1. Introduction of FEA and Abaqus Preface: Abaqus like a large building with many rooms. It is not necessary to be familiar with all the rooms for Abaqus users. The things you should know are your target room and the way to access it. It is hoped that the two days Abaqus training can provide you the entrance and the map of the large building. 1.1 Seven Questions Q1: What is FEA? FEA is the abbreviation of Finite Element Analysis. Generally, engineering analysis can be classified into two types: Classic method and Numerical method. FEA is a numerical method for solving partial differential equation as well as integral equations generated from complex structure. It starts the analysis by dividing the interested object into a number of non-uniform regions (finite elements) that are connected to associated nodes as shown in Fig.1. Figure 1 Discrete element For each typical element, there exit dependent variables at the nodes such as displacement. An interpolation function is defined relative to the values of the dependent variables at the nodes associated with the element. K U F K e e e is the elementary stiffness matrix, which is determined by geometry, material property and element property. U is the elementary displacement vector, which describe the motion of nodes under e force. F is the elementary force vector, which describe the force applied on element. e The functions of all the elements are assembled into global matrix equation (governing algebraic equations) to represent the object we study as shown in Fig.2. K U F e
Figure 2 Assembly of global matrix After applying boundary condition, the governing algebraic equations can be solved for the dependent variable at each node. The strain and stress can be calculated based on the displacement of nodes associated with the element. Tip: The theory about finite element analysis can be found in any FEA or FEM books from the University library or internet. Q2: What can FEA do? At present, FEA is a popular method for mechanical, structural, civil, biomedical, and related engineering applications. It is an advanced engineering tool that is used in design as an alternative of experimental testing. Tip: Google example using FEA. For example Wheel tooth Q3: Is it necessary to know the background theory (FEA) before learning Abaqus? No, it is not necessary. You still can study and use Abaqus even though you don t know FEA theory or know a little. Tip: In this training, we will study how to use Abaqus rather than FEA. In your further study, you can also solve your problem about Abaqus using Abaqus documentation.
Q4: What is Abaqus? Abaqus is one of the most famous FEA commercial software in the world. Generally, the Abaqus FEA Product Suite include Abaqus/CAE-with ABAQUS/CAE you can quickly and efficiently create, edit, monitor, diagnose and visualize advanced ABAQUS analysis. Easy-to-use environment make it simple to learn for new users. Abaqus/Standard-employs solution technology ideal for static and low-speed dynamic events where highly accurate stress solutions are critically important. Abaqus/Explicit-is a finite element analysis product that is particularly well-suited to simulate brief transient dynamic events such as consumer electronics drop testing, automotive crashworthiness and ballistic impact. Q5: Can Abaqus provide the solution you need? Abaqus can provide muti-discipline solution across a number of areas such as Aerospace, Architecture, Automotive, Consumer goods, Energy, Life sciences, et al. It can provide the solutions about stress and strain, natural frequencies and mode shape, forced response, fatigue and lifetime estimation, plastically and nonlinear material, et al. Tip: Further details to http://www.simulia.com/ Q6: What is the objective of this training? Under the support of Birmingham Environment for Academic Research (BEAR) training strategy, the training of Abaqus & Finite Element Analysis (FEA) will be held in campus in the coming year. This training aims to encourage more students to take advantage of the University facilities. And it helps new Abaqus users be familiar with the software as soon as possible and speed up their research. Meanwhile, it also provides a space to know the people from Abaqus group in the University. During the training, you can learn the basic skills using Abaqus/CAE including modelling, meshing, submitting job and visualizing results, etc. Meanwhile, some useful tips and sample workshops will assist you pick up Abaqus/CAE as soon as possible. Tip: You can find the relevant information, training tutorial and workshops from http://www.fea.bham.ac.uk/index.shtml Q7: What kind of support can you get from University for FEA and Abaqus? You can use University s high performance cluster (bluebear) to solve your complex Abaqus model. You can join in the Abaqus group held by Bluebear. You can also get the opportunity to attend the Abaqus forum in the campus. Tip: more information from http://www.bear.bham.ac.uk/index.shtml
1.2 General Finite element analysis procedure General Finite Element Analysis Procedure includes the following three steps which also construct the main framework of available FEA software. 1. Preprocessing: in this step, the user constructed model is divided (meshed) into a number of discrete subregions or "elements", connected at discrete nodes. Certain boundary conditions are applied to some of the nodes in displacement or load. In one word, after preprocessing of FEA, the finite element model should be ready for being submitted to the solution. 2. Solution/Analysis: in this step, the finite element model is submitted to the solver as input in finite element code. A series of linear or nonlinear equations will be solved to generate numerical output of displacement, stress, et al., on nodes. 3. Postprocessing: in this step, the postprocessing provides a visualization environment for users to display the solutions in colored contours or other approaches, which assist the users to get a better understand of the results. 1.3 Interface of Abaqus/CAE Abaqus/CAE is a complete ABAQUS environment that provides a simple, consistent interface for creating, submitting, monitoring, and evaluating results from Abaqus/Standard and Abaqus/Explicit simulations. ABAQUS/CAE is divided into modules, where each module defines a logical aspect of the modeling process; for example, defining the geometry, defining material properties, and generating a mesh. As you move from module to module, you build the model from which Abaqus/CAE generates an input file that you submit to the ABAQUS/Standard or ABAQUS/Explicit analysis product. The analysis product performs the analysis, sends information to Abaqus/CAE to allow you to monitor the progress of the job, and generates an output database. Finally, you use the Visualization module of ABAQUS/CAE to read the output database and view the results of your analysis The interface of Abaqus/CAE is shown in Fig.3.
Figure 3 Abaqus/CAE interface Title bar: The title bar indicates the version of ABAQUS/CAE you are running and the name of the current model database. Menu bar:the menu bar contains all the available menus; the menus give access to all the functionality in the product. Different menus appear in the menu bar depending on which module you selected from the context bar. Toolbar:The toolbar provides quick access to items that are also available in the menus. Context bar: ABAQUS/CAE is divided into a set of modules, where each module allows you to work on one aspect of your model; the Module list in the context bar allows you to move between these modules. Other items in the context bar are a function of the module you are working in. For example, the context bar allows you to retrieve an existing part while creating the geometry of the model or to change the output database associated with the current viewport. Similarly, in the Mesh module you can choose whether to display the assembly or a particular part. Model Tree:The Model Tree provides you with a graphical overview of your model and the objects that it contains, such as parts, materials, steps, loads, and output requests. In addition, the Model Tree provides a convenient, centralized tool for moving between modules and for managing objects. If your model database contains more than one model, you can use the Model Tree to move between models. When you become familiar with the Model Tree, you will find that you can quickly perform most of the actions that are found in the main menu bar, the module toolboxes, and the various managers. Toolbox area: When you enter a module, the toolbox area displays tools in the toolbox that are appropriate for that module. The toolbox allows quick access to many of the module functions that are also available from the menu bar.
Canvas and drawing area:the canvas can be thought of as an infinite screen or bulletin board on which you post viewports;the drawing area is the visible portion of the canvas. Viewport:Viewports are windows on the canvas in which ABAQUS/CAE displays your model. Prompt area: The prompt area displays instructions for you to follow during a procedure; for example, it asks you to select the geometry as you create a set. In the Visualization module a set of buttons is displayed in the prompt area that allow you to move between the steps and the frames of your analysis. Message area: ABAQUS/CAE prints status information and warnings in the message area. To resize the message area, drag the top edge; to see information that has scrolled out of the message area, use the scroll bar on the right side. The message area is displayed by default, but it uses the same space occupied by the command line interface. If you have recently used the command line interface, you must click in the bottom left corner of the main window to activate the message area. Note: If new messages are added while the command line interface is active, ABAQUS/CAE changes the background color surrounding the message area icon to red. When you display the message area, the background reverts to its normal color. Command line interface: You can use the command line interface to type Python commands and evaluate mathematical expressions using the Python interpreter that is built into ABAQUS/CAE. The interface includes primary (>>>) and secondary (...) prompts to indicate when you must indent commands to comply with Python syntax. The command line interface is hidden by default, but it uses the same space occupied by the message area. Click in the bottom left corner of the main window to switch from the message area to the command line interface.