Numerical Modelling and Validation of Mixed-Mode Fracture Tests to Adhesive Joints Using J-Integral Concepts

The interest in the design and numerical modelling of adhesively-bonded components and structures for industrial application is increasing as a research topic. Although research on joint failure under pure mode is widespread, applied bonded joints are often subjected to a mixed mode loading at the crack tip, which is more complex than the pure mode and affects joint strength. Failure of these joints under loading is the objective of predictions through mathematical and numerical models, the latter based on the Finite Element Method (FEM), using Cohesive Zone Modelling (CZM). The Single leg bending (bending) testing is among those employed to study mixed mode loading. This work aims to validate the application of FEM-CZM to SLB joints. Thus, the geometries used for experimental testing were reproduced numerically and experimentally obtained properties were employed in these models. Upon the validation of the numerical technique, a parametric study involving the cohesive laws’ parameters is performed, identifying the parameters with the most influence on the joint behaviour. As a result, it was possible to numerically model SLB tests of adhesive joints and estimate the mixed-mode behaviour of different adhesives, which enables mixed-mode modelling and design of adhesive structures.info:eu-repo/semantics/publishedVersio

Design of a Spiral Double-Cutting Machine for an Automotive Bowden Cable Assembly Line

The manufacture of automotive components requires innovative technologies and equipment. Due to the competitiveness in the sector, the implementation of automatic and robotic equipment has been vital in its development to produce the largest number of products in the shortest amount of time. Automation leads to a significant reduction in defects and enables mass production and standardization of the final product. This work was based on the need of an automotive components’ company to increase the rate of spiral cable cutting, used as protection for Bowden (control) cables. Currently, this component, used in automotive systems, is processed with simple cutting machines and cleaning machines. Based on the design science research (DSR) methodology, this work aims to develop a machine capable of performing the cutting and cleaning of two spiral cables simultaneously and automatically. The development of this machine was based on existing machines, and the biggest challenge was the implementation of a double-cutting system. The designed machine met the initial requirements, such as enabling the simultaneous cut of two spirals, being fully automatic, doubling the output over the current solution, and fully complying with the current legislation.info:eu-repo/semantics/publishedVersio

Improving the Efficiency of the Bowden Cable Terminal Injection Process for the Automotive Industry

Control cables transfer force between two separate locations by a flexible mean, and hence, they are important in the automotive industry and many others; their terminals interact with both moving and moved mechanisms, so they must be strong. Cable terminals are commonly made of ZAMAK and are created by injection molding. However, such a production method requires leaving extra material to allow the correct molding, also known as sprues, which are removed later in the process. In this case, the sprues were separating from the terminals in an uncontrolled way. In this work, the cause of sprues separating prematurely from the terminals in a production line is addressed. The whole process was analyzed, and each possible solution was evaluated using process improvement techniques and the Finite Element Method, leading to the best solutions. Molds, mold structures, and auxiliary equipment were improved, resulting in a minimally invasive intervention and remaining compatible with other equipment. Cost analyses were done, indicating an investment return in less than a year. The modification led to a reduction of 62.6% in the sprue mass, while porosity was reduced by 10.2% and 55.9%, corresponding to two terminal models. In conclusion, the interventions fulfilled the requirements and improved the operation of the line.info:eu-repo/semantics/publishedVersio

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Numerical analysis of the dynamic behaviour of adhesive joints: A review

Adhesive joints are being increasingly used in various industries, including the automotive or the wind turbines industries. Such increasing interest is a direct result of its high structural efficiency and also the product of its related scientific research. Therefore, the state-of-the-art on adhesive joints is significantly expanding. The current work aims to discuss the most recent works dedicated to the numerical analysis of the dynamic behaviour of adhesive joints. Dynamic behaviour was divided into three separate fields: fatigue, variable strain rate and impact, and modal analysis. It was found that Cohesive Zone Models are a popular approach to study fatigue, variable strain rates and impact. Additionally, the available literature focused on fatigue and impact is more extensive than the one focused on modal analysis. Overall, it was found that the available research on the numerical analysis of the dynamic behaviour of adhesive joints is increasing at a solid rate, and many geometrical and material variations have been tested numerically. With this review designers and researchers of adhesive joints should be able to choose the most suitable numerical technique for their specific dynamic analysis.The authors truly acknowledge the funding provided by Ministério da Ciência, Tecnologia e Ensino Superior – Fundação para a Ciência e a Tecnologia (Portugal), under project funding MIT-EXPL/ISF/0084/ 2017, POCI-01-0145-FEDER-028351 and SFRH/BD/147628/2019. Additionally, the authors gratefully acknowledge the funding of Project NORTE-01-0145-FEDER-000022 – SciTech – Science and Technology for Competitive and Sustainable Industries, co-financed by Programa Operacional Regional do Norte (NORTE2020), through Fundo Europeu de Desenvolvimento Regional (FEDER).info:eu-repo/semantics/publishedVersio

