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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

ON FURTHER MODELING OF STIFFNESS AND DAMPING OF CORRUGATED CARDBOARDS FOR VIBRATION ISOLATION APPLICATION

2014 October 1900 (has links)
In a recent study, an environment-friendly material, corrugated cardboard, was used as a building block for the vibration isolator with a preliminary study. The present thesis was motivated to advance technology for improving the design of such a corrugated cardboard vibration isolator with a focus on the modeling of its stiffness and damping. In particular, this study has performed the following works: (1) improving the FE (finite element) model of the stiffness of the corrugated cardboards by more accurately identifying the material parameters in the cardboard material constitutive equation; (2) analyzing the effect of the error in geometry of the corrugated cardboards in the FE model; (3) developing the Rayleigh damping model of the corrugated cardboards and evaluating its accuracy. Several conclusions were drawn from this study: (1) the parameter identification procedure based on the inverse analysis is feasible for improving the accuracy of the model of the stiffness of the cardboard. (2) The FE model of the cardboards with a greater in-plane geometrical deflection has less vertical compressive stiffness. The geometrical deflections of the corrugated cardboards also change the condition of the contact friction stress and the compressive deformation. (3) Rayleigh damping model is accurate enough for calculating the damping of the corrugated cardboards. The contributions of the thesis include: (1) provision of a more accurate model for the compressive stiffness the corrugated cardboards, (2) finding that the friction between the cardboard and the vibrator and the geometrical error of the cardboards have a significant influence over the accuracy of the FE model, (3) finding that in practice the foregoing influence can significantly degraded the performance of the cardboards as a vibrator isolator, and (4) provision of a model for the compressive damping of the corrugated cardboards.
2

INVESTIGATION OF CORRUGATED CARDBOARD FOR VIBRATION ISOLATION

2013 April 1900 (has links)
Vibration isolation is a common approach to reduce the undesired vibration of a dynamic system from its surrounding. The common material used for the vibration isolator is rubber (for example) which is known to be environmentally unfriendly. This thesis presents a study on the use of corrugated cardboard for the vibration isolator, which is known to be a highly environment-friendly material. The focus of the study is on understanding and modeling of stiffness and damping of cardboard when it or its system (several cardboards) is used for isolating the vibration coming from the vertical direction of cardboard. In this thesis, a study is presented of finite element modeling of stiffness of corrugated cardboard in its vertical direction with the aim of overcoming two major shortcomings in modeling in the current literature: (1) the width effect is neglected even for cardboard with its width greater than length and (2) the non-linear constitutive relation is not accurately determined. Indeed, it is likely that these shortcomings are responsible for inaccuracy with the models in the current literature to predict the stiffness and peak load. Further, a test bed was set up for the measurement of damping of cardboards in this study. This thesis also presents an application of the theoretic development in the stiffness and damping of corrugated cardboard to design an isolator for the vacuum pump at Canadian Light Source. Several conclusions are drawn from this study: (1) modeling with consideration of the width effect and non-linear constitutive relation is necessary to improve the accuracy of prediction of stiffness of cardboard; (2) set up for the measurement of damping of cardboard is accurate; and (3) cardboard systems are feasible for vibration isolation in terms of the reduction of amplitude of vibration. The contribution of this thesis includes: (1) providing a finite element method for modeling of corrugated cardboards which have a complex non-linear constitutive relation, variable contact configuration, and 3D geometrical effect and (2) providing the feasibility of proving that corrugated cardboard can be used for vibration isolation.
3

