This work resulted in a simulation platform and a validated numerical framework, which can precisely model the packaging material that are made of complex paperboard composite laminates and predict the material behaviour when it undergo es processing and converting procedures. Due to their specific advantages such as flexibility, hygiene, cost-effectiveness and environmental compatibility, paperboard composite materials are widely us ed for food and beverage packaging. The packaging materials are made of multi-layer sandwich laminates and mainly consists of several carton plies, a thin aluminium foil and several polyethylene layers. Compared to other conventional composite structures, such as carbon fibre composites, carton-based packages have an extremely thin composite structure with significantly softer material properties. To obtain a robust and well-formed commercial packaging, many manufacturing processes are usually carried out, for instance creasing, folding or bottom and gable sealing. In addition to the structural and architectural aspects, various technical requirements must b e met regarding functionality, rigidity and robustness of the packaging. During the converting procedures; especially at higher production speeds, unexpected operational flaws might b e observed often for material rupture and inter-layer delamination influencing the quality of a package performance. Furthermore, to examine the new paperboard material generations and operational developments, it is necessary to characterize and predict materials behaviour and packaging process if higher converting speeds, extended performance and efficiency are demanded. To satisfy the above-mentioned technical requirements, mathematical modelling and simulation methods are an appropriated way to formulate the paperboard material characteristics and analyse converting processes such as creasing and folding. A series of quasi-static and high-speed tensile tests were carried out to determine the mechanical properties of the highly anisotropic carton material. In addition to the classical tensile test, improved tests were also conducted specifically to measure the shear strength of the paperboard plies. Tests such as the Rigid Block Shear Test (RST) and the Double Notches Shear Test (DNST) were performed to obtain the shear stress curve and maximum shear strength across the paperboard thickness, respectively. Furthermore, the z-directional tensile test (ZDT) was also employed to identify the paperboard interfacial characteristics in terms of traction-separation curves. A mathematical model based on the finite element method (FEM) has been develop ed and implemented in the commercial ABAQUS software to simulate material behaviour under highly dynamic loads. The simulation model includes both constitutive elasticplastic formulation of packaging composite structure and a description of interlayer interaction and delamination between the composite plies as well. A formulation according to the Hill ´criteria has been used to formulate the anisotropic elastic-plastic behaviour of the material based on its rate-dependent characteristics. The interaction between the paperboard layers and the corresponding delamination during the creasing and folding processes have been implemented using an anisotropic traction separation model in respect to the relative sliding and opening of the adjacent interfaces. The most important simulation parameters have been comprehensively investigated and optimized regarding the calculation accuracy, simulation costs and efficiency. Subsequently, the obtained numerical results were successfully validated with available experimental data for practical static and dynamic creasing and folding processes.:1. Introduction 2. The State of the Art 2.1 Introduction 2.2 Paperboard and packaging composites manufacturing process 2.3 Paperboard converting process: creasing and folding 2.4 Analyzing of existing models for packaging materials and packaging procedures 2.5 Conclusions 3 Objective and Research Program 3.1 Objective 3.2 Research Program 4 Continuum Mechanics and Modeling of Packaging Process 4.1 Introduction 4.2 Continuum mechanics 4.2.1 Deformation gradient 4.2.2 Finite strain equations 4.2.3 Constitutive model and stress decomposition 4.2.4 Velocity gradient and rate of deformation 4.2.5 Yield criteria 4.2.6 Hardening law and plastic flow 0 4.3 Analytical model for paperboard material characterization 4.3.1 Constitutive equations 4.3.2 Elasticity 4.3.3 In-plane plasticity 4.3.4 Out-of-plane plasticity 4.4 Contact and interfacial formulation 4.4.1 Normal contact analysis 4.4.2 Tangential contact analysis 4.4.3 Interface model 4.5 Conclusions 5 Development of Experimental Methods for Paperboard Material Identification 5.1 Introduction 5.2 Quasi-static tensile test 5.3 Shear and interfacial experiments 5.3.1 Rigid block shear test (RST) 5.3.2 Double notched shear test (DNST) 5.3.3 Z-directional tensile test (ZDT) 5.4 Paperboard dynamic material characterizations 5.4.1 Dynamic test set-up and measurement 5.4.2 Dynamic material calibration and parameter identification 5.5 Conclusions 6 Paperboard Composites Converting Process Experiments and Finite Element Modeling 6.1 Introduction 6.2 Material and interfacial numerical modeling 6.3 Punching creasing 6.3.1 Punching creasing experiment 6.3.2 Punching creasing FE simulation 6.4 Dynamic creasing 6.4.1 Dynamic creasing experiments 6.4.2 Dynamic creasing simulation 6.5 Folding model 6.5.1 Folding experiment 6.5.2 Folding simulation 6.6 Conclusions 7 Results and Discussion 7.1 Introduction 7.2 FE results and validation 7.2.1 Quasi-static punching creasing process 7.2.2 High speed rotating dynamic creasing process 7.2.3 High speed folding process 7.3 Conclusions 8 Potential Analysis of Material and Process Optimization 8.1 Introduction 8.2 Material optimization 8.2.1 Material continuum characterization 8.2.2 Material interface characterization 8.2.3 Material shear characterization 8.3 Conclusion 9 Summary and Outlook

