Fiber-reinforced concrete (FRC) is nowadays extensively used in civil engineering throughout the world due to the composites of FRC can improve the toughness, flexural strength, tensile strength, and impact strength as well as the failure mode of the concrete. It is an easy crazed material compared to others materials in civil engineering. Concrete, like glass, is brittle, and hence has a low tensile strength and shear capacity. At present, there are different materials that have been employed to reinforce concrete. In our experiment, nanostructures iron oxide was prepared by electrodepostion in an electrolyte containing 0.2 mol/L sodium acetate (CH3COONa), 0.01 mol/L sodium sulfate (Na2SO4) and 0.01 mol/L ammonium ferrous sulfate (NH4)2Fe(SO4)2.6H2O under magnetic stirring. The resulted showed that pristine Fe2O3 particles, Fe2O3 nanorods and nanosheets were synthesized under current intensity of 1, 3, 5 mA, respectively. And the pull-out tests were performed by Autograph AGS-X Series. It is discovering that the load force potential of nanostructure fibers is almost 2 times as strong as the control sample.

Hållfasthetslära är ett viktigt och centralt område inom ingenjörsutbildningar. Men att ha grundläggande kunskap om vad som gör konstruktioner hållfasta är dock något som inte enbart bör vara förbehållet ingenjörer, utan det är även ett område som tillhör allmänbildningen. Det är av den anledningen området hållfasthet tas upp redan i grundskolans lägre åldrar i skolämnet Teknik och fördjupas successivt upp till gymnasiets tekniska program. I denna studie har fem läroböcker för ämnet Teknik för grundskolans årskurs 7-9 samt två läroböcker för kursen Teknik 1 i gymnasieskolans årskurs 1, studerats för att utreda hur området hållfasthetslära beskrivs. Metoden som används i analysen är textanalys i form av en kvantitativ innehållsanalys av förekomsten av hållfasthetsrelaterade begrepp samt en kvalitativ analys av hur begreppen beskrivs. Därtill görs en analys av hur läromedlen uppfyller styrdokumentens krav och riktlinjer. Studien visar att böckerna har stor variation i hur området hållfasthetslära framställs, dock med generaliseringar att högstadieboken beskriver området med text och gymnasieboken med formler. De studerade läroböckerna tar visserligen upp många ämnesspecifika begrepp men det är en markant skillnad mellan böckerna hur dessa begrepp beskrivs. Den fördjupade analysen som studerar om läroböckerna uppfyller styrdokumentens kursplaner i Teknik för grundskolan och Teknik 1 för gymnasieskolan påvisar även den en stor spridning mellan läroböckerna. Av studiens valda bedömningskriterier kan utläsas att området behandlas utförligt endast av två av böckerna: grundskolans Teknik Direkt (2018) från förlaget Sanoma Utbildning samt gymnasiets Teknik (2011) från förlaget Liber. Gemensamt för de valda gymnasieböckerna är att området hållfasthet behandlas mycket mer matematiskt än i högstadieböckerna och stort fokus ligger på olika former av spänningsberäkningar. Dock är det ett markant språng i abstraktionsnivå från de enklare textbaserade högstadieböckerna till gymnasieböckerna med matematiska beräkningar. Slutsatsen av detta är att varken högstadieböckerna eller gymnasieböckerna ger en heltäckande bild av viktiga grundläggande begrepp inom området hållfasthet. Studien visar att de bästa av böckerna kan i viss mån komplettera varandra, men med ogrundade val av läromedel riskerar det att bli osammanhängande. Det är därmed viktigt att läraren noggrant utvärderar lämpliga läromedel så de uppfyller det tänkta syftet i undervisningen. / Strength of materials and solid mechanics theory is an important and central area in engineering education. But having a basic knowledge of what makes structures durable, however, is not only reserved for engineers, but is also an area that belongs to general education. For this reason, the area of strength is already taken up in the elementary school's lower age in the subject of technology and is gradually expanded up to the high school's technical program. In this study, five textbooks for the subject of Technology for comprehensive school upper stage, grade 7-9, and two textbooks for the course Technology 1 in high school year 1 were studied to investigate how the field of strength theory is described. The method used in the analysis is text analysis in the form of a quantitative content analysis of the presence of strength-related concepts as well as a qualitative analysis of how the concepts are described. In addition, an analysis is made of how the teaching materials meet the requirements and guidelines of the steering documents. The study shows that the books have a great variety in how