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- 21st century quality: Looking into the “Crystal ball”Publication . Fonseca, Luís Miguel CiravegnaThe discussion of possible scenarios for the future of Quality is on the priority list of major Quality Practitioners Societies. EOQ – European Organization for Quality (EOQ, 2014) main team for its 58th EOQ-Congress held June 2014 in Göteborg was “Managing Challenges in Quality Leadership” and ASQ - American Society for Quality (ASQ, 2015) appointed “the Future of Quality” for Quality Progress Magazine November 2015 issue. In addition, the ISO 9001:2008 revision process carried by ISO/TC 176 aims to assure that ISO 9001:2015 International Standard remains stable for the next 10 years (ISO, 2014) contributing to an increased discussion on the future of quality. The purpose of this research is to review available Quality Management approaches and outline, adding an academic perspective, expected developments for Quality within the 21st Century. This paper follows a qualitative approach, although data from international organizations is used. A literature review has been undertaken on quality management past and potential future trends. Based on these findings a model is proposed for organization quality management development and propositions for the future of quality management are advanced. Firstly, a state of the art of existing Quality Management approaches is presented, for example, like Total Quality Management (TQM) and Quality Gurus, ISO 9000 International Standards Series (with an outline of the expected changes for ISO 9001:2015), Six Sigma and Business Excellence Models.Secondly, building on theoretical and managerial approaches, a two dimensional matrix – Quality Engineering (QE - technical aspects of quality) and Quality Management (QM: soft aspects of quality) - is presented, outlining five proposed characterizations of Quality maturity levels and giving insights for applications and future developments. Literature review highlights that QM and QE may be addressing similar quality issues but their approaches are different in terms of scope breadth and intensity and they ought to complement and reciprocally reinforce one another. The challenges organizations face within the 21st century have stronger uncertainty, complexity, and differentiation. Two main propositions are advanced as relevant for 21st Century Quality: - QM importance for the sustainable success of organizations will increase and they should be aware of the larger ecosystem to be managed for improvement, possibly leading to the emergence of a new Quality paradigm, The Civilizacional Excellence paradigm. - QE should get more attention from QM and the Quality professionals will have to: a) Master and apply in wider contexts and in additional depth the Quality Tools (basic, intermediate and advanced); b) Have the soft skills needed for its success; c) Be results oriented and better understand and demonstrate the relationships between approaches and results These propositions challenge both scholars and practitioners for a sustained and supported discussion on the future of Quality. “All things are ready, if our mind be so.” (Shakespeare, Henry V, circa 1599).
- 3D finite element analysis and optimization of cap ply production system in the tire industryPublication . Silva, André; Silva, Francisco J. G.; Campilho, R.D.S.G.; Neves, Pedro M.P.F.In automotive industry, tires play a key role. They are a composite structure formed by multiple layers of different materials such as rubber compounds, steel and polyamide cords. Between the tread and steel belts, a cap ply layer is used to restrict the growth of the tire, due to centrifugal forces. Cap ply is produced by using a pultrusion process that impregnates polyamide cords with rubber, resulting in a rubberized strip. When the controlling of the process is incorrect, premature vulcanization or lack of impregnation is often observed. To optimize the production process, CFD (Computational Fluid Dynamics) simulations were performed to study the flow of rubber inside the extrusion head channels by modelling the fluid properties and the domain. Laboratory tests were also conducted to determine the physical and cure properties of the rubber compound used. Crossing the results of the simulations with the laboratory tests was found that the temperature control used was inadequate. Simulations were also supported with the results provided by a temperature sensor controlled by an external device (Arduino). By using a proportional integral derivative controller and changing the setpoints for the thermal resistance, the amount of scrap generated by vulcanized rubber and lack of rubber in the cap ply strips was reduced by 100%.