The Discrete element method (DEM) is a methodology to investigatethe interactions among granular materials. It analyzes the behavior of par-ticulate environments by solving force-displacement equations that adhereto Newton’s second law of motion. Despite its usefulness, the DEM is notwithout limitations, and researchers are still facing certain challenges thatrestrict them from performing detailed analyses of granular materials. Thisstudy addresses two issues in DEM modeling of granular materials in rail-way embankments. Firstly, the long computational time required by theDEM for modeling fine angular particles in granular materials is addressedby exploring the effects of particle scaling on the shear behavior of granularmaterial. This study investigates the impact of particle size distribution,particle angularity, and the amount of scaling on the accuracy and compu-tational efficiency of DEM. Secondly, the limitations of DEM in includingthe continuous rail beam structure in the track are addressed by verifyinga DEM model against physical measurements of a full-scale ballasted trackand investigating the influence of including the rail beam structure on high-speed railway ballasted tracks. The results show that the use of particlescaling in the first study significantly improves the computational efficiencyof the DEM while maintaining accuracy, and this method is used in thesecond study to investigate the influence of the rail beam structure on thebehavior of railway tracks. / Diskreta elementmetoden (DEM) är en effektiv metod för att undersö-ka interaktioner i granulära material. Metoden analyserar samverkan mellanpartiklar genom att lösa kraft-deformationsekvationer som följer Newtonsandra lag. Trots dess användbarhet har DEM vissa begränsningar och fors-kare stöter fortfarande på vissa utmaningar som hindrar dem från att ge-nomföra detaljerade analyser av granulära material. Denna studie tar upptvå frågeställningar vid DEM-modellering av granulära material i järnvägs-bankar. För det första behandlas den långa beräkningstiden som krävs föratt modellera granulära material genom att utforska effekterna av parti-kelskalning på skjuvbeteendet. Studien undersöker effekten av partikelstor-leksfördelning och spetsighet på noggrannheten och beräkningseffektivite-ten. För det andra behandlas begränsningarna hos DEM när det gäller attinkludera den kontinuerliga rälsstrukturen i spåret genom att verifiera enDEM-modell mot fysiska mätningar av ett ballasterat spår i full skala ochundersöka inverkan av att inkludera rälsstrukturen. Resultaten i den förstastudien visar att tillämpningen av partikelskalning avsevärt förbättrar be-räkningseffektiviteten samtidigt som noggrannheten bibehålls. Partikelskal-ning används i den andra studien för att undersöka inverkan av rälsstruk-turen på beteendet hos järnvägsspår. / <p>QC 230508</p>