the field of strength theory is presented, however with generalizations that the upper stage textbook describes the area with text and the high school describes with formulas. Although the textbooks studied have many subject-specific concepts, it is markedly different between the books how these concepts are described. The in-depth analysis that studies whether the textbooks meet the syllabus of the steering documents in Teknik for the elementary school and Teknik 1 for the upper secondary school also shows a large distribution between the textbooks. From the chosen assessment criteria in the study, it can be seen that the area is in depth covered by only two of the books: Teknik Direkt (2018) from publisher Sanoma Utbildning (for the elementary school) and Teknik (2011) from publisher Liber (from upper secondary school). Common to all the selected high school books is that the area of strength is treated much more mathematically than for the upper stage books and great focus is placed on various forms of stress calculations. However, there is a significant leap in abstraction level from the simpler text-based upper stage books to the high school books with mathematical calculations. The conclusion of this is that neither the upper stage school books nor the high school books provide a comprehensive picture of important basic concepts in the area of strength. The study shows that the best of the books can to some extent complement each other, but with unfounded choice of study material it risks becoming incoherent. It is therefore important that the teacher carefully evaluates appropriate teaching material so that they fulfill the intended purpose of the teaching.

Thesis (MScEng)--Stellenbosch University, 2013. / AFRIKAANSE OPSOMMING: Saamgestelde materiale het baie gewilde materiale in die lugvaart- en motor industrië geword as gevolg van die gewigsbesparende voordele wat dit inhou. Kostes en ander verwerkingsprobleme het tradisioneel die wydverspreide gebruik van spesifiek termoplasties-versterkte vesels in hierdie areas verhinder. Baie van die vervaardigingsprobleme (spesifiek lang siklusse) is aangespreek met die aanvang van termoplastiese matriks materiaal soos Polyphenolien Sulfied (PPS). Hierdie materiaal voldoen ook aan die lugvaart-industrie se brand-, rook- en giftigheidstandaarde. Termoplastiese saamgestelde materiale kan byvoorbeeld gevind word op komponente in vliegtuie se binneruimtes en ook die voorste rand van die vlerke. Hierdie komponente is hoogs vatbaar vir impakskade. Die hoë sterkte en styfheid tot gewig verhoudings van saamgestelde materiale laat toe vir dun materiaal dwarssnitte. Komponente is dus kwesbaar vir uit-vlakkige impak beladings. Saamgestelde materiale kan ook intern deur hierdie beladings beskadig word en kan nie met die blote oog waargeneem kan word nie. Dit is dus nodig om die skade weens hierdie beladings tydens normale gebruik akkuraat te voorspel. Verder sal dit nuttig wees om die struktuur se gedrag te bepaal in toepassings waar byvoorbeeld passasier veiligheid krities is, soos op vliegtuig ruglenings tydens noodlandings. In hierdie studie is die potensiële vervaardigingsvoordele van termoplastiese saamgestelde materiale gedemonstreer. Daarbenewens is 'n uit-vlakkige impak deur 'n sagte liggaam herbou in 'n laboratorium omgewing. Die primêre doelwit van hierdie studie was om die impak numeries te modelleer. Vervaardigingsvoordele van `n vesel versterkte termoplastiese laminaat is gedemonstreer deur die vervaardiging van 'n konkawe, agt laag laminaat uit 'n vooraf gekonsolideerde geweefde doek. Die totale verwerkingstyd van die plat laminaat na 'n konkawe laminaat was minder as vyf minute. 'n Eenvoudige plat laminaat en 'n konkawe laminaat is onderwerp aan 'n lae snelheid impak deur 'n sagte projektiel. Die impak is gemodelleer deur die evaluering van drie modelleringsmetodes vir die saamgestelde paneel. Die evalueringskriteria het o.a. ingesluit of laminaat se volle gedrag suksesvol gemodelleer kon word met behulp van slegs 2D dop elemente. Die reaksie van die saamgestelde paneel en gepaardgaande faling is met wisselende vlakke van sukses deur die drie geëvalueerde modelle voorspel. Die faling van tussen-laminêre bindings (verwys na as delaminasie) kon nie deur enige van die modelle voorspel word nie. Twee van die modelle het egter in-vlak faling met redelike akkuraatheid voorspel. / ENGLISH ABSTRACT: Due to weight saving advantages composite materials have become a highly popular material in the aerospace and automotive industries. Traditionally processing difficulties and costs have been a barrier to widespread composite material use in these industries. With the advent of thermoplastic matrix materials such as Polyphenoline Sulphide (PPS) the processing difficulties (especially long cycle times) experienced with traditional thermosetting resins can be addressed while maintaining aerospace Fire-Smoke and Toxicity (FST) approval. Thermoplastic composites can for example be found on aircraft interior components and leading edges of the wings. These areas are highly susceptible to impact damage. The high strength- and stiffness to weight ratios of composites allows for thin material cross sections. This leaves the components vulnerable to out-of-plane impact loads. Composite materials may also be damaged internally by these loads, leaving the damage undetectable through visual inspections. It may therefore be necessary to predict the amount of damage a component would sustain during normal operation. Additionally, it would be useful to predict structural response of these materials in applications where passenger safety is crucial, such as aircraft seat backrests during emergency landings. In this study the potential processing benefits of thermoplastic composite materials were demonstrated. Additionally an out-of-plane impact from a soft bodied projectile was reconstructed in a laboratory environment. The primary objective was to numerically model the impact event. Processing benefits of thermoplastics were demonstrated by producing a single curvature eight layered laminate from a pre-consolidated woven sheet. The total processing time from flat panel to a single curvature panel was below five minutes. A simple flat laminate and a single curvature laminate were subjected to a low velocity drop weight impact load from a soft bodied projectile. These impact events were modelled by evaluating three modelling methods for the composite panel structural response and damage evolution. Part of the evaluation criteria included whether laminate failure could be modelled successfully using only 2D shell elements. The response of the composite panel and accompanying failure were predicted with varying levels of success by the three evaluated models. The failure of interlaminar bonds (referred to as delamination) could not be predicted by either model. However two of the models predicted in-plane failure with reasonable accuracy.

Os perfis de aço formados a frio possuem até 3 modos de flambagem: local, distorcional e global. Essa diversificação torna muito complexa a verificação de esforços resistentes nesses perfis. Recorre-se, então a métodos simplificados e interativos, com o intuito de fornecer ao engenheiro civil ferramentas que sejam práticas e apresentem um bom resultado. Métodos numéricos, como o MFF (métodos das faixas finitas), apesar de serem mais precisos, não são ainda, de uso corrente em projetos. O enfoque principal deste trabalho são as normas brasileiras de perfis formados a frio NBR 14762:2001 “Dimensionamento de estruturas de aço constituídas por perfis formados a frio" e NBR 6355:2003 “Perfis estruturais de aço formados a frio - Padronização". Comparam-se as tabelas D1 e D2 na NBR14762:2001, referentes à flambagem distorcional, a resultados calculados por meio do processo recomendado pela norma. Verificaram-se quais perfis padronizados pela NBR 6355:2003 dispensam a verificação da resistência por distorção da seção transversal. Uma análise geral de perfis de aço formados a frio, a fim de identificar aqueles que possuem melhor eficiência (perfis que resistem esforços mais elevados com menor área da seção transversal) também é feita. Para a realização desta pesquisa foi desenvolvido um programa de computador. / The cold formed steel members have up to 3 buckling modes: local, distortional and global. This diversification makes very complex the verification of these members’ resistance. For this reason it is used simple and interactive methods to provide the Civil Engineers tools that are practical and present a good result. Although numerical methods such as FDM (Finite Strip Methods) are more precise, they are still not currently used in projects. The main focus of this dissertation is the Brazilian rules regarding the cold formed steel members NBR 14762:2001 “Dimensioning steel structures made of cold formed profiles" and NBR 6355:2003 “Cold formed steel members – Standardizing". It compares the D1 and D2 tables of NBR14762:2001, regarding the distortional buckling, with the calculated results recommended by these rules. In this way it is verified which NBR 6355:2003 standardized profiles do not require the verification of resistance by distortional buckling. It is also made a general analysis of these cold formed steel members. And to make this research it was developed a computer program.