- 3D printed devices to avoid hand contact with commonly shared surfacesPublication . Pais, A.; Ferreira, C.; Pires, V.; Silva, V.; Alves, J. Lino; Bastos, João; Belinha, JorgeIn the context of the COVID-19 pandemic, public spaces had to be quickly adapted to the new circumstances especially under the uncertainty of the pandemic development. Door handles are some of the most touched surfaces and so, this point of contagion was chosen to be tackled and two solutions were developed that would prevent direct touch with the handle: a portable and a fixed device. The portable device (HYHOOK + HYTIP) is a hook-like device holding a finger cover, which permits to open doors and push buttons safely. The fixed device (HANDGENIC) is meant to be assembled in door handles to equip buildings, such as universities or schools. With the fixed device, the user can open the door using their forearm which makes them less likely to transfer any particles to eyes, nose or mouth. The 3D printing Fused Filament Fabrication (FFF) process was selected as manufacturing technique, which allows the fast production of prototypes. This work portrays the development process and design iterations taking into consideration the concerns about the functioning of the devices and possible failures or alternative uses. To assure structural integrity of the parts, finite element (FE) analysis was used to verify its mechanical response. As conclusion, it was found that FE analysis indicate that the devices are structurally sound to be used in public spaces and that 3D printing is a useful way to rapidly develop devices while testing several design possibilities.
- Adherend effect on the peel strength of a brittle adhesivePublication . Pereira, J.P.O.; Campilho, R.D.S.G.; Nóvoa, P.J.R.O.; Silva, Francisco J. G.; Gonçalves, D.C.Peel tests are widely used to characterize the peel strength of bonded joints and control adhesion quality. There are various configurations of peel test, such as the T-peel test, peel testing at 180°, the floating roller peel test, and the climbing drum peel test. These methods have been widely used mainly in the aeronautical industry, as a way of assessing the peel strength of metallic joints. However, with the growing use of composite materials in industry, it is necessary to characterize bonded joints with these materials when subjected to peeling loads. In this research, the adherend effect on the peel strength of a brittle adhesive is experimentally studied using the floating roller peel test with the aim of evaluating how adherend changes affect adhesion properties of brittle adhesives and also to assess the viability of using the floating roller peel test in composite-to-composite and composite-to-aluminum joints, as well as make a comparison with aluminum-aluminum joint performance. It is also intended to prove the applicability of this test for quality control of adhesion and determination of peel strength in joints with composite materials. The results show the Araldite® AV138 performance falls within the characteristic values of peel strength of other structural adhesives, particularly when composite adherends are concerned, and with reasonable repeatability considering it is a brittle adhesive.
- Adherend thickness effect on the tensile fracture toughness of a structural adhesive using an optical data acquisition methodPublication . Campilho, Raul; Moura, Daniel C.; Banea, Mariana D.; Silva, Lucas F. M. daAdhesive bonding is nowadays a serious candidate to replace methods such as fastening or riveting, because of attractive mechanical properties. As a result, adhesives are being increasingly used in industries such as the automotive, aerospace and construction. Thus, it is highly important to predict the strength of bonded joints to assess the feasibility of joining during the fabrication process of components (e.g. due to complex geometries) or for repairing purposes. This work studies the tensile behaviour of adhesive joints between aluminium adherends considering different values of adherend thickness (h) and the double-cantilever beam (DCB) test. The experimental work consists of the definition of the tensile fracture toughness (GIC) for the different joint configurations. A conventional fracture characterization method was used, together with a J-integral approach, that take into account the plasticity effects occurring in the adhesive layer. An optical measurement method is used for the evaluation of crack tip opening and adherends rotation at the crack tip during the test, supported by a Matlab® sub-routine for the automated extraction of these quantities. As output of this work, a comparative evaluation between bonded systems with different values of adherend thickness is carried out and complete fracture data is provided in tension for the subsequent strength prediction of joints with identical conditions.
- Adhesive selection for hybrid spot-welded/bonded single-lap joints: Experimentation and numerical analysisPublication . Marques, G.P.; Campilho, Raul; Silva, F.J.G. da; Moreira, R.D.F.The applications of adhesive joints are increasing in various industrial applications because they offer several advantages over traditional methods. The combination of adhesive bonding with spot-welding enables some advantages over adhesive joints such as increased stiffness, and higher static and fatigue strength. This work relates to the adhesive selection for single-lap adhesive joints by the bonding and hybrid (bonded and welded) techniques with different overlap lengths (LO). The adhesives are the brittle Araldite AV138®, and the ductile Araldite® 2015 and Sikaforce® 7752. The experimental results were compared against a Finite Element (FE) study coupled with Cohesive Zone Modelling (CZM). The results validated the numerical technique and also showed varying strength improvements of the hybrid joints over bonded joints depending of the adhesive.
