04 / Feb / 2016

MANHO. Daniel Pastorino Junquero

MANHO. Daniel Pastorino Junquero

The use of composite materials is widely extended due to its great specific properties. It is largely used in primary structures of recent aircraft developments. It is usual to find composite structures weakened by the inclusion of holes, maintenance access and cutouts, which implies an important reduction of the mechanical properties that should be quantified for the appropriate design of the structure.

The stress distribution of composite structures weakened by cutouts could be determined making use of finite elements. However, the high computational capacity required to perform parametric studies together with the need of re-meshing the model with each parameter change make it not recommendable for the initial phases of the structural design.

For this reason, from the industrial sector arises a line of research in order to simplify the aforementioned structural analysis. It could be achieved by means of analytical calculation and strength prediction methods with the aid of semi-empirical failure criteria. The project MANHO arises as a collaboration between university and industrial sector with a common objective. Within this framework, FIDAMC funds a PhD for the development of the activities in such field of study.

What are the principal aims of the PhD?

The main aim of the MANHO project is to offer a method for the strength estimation of a weakened composite plate structure with an elliptical or circular cutout. The developed method should be simple and fast to accomplish the requirements of the initial phase of the structural design, as well as reliable.

How is planned the PhD?

The PhD planning could be decomposed in two dependents research lines. On the one hand, it will be needed to develop a methodology for the analytical estimation of the stresses on the area of interest. To this end, it is proposed a model based in the complex variable formalism developed by Lekhnitskii.

On the other hand, a failure criteria simple approach is required in order to estimate the reserve factor of a component under specific loadings. It could be achieved using the stresses estimated in the first section. The point (or average) stress method from Whitney and Nuismer is very used in industrial sector; however, it requires large test campaigns in order to fit the parameters of the method. One of the objectives is to reduce the number of tests to be performed in order to minimize costs.

1. Displacements.png  2. Forces around hole boundary.png  3. Forces over the plate.png  4. Forces over the plate.png  5. Forces over the plate.png  6. Moments at the opening for different hole length.png  7.png