[pt] Esta pesquisa teve como objetivo investigar o comportamento tensão-deformação-resistência da areia da Praia de Ipanema, RJ, em ensaios de cisalhamento simples (DSS) realizados em corpos de prova secos, cisalhados a volume constante sob carregamento monótono de deformação controlada. Foi desenvolvido um procedimento para moldagem de corpos de prova de areia na condição seca para ensaios de DSS. Os corpos de prova foram moldados nos domínios de compacidade relativa (CR) fofo, médio, compacto e muito compacto. Para cada um desses domínios de CR, foram realizados ensaios de DSS sob os seguintes valores de tensão vertical inicial: 25, 50, 100, 150, 300, 500 e 750 kPa. Os resultados permitiram avaliar a influência da tensão vertical inicial e do índice de vazios pré-cisalhamento (epc) na variação da tensão vertical (variação da tensão vertical no cisalhamento) necessária para manter a altura (e o volume) do corpo de prova constante durante o cisalhamento, na taxa de mobilização de ângulo de atrito no plano horizontal em relação à distorção, no valor do ângulo de atrito máximo mobilizado no plano horizontal, no valor da tensão cisalhante na ruptura, no valor da distorção na ruptura, bem como nos valores dos módulos de cisalhamento secantes G25 e G50. / [en] This research aimed to investigate the stress-strain-strength behavior of the Ipanema Beach (RJ) sand in direct simple shear tests (DSS) carried out on dry specimens, sheared at constant volume under strain-controlled static loading. A procedure for preparing dry sand specimens was developed for DSS tests. The specimens were prepared in loose, medium, dense and very dense domains of relative density (Dr). For each of these Dr domains, DSS tests were carried out under the following initial vertical stress values: 25, 50, 100, 150, 300, 500 and 750 kPa. The results allowed to evaluate the influence of the initial vertical stressand the pre-shear void ratio (epc) on the vertical stress change (variation of vertical stress in shear) necessary to keep the specimen height (and volume) constant during shear, on the rate ofmobilization of the friction angle in the horizontal plane in relation to distortion, on the value of the maximum friction angle mobilized in the horizontal plane, on the value of the shear stress at failure, on the value of the distortion at failure, as well as on the values of the secant shear modulus G25and G50.

Fabric Reinforced Cementitious Matrix (FRCM) composites utilize a mineral mortar matrix as a substitute for epoxy resin that is used for Fibre Reinforced Polymer (FRP). This eliminates issues associated with the low thermal compatibility of FRP with concrete, susceptibility to UV radiation, and sensitivity to high temperatures in which organic polymers undergo vitrification. This study discussed the effect of varying parameters like the number of Carbon-FRCM (C-FRCM) layers (1, 2 and 3 layers), different anchorage configurations (non-anchored, spike anchor, wrap anchor and mechanical anchor), bond length (300 or 200 mm), and the fabric type (unidirectional and bidirectional) on the direct shear behaviour of C-FRCM composites bonded to a concrete substrate, especially the fibre-matrix bond which is the most common debonding interface of FRCM composites. Calibrated models of the bond – slip behaviour are provided based on the fabric type and number of fabric layers. The results indicate that the anchor type and the overall composite thickness are the main factors that control the failure mode of the composite. All properly anchored specimens using spike and wrap anchors failed due to fabric rupture. Moreover, a considerable number of the non-anchored specimens failed due to composite-substrate debonding, although premature fabric rupture was frequently observed. Furthermore, specimens with bidirectional fabric demonstrated shallower penetration of the strain into the composite which may be due to the horizontal fabric strands providing some anchorage for the longitudinal strands. They also exhibited slip initiation at a higher stress compared to unidirectional specimens. In addition, slip initiation stress of unidirectional specimens decreased with more fabric layers which may indicate that the additional layers have a lower bond efficiency. For the same reason, specimens with three layers of fabric generally experienced deeper strain penetration into the composite than one-layered or two-layered specimens regardless of the anchor type. The results also indicate that the use of bidirectional fabric and anchorage systems decreases the strain penetration into the composite and correspondingly, the effective length is shortened. Surface strain measurements captured using digital image correlation generally did not match the internal fabric strain values obtained from strain gauges.

