Delmade paves the way forward with CAD technology
Posted Mar 24, 2020
Delmade is super excited to be using new CAD technology to assist with drawings for our equipment. One of the impressive features of the new software is the ability to complete computer-based stress testing.
Anybody with an interest in machinery, be it motorcycles, outboard motors, Formula 1 racing cars, or almost anything else, should have noticed that today’s machines are much lighter than those of a few decades ago. Not only are machines lighter, but performance has increased. New designs go into production with much shorter development periods than before, yet reliability has not been compromised. This change has, to a large extent, been driven by the availability of computer-based stress-analysis methods (Finite Element Analysis, or FEA for short.)
Delmade now has access to this technology, which is of great benefit in the design of custom equipment. It is particularly useful when the designer does not have the ‘luxury’ of building a prototype that can be tested to destruction.
FEA allows the designer to investigate stress and deformation of parts that are too complex to be analyzed by manual calculation. The software gives a graphic representation of the stress distribution (and deflection), which makes it immediately obvious where the stress (or deflection) is too high. It also indicates material that is ‘doing very little’, so material can be removed (if weight and material cost is an important factor).
The picture below shows a shaft support bracket that has to take a combination of axial and radial loading. The combined loading, plus the complex shape of the casting rules out comprehensive analysis by manual calculation. The use of FEA is the solution.
The stress plot has been set so that yellow corresponds to the yield strength of the material. All the ‘red’ in the plot indicates that we are in trouble!
Induced stress is one important criterion for design, while another is deflection. (An item can be more than strong enough for its function, but it should also not deform beyond certain limits.)
The deflection plot below indicates that the one end of the cylindrical support (in red) will deflect more than 8mm. This is clearly not acceptable.
The design engineer can now experiment by adding material to the areas of high stress, until an acceptable solution has been found. The picture below shows the ‘second pass’ stress plot, with the beefed-up component, and stress within limits. The remaining ‘red spots’ (localized areas of high stress) can be dealt with by adding fine detail, such as fillets, in a third-pass analysis.
If the model is set up as in the example, the software will also analyze the stress in fasteners (bolts and nuts), and the induced stress in the material around the fasteners. This would have been a daunting, if not impossible, task to duplicate by the use of manual calculations. The powerful software takes into consideration the bolt material, the tightening torque, and the coefficient of friction, to give a load and stress summary for each bolt.
Computer-aided design, including finite element analysis, is a powerful tool that enables the designer to improve product quality and reduce production costs. When parts or assemblies that are too complex for manual analysis are involved, the use of FEA can eliminate the need for prototype testing, while giving the designer a high level of confidence in the integrity of the product.
In a competitive market, FEA is a vital ‘tool’ for survival. Delmade is proud to be moving ahead of the curve and embracing new technologies that make our machinery stronger, longer-lasting and better than ever before.
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