|
|
Frequently Asked Questions
How accurate is it? / Is it verified? Numerical analysis is an approximation but our software package includes a number of benchmarks which demonstrate the good accuracy of FEMdesigner when compared to theoretical results. Independent tests by our users have also shown that the results compare well to other commercial FE software. This is not that surprising because most of the fundamental techniques are the same for all FE codes. Why does it cost less than most other FE software? We don't have sales staff, we don't go to conventions and we reduce our paperwork and advertising as much as possible. FEA is still often seen as a specialist procedure, with a limited market so the original idea of the low cost was to encourage all engineers, not just specialists to try it out, thereby creating a new market for budget FEA, (like budget CAD or budget Desktop publishing). We firmly believe FEA should be in continual use by every design engineer because just by using FE software you become a better engineer and you no longer have to limit yourself to shapes that can be verified by hand-calculations. Every engineer can buy FEMdesigner, so everyone can improve their design skills, and hence produce better products.  What meshing tools are available? Generating the mesh can be the most time-consuming part of FE analysis. To make it easier, FEMdesigner includes 3 ways to make the mesh. In each, elements are created from "regions" of points. For each region edge you can control the amount and shape of the elements within the region. Method 1: Create regions by picking points on the screen using the mouse. With this method, the region points can be defined in cartesian, cylindrical or polar coordinate systems and can be defined relative to another point. Point coordinates may also be input as expressions with variables, eg. a+(b/2), allowing you to rapidly modify a mesh for different geometries, just by changing the values of the variables. Method 2: You can also create a CAD line drawing with extra line, curve and arc entities which differentiate plane and solid regions. On importing as a dxf file, drawing errors are fixed, intersections are found, and plane, shell or solid regions are automatically identified and created. The above two procedures create fast, accurate curved quadrilateral 2D and hexahedral 3D elements and are recommended for simpler structures. Method 3: You can import a solid model as an IGES file from your CAD or solid modeller application. This is the recommended method for very complex geometries. You still have local mesh control at the surface of the 3D mesh but you also specify a global element size for greater simplicity. These models tend to be quite large so a fast iterative solver was developed for them. Click here for some mesh samples. Once the regions are created, they can be manipulated and tweaked until the user is happy with the mesh. Restraints, constraints and loads can be applied directly to the regions and will be automatically transferred to the mesh. If the stresses are beyond the allowable limits then the geometry can be readily altered by moving the points which define the regions and the analysis may be re-run. This procedure can be repeated as many times as required, allowing the user to see graphically the effect of changes. How easy is it to use / is there a training course? There is currently no training course because we feel it is not necessary: There are not that many things to learn and the manual is short enough to encourage you to read it. We've found that it takes an experienced user 2 days, or a novice a week, to learn the software using just the user manual and our free email user support. Check out the videos on the home page...it's as easy as that! Ease-of-use is a very subjective term but we believe that simplicity is best. We find that users are mesmerised by the number of buttons and bobs on their software and they immediately think "I need a training course". The odd thing about much commercial FE software is that you may know exactly what you are looking for but you can't find it because it is ten layers deep on a multipage "options" dialog box. Another trick is to give you many ways of doing exactly the same thing, and each way is described in complex terminology. None of this is accidental. Software vendors make good money both from new versions with new interfaces and (surprisingly few) new features and from the training courses to understand these interfaces. But let's distinguish between a training course to learn a specific interface and a course to learn more about the use of Finite Elements. The former may be a waste of money but the latter is a very good idea. NAFEMS (www.nafems.org) organise such courses. Who uses FEMdesigner? FEMdesigner was introduced for the pc in 1995 and was advertised monthly in the "Professional Engineering" magazine up to last year. It is used by a wide cross-section of individuals and institutions all over the world. Students use it because it is easy, quick and works well on their (often old) computers. Colleges and Universities use it because it is ideal for teaching and the small space requirement doesn't clog up the network. Engineering contractors and consultancies use it because it is inexpensive, flexible and quick. Small manufacturing companies use it because it doesn't represent a big investment. Large companies often use it either because they do not like (or cannot easily use) the FE software which has already been bought by their management, or they want the convenience of using FE at the design stage rather than referring to their specialist stress analysis departments. A short cross-section of companies and institutions, large and small, who use FEMdesigner is given below (note that some companies have since changed their names):
What are the system requirements For small models any specification of computer/OS will do (you can run it on a 386 computer using W95 and 4MB of Ram). However, for large models you should have Windows 2000 or XP because previous Windows versions had poorer memory management. The more RAM, the better because it will run much faster if the entire model can be stored in RAM - 512Mb is recommended. Disk space is unimportant because if you run out of space for the direct solver you can use the iterative solver, which requires minimal space. Does it come with a User Manual? Yes, with appropriate tutorial examples to introduce you gently to FE analysis. You must print it out yourself though. What are the registration procedures? After the trial is over you contact us for a registration number. You can register two computers, which allows you to use it on your notebook pc too. If you need to change o/s, computer or disk drive then contact us and we will supply a new registration. We work on the rough assumption that this is only necessary about once a year. Can I buy the elastic version then upgrade later? Yes, you can upgrade for the difference in price between the two versions. 
|