Introduction to LUSASBasics Geometry Mesh Attributes Loading Analysis Viewing Results Basics Opening Lusas: 10806 – Linear 10805 – Nonlinear 10804 – Time History .mdl – the model file .mys – the results file Basics Attributes Loadcases Groups Utilities Reports Layers . Basics Units . Basics Geometry Mesh Attributes Loading Analysis Viewing Results . Geometry Creates the basic shape of the model Points Lines Surfaces Volumes . . Or: To create new entry fields press Tab. it is recognised as 0. When the Z-ordinate is omitted.Geometry Points defined using Geometry> Point> Coordinates. Geometry Lines are created between points by selecting 2 points and using : Surfaces are created between lines by selecting lines and using: Volumes are created by selecting surfaces and using: . Moving: Copying: Sweeping: . moved or swept. surfaces and volumes can all be copied. lines.Geometry Points. Geometry . . Basics Geometry Mesh Attributes Loading Analysis Viewing Results . Chose element type(s) .Meshing The Geometry defines the shape of the model only – the mesh is what is actually analysed To create the mesh: .Assign the elements to the geometry . Meshing .Elements Beam Elements • 2 or 3 Dimensional • Straight or Curved • Thick or Thin (Shear Flexibility) • Other linear elements : – Bars or Cables . Elements Beam Elements • GRILL – 2D linear • BEAM – Thick 2D linear • BMS3 – Thick 3D linear • BTS3 – Thick nonlinear 3D linear • BM3 – Thin 2D quadratic • BS4 – Thin 3D quadratic • BMX3 – Cross Section Thin 2D quadratic • BSX4 – Cross Section Thin 3D quadratic Quadratic = more nodes = curved .Meshing . Meshing .Elements Surface Elements • More analytically expensive than Beams • Triangular or Quadrilateral • Number of nodes / gauss point • Thick or Thin Elements – Thin – no shear flexibility – simpler but only use if all plates are very thin – Thick – include shear flexibility – required for most analysis . Meshing .Elements Surface Elements • Plates – For flat models • Shells Thin TS3 Triangles TSL6 QSI4 Quadrilaterals QSL8 Thick TTS4 TTS6 QTS4 QTS8 . with translational and rotational stiffness.Elements Joint (spring element) Joint elements are used to connect two or more nodes by springs.Meshing . Mass only joints can be defined . They may have an associated mass and damping. The number of elements in a regular mesh are controlled by defining line meshes on the boundary lines with no element type.. . select the surface to be meshed. To assign the mesh to the surface.Elements To select the element types: Use Attributes> Mesh..Meshing . then use the treeview and drag the appropriate mesh name from it onto the surface. Elements .Meshing . Meshing . .Layout • Balance between accuracy and effort • Ideal value depends on what model is for • Use sensitivity tests to get right • set up part / all of model • identify key result areas • vary mesh density and compare results • use lowest density that gives consistent results Consider varying mesh density through model. Layout .Meshing . Layout Mesh Aspect Ratios • High aspect ratios can cause numerical problems in the analysis • General guideline – keep ratio less than 10 .Meshing . Basics Geometry Mesh Attributes Loading Analysis Viewing Results . Attributes Mesh Geometric Material Supports . .Attributes .Geometric Geometric Attributes – not to be confused with Geometry.. For line elements need to enter the cross sectional properties For surface elements need to enter the thickness . New cross section properties can be defined and imported into a model by creating a separate 2d lusas model with the cross section shape.Geometric Attributes> Geometric> Cross section properties can be obtained from a library or entered directly. .Attributes . Or. as well as having a coloured beside it.Attributes .Material Use Attributes> Material> Material Library/Composite Library and select a material. . use rightclick on the attribute in the treeview. then Select Assignments to see which parts have that particular attribute. material properties can be entered directly To check where any attribute is assigned. . and can only be manipulated when that loadcase is active.Attributes . it will be visualised by a green arrow on the point or line. They can be rigid or springs When a support is assigned. If several load cases are created the supports are only applied in the first loadcase. lines or surfaces.Supports Supports can be assigned to points. Use the icon to turn this on/off. Basics Geometry Mesh Attributes Loading Analysis Viewing Results . 81 The arrows can be turned on and off using: . and applied to the geometry. A self weight can be added to the model by selecting Body Force and then entering a linear acceleration of -9.Loading A load is defined as an attribute. Loading Load Types: Structural – Applied to Structure Prescribed .Moves structure Discrete – defined on local coordinate system and projected onto structure . When a load is assigned to the model it must be assigned to a loadcase. Supports are defined in first Loadcase .Loadcases Any number of loadcases can be created. • Basic Combinations • Smart Combinations • Envelopes When loads are assigned to the geometry a load factor can be applied. .AUTOLOADER Attributes > Influence Displace or rotate elements. Bridge > Run Influence Analysis. ..Traffic Loading . Traffic Loading . .AUTOLOADER Bridge > Vehicle Load Optimisation… Doesn’t cover Eurocodes yet. Basics Geometry Mesh Attributes Loading Analysis Viewing Results . Analysis or File> LUSAS Datafile… gives more advanced options . Basics Geometry Mesh Attributes Loading Analysis Viewing Results . bottom being most visible .Visualisation of a Model Geometry Mesh Attributes Labels Contours Vectors Deformed Mesh Diagrams Values The order of the layers on display is shown by the order in the treeview. Viewing Assignments In the layers treeview right click on geometry and select properties . . The groups function assigns geometry features to different named groups so they can be made visible and invisible easily Selection: .Viewing Model Groups: Different parts of the model can be made visible and invisible at any stage. Utilities > Print Results Wizard . Gives tables of results for the visible model ...Viewing Results To view the results of the analysis. the loadcase used needs to be set active. Viewing Results Used to plot deflections. diagrams and contours . Other things Lusas can do: • Frequency analysis • Buckling analysis • Non-linear analysis • Automation using Visual Basic Scripts . com/sites/StructuresWG/default.aspx Lusas Technical Support Support@lusas. www..atkinsglobal.com Username: lusas Password: powerfulfe Bridge Engineers’ Working Group Site https://communities.Help.lusas.com ..eu. OUT) for any warning messages. 4.html . Check mesh refinement 6.com/protected/instruct/basic_checklist.Checks 1. Check the deformed shape 3. Check element axis http://www. Check the reactions 2. Check the value of the deformations.lusas. Check your LUSAS Solver text output file (*. 5.