element, and finally a worked example is provided.

To download the guide please click here.

Dynamic Gauging (UK Method)

Owen Evans, Principal Engineer, AtkinsRéalis

The gauging of railway vehicles is the process used to determine their 'swept envelope', i.e. the space they require while in operation. This is not as simple as it sounds, since railway vehicles have several characteristics which influence their swept envelope, and these characteristics are not always easy to define.

The main aim of this Advanced Tutorial Guide is to familiarise the user with the process used for dynamic gauging in Great Britain, but it also serves as a worked example of Vampire automation, relying as it does on the use of Task and Command files. The format of data to be used is set out in the Rail Safety and Standards Board (RSSB) document ‘RIS-2773-RST Format for Vehicle Gauging Data’.

To download the guide please click here.

Freight Vehicle Modelling

Owen Evans, Principal Engineer, AtkinsRéalis

Freight vehicles around the world commonly use friction damped suspensions as they provide a low cost and low maintenance suspension solution. Although many different configurations of freight vehicle suspensions exist, there are a few principles involved that are common to all the different types of friction damped freight bogie such as two stage suspensions, suspension guides and load dependent friction damping.

This guide introduced the principles of freight suspension modelling. These are examined via three different examples, namely a hornguide suspension, a friction wedge suspension and a Lenoir link suspension. As well as this introductory guide to freight vehicle suspensions, other Advanced Tutorial Guides are available providing tutorials on modelling of the Y25 and 3-Piece truck freight bogies.

To download the guide please click here.

How Line Elements Work

Alan Minnis, Principal Consultant, AtkinsRéalis

Line elements are a group of modelling elements in Vampire Pro which essentially have a fixed line of action. These elements are Stiffness, Bumpstop, Damping, and Friction. Line elements were the original set of elements developed for the first Vampire Pro release. They are often seen as simplistic and in some cases are now superseded by more sophisticated elements; however, this group of elements have unique properties that make them extremely useful in certain modelling situations.

This guide introduces these Vampire Pro modelling elements and highlights the advantages and disadvantages of their use in different modelling applications. The guide first describes the dynamic characteristics of each line element and then describes their common geometric behaviour.

To download the guide please click here.

Longitudinal Dynamics

Owen Evans, Principal Engineer, AtkinsRéalis

In the standard implementation of Vampire, the speed of the vehicle in a transient simulation is set to either a constant value or else follows a predetermined speed profile. Using the new Longitudinal Dynamics solver, changes all this. Initial vehicle speed is set by the run file but thereafter it can be affected by external forces and wheelset pitch torques, gradients and train resistance from curves and influences such as friction and aerodynamic drag.

This guide introduces the Longitudinal Dynamics solver and the application of the external resistance forces can that affect the vehicle. Vampire input formats for the different resistance types are described; and an example user subroutine implementation of speed control is presented.

To download the guide please click here.

Model Checking

Alan Minnis, Principal Consultant, AtkinsRéalis

The possible complexity of a vehicle dynamic model makes the checking and validation of the model an extremely important part of the modelling and simulation process.

This guide reviews the methods that can be used for checking a vehicle model in Vampire. Checking ensures the syntax of the model file is correct, that the elements are connected to the masses as intended, and some of the basic physical properties are within realistic boundaries. Checking a model is different from model validation; checking a model does not necessarily require any physical test data and should be performed during model construction and on completion of the model.

Once a model has been checked it can be validated and used for prediction work. Model validation usually follows the checking phase to ensure that the model accurately represents the real physical system being modelled. This is described further in the Model Validation tutorial guide.

To download the guide please click here.

Modelling Flexible Modes

Alan Minnis, Principal Consultant, AtkinsRéalis

A Vampire vehicle model comprises a number of inertia elements representing vehicle bodies, bogie frames, wheelsets, traction motors etc. These are connected by various types of suspension elements to form the complete vehicle model. The flexible mode element represents a single flexible mode of vibration of a body. Several flexible modes can be included in a vehicle model to represent different modes of vibration of the same body, or to represent modes of vibration of different bodies.

In this tutorial guide the theory of flexible modes is reviewed together with how a flexible mode is implemented in a Vampire vfe file. The tutorial guide then gives examples on setting up flexible modes to model dynamic response and static flexibility. The examples cover the requirements to be considered when data is derived from both simple beam models and finite element data.

To download the guide please click here.