Not Playing By The Rules

Casta, Maline January 2014 (has links)
My degree project consists of several parts: a theorethical essay, sketches, modells, photos, experiments and an installation showed at Konstfack Spring Exhibition 2014. Departing from the infamous Fredric Jameson quote ”It’s easier to imagine the end of the world than the end of capitalism” I have investigated the relationship between play, daydreaming and economical system. Political scientist Wendy Brown has argued that we exist at a time in history where we have an urgent need for alternative spaces, both in the physical room and in the mind, where an alternative longing can grow. In my degree project I have taken a closer look at this space – what could it be, how does it work, what would it look like if it was made real? By exploring play theory I try to understand how and if play can be triggered and how this can be translated into a space. By deepening my knowledge about imagination and the relation between imagination and social development, I try to seek answers to how play can be used as a starting point for change. By treating play as a space in a double sense – both as a physical room and a special place inside us, I explore the possibilities this space has for creating new dreams. This is also a project where I try to restore my own belief in storytelling as something beyond escapism. Aiming to create an in-between, a fusion between scenography, illustration and installation, I seek to create a platform where my work can be the basis for new discussions and meetings. By exploring the performative elements of a room I want to invite the visitor to enter the image and merge with the content. I want to create a work that embraces the visitor and that can be experienced on many different levels depending on the visitor’s interest, age and prerequisites. The essay consists of three parts. My project started with an analysis of the current economical situation. In the first part of this essay I make a summary of this research, and give a brief background to my experiences working in the gap of storytelling and economics. In the second part I will investigate the basic functions of imagination and play, and see how our longing is linked to the development of society. In the third part I will talk about the physical outcome of my project - my process, choices, difficulties and conclusions. For practical reasons I have choose to put all images in a separate appendix at the end. These images shows extracts from my artistic process as well as a documentation of the installation showed at the Spring Exhibition.
4

Modélisation numérique du comportement dynamique de structures d'emballages complexes par méthodes d’homogénéisation. / Numerical modeling of the dynamic behavior of complex packaging structures by homogenization methods.

Duong, Pham Tuong Minh 23 November 2012 (has links)
Les palettes sont très largement utilisées pour le transport, le stockage et la manutention de marchandises. Une palette chargée de bouteilles d'eau (emballage tertiaire) est constituée : d'une palette en bois, des packs (emballages secondaires) contenant un ensemble de 6 bouteilles d'eau (emballages primaires) enveloppés par un film plastique, des intercalaires en carton ondulé, et d'une housse plastique rétractable ou étirable pour le maintien et la protection de la marchandise palettisée. L'objectif général de cette thèse est de modéliser et de simuler le comportement statique et dynamique d'une palette durant le transport routier à l'aide du logiciel Abaqus. La simulation détaillée des bouteilles, des packs et des intercalaires constituants la palette est très fastidieuse et complexe à mettre en œuvre. Nous proposons de réaliser l'homogénéisation sur les packs et les intercalaires pour diminuer largement le temps de préparation des géométries et des maillages, ainsi que le temps CPU. Un modèle d'homogénéisation de l'intercalaire en carton ondulé est proposé. Il consiste à calculer les rigidités globales pour une plaque homogène équivalente. Ce modèle d'homogénéisation analytique permet de calculer rapidement et correctement ces rigidités globales et leurs couplages. Le comportement suivant l'épaisseur de l'intercalaire a beaucoup d'influence sur le glissement des packs. Nous avons donc développé un modèle solide en trois couches pour prendre compte le comportement élasto-plastique suivant l'épaisseur. Le pack de 6 bouteilles d'eau a été homogénéisé en caractérisant son comportement global par des essais expérimentaux et des simulations par la méthode des éléments finis. Le remplacement des packs par des solides homogènes de forme simplifiée permet de diminuer largement le nombre d'éléments et d'éviter le traitement du contact bouteille-bouteille et bouteille-film. De nombreux essais expérimentaux et simulations numériques avec nos modèles d'homogénéisation ont été réalisés pour étudier le comportement statique et dynamique de palettes chargées de bouteilles d'eau. Les résultats obtenus par les essais expérimentaux et les simulations numériques sont comparés pour valider nos modèles d'homogénéisation. / Pallet systems are widely used for the transport, storage, stacking and handling of goods. A pallet charged with bottles of water (tertiary packaging) is composed of: a wooden pallet, packs (secondary packaging) containing a set of 6 bottles of water (primary packaging) wrapped with a plastic film, the cardboard sheet insert, and a plastic film for the maintenance and protection of the palletized goods. The aim of this thesis is to model and to simulate the static and dynamic behaviors of a charged pallet during the transport using the Abaqus software. The detailed simulation of the bottles, the packs and the cardboard sheet inserts constituting the pallet is very tedious and complex. We propose to homogenize the packs and cardboard inserts to largely reduce the time for the preparation of geometries and meshes, as well as the CPU time. A homogenization model for the cardboard inserts is proposed. It consists in calculating the global stiffness of the equivalent homogeneous plate. This analytical homogenization model allows calculating these global rigidities and their couplings quickly and correctly. The behavior in the thickness direction of the cardboard has a great influence on the sliding of the packs. We have developed a three layers solid model to take into account the elasto-plastic behavior through the thickness. The pack of 6 bottles of water is homogenized by characterizing its global behavior by experimental measurements and simulations with the finite element method. Replacing the packs by a simplified homogeneous solid permit to greatly reduce the number of elements and avoid the contact treatment between bottle-bottle and bottle-film. Many experimental tests and numerical simulations using our homogenization models have been achieved to study the static and dynamic behaviors of pallets. The results obtained by experimental tests and numerical simulations are compared to validate our homogenization models.
5

Problemas de programação de produção em indústrias de embalagens de papelão ondulado. / Problems of production programming in corrugated cardboard packaging industries.

Ferreira, Marcelo 31 July 2018 (has links)
Submitted by Marcelo Ferreira (clikmarcelo@yahoo.com.br) on 2018-09-05T04:31:34Z No. of bitstreams: 1 Tese de Marcelo Ferreira - Doutorado em Matemática.pdf: 2503649 bytes, checksum: 7e5babb359afbdff94f0d88f504985c5 (MD5) / Rejected by Elza Mitiko Sato null (elzasato@ibilce.unesp.br), reason: Solicitamos que realize correções na submissão seguindo as orientações abaixo: Problema 01) A paginação deve ser sequencial, iniciando a contagem na folha de rosto e mostrando o número a partir da introdução, a ficha catalográfica ficará após a folha de rosto e não deverá ser contada, você iniciou a contagem na página que contém a lista de figuras. A correção deve ser feita também no sumário. OBS:-Estou encaminhando via e-mail o template/modelo das páginas pré-textuais para que você possa fazer as correções, sugerimos que siga este modelo pois ele contempla as normas da ABNT Lembramos que o arquivo depositado no repositório deve ser igual ao impresso, o rigor com o padrão da Universidade se deve ao fato de que o seu trabalho passará a ser visível mundialmente. Agradecemos a compreensão. on 2018-09-05T13:47:24Z (GMT) / Submitted by Marcelo Ferreira (clikmarcelo@yahoo.com.br) on 2018-09-05T17:21:36Z No. of bitstreams: 1 Tese Marcelo Ferreira.pdf: 2501829 bytes, checksum: 90e5dbff7459a9f26f354110d615fe46 (MD5) / Approved for entry into archive by Elza Mitiko Sato null (elzasato@ibilce.unesp.br) on 2018-09-05T18:50:17Z (GMT) No. of bitstreams: 1 ferreira_m_dr_sjrp.pdf: 2463292 bytes, checksum: c3ef62f0a5f3a7e55c2010f641a09d3c (MD5) / Made available in DSpace on 2018-09-05T18:50:17Z (GMT). No. of bitstreams: 1 ferreira_m_dr_sjrp.pdf: 2463292 bytes, checksum: c3ef62f0a5f3a7e55c2010f641a09d3c (MD5) Previous issue date: 2018-07-31 / Nessa tese abordamos dois problemas reais identificados no processo produtivo de indústrias de embalagens de papelão ondulado, que denotaremos por Problema de Minimização de Trocas de Gramaturas e Rolos Corrugadores (PMTGRC) e Problema da Alocação de Bobinas no Corrugador (PABC). Ambos os problemas ocorrem no corrugador, máquina multiestágio que produz as chapas de papelão ondulado. O PMTGRC surge da necessidade de minimizar trocas de gramaturas e rolos corrugadores durante o processo de produção dos boletins, uma vez que cada boletim traz as gramaturas específicas das camadas da chapa, além do tipo de onda empregada no(s) miolos(s). O sequenciamento dos boletins impacta na quantidade de mudanças de gramaturas nos porta-bobinas e se haverátrocaderoloscorrugadoresparadoisboletinssubsequentes. Astrocasdegramaturas impactam em custos de transporte de bobinas e as trocas de rolos corrugadores impactam em perda de produtividade. Para o PMTGRC propomos quatro modelos inéditos de programação inteira capazes de integrar essas duas considerações. O PABC integra várias considerações relacionadas à alocação das bobinas no corrugador, como por exemplo, a minimização das sobras não aproveitáveis e das quantidades de consumos parciais, fatores que influenciam diretamente nos custos de produção. Um modelo linear inteiro misto inédito é proposto, determinando quais bobinas serão utilizadas em cada porta-bobinas. Além disso, propomos uma estratégia de sequenciamento das bobinas em cada porta-bobina, evitando paragens no corrugador. Uma série de testes computacionais utilizando instâncias geradas com base em dados reais foram realizados. Os resultados indicam que os modelos foram eficientes em tratar os problemas propostos. / In this thesis we approached two real problems identified over the productive process of corrugated cardboard industries, which we will denote as the Minimization of Converting Weights and Corrugators Problem (MCWCP) and the Corrugators Coil Allocation Problem (CCAP). Both of these problems happen in the corrugators, a multistage machine which produces corrugated cardboard. The MCWCP appears from the necessity to minimize changes of weight and corrugator rolls during the production process of the bulletins, since each one brings the specific layers’s weight of the sheets, besides the kind of wave put in the middle. The sequence of bulletins impact in the number of weight changes in the coil holders and if there will be corrugating rollers’s exchange for two following bulletins. The gramature’s exchanges impact in the costs of transportation and the corrugating rollers exchange causes lost in the productivity. We propose four whole programming models capable of integrating both considerations. The CCAP integrates many considerations related to the coils’s allocation on the corrugators, for example, the minimization of the non-usable leftovers and the amount of partial consumption, factors which influence directly on the production’s costs. A whole new mist linear model is proposed, determined which coil on the corrugators are going to be used in each coil holder. Besides this, we propose a sequel strategy for the coils in each coil holder, avoiding stops on the corrugators. A series of computation tests using instances created based on real data were made. The results indicate that the models were efficient in solving the problems.
6