Submitted by Marlucy Farias Medeiros (marlucy.farias@unipampa.edu.br) on 2018-09-27T20:33:58Z No. of bitstreams: 1 ANTÔNIO RODRIGUES PETTERLE- 2018.pdf: 2305522 bytes, checksum: 69cc82567d353c585b3c2aad186edee3 (MD5) / Approved for entry into archive by Marlucy Farias Medeiros (marlucy.farias@unipampa.edu.br) on 2018-09-27T21:03:54Z (GMT) No. of bitstreams: 1 ANTÔNIO RODRIGUES PETTERLE- 2018.pdf: 2305522 bytes, checksum: 69cc82567d353c585b3c2aad186edee3 (MD5) / Made available in DSpace on 2018-09-27T21:03:54Z (GMT). No. of bitstreams: 1 ANTÔNIO RODRIGUES PETTERLE- 2018.pdf: 2305522 bytes, checksum: 69cc82567d353c585b3c2aad186edee3 (MD5) Previous issue date: 2018-03-01 / Placas cerâmicas prensadas foram obtidas a partir de misturas com diferentes proporções contendo argila caulim, sílica extraída da casca de arroz após queima em temperatura controlada e lodo de estação de tratamento de águas (LETA). Propriedades físicas como densidade aparente, absorção de água e porosidade, propriedades mecânicas como resistência à compressão, e propriedades térmicas como condutividade térmica das placas cerâmicas após queima (Norma DIN EN12667) foram avaliadas. A sílica quando inserida na argila caulim propicia aumento da fase vítrea, redução na fase porosa, redução de condutividade térmica e aumento de resistência mecânica. O uso do LETA quando inserido na massa cerâmica propicia aumento considerável dos picos de mulita e de cristobalita, expressivo aumento de porosidade e diminuição das resistências térmica e mecânica. As placas cerâmicas com traço de mistura contendo 80% argila caulim, 20% sílica de casca de arroz e 10% LETA apresentaram o menor valor de condutividade térmica na placa cerâmica após queima de 0.2574W / mK, e a maior resistência à compressão de 189.97 MPa quando comparada aos demais traços testados. Em função dessas propriedades termomecânicas, as placas cerâmicas com esta formulação foram aplicadas como revestimento em uma parede de alvenaria em escala real com dimensões 1,20 m de largura x 2,20 m de altura, sendo submetida ao ensaio de calor e choque térmico (ABNT NBR 15575). O desempenho a durabilidade indicou que a placa cerâmica contendo está formulação tem potencial para ser utilizada como revestimento em fachadas de edifícios. O resultado do ensaio de durabilidade não apresentou nenhuma degradação tais como: deformação, fissuras ou desnivelamento, e apresentou um deslocamento horizontal de 1,13 mm, sendo este um valor abaixo do estabelecido na norma NBR 15575 que prediz 8 mm para uma altura de 2,40m. / Pressed ceramic plates were obtained from mixtures with different proportions containing kaolin clay, silica extracted from the rice husk after burning at controlled temperature and sludge from a water treatment plant (LETA). Physical properties such as bulk density, water absorption and porosity, mechanical properties such as compressive strength, and thermal properties as thermal conductivity of the ceramic plates after firing (DIN EN12667) were evaluated. The silica when inserted in the kaolin clay provides an increase in the glassy phase, reduction in the porous phase, reduction of thermal conductivity and increase of mechanical resistance. The use of the LETA when inserted in the ceramic mass provides a considerable increase of the mullite and cristobalite peaks, expressive increase of porosity and decrease of the thermal and mechanical resistances. The ceramic plates with a mixture trace containing 80% kaolin clay, 20% silica rice husk and 10% LETA showed the lowest value of thermal conductivity in the ceramic plate after burning of 0.2574W / mK, and the highest compressive strength of 189.97 MPa when compared to the other traits tested. Due to these thermomechanical properties, the ceramic plates with this formulation were applied as a coating on a real-scale masonry wall with dimensions 1.20 m wide x 2.20 m high, being submitted to the heat and thermal shock test (ABNT NBR 15575). The durability performance indicated that the ceramic plate containing this formulation has potential to be used as coating on building facades. The results of the test of durability did not present any degradation such as: deformation, cracks or unevenness, and presented a horizontal displacement of 1,13 mm, being this a value below that established in norm NBR 15575 that predicts 8 mm for a height of 2 , 40m.

D. Tech. Mechanical Engineering. / Discusses the main objective of this study was to extend the hybrid method developed by Paskaramoorthy, et al (1988). This objective was to study the effect of elastic wave on any particulate reinforced metal matrix composite (PRMMC). The specific objectives were: to compare the effect of plane wave and shear vertical wave on a particular particulate reinforced metal matrix composite (PRMMC)-Mg/TiC, using analytical method ; to use the extended hybrid method to determine the effect of particle size and single interface layer on Mg/TiC.

The objective of the present study is the computational and analytical modelling of a stress and strain state of the composite laminated structures. The exact three dimensional solution is derived for laminated anisotropic thick cylinders with both constant and variable material properties through the thickness of a layer. The governing differential equations are derived in a such form that to satisfy the stress functions and are given for layered cylindrical shell with open ends. The solution then extended to the laminated cylindrical shells with closed ends, that is to pressure vessels. Based on the accurate three-dimensional stress analysis an approach for the optimal design of the thick pressure vessels is formulated. Cylindrical pressure vessels are optimised taking the fibre angle as a design variable to maximise the burst pressure. The effect of the axial force on the optimal design is investigated. Numerical results are given for both single and laminated (up to five layers) cylindrical shells. The maximum burst pressure is computed using the three-dimensional interactive Tsai-: Wu failure criterion, which takes into account the influence of all stress components to the failure. Design optimisation of multilayered composite pressure vessels are based on the use of robust multidimensional methods which give fast convergence. Transverse shear and normal deformation higher-order theory for the solution of dynamic problems of laminated plates and shells is studied. The theory developed is based on the kinematic hypotheses which are derived using iterative technique. Dynamic effects, such as forces of inertia and the direct influence of external loading on the stress and strain components are included at the initial stage of derivation where kinematic hypotheses are formulated. The proposed theory and solution methods provide a basis for theoretical and applied studies in the field of dynamics and statics of the laminated shells, plates and their systems, particularly for investigation of dynamic processes related to the highest vibration forms and wave propagation, for optimal design etc. Geometrically nonlinear higher-order theory of laminated plates and shells with shear and normal deformation is derived. The theory takes into account both transverse shear and normal deformations. The number of numerical results are obtained based on the nonlinear theory developed. The results illustrate importance of the influence of geometrical nonlinearity, especially, at high levels of loading and in case when the laminae exhibit significant differences in their elastic properties. / Thesis (Ph.D.)-University of Natal, Durban, 1995.

Edited by Ali S. Argon. / Published in honor of Egon Orowan. / Includes bibliographies.

Estima-se que existam cerca de seis mil edifícios tipo caixão na região metropolitana do Recife que apresentam estrutura em situação de risco. Cerca de doze edifícios colapsaram espontaneamente, treze foram demolidos e dezenas de outros foram constatadas manifestações patológicas graves, motivando suas interdições. Este trabalho apresenta uma metodologia para o enfrentamento do problema, contemplando não apenas os aspectos técnicos, mas questões referentes aos riscos. Com isso se espera eliminar o estigma dessas edificações e resgatar a dignidade e segurança dos moradores dos prédios, através de um trabalho que tenham como base conceitos técnicos e científicos consagrados na Engenharia. A solução para o problema trata-se de uma proposta de criação de uma estrutura metálica a ser implantada nos prédios construídos em alvenaria resistente, em casos de falência das alvenarias que originalmente serviram de suporte para cargas que atuam na referida obra. Esta estrutura foi modelada e dimensionada pelo programa computacional Metálica 3D, apresentando resultados que responderam com total segurança todas as ações de carregamento que atuam nesse tipo de edificação para a modelagem adotada. Espera-se que a solução aqui proposta tenha um impacto social bastante significativo, dado a ocorrência de diversos acidentes com edifícios desta natureza, construídos em alvenaria resistente com a utilização de tijolos de vedação, vulgarmente conhecidos como prédios caixão / One can estimate that there are approximately six thousand four storey residential box-type buildings in Recife Metropolitan Region which presents structures in risk situation. Among those buildings, twelve collapsed spontaneously, thirteen were demolished and in many others it was observed serious pathologies that demanded restrictions to their occupation. This work presents a methodology to deal with this problem, contemplating technical aspect as well as risks issues. One expects to eliminate the stigma of these buildings and to contribute to give dignity and security back to their inhabitants through a work that must be done based on technical and scientific concepts accepted worldwide in structural engineering. The solution to the problem consists of a proposal to create a steel structure to be installed in such building that, in case of collapse of their support walls, should carry all loads that act on them. This solution was modeled and designed using a software called Metálica 3D, showing results that assure security to all load cases that usually act in this type of structure. One expects that the proposed solution can generate significant social impact, due to the occurrence of several accidents with this type of buildings constructed with non structural bricks carrying loads beyond its own weight

A obtenção de estruturas pré-moldadas de gesso apresentando resistências mecânicas consideráveis em relação aos pré-moldados convencionais tem sido obtidas com auxílio de aditivos, mais especificamente a adição de fibras sintéticas ou naturais, à pasta de gesso. Recentes trabalhos têm utilizado a prensagem como forma de dar ao pré-moldado de gesso características mecânicas bem superiores à aditivação por incorporação de fibras. Por se tratar de assunto de grande interesse comercial, a revelação das formas mais recentes de aditivação por prensagem não revelam tais parâmetros operacionais. O presente trabalho revisa a literatura sobre o assunto e define estratégias para a otimização das condições ótimas de produção desse tipo de pré-moldado. Os experimentos foram orientados por um delineamento composto central rotacional (DCCR) e analisado com auxílio da metodologia de superfície de resposta (MSR). A redução da água de empastamento e a compressão da pasta de gesso, de baixo desempenho mecânico, por prensagem, conferiram à microestrutura do pré-moldado características mecânicas especiais. Quando comparados com diferentes tipos de aditivação os resultados mostraram a validade do tipo de manuseio proposta para a confecção de pré-moldados / Obtaining structures precast gypsum having substantial mechanical resistance compared to conventional pre-molded has been obtained with the aid of additives, more specifically the addition of synthetic fibers or natural gypsum to the slurry. Recent studies have used as a way of pressing the pre-molded gypsum mechanical characteristics far superior to the additive by incorporation of fibers. Because it is matter of great commercial interest, the revelation of the newer forms to additive by pressing doesnt reveal such operational parameters. This paper reviews the literature on the subject and sets strategies for the optimization of the terms conditions for producing this type of precast. The experiments were guided by a central composite rotational design (CCRD) and analyzed with the aid of response surface methodology (RSM). The reduction of the water pasting and folder compression gypsum of poor mechanical properties by pressing conferred the pre-molded microstructure of special mechanical characteristics. When compared with different types of additives results showed the validity of the type of handling proposed for making precast