This is because the object’s mass is balanced along this axis in front and back of the plane of symmetry. Here we see zero values for all cross-products containing the Z-axis (no wobble in Z-direction). Let’s look at an example of an object that is symmetrical about only one plane (XY): In our example model above, we would expect its cross-product values to be zero for rotation about the COM axes and non-zero about any different axes. Think of a car wheel being balanced to prevent wobble. If it is non-zero, then we can expect an off-axis torque or acceleration that will result in a wobble of the object not a pure rotation. Cross-Product MOI is really just an indication of the symmetry of the object. Any non-diagonal element represents a Cross-Product Moment of Inertia. Without getting too technical, the diagonal elements of theses matrices always represent Moments of Inertia about the primary axes of an established coordinate system. The groups of numbers (3X3 matrices) at the bottom of the Mass Properties window represent Inertia Tensors. If it is rotated about any one of these axes, we will see Principal Moment of Inertia values which are displayed in units of ML 2: It all goes back to Moments of Inertia which depend on an object’s mass, shape, and axis of rotation.Įvery object has a Center of Mass that, if suspended in midair from this point, will be perfectly balanced. Taking the following symmetrical object as an example, we can see the principal axes through its center of mass. But how in blazes does someone interpret the rest of the information included in Mass Properties, particularly the numbers at the bottom? What exactly are they telling us? This entry was posted in CCSL Blogs, Simulation, SOLIDWORKS and tagged CCSL, CCSL Simulation, CCSL SOLIDWORKS, SImulation, Simulation vs Hand Calculations, SOLIDWORKS, SOLIDWORKS Simulation.We have all referred to Mass Properties when working with solid models, especially when taking SOLIDWORKS certifications! For the most part, very useful information is available at a glance i.e., Density, Mass, Volume, Surface Area, etc. To find out more on SOLIDWORKS Simulation, please Click Here These exercises are useful in understanding the software and understanding how it can assist in the design process by making virtual testing easy. This simple exercise validates the SOLIDWORKS simulation software against theoretical hand calculations. Plot showing the displacement in the Y direction, with a max displacement of 0.0167m at the unsupported end of the beam. Showing the max stress located at the supported end of the beam. The front plane and along the plane were used.īelow is the Normal stress plot for X axis with a max stress of 4.22×10 8 N/m 2. The force is being applied to the right edge of the beam to add the correct for a direction needs to be added using a reference plane. This will have no translation or rotation so a standard fixed geometry can be used here. The left most edge is where the beam connects to the wall. Our model now represents the beam in the problem, now the fixture and load can be applied. Right click the part in the simulation window and add this to the definition. For this example, the Cantilever beam is 10mm thick. Unlike with 3D meshes the thickness of the model has to be defined in the definition of the shell. I have created a custom material with these qualities and applied it to the surface. The material properties given in the problem are the elastic modulus and Piossons ratio. Next a Static study was created in the Simulation module. Shell meshing can greatly reduce the calculation time for suitable studies, the beam is modelled below with the following dimensions (mm). The beam can be modelled as a 3D shape or represented as a surface, making use of SOLIDWORKS Shell meshing. Where the equation for Second moment of inertia- I=(TH 3)/12 To work out the displacement and stress, 4 equations will be needed. We want to find out what the deflection at the end of the beam will be and the Stress at the supported end. The beam is to be supported at one end and free at the other, there is a load applied downwards at the free end of the beam. Below I will show a comparison against the hand calculations and SOLIDWORKS The Problem The blog below goes through one of these examples, a Cantilever beam problem. These can be reviewed by going to Help>SOLIDWORKS Simulation>Validation>NAFEMS Benchmark SOLIDWORKS works with NAFEMS (National Agency for Finite Element Methods and Standard) to validate the code against industry problems. When discussing simulation, we are often asked about the accuracy of the results. SOLIDWORKS Simulation is a very powerful tool capable of a range of broad studies. SOLIDWORKS Simulation VS Hand Calculations
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |