Simulating Postbuckling Behaviour and Collapse of Stiffened CFRP Panels

Advanced composite materials are well known for their outstanding potential in weight-related stiffness and strength leading to an ever increasing share in aerospace structural components out of Carbon Fibre Reinforced Plastics (CFRP). In order to fully exploit the load-carrying capacity of such structures an accurate and reliable simulation is indispensable. Local buckling is not necessarily the load bearing limit for stiffened panels or shells; their full potential can be tapped only by utilizing the postbuckling region. That, however, requires fast tools which are capable of simulating the structural behaviour beyond bifurcation points including material degradation up to collapse. The most critical structural degradation mode is skin stringer separation; delamination, especially within the stringer, is a critical material degradation. A reliable prediction of collapse requires knowledge of degradation due to static as well as low cycle loading in the postbuckling region. Earlier projects have shown that it needs considerable experience in simulating the postbuckling behaviour. Though a great deal of knowledge about CFRP structural and material degradation is available its influence on collapse is not yet sufficiently investigated. It is the aim of the project COCOMAT (Improved MATerial exploitation at safe design of COmposite airframe structures by accurate simulation of COllapse) to develop means for and gain experience in fast and accurate simulation of the collapse load of stringer stiffened CFRP curved panels taking degradation and cyclic loading as well as geometric nonlinearity into account. COCOMAT is a Specific Targeted Research Project supported by the EU 6th Framework Programme; it started 2004 and runs for 4 years. Main deliverables are: • test results for buckling and collapse of undamaged and pre-damaged stiffened CFRP panels under static and cyclic loading, • improved material properties and degradation models, computational tools for design and certification of stiffened fibre composite panels which take postbuckling behaviour, degradation and collapse into account, • and finally design guidelines and industrial validation. The work will lead to an extended experimental data base, relevant degradation models and improved simulation tools for certification as well as for design. These results should allow setting up a future design scenario which exploits the existing reserves in primary fibre composite structures. The paper starts out from results provided by the forerunners of COCOMAT, describes the main objectives of the project, gives a general status of the progress reached so far and presents first results

ARMD Workshop on Materials and Methods for Rapid Manufacturing for Commercial and Urban Aviation

This report documents the goals, organization and outcomes of the NASA Aeronautics Research Mission Directorates (ARMD) Materials and Methods for Rapid Manufacturing for Commercial and Urban Aviation Workshop. The workshop began with a series of plenary presentations by leaders in the field of structures and materials, followed by concurrent symposia focused on forecasting the future of various technologies related to rapid manufacturing of metallic materials and polymeric matrix composites, referred to herein as composites. Shortly after the workshop, questionnaires were sent to key workshop participants from the aerospace industry with requests to rank the importance of a series of potential investment areas identified during the workshop. Outcomes from the workshop and subsequent questionnaires are being used as guidance for NASA investments in this important technology area

Proceedings of Abstracts Engineering and Computer Science Research Conference 2019

© 2019 The Author(s). This is an open-access work distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. For further details please see https://creativecommons.org/licenses/by/4.0/. Note: Keynote: Fluorescence visualisation to evaluate effectiveness of personal protective equipment for infection control is © 2019 Crown copyright and so is licensed under the Open Government Licence v3.0. Under this licence users are permitted to copy, publish, distribute and transmit the Information; adapt the Information; exploit the Information commercially and non-commercially for example, by combining it with other Information, or by including it in your own product or application. Where you do any of the above you must acknowledge the source of the Information in your product or application by including or linking to any attribution statement specified by the Information Provider(s) and, where possible, provide a link to this licence: http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/This book is the record of abstracts submitted and accepted for presentation at the Inaugural Engineering and Computer Science Research Conference held 17th April 2019 at the University of Hertfordshire, Hatfield, UK. This conference is a local event aiming at bringing together the research students, staff and eminent external guests to celebrate Engineering and Computer Science Research at the University of Hertfordshire. The ECS Research Conference aims to showcase the broad landscape of research taking place in the School of Engineering and Computer Science. The 2019 conference was articulated around three topical cross-disciplinary themes: Make and Preserve the Future; Connect the People and Cities; and Protect and Care

Approach to the assessment of the hazard

An overview of the carbon fiber hazard assessment is presented. The potential risk to the civil sector associated with the accidental release of carbon fibers from aircraft having composite structures was assessed along with the need for protection of civil aircraft from carbon fibers

Economic De-integration in North America and Foreign Direct Investment from Japan

We investigate the impact of US steel and aluminum tariffs, and the resumption of auto tariffs under the revised North American Free Trade Agreement, on trade in North America and foreign direct investment (FDI) from Japan, from the perspective of the auto industry. The results of policy simulation analyses with a recursive dynamic computable general equilibrium model are as follows. Canada and Mexico would benefit from US steel and aluminum tariffs, being alternative trade partners with both the US and other countries. Due to the auto tariffs on intra-North America exports, Canada and Mexico would lose a large part of the windfall benefits from the US steel and aluminum tariffs. Japan’s FDI in Canada and Mexico would fall sharply. The more de-integrated North American economies become, the more Japan would regain its auto production, although at a painful cost in terms of welfare. That negative welfare impact would be neutralized by abolition of auto tariffs with the US.This study is partly supported by JSPS KAKENHI (Nos. 16H0360, 19K01622). Firm-level data in the Survey on Overseas Business Activities are provided by the Japanese Ministry of Economy,Trade and Industry.http://www.grips.ac.jp/list/jp/facultyinfo/hosoe_nobuhiro