<p dir="ltr">Biorefineries rely on compression feed screws to transport biomass for biofuel production in chemical reactors. However, flowability issues within these feedscrews often lead to production downtime, impacting profitability. Modeling biomass flow within the feedscrews is crucial to optimize processing parameters like torque and speed, reducing downtime. Biomass is a non-uniform granular material which faces flowability issues. The problems in flowability is influenced by factors such as particle size, moisture content, material composition, and processing methods. Identifying key parameters that can influence the material behavior is vital to minimize production downtimes. Feedscrews operate under high pressures which makes obtaining accurate material parameters at these high pressures challenging. Many methods used within the pharmaceutical industry to obtain material parameters are unable to reach the larger pressures that the material experiences within the feedscrew. However, Triaxial testing can be used to test the material at the high pressure of interest. Triaxial testing has been used within the civil engineering field to test granular materials such as soils, sand, and rocks. The Finite Element Method (FEM) using a continuum model is used for modeling systems with a large number of particles. The modified Drucker-Prager Cap (mDPC) continuum model is often used to capture complex material behavior, including densification and shear yielding in granular materials. This model seems well suited to capture the behaviors of biomass material. The focus of the thesis is to obtain the shear failure properties of corn stover using triaxial testing and the Drucker-Prager Cap continuum model. Simulations and experimental data are utilized to establish a criterion for identifying shear failure. While simulations depict ideal behavior of a DPC material with frictionless and frictional platens, experimental data shows trends of real-life corn stover. Simulation results effectively predict the material’s friction angle but show larger errors in estimating cohesion, potentially due to extrapolation or cohesion’s sensitivity to volumetric plastic strain. Further simulations at smaller hydrostatic unloading pressures are recommended to reduce this error. Experimental trends for shear failure seem to align with simulation trends for shear failure identification. However, the densification trends in experiments lack the clarity observed in the trends from the simulations. More triaxial experiments should be run to determine if the trends are consistent at other hydrostatic loading and unloading pressures. More than two experiments at the same hydrostatic loading pressure should also be run to estimate the shear failure line to obtain a better estimation. Experimentally there are a number of other factors that could contribute to errors such as the estimated material diameter used to calculate Mises stress, if corrections were made for items such as the moving piston, latex membrane, and more, and how far the shear failure line is extrapolated to the vertical axis.</p>

No description available.

[pt] O estudo avalia o comportamento mecânico de uma areia reforçada com polímero, em comparação à areia pura. Foram realizados ensaios cisalhamento direto em amostras de areia pura e desta com a adição do copolímero de butadieno e estireno modificado (XSBR). O copolímero de butadieno e estireno é um elastômero composto de aproximadamente 75 porcento de butadieno e 25 porcento de estireno, presente em solução aquosa, sendo muito utilizada na indústria automobilística, para a produção de pneus. Pode ser produzido a partir dos processos de polimerização em emulsão ou polimerização em solução. A escolha destes materiais está relacionada às suas propriedades serem compatíveis as exigências para melhoramento de solos em obras geotécnicas. As amostras de areia com polímero apresentavam 50 porcento de densidade relativa, 10 porcento de umidade, nas proporções em volume água-polímero de 1:1, 1:2 e 1:4, sem tempo de cura, ou com tempos de cura de 24, 48, 72, 96, 576, 720 e 1080 horas. Foram constatadas melhorias nos parâmetros de resistência das amostras de areia com adição de polímero, em comparação aos parâmetros da areia pura, mostrando que a melhoria de solos com polímero é satisfatória para a aplicação em obras geotécnicas, como por exemplo: aterros sobre solos moles, solos de fundações superficiais e para a estabilidade de taludes. / [en] The study evaluates the mechanical behavior of a sand reinforced with polymer compared to pure sand. Direct-cut tests were carried out on pure sand samples and with the addition of modified styrene butadiene-styrene (XSBR) copolymer. The copolymer of butadiene and styrene is an elastomer composed of approximately 75 percent butadiene and 25 percent styrene, purchased in aqueous solution, being widely used in the automotive industry for the production of tires. It may be produced from the emulsion polymerization or solution polymerization processes. The choice of these materials is related to their properties being compatible the requirements for soil improvement in geotechnical works. Polymer sand samples had 50 percent relative density, 10% moisture, in water-polymer volume ratios of 1:1, 1:2 and 1:4, without curing time, or with times of cure 24, 48, 72, 96, 576, 720 and 1080 hours. Improvements in the resistance parameters of the sand samples with polymer addition were verified in comparison to the pure sand parameters, showing that the improvement of soils with polymers is satisfactory for the application in geotechnical works, such as: landfills on soft soils, soils of shallow foundations and for slope stability.