Quick Start Guide

AtkinsRéalis

Vampire Pro assembles various methods for the prediction of railway vehicle dynamic behaviour that have been developed and carefully validated using sophisticated test facilities and equipment, over many years, to allow real problems in railway vehicle dynamics to be solved quickly and cost-effectively.

This Quick Start guide is intended to get users running the Vampire Pro software, from installation and licence activation through to vehicle modelling and analyses. The guide provides a broad introduction to Vampire; users will be able to follow along with the examples provided to become familiar with the software basics. Further details are provided in the comprehensive Vampire Manual which is packaged with the software.

To download the guide please click here.

Track Gauge

Alan Minnis, Principal Consultant, AtkinsRéalis

A unique aspect of railway vehicle dynamics compared to other forms of vehicle dynamics is the track. Railway vehicles are guided systems i.e. they follow a prescribed path defined by the track the vehicle is running over. The track gauge and the relationship between the track and wheelsets therefore forms a critical part of railway dynamics analysis.

This guide introduces how to model track gauge in Vampire. This includes creating simulations for the track gauge adopted by railway administrations, for example narrow gauge and broad gauge railways. The guide also covers simulating gauge variations including local gauge widening on tight curves and gauge irregularities arising from the physical track installation and general degradation in service.

To download the guide please click here.

Vampire Projects

Alan Minnis, Principal Consultant, AtkinsRéalis

The concept of ‘projects’ was introduced in Vampire to assist managing the input files and simulations that make up a dynamic analysis. Some simulations can involve many input files and dynamic analyses often require many of these simulations to be undertaken. This can quickly lead to a large set of files to undertake a complete dynamic analysis and it can become difficult to keep track of which inputs files are being used and which analyses are up to date.

A Vampire project provides a method to reference the files required to undertake a specific set of analysis tasks and to manage the relationships between the files. The Vampire front end displays a Vampire project in a tree structure which shows the relationship between files and also provides specific options for the files referenced by the project. This guide gives users a comprehensive introduction to the features of the Vampire project system.

To download the guide please click here.

Wheel and Rail Profiles

Phil Rogers, Technical Director, AtkinsRéalis

For full non-linear calculations with Vampire, using the transient or curving analysis programs and the non-linear creep law, information is needed on the actual shape of the wheel and rail. This shape information is used to generate the Contact Data file describing the geometry of the wheel/rail contact.

This guide describes the file formats that Vampire supports and their use; the advantages of each are described.

To download the guide please click here.

Y25 Bogie Modelling

Alan Minnis, Principal Consultant, AtkinsRéalis

This tutorial guide describes the modelling of the Y25 bogie which is a friction damped freight bogie widely used in Europe and the UK for a variety of freight wagons. The guide specifically refers to the Y25 bogie, but the advice can equally be applied to other Y series bogies such as the Y27 and Y33.

The advice contained in this guide will enable the reader to construct a base model of a vehicle with Y25 bogies, from which more sophisticated variations can be created for specific applications and analyses. The guide includes an example model of a Y25 container wagon in IVB format.

To download the guide please click here.

Introduction to User Subroutines

Alan Minnis, Principal Consultant, AtkinsRéalis

User Subroutines further extends the capabilities of Vampire by allowing users to develop their own bespoke simulations. The Vampire User Subroutine feature allows users to create code that integrates into the Transient analysis simulation.

This introductory guide explains how the User Subroutine feature works, how to install a supported compiler, how to create a user subroutine module and then compile and execute it. The guide describes the library functions available to access analysis variables during a simulation and concludes with a number of practical examples showing how some non-standard simulations can be performed using this feature.

To download the guide please click here.

Workflow and Automation

Alan Minnis, Principal Consultant, AtkinsRéalis

This tutorial guide describes the features and use of Vampire Task files and Command files including some more advanced techniques.

In some cases, analyses can involve hundreds or thousands of calculations along with the associated data processing and collation of the results. Process automation allows full advantage to be taken of Vampire’s capabilities. This is achieved through the use of Vampire Task files and Command files. The functionality of these files and the programs controlling them has been designed to provide automation of calculation processes, and to allow them to be integrated into the design workflow.

To download the guide please click here.

Switches and Crossings

Alan Minnis, Principal Consultant, AtkinsRéalis

Switch and crossing performance is crucial to the safe operation of the railway. It is also typically a significant contributor to the total number of track faults that develop and therefore accurate modelling is essential to understand the behaviour of this trackwork.

This guide introduces the features of switches and crossings and discusses how these features are modelled in Vampire.

To download the guide please click here.