Development of a rotation and lifting system for pallet rotary tables

Nowadays, the flow of raw materials and finished products is important for the success of the supply chain. Intra-logistics integrates, optimises, manages and automates the logistics of materials in warehouses, to maximise productivity. Thus, the flow of products needs to be as efficient as possible. Conventional pallet handling equipment is commercially available from specialised manufacturers. However, if a combination of movements such as rotation, transfer and lifting is required, two solutions can be adopted. One possibility consists of arranging several commercial pieces of equipment to complete the task. Another choice is to develop a custom equipment, as no commercial device can perform all tasks with a small footprint. In this work, a fully automatic pallet handling device is designed and validated, using numerical modelling, to serve as a rotation and lifting system for pallets within a commercial warehouse. The device is designed to fit into an existing conveyor system composed of roller and chain conveyor types. Thus, the device compensates for the difference in height between the two conveyor systems, easing the pallet transport using forklifts by rotating them. The device was designed following the customer’s design requirements and incorporates four main systems. After the entire process of designing and defining the device, it was produced, assembled, and installed in the client’s warehouse. The end-product is a fully functional and validated automatic solution for the rotation of pallets where it was possible to facilitate the pallets’ handling through forklifts, simplifying the necessary manoeuvres.info:eu-repo/semantics/publishedVersio

Introductory application of a natural neighbour meshless elastic formulation to double-lap adhesive joints

Nowadays, adhesive bonding is an essential joining technique in top-end sectors, such as aircraft, automotive, and construction industries. Due to their advantages over traditional joining methods, adhesive joints research has been under huge developments in recent years, being the development of accurate and efficient numerical techniques a leading challenge in adhesive joint design. Although the finite element method (FEM) is an established discretisation technique, meshless methods emerged as alternative discretisation methods to evaluate adhesive joints. Nonetheless, meshless techniques still require deeper research in adhesive joint simulations, where strength prediction is hindered by intricate stress states and material behaviour. This paper aims to evaluate the natural neighbours radial point interpolation method (NNRPIM) in the linear analysis of adhesive joints. The capability of the method was addressed by comparing it with analytical models, the FEM and experimental data. As the applications of meshless methods to analyse adhesive joints are scarce, this work evaluates the behaviour of double-lap joints (DLJ) considering distinct overlap lengths and adhesive materials. DLJ has a different behaviour than single-lap joints, which are more commonly analysed. Thus, this work provides a preliminary linear analysis, which could be the basis for further analyses of adhesive joints combining the NNRPIM with elastic–plastic, hyper-elastic, and large deformations formulations. Although it is remarked that elastic formulations underpredict joint strength, the NNRPIM shows similar results to the FEM, which supports the extension of the NNRPIM to more representative mathematical formulations and complex joint designs.This work has been funded by the Ministério da Ciência, Tecnologia e Ensino Superior through the Fundação para a Ciência e a Tecnologia (from Portugal), under project fundings ‘MITEXPL/ISF/0084/2017’, ‘POCI-01-0145-FEDER-028351’, and ‘SFRH/ BD/147628/2019’. Additionally, the authors acknowledge the funding provided by the Associated Laboratory for Energy, Transports and Aeronautics (LAETA), under project ‘UIDB/50022/2020’.info:eu-repo/semantics/publishedVersio

Search for narrow resonances using the dijet mass spectrum in pp collisions at s√=8 TeV

Results are presented of a search for the production of new particles decaying to pairs of partons (quarks, antiquarks, or gluons), in the dijet mass spectrum in proton-proton collisions at s√=8  TeV. The data sample corresponds to an integrated luminosity of 4.0  fb−1, collected with the CMS detector at the LHC in 2012. No significant evidence for narrow resonance production is observed. Upper limits are set at the 95% confidence level on the production cross section of hypothetical new particles decaying to quark-quark, quark-gluon, or gluon-gluon final states. These limits are then translated into lower limits on the masses of new resonances in specific scenarios of physics beyond the standard model. The limits reach up to 4.8 TeV, depending on the model, and extend previous exclusions from similar searches performed at lower collision energies. For the first time mass limits are set for the Randall–Sundrum graviton model in the dijet channel