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Evaluation of LAminate composite Distortion by an Integrated Numerical-Experimental approach

Periodic Reporting for period 1 - ELADINE (Evaluation of LAminate composite Distortion by an Integrated Numerical-Experimental approach)

Reporting period: 2019-09-01 to 2021-02-28

ELADINE aims to implement a numerical tool that can reduce the recurring costs of low-volume composite manufacturing of airframe parts and, with this benefit, the reducing of the overall manufacturing effort and carbon emissions through three converging manners:

1. The design and geometry compensation of the tooling itself as an essentially integrated phase of the manufacturing cycle. ELADINE focuses specifically on composite tooling and the overall behavior of the tools and the parts during the entire curing process;

2. Mastering the capacity of controlling the manufacturing process in order for large aero-structures and their assemblies not to fail the tolerance constraints;

3. Optimizing the number of coupons and specimen testing before manufacturing of aero-structures, by a thorough understanding of thermal, chemical and mechanical behavior of tooling and parts, tool-part interaction and resin flow.
The main outcome of ELADINE project is to develop a cost-competitive method for the analysis and simulation of the spring-in phenomena for integral structures based on detailed design information, materials properties and process definition. The numerical tool will be validated for two materials systems and manufacturing processes chosen in the OPTICOMS Project, but the development of this tool will not be limited exclusively to these materials and processes.
Since the beginning of the project, the ELADINE consortium has set up a comprehensive experimental campaign that assesses relevant airframe geometries in a ‘crescendo’ manner – starting with basic geometries up to an integral structure consisting of skin-and-spars assembly. After the important process parameters had been identified, the numerical tool has been set-up, including the backing mathematical model that defines the curing process. The experimental campaign and the numerical model development run in parallel. Up to this moment, the Liquid Resin Infusion coupon manufacturing has been completed, as well as most of the pre-preg coupon manufacturing.
The goal of ELADINE is to be achieved through experimental trials – manufacturing composite test coupons of increasing complexity. In parallel, a numerical model will virtually simulate the experimental campaign. Finally, the two different paths will converge into a reality-based numerical model by fine-tuning the virtual software with experimentally-gathered process parameters.
By the end of the project, ELADINE will offer a numerical tool that is capable of accurately predicting spring-in on complex aero-structures compatible with two major composite-manufacturing methods.
Is ELADINE progressing beyond currently existing techniques of spring in evaluation? We have a strong belief we do because of approaching the numerical simulation strongly supported on the experimental process monitoring. The simulations are not only dealing with simple coupons but also a combination of shapes that are the basis of most airframe structures: skin + stringers/stiffeners configuration.
ELADINE has aimed at dealing with several factors that influence the spring in phenomena: the thermal anisothropy, the resin shrinkage, the cure kinetics and the tool-part interaction. The numerical tool is being calibrated using experimental data in order to correlate the numerical analysis in order to replicate a very complex behavior both in terms of accuracy and precision.