Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - OUTCOME (The outstanding challenge in solid mechanics: engineering structures subjected to extreme loading conditions)

Teaser

We aim at training ESRs in what is referred to as an outstanding challenge in solid mechanics: developing novel solutions for the analysis and design of aerospace and civilian-security structures subjected to extreme loading. Structural elements used in these sectors are...

Summary

We aim at training ESRs in what is referred to as an outstanding challenge in solid mechanics: developing novel solutions for the analysis and design of aerospace and civilian-security structures subjected to extreme loading. Structural elements used in these sectors are frequently subjected to a large variety of unusually severe thermo-mechanical solicitations. One easily realizes that this type of structures has to be designed to sustain extreme temperatures, which may vary hundred degrees in short periods of time, and extreme mechanical loadings like hypervelocity impacts. New specific structural solutions are constantly developed to fulfill such requirements, which place these industrial sectors in the forefront of the technological innovation. Hereby, aerospace and security industries constitute the natural meeting point between academia and entrepreneurial fabric. A deep understanding of the response of structures under the aforementioned sharp solicitations is mandatory for design purposes. Unfortunately, not even today is easy to find researchers in the labour market with such specific understanding. Aerospace and security industries require highly-qualified technical staff capable of developing research and innovation within the framework of structural mechanics. This is the precise context where OUTCOME lies. We have formed a consortium composed of 3 academic beneficiaries and 2 industrial beneficiaries to develop specific training for early-stage researchers within the field of aerospace and civilian-security structures subjected to severe thermo-mechanical loads.

Work performed

International conference: IUTAM Symposium of Dynamic Instabilities in Solids. OUTCOME has sponsored this international conference organized by the UC3M and the TECHNION from 17 to 20 May 2016 in Madrid.

Symposium on Damage and Failure Mechanics: from Microstructure to Macroscopic Response. OUTCOME has also sponsored this symposium within the framework of the EMI 2016 International Conference that was held in the UL from 25 to 27 October 2016.

The first Network-Wide meeting: it was held in Metz on October 27-28 of 2016. It was a great opportunity for the ESRs to have the first contact with all the people involved in OUTCOME.

The first Industrial Workshop: it was organized by AEROSERTEC at their premises in Getafe (Madrid) on 22-23 June 2017.

Scientific publications and participation in international conferences: while the ESRs have been enrolled in OUTCOME too recently to be able to publish any scientific paper yet (nevertheless they have already submitted few for publication), the academic members of the consortium are incorporating specific acknowledgements to the project in their scientific publications.

Seminars of visiting scientists: we are organizing periodic scientific seminars sponsored by OUTCOME in all the institutions of the consortium.

Web site: the web site of the project is operational since April 2016 http://outcome-itn.com/.

Scientific Network: we have registered OUTCOME as an on-going project in ResearchGate.

Social Networks: we have created official accounts of OUTCOME in Twitter and Facebook.

Final results

WP1 – Mechanical Damage: the goal is to uncover the key mechanisms which control damage initiation and progression in structural materials subjected to extreme loading conditions. The task 1.1. of this WP will lead to a homogenized yield function, developed within the framework of crystal plasticity, which includes the strain, strain rate and temperature effects of the material, the evolution of its texture and the porosity growth. The model will allow to unravel the mechanisms which control shear damage at large strains, under static conditions, from a microstructural perspective. The task 1.2. of this WP will lead to a constitutive model to predict damage in metallic materials subjected to dynamic loading. The key of the constitutive model is that it includes microinertia effects and, for the first time, it will be implemented into a 3D framework to bring to light how the size of cylindrical voids embedded into a viscoplastic matrix affect the evolution of damage in metallic materials subjected to complex stress states. The task 1.3. of this WP provide the main guidelines to design components and parts, made of quasi-brittle materials, that demise/fail/break following a pre-defined path. This is a critical problem for the aerospace industries that include in their designs “sacrificial parts” that aim to fail in order to preserve the structural integrity of components with high(er) structural responsibility.

WP2 – Mechanical Failure: the goal is to develop an integral approach to address the failure of structural materials used in aerospace and defense applications. The task 2.1. of this WP will lead to original analytical models to identify the mechanisms which govern the formation of necking instabilities in anisotropic metallic plates subjected to dynamic loading. This problem will also be addressed numerically and experimentally to confirm the analytical predictions. At the completion of the research, we will be able to customize the failure pattern, and thus the energy absorption capacity, of metallic sheets and plates used in aerospace structures and subjected to dynamic loading. The task 2.2. of this WP aims at developing a microstructure-based homogenized constitutive model to simulate the fully coupled thermomechanical problem for dynamically propagating micro-cracks with thermal dissipation. Including thermal effects is a key and largely original feature of this model which allow to obtain accurate predictions of the influence of dissipative effects in the dynamic failure of quasi-brittle engineering materials. The task 2.3. of this WP is developing a new constitutive model, based on dislocations dynamics, with, for the first time, capacity to predict the energy stored by the material (metal) during plastic deformation and thus the increase of temperature due to the dissipative character of plastic strains. The improved model will be then calibrated and validated with experiments in which the temperature increase of the material is measured using infrared detectors.

WP3 – Practical applications: the goal is to explore 2 open problems in aerospace industry in which development of damage and failure causes the loss of load carrying capacity of structural elements subjected to extreme loading. The task 3.1. of this WP aims to develop a measurement methodology, based on the Structured Light and Plenoptic technology, to detect mechanical damage in aircraft components. Accurate measurements of the displacements that appear in aerospace structures when subjected loading is a critical issue for the aerospace industry that needs to guarantee the reliability of aircrafts, for which they invest an important amount of money every year. The task 3.2. of this WP aims to unravel the mechanisms which control the strength of the interface between the copper film and the polymeric substrate of Printed Circuit Boards subjected to temperature variations. Debonding of this interface, and the subsequent mechanical damag

Website & more info

More info: http://outcome-itn.com/.