Conceptual Development of an Automated Corrugated Cardboard Box Filler

Nordstedt, Tobias January 2018 (has links)
The project aimed at conceptually develop a solution that is able to automatically transfer an already stacked and measured heap of goods from an order tote into an erected corrugated cardboard box, whereas the dimensions of the corrugated cardboard box and the stack are allowed to vary within a specified interval. The method for this project consisted of five main parts: feasibility study; concept generation; concept choice; design; and evaluation. The project was initiated by a feasibility study where the problem was clarified and knowledge regarding the problem was gathered. The feasibility study resulted in an user requirement specification and a product requirement specification. The product requirement specification was utilized in the evaluation processof the final developed concept. The concept generation was conducted according to structured methods prescribed by Ulrich and Eppinger. The concept choice was done by the use of Pughs concept choice matrix. The result of this project consists of a conceptual proposal of how the previously described problem may be solved. The final developed concept resulted in a cad model. The evaluation showed that the concept did not fulfill the product requirement specification, despite this it is assessed that the concept in its working principle has good merits that are worth further investigation. Further development of the concept remain and validation of the working principle is needed. Further choices concerning form, material, and components remain. The report contributes to a foundation for further development of an automated filling mechanism for erected corrugated cardboard boxes.
7

Modelling of heat and moisture transport in a corrugated board stack / Modellering av värme- och fukttransport i en wellpappstack

Xynou, Marianna January 2014 (has links)
The corrugated board is considered as the second most used packaging material and the world’s environmentally acceptable solution for packaging, with wide range of applications. After the manufacturing process, the corrugated board is cut into sheets and stored in a stack until optimum moisture content has been reached in order to avoid undesired properties. However, due to complex and various structures, it is difficult to estimate the appropriate time so to achieve the acceptable moisture level of the corrugated board stack. So a homogenized model of the stack has to be created which will have the same average properties as the real stack. In order to achieve this goal the behavior of a smaller part of the stack, the unit cell, is investigated. In the second step a homogenized model is created with the average transport of mass and heat. At the end, the unit cell is scaled up. In this master thesis, only the first and the second steps were simulated. This was achieved by creating a 3-D mathematical model using finite element method and simulating its properties in COMSOL Multiphysics®. Four mathematical models were used in the description of the 3-D model: the heat transfer, the moisture transfer, the vapour concentration and the gas pressure. Moreover, by applying the gradient in one direction in each case, the behavior of the detailed unit cell was investigated. Finally different simplified geometries were created and investigated so to approach a homogenized model which described better the average properties of the detailed model. By comparing the results of the models, it was concluded that the homogenized models 2 and 3 approached the values of the second detailed model but only inside of the unit cell. However, the deviation was not negligible and further investigation is required in order to find a new homogenized method.
8