Inflatable structures for Mars Base 10

A permanent manned settlement on the Martian surface requires the use of advanced technology concepts in order to become technically and financially feasible. The former developed Mars Base 10 concept incorporates novel ideas, increasing the feasibility of a continous human base on Mars. The most advanced feature of the MB10 design is the concept of increasing the habitable space of the Mars base once landed with an inflatable torus like structure. This paper gives an overview on the MB10 design and has its primary focus on the deployment of the inflatable structure. The deployment simulations show the final inflated shape of the MB10 concept on Mars from an un-inflated initial shape on Earth. The deployment strategy, simulations and rigidization techniques are discussed to provide a conceptual solution for large inflatable components of the MB10 habitat. Further applications of secondary inflatable smart structures are presented as well. These secondary structures are self deploying at the Martian ambient pressure which results in low storage volume and mass. These structures are well-suited to carry on for astronauts on EVAs for example

Employment Effects of FTA Agreements: The Perspectives from Bangladesh

Bangladesh has entered into several regional FTA agreements and is in the process of signing bilateral FTA agreements with a number of countries. The study uses several models such as WITS/SMART global partial equilibrium model, SAM multiplier model, CGE model and an employment satellite matrix to explore the employment effects in Bangladesh out of three different FTA scenarios. In the WITS/SMART model, three FTA scenarios are run which assume full elimination of bilateral tariff between Bangladesh and India (under Bangladesh-India bilateral FTA), full elimination of bilateral tariff between Bangladesh and Malaysia (under Bangladesh-Malaysia bilateral FTA) and full elimination of tariff on trade among the BIMSTEC member countries (under BIMSTEC). The analysis of the macro impacts of the FTA scenarios suggest that such bilateral and regional FTAs would be beneficial for Bangladesh in terms of impact on consumer prices, exports, real wages and employment. At the sectoral level, a number of export oriented sectors would gain from such FTAs. However, the sectoral level impacts also suggest that a large number of sectors would experience fall in production because of large inflow of imports, which will result in loss in employment in these sectors. Therefore, these FTAs have important sectoral implications in terms of production, exports, import and employment. It however appears that at the aggregate level employment would rise which would mean that the loss in employment in some sectors will be more than compensated by rise in employment in other sectors. Therefore, the net effect on employment is likely to be positive

Impact of Switching Production to Bioenergy Crops: The Switchgrass Example January 2005

This paper reports the results of a series of simulations that evaluate the general equilibrium effects of substituting crude oil by biomass, specifically switchgrass, in the production of petroleum in the USA. The simulations are inspired by debates over the implications for developing countries if agricultural policies in the USA are changed so that agricultural land is transferred from the production of cereals and other crops to biomass production. The results confirm expectations that such a policy shift would raise cereal and other agricultural prices, due to a general reduction in food production in the USA. However, the reduction in the demand for crude oil in the USA causes terms of trade effects that more than offset any potential benefits for developing countries due to the depreciation of their exchange rates, causing a general decline in economic welfare. Moreover, the declines in welfare are proportionately greater for developing countries due to their small levels of production of the commodities whose prices increase with the change in USA agricultural production

Business and Financial Services: New Engine of Economic Growth

Original paper can be found at: http://www.ecomod.net/conferences/ecomod2006/ecomod2006.htmDoes the continuous shift of resources from the traditional sectors to the business and financial services sector imply inevitable stagnation in the aggregate productivity growth in the developed economies Economic inquiry into this issue has generated contradictory conclusions. This paper evaluates the traditional stagnationist and the modern optimist arguments and employs an applied general equilibrium multi-sectoral growth model to simulate the impact of unbalanced sectoral productivity growth on the overall productivity growth path. A particular focus is on the relationship between a sector s industrial linkages and its impact on overall growth. The simulation results suggest that the actual aggregate productivity growth path in the long-run deviates from either case

CoFeD: A visualisation framework for comparative quality evaluation

Evaluation for the purpose of selection can be a challenging task particularly when there is a plethora of choices available. Short-listing, comparisons and eventual choice(s) can be aided by visualisation techniques. In this paper we use Feature Analysis, Tabular and Tree Representations and Composite Features Diagrams (CFDs) for profiling user requirements and for top-down profiling and evaluation of items (methods, tools, techniques, processes and so on) under evaluation. The resulting framework CoFeD enables efficient visual comparison and initial short-listing. The second phase uses bottom-up quantitative evaluation which aids the elimination of the weakest items and hence the effective selection of the most appropriate item. The versatility of the framework is illustrated by a case study comparison and evaluation of two agile methodologies. The paper concludes with limitations and indications of further work