Simulations CAE, predict the behavior of a piece before its manufacture

There is some uncertainty when a design becomes the stage of manufacture, that it cannot ensure chosen design (such as material and form) features most appropriate for the final product. This fact can be done to apply an overly broad general of parts, which translates into an excessive use of material.

In this sense, Aiju knows first hand those simulation tools that may be useful to predict the behavior that will have designed pieces, under certain conditions.

These studies can offer the company a competitive advantage, it is able to predict the behavior of the pieces or sets before the stage of manufacture. In addition, they are a perfect tool to innovate in new designs, and can take the realization of more risky models, that the designer can assess in advance how the new model will behave and even if it will be within rules.

The project Optiparc (project funded by the Generalitat Valenciana, Impiva r & d line) developed by Aiju, has created a specific methodology to simulate the set of elements of a children's playground.

They are simulations that are made from a CAD model in 3D, making changes in the variables of types of materials, and design allow the designer:

-Predict the structural behaviour and cinematic of the elements of the games of activity.

-Optimizing the sizing of the elements for the cost savings.

-Predict the compliance with applicable safety standards, in this case, the UNE-EN 71-8 and UNE-EN 1176.

-Replacement or study of different materials.

-Structural verification in new designs.

All of this using advanced tools of simulation by dynamic simulation and finite elements. This Aiju has the tools falls: NX Nastran and MSC Adams.

The progress of such tools, means that increasingly they can cover more complex projects and simulating joint with different materials such as metals, plastics or composites, etc.

To perform a simulation is necessary to previously have the following information:

-Model in CAD 3 dimensions.

-Mechanical properties of the materials you wish to use for each piece (especially the following characteristics: density, yield strength, Poisson coefficient and Young module).

-In the case of raising a simulation to verify the goodness of the design according to the applicable safety regulations, must be made the preparation and programming of the requirements of the corresponding section that you want to simulate.

-Prediction of structural behavior and cinematic of the model, avoiding that a piece can break or deform permanently or, on the contrary, that is oversized.

-Get to know in advance if the designed model favorably happen concerning safety testing.

-In the case of a negative behaviour of the model or piece, a few suggestions for improvement will be made to redesign the affected piece.

-Replacement of a material on the other. Have knowledge of the thickness or amount of material needed for implementation of new materials to already designed parts.

-Optimize the design by reducing the thickness of the parts, in such a way that would reduce the total cost, ensuring also that the corresponding test will go favourably.

It is a rocker that allows to illustrate, a simple example, one of the types of simulations is possible to perform on the stages of the design:

This was attended to the regulations is applicable security: the UNE-EN 1176 in the section on seesaws, which specifies that "apply a load on the team in the worst case of seating positions, measuring the angle of inclination and by examining if the ends of the team touch the ground." The value of the force to be applied is 167 N +/-2.1 N (0-4 years age group) harassing a force of 279 N +/-5 N (0 to 8 years age group) in each of the seats, and the angle of inclination must be measured. "This angle should not exceed 30 degrees and the extreme parties must not touch the ground."

The objective of this study was the make a comparison by varying the length of the seat (distance between the Centre of the rocker and the end of the seat), so you could increase this measure but checking what would happen for security testing.

-Example 1: length of 350 mm seat: inclination of 17 ° (in standard).

-Example 2: length of 500 mm seat: inclination of the twenty-third (in standard).

-Example 3: length of 650 mm seat: inclination of thirty-second (out of norm).

Simulates the test and get the maximum stresses and deformation suffered.

The third model of rocker would not exceed the test, as the quay suffers a greater than 30 ° inclination.

In this simple example, it is possible to study a certain form in the design according to a set of rules. Also, always check that tensions to bear by the model are appropriate to the materials used and will not have any break or a permanent deformation by exceed the elastic limit of the materials used.