Konstruktionskoncept till att skapa wellpappsprover i laboratoriemiljö / Construction concept to create samples of corrugated cardboard in laboratory environment

Gussman Lennström, Anton, Lundberg, Selma January 2022 (has links)
Kraftliners är något som används till att skapa bland annat ytskiktet till pappersprodukten wellpapp. Wellpapp består av ett lager kraftliner på antigen en- eller vardera sidan av ett vågigt papper, kallat flute. På uppdrag av SCA R&D undersöker detta kandidatarbete möjligheten till att skapa en konceptuell prototyp till en maskin som kan konstruera wellpappsprover på deras laboratorium. Detta för att via tester kunna prediktera hur variationer i wellpappens struktur påverkar dess egenskaper. Arbetet utfördes med hjälp av en iterativ metod där koncept först togs fram och sedan utvärderades repetitivt tills ett slutgiltigt koncept var framtaget. Konceptframtagningen bestod av fem iterationer med faserna konceptgenerering, modellering, prototypframtagning, tester av prototyp och utvärdering. Arbetet resulterade i ett slutgiltigt koncept som ledde till en illustrerad prototyp i mindre skala som visar hur wellpappsprover skulle kunna skapas i SCA’s R&D-laboratorium. / Kraftliners are used to create, among other things, the surface layer for the paper product corrugated board. Corrugated board consists of a layer of kraftliner on either one or both sides of a wavy paper, called flute. On behalf of SCA R&D this bachelor's thesis investigates the possibility of creating a conceptual prototype for a machine that can create corrugated board samples in their laboratory. This is to be able to predict, via tests, how variations in the structure of the corrugated board affect its properties. The work was carried out using an iterative method where concepts were first developed and then evaluated repetitively until a final concept was developed. The concept development consisted of five iterations with the phases of concept generation, modeling, prototype development, prototype testing and evaluation. The work resulted in a final concept that led to an illustrated prototype on a smaller scale that shows how corrugated board samples could be created in SCA's R&D laboratory.
9

Jämförelse av klimatavtrycket från tre olika skivmaterial i ett vattenburet golvvärmesystem : EPS, kork och wellpapp

