Simulation in the Inventor® program

Autodesk Inventor® provides software for 3D mechanical design, simulation, creat-ing tools and design communication that enables profitable workflow design, Digital Prototyping to design and manufacture products in less time generating manufactur-ing documentation directly from validated 3D digital prototypes reducmanufactur-ing errors and allowing changesto be made to orders before manufacturing, and offers rapid and accurate production of drawings directly from the 3D model. Among its features are:

parametric solid design of highly complex assemblies handling more than 1000 compo-nents, creating presentations and cuts, automatic generation of production drawings, customizable management technology, 3D module welding, bending modulus Reed, mechanical module for animation and photo realism, etc. What follows will be a description of how to use this software with application to the wind and mechanical analysis of a greenhouse, using the tool as a basis inventor and CFD program from the same platform, fluid analysis, in this case the wind.

The first step is to get to know the environment Inventor®, for this, the home screen is as follows (Figure 4.2).

Figure 4.3 Selecting screen of work, learn or extend, Inventor®.

Then in the next screen that appears (Figure 4.3), select an existing file or create a new one.

In the next screen (Figure 4.4) you can set the basic configuration of the template or you can do so when you are already working within the Inventor® environment.

The Inventor® template defines the type of file to be used, such as; component files, assemblies, presentations and manufacturing drawings, it also sets the unit system for modeling, refining, text styles, dimensions, and tables notes, types of welding, modeling preferences, flat feet and frames, among other features that can be pre-configured to support the user in its standardization and accuracy.

Since it was installed, Inventor® creates three shrines: Default, Metric and English, but the user can create any number of inserts required. Each folder created inside the Templates folder, creates an additional tab in the New File window and each is saved within the file created in the folder and will become a user template.

To start a sketch, a new file is opened; a sketch tool is selected and then it begins to draw in the Inventor® window (Figure 4.5). While it is automatically plotting it applies certain rules allowing the required stroke. For that reason the following screen is created and it is necessary begin in a 2D sketch.

When you start working on the piece, the following screen appears which presents all the commands that can be used to create the piece, for example: lines, splines, circles, ellipses, arcs, rectangles, polygons, or points. You can cut corners, extend or apply radios or chamfers, and compensate and project geometry of other features.

When working with the figure in the work plane it shows some tools to begin the piece

Figure 4.4 Configuration of the template, Inventor®.

Figure 4.5 First screen of the sketch in Inventor®.

Figure 4.6 Example of the auxiliary tools, Inventor®.

construction; the advantage of using this program is that it is very intuitive and to every action to be performed there are alternative tools to enhance the piece (Figure 4.6).

All projects begin with a sketch that has a starting point whether you are creating a sketch or a profile. A sketch is the profile of a Feature (3D operation) and any geometry (such as a sweep path or axis of rotation) that are required to create a 3D object. All sketch geometry is created and fixed in the sketch environment, using the tools in the tool pane.

On the other hand, it is important to mention that there are 5 basic methods to generate features based (solid, three-dimensional objects or surfaces) in Inventor®:

Extrude, Revolve, Sweep, Loft and Coil, Helicoid. In addition to the creation of these objects the Work Features that are used for the abstract construction geometry (auxil-iary) can be used when the one that already exists in a model is insufficient for creating and positioning new features that are needed. To fix the position of the work features, you can restrict several complementary tools that help create increasingly complex parts such as: holes, shells, fillets, chamfers, face drafts, and threads. Inventor® allows you to create pieces with maximum detail, for which it relies on tools that will create more complex geometries such as Move Face, Face Draft Split, Thicken/Offset, Decal or Emboss.

Inventor® provides important information to validate model geometry, using various analysis tools. For more basic information you can consult the following link: http://usa.autodesk.com.

Figure 4.7 Sketch with general characteristics of the structure.

Subsequent to getting to know and how to use the basic commands, you can start with the construction of a structure, which initially takes place in 2D and then moves to 3D projects. To develop a 3D model of a structure, it is necessary to take into account that this is formed by united frames using rails, then the first step is to create the sketch containing the general characteristics of the structure, in this case the dimensions and restrictions are specified in mm (Figure 4.7).

Later levels are used to determine the depth of the structure and create a 3D sketch (Figure 4.8 in mm) which will join the frames using rails.

Once the sketch is generated for the structure the beams shall be inserted, within the program it is possible to determine characteristics such as: type of rule, shape, size and material, in this case it has been selected a line of 1/2×0.145 in galvanized steel (Figure 4.9).

To perform a study and an analysis of the mechanical properties of the structure it is necessary to know:

General data of the structure – Type of structure that is analyzed.

Nomenclature and coordinates of the nodes that make up the structure that is analyzed.

Nomenclature and incidents of the bars in the structure.

Location and nomenclature of the flat elements.

Geometry of the elements – Number of dimensions that the bars and the flat elements have.

Properties of the materials – which include the type of material that constitutes each elements as well as its modulus of elasticity, coefficient of Poisson, its density, its resistance, among others.

Features of the connections with the foundation – This is, if there are under rides or some degree of freedom in these connections.

Figure 4.8 3D sketch.

Figure 4.9 Approach characteristics of the structures.

4.6.3 Characteristics of the loads that are applied to the