Advanced Loads. Patrick Cunningham. CAE Associates Inc. and ANSYS Inc. Proprietary 2013 CAE Associates Inc. and ANSYS Inc. All rights reserved.

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Loraine Gray
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2 E-Learning Webinar Series This presentation is part of a series of E-Learning webinars offered by CAE Associates. Other E-Learning webinar topics coming up are: Solving Transient Dynamic Problems with ANSYS LS-Dyna February 12 th and 14th Working with APDL Command Objects in Workbench March 5 th and 7th Visit for details. If you are a New Jersey or New York resident you can earn continuing education credit for attending the full webinar, participating in the polls and completing a survey at the conclusion of the presentation. 2

3 Topics 1. Using Tabular and Functional loads in ANSYS/Mechanical 2. Mapping imported data onto the ANSYS Mechanical model using the External Data Utility. 3

5 Load Definition in ANSYS/Mechanical Most loads in the ANSYS/Mechanical environment can be defined in one of the following ways: Constant: The magnitude of the load does not vary by position and can vary only linearly with time throughout the duration of the load step. Tabular: Can be defined by a table of the load magnitude and one primary variable (x, y, z, time). Functional: A math expression is used to define the load magnitude as a function of one primary variable (x, y, z, time). 5

6 Variable Loading in ANSYS/Mechanical A cantilever beam is loaded with the following: A pressure distribution in the top surface that varies along the length. A periodic load at the free end. A transient analysis is needed to combine the effects of the constant and time varying loads. Constant pressure is distributed over the beam length. Sinusoidal force applied at the free end. 6

7 Tabular Loading in ANSYS/Mechanical Tabular loads defined in Mechanical can be a function of one primary variable only (x, y, z or time). Tabular loads can be defined in local Cartesian and cylindrical coordinate systems. 7

8 Functional Loading in ANSYS/Mechanical Functional loads are also limited to one primary variable only (x, y, z or time). Specify the Number of Segments to control the resolution of functional load data. 8

9 Functional Loading in ANSYS/Mechanical Functional loads can be also defined with respect to local Cartesian or cylindrical coordinate systems. 9

10 Functional Loading in ANSYS/Mechanical Functional loads defined with respect to time can be activated and deactivated on a per load step basis. 10

11 Functional Loading in ANSYS/Mechanical If you are using a periodic function take care to set the angle units accordingly. Example: Define a force load with the magnitude F = F max *sin(ωt). 1. Set the angle unit to Radians prior to defining the load. 2. Add a force load with a magnitude defined as a function. 3. Define ω in radians/s in the function. Note: Changing the units after the load is defined will not change the setting in the function. 11

12 Tabular and Functional Loading Types Not all load types can be defined with tables and functions as detailed in the table below: Tabular Functional Load (time) (x or y or z) (time) (x or y or z) Force + X + X Remote Force + X + X Nodal Force Moment + X + X Pressure Nodal Pressure Displacement Remote Displacement Nodal Displacement Bearing Load X X X X Thermal Load Joint Load + X + X Acceleration + X + X Angular Velocity + X + X Note: Only Pressure and Nodal Pressure tabular and functional loads are available in a Harmonic Response Analysis 12

13 Variable Loading in ANSYS/Mechanical The example consists of a steel cantilever beam 0.5 in height and 25 in length. A pressure load varying along the length of the beam is applied to the top surface as shown: 13

14 Variable Loading in ANSYS/Mechanical The static displacement due to the distributed pressure is in the global Y direction. 14

15 Variable Loading in ANSYS/Mechanical A modal analysis shows the natural frequency of the first bending mode at Hz. 15

16 Variable Loading in ANSYS/Mechanical The same distributed pressure load is then applied in a transient analysis. A beta damping coefficient is input as follows: β = 2ξ cr / 2πf where ξ cr = 1 and f= Hz The resulting displacement is consistent with the static analysis result. 16

17 Variable Loading in ANSYS/Mechanical Add a periodic load on the end of the beam at the natural frequency of the 3 rd bending mode: Add enough function segments to describe the periodic load in the time domain. 17

18 Variable Loading in ANSYS/Mechanical Solve and compare to the previous transient solution. Static pressure Static pressure + periodic load 18

19 The External Data Utility We have seen how Tabular and Functional loads can be useful in ANSYS Mechanical but what if the load distribution varies in more than one direction? For a three dimensional spatially defined load the External Data Utility can be used. The External Data Utility is found in the Component Systems menu. 19

21 The External Data Utility When should I use the External Data Utility? 1. When I have CFD results that I need to distribute on my Mechanical model. 2. When I have temperature results from a different finite element mesh. 3. When I have test data that I want to load onto my model. 4. When I have a non uniform thickness shell and I have a table of coordinates versus thickness that I want to assign to my elements. Basically, if you have coordinates and data, the External Data Utility can map it onto your model for the following quantities: 21

22 The External Data Utility The External Data Utility is found in the Component Systems section of the Project Page. 22

23 The External Data Utility The External Data Utility has an easy to use interface. Setting it up requires the four basic steps shown here. 3. Label the data columns accordingly. 1. Identify the source data file. 2. Set the format type. 4. Check the data preview. 23

24 The External Data Utility Once the External Data Utility is set up a simple drag and drop connects the data to the analysis system. Drag and drop. 24

25 The External Data Utility After the drag and drop a refresh of the Setup row of the analysis system is required. RMB - Refresh es 25

26 The External Data Utility After refreshing the Setup row you will find an Imported Load folder in the Mechanical environment. RMB click on the folder to insert the desired load. 26

27 The External Data Utility 1. Scope the imported load by either Named Selection or geometry picking. 2. If you have multiple data files in the External Data Utility identify the file and quantity (column) to be imported. 3. You can display the source points to confirm that the data and the model are geometrically consistent

28 The External Data Utility RMB click on the quantity to import the load. 28

29 The External Data Utility Once the load is imported and mapped onto the mesh turn off the source point display. RMB click on the imported load and insert a Validation to check the quality of the data mapping. As an example, set the type to Source Value and Display on Parent to On. RMB click on the validation and choose Analyze. 29

Getting Started with ANSYS ANSYS Workbench Environment

Getting Started with ANSYS ANSYS Workbench Environment Overview The purpose of this tutorial is to get you started with the ANSYS Workbench environment. We will use a simple, static analysis of a single