Jacobson, Towa, Skogstad, Mathilde January 2022 (has links)
Byggbranschen står inför en brådskande omställning till en lägre klimatpåverkan från byggnader. Ett sätt att minska påverkan är att implementera byggvaruprodukter och material med lägre klimatavtryck, det vill säga produkter som ger upphov till mindre växthusgasutsläpp under sin livstid. För att kunna göra bättre val behöver branschen en noggrann utvärdering av växthusgasutsläppen från byggprodukter ur ett livscykelperspektiv. Den här studien undersöker vilket av materialen expanderad polystyren (EPS), kork och wellpapp som orsakar minst växthusgasutsläpp under 50 år som skivmaterial i ett golvvärmesystem producerat av företaget Flooré AB. Studien undersöker även skillnaden i klimatpåverkan för skivmaterialen under användningsstadiet, baserat på grundläggningsmetoderna isolerad platta på mark, vanligt för nyare svenska småhus, samt en äldre platta med bristande isolering, vanligt förekommande i hus uppförda i Sverige på 1970-talet. Beräkningen av utsläppen från respektive skivmaterial sker med livscykelanalys som metod och ämnar att bestämma materialens klimatpåverkan (GWP) som utsläppen av koldioxidekvivalenter (CO2e) orsakat av 1 m2 golvskiva i ett golvvärmesystem under ett år. Ettårsperspektivet lägger grunden för en enkel omvandling av skivans klimatpåverkan till valfri tidsram. Den här studien bedömer att golvvärmesystemet bör vara funktionellt i minst 50 år och tittar därför närmare på den livslängden. Studien fastslår att wellpapp i de flesta fall orsakar 14–29 procent lägre växthusgasutsläpp än EPS under ett år som skivmaterial i ett värmegolv beroende på grundläggningsmetod, och ungefär 13–23 procent lägre utsläpp än kork. Som svar på vilket av materialen EPS, kork och wellpapp som orsakar lägst klimatavtryck som 1 m2 skivmaterial i ett golvvärmesystem under 50 år multipliceras materialens utsläpp under användningsstadiet med 50. Resultaten belyser fördelarna med låga värmeförluster i ett golvvärmesystem över tid, då wellpapp orsakar störst växthusgasutsläpp för platta på mark med bristande isolering med 119 kg CO2e/m2 , medan EPS orsakar det lägsta utsläppet på 111 kg CO2e/m2. För fallet med isolerad platta är wellpapp det material som orsakar lägst utsläpp med 7,9 kg CO2e/m2, medan EPS orsakar det högsta utsläppet om 8,9 kg CO2e/m2. Avseende klimatpåverkan är wellpapp det bästa alternativet för implementering som skivmaterial i ett golvvärmesystem med en livslängd på 50 år i nya välisolerade svenska småhus. För äldre småhus som saknar tilläggsisolering är EPS det materialet som orsakar lägst klimatpåverkan, tack vare materialets isoleringsförmåga. / The construction industry is facing an urgent transition to a lower climate impact from buildings. One way to reduce this impact is to implement products and materials with a lower climate footprint, i.e. products that cause less greenhouse gas emissions during their lifetime. In order to make better choices, the industry needs a careful evaluation of greenhouse gas emissions from products used in building production from a life cycle perspective. This study examines which of the materials expanded polystyrene (EPS), cork and corrugated cardboard that causes the least greenhouse gas emissions during a 50-year lifespan as a floorboard in an underfloor heating system produced by the company Flooré AB. The study also examines the difference in climate impact for each floorboard material during the use stage, based on the founding methods thermally insulated slab on ground, common for newer Swedish single-family homes, and an older slab with insufficient insulation, common in houses built in Sweden in the 1970s. The calculation of the emissions from each board is performed with a life cycle analysis method and intends to determine the Global Warming Potential (GWP) of the materials as emissions of carbon dioxide equivalents (CO2e) caused by 1 m2 floorboard in an underfloor heating system for one year. The one-year perspective simplifies conversion of the floorboard climate impact during one year to any other time frame. This study estimates that the system will be functional for at least 50 years, and therefore examines this service time further. The study found that corrugated cardboard, in most cases, causes 14-29 percent lower greenhouse gas emissions than EPS during a year as a floorboard in an underfloor heating system depending on the building's foundation method, and approximately 13-23 percent lower emissions than cork. In response to which of the materials EPS, cork and corrugated cardboard that causes the lowest climate footprint as 1 m2 floorboard in an underfloor heating system for 50 years, the material’s emissions during the use stage are multiplied by 50. The results highlight the benefits of low heat losses in an underfloor heating system over time, as corrugated cardboard causes the greatest climate gas emissions when used with poorly insulated slab with 119 kg CO2e/m2, while EPS causes the lowest emissions of 111 kg CO2e/m2. In a case with insulated slab foundation, corrugated cardboard causes the lowest emissions of 7,9 kg CO2e/m2, while EPS causes the highest emissions of 8,9 kg CO2e/m2. In terms of climate impact, corrugated cardboard is the best alternative for implementation as a floorboard material in an underfloor heating system with a lifespan of 50 years in a newly built and well-insulated Swedish single-family home. For older detached houses that do not have additional slab insulation, EPS is the material that causes the least climate impact, thanks to the material’s insulating ability.
10

INCORPORATION OF BIO BASED FLAX FIBER REINFORCED POLYMER SKINS FOR PACKAGING ENHANCEMENTS

Sufia Suleman Sukhyani (11679325) 20 December 2021 (has links)
This thesis provides an approach to incorporate natural composites like Flax Fiber using a resin with 30% bio-content to enhance the packaging boxes made of corrugated cardboard. The objective of introducing natural composite skins is to reduce/eliminate the compressive loading subjected to the boxes while stacking in warehouses.

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