The lap shear strength of chromic acid anodized, primed, Ti-6Al-4V alloy bonded with a high performance FM-5 polyimide adhesive has been investigated as a function of thermal treatment for selected times at various temperatures in air. The research findings indicate that the lap shear strength decreases with the increase in duration of the thermal treatment at constant temperature and with the increase in temperature at constant time. The bond fails increasingly in the oxide coating with increasing treatment temperature and time of treatment. Surface analysis results for debonded specimens suggest that the process leading to failure is the formation of fluorine-containing materials within the oxide, which weakens the adherend-adhesive bond. The formation of the fluorine components is facilitated by treatment at elevated temperatures. This study suggests that the presence of fluoride ions in the anodic oxide coating, prior to bonding, is detrimental to the bond strength of adhesively bonded Ti-alloy when exposed to high temperatures. The wedge test configuration was used to investigate the influence of temperature on the bond durability of adhesively bonded chromic acid anodized Ti-6Al-4V alloy in air. Based on the average crack length vs. exposure time data, the bond durability varied in the order -25°C > 24°C > 177°C. In each case, the bonded joint failed cohesively within the adhesive, irrespective of the temperature of exposure. XPS analysis and scanning electron photomicrographs of failure surfaces revealed that the failure occurred at the scrim cloth/adhesive interface. The influence of thermal treatment history on the bond durability of adhesively bonded chromic acid anodized Ti-6Al-4V alloy immersed in boiling water was also investigated. The average crack length vs. immersion time indicated no significant differences for specimens that were thermally treated and then bonded compared to the non-thermally treated specimens. In addition, the failure mode was cohesive within the adhesive for specimens prepared using various thermal treatment conditions. The crack growths for samples treated for 0.5 hour and 1.0 hour and for non-thermally treated specimens for any given exposure time were equivalent. In addition, cohesive failure (failure within adhesive) was observed for each specimen under each treatment condition. The specimens that were bonded and then thermally treated for 3 hours, failed in the oxide coating immediately upon insertion of the wedge. Surface analysis results for debonded specimens suggest that the process leading to failure is the formation of fluorine-containing materials within the oxide. The measured average activation energy for the formation of aluminum fluoride species is 149 kJ/mol. The high activation energy suggests that the rate of aluminum fluoride formation is substantial only at high temperatures. In summary, the presence of fluorides in the anodic oxide coatings prior to bonding is detrimental to the overall strength and durability of adhesively bonded chromic acid anodized Ti-6Al-4V joints which have been exposed to high temperatures (350°C-399°C). / Ph. D.

No description available.

Inadequate financial allocation for road maintenance is a threat to the impaired rural highways in Atlantic Canada. The conventional means of pavement rehabilitation has been to place a hot mix asphalt concrete overlay on the existing worn out pavement which is only a short term adjustment. The purpose is to provide a smooth wearing surface at a low cost. This traditional way of pavement repair does not fix the damage embedded within the pavement structure. After a certain extent of time the cracks in the original pavement start to reflect to the smooth new wearing surface, causing deterioration on the overlay. The advanced approach which is becoming more popular is the application of Full Depth Reclamation (FDR). This technique helps to repair the extensively defective roads by pulverizing the flexible pavement along with a fraction of the underlying damaged base layer. Thus a damage free base layer can be obtained by stabilizing and recompacting the pulverized materials. FDR is a sustainable and an environmentally beneficial repair method as it re-uses the in-situ materials. FDR process has been used around the world for over 25 years yet confronts some difficulties regarding the fluctuation in the strength of materials in various projects. It is inferred that some of these difficulties are due to the variability and poor quality in the restored materials. The variability in the recycled base layer is a result of currently utilizing a retroactive depth control method to attain a specific blend of asphalt concrete to granular base for the pulverized materials. Two FDR projects applying two different pulverization control methods (conventional retroactive and GPR depth control methods) were analyzed to investigate the improvements in consistency of the restored materials by using Ground Penetrating Radar (GPR). A wide range of asphalt concrete/base layer blend ratio was detected in retroactive control section, while consistent blend ratio was maintained in GPR survey by mapping the variability in the depth of pavement and sub-dividing the test sections accordingly. A GPR controlled constant blend ratio during pulverization displayed improvements in consistency of materials, physical and mechanical properties and performance as anticipated. The materials obtained by using the conventional retroactive depth control method exhibited higher variability in grain size distribution, optimum moisture content, optimum density, California Bearing Ratio, resilient modulus and shear strength. All materials from both projects exhibited excessive air voids and inadequate fines content as the as-obtained particles acted as conglomerated particles and enough fines were not generated after the pulverization. It is recommended that efficient quality control, precise specifications and appropriate pulverization methods will provide more reliable and impressive FDR pavements. / This thesis contains research on unstabilized full depth reclaimed aggregates properties