- Adhesive selection for single lap bonded joints: Experimentation and advanced techniques for strength predictionPublication . Fernandes, Tiago; Campilho, Raul; Banea, Mariana D.; Silva, Lucas daThe integrity of multi-component structures is usually determined by their unions. Adhesive-bonding is often used over traditional methods because of the reduction of stress concentrations, reduced weight penalty, and easy manufacturing. Commercial adhesives range from strong and brittle (e.g., Araldite® AV138) to less strong and ductile (e.g., Araldite® 2015). A new family of polyurethane adhesives combines high strength and ductility (e.g., Sikaforce® 7888). In this work, the performance of the three above-mentioned adhesives was tested in single lap joints with varying values of overlap length (LO). The experimental work carried out is accompanied by a detailed numerical analysis by finite elements, either based on cohesive zone models (CZM) or the extended finite element method (XFEM). This procedure enabled detailing the performance of these predictive techniques applied to bonded joints. Moreover, it was possible to evaluate which family of adhesives is more suited for each joint geometry. CZM revealed to be highly accurate, except for largely ductile adhesives, although this could be circumvented with a different cohesive law. XFEM is not the most suited technique for mixed-mode damage growth, but a rough prediction was achieved.
- Adhesive thickness effects of a ductile adhesive by optical measurement techniquesPublication . Campilho, Raul; Moura, D.C.; Banea, Mariana D.; Silva, L.F.M. daAdhesive bonding is an excellent alternative to traditional joining techniques such as welding, mechanical fastening or riveting. However, there are many factors that have to be accounted for during joint design to accurately predict the joint strength. One of these is the adhesive layer thickness (tA). Most of the results are for epoxy structural adhesives, tailored to perform best with small values of tA, and these show that the lap joint strength decreases with increase of tA (the optimum joint strength is usually obtained with tA values between 0.1 and 0.2 mm). Recently, polyurethane adhesives were made available in the market, designed to perform with larger tA values, and whose fracture behaviour is still not studied. In this work, the effect of tA on the tensile fracture toughness (View the MathML source) of a bonded joint is studied, considering a novel high strength and ductile polyurethane adhesive for the automotive industry. This work consists on the fracture characterization of the bond by a conventional and the J-integral techniques, which accurately account for root rotation effects. An optical measurement method is used for the evaluation of crack tip opening (δn) and adherends rotation at the crack tip (θo) during the test, supported by a Matlab® sub-routine for the automated extraction of these parameters. As output of this work, fracture data is provided in traction for the selected adhesive, enabling the subsequent strength prediction of bonded joints.
- Advanced Characterization of Adhesive Joints and AdhesivesPublication . Campilho, Raul; Madani, Kouider; Prakash, ChanderStructural adhesives have shown significant improvements in their behavior over the past few decades. This has enabled their application to become a reality in many sectors of activity, including the aeronautics and the automotive industry [1]. This evolution has been strongly supported by an intense investigation into adhesive joints and their behavior. Despite this intense research, there is still much to be explored regarding this matter, which translates into a continuous investigation of the failure modes of these types of joints, the characterization of new adhesives, the design of new joint geometries, and the use of hybrid joints, with a view to eliminating or reducing the less positive aspects presented by these joints, taking advantage of the best characteristics of each type of joint. Numerical methods have played an extremely important role in the prediction of the joints’ behavior, helping to find the best solutions to the typical problems presented by these kinds of joints [2]. Strength prediction techniques can be mainly divided into static and dynamic, with the former being subjected to a wider research effort from the academic community. Nonetheless, recently, significant efforts have been made to address complex dynamic loadings, such as fatigue and impact. (...)
- Advanced numerical methods for the strength prediction of hybrid adhesively bonded T-peel jointsPublication . Faria, R.V.F.; Campilho, R.D.S.G.; Gonçalves, P.J.A.; Rocha, R.J.B.The market requirements impose searching for new joining solutions, which must be simple and effective. Adhesive joints are currently used, for example in the automotive and aeronautical industries, since welding is not possible in many cases and because drilling the base materials is not required. To analyse adhesive joints, the Finite Element Method (FEM) is increasingly used. The Extended Finite Element Method (XFEM) is able to predict crack growth and joint strength in adhesive structures. However, there are still not many case studies about its suitability. On the other hand, hybrid joints, which combine spot-welding with adhesive bonding, are being increasingly used in different industries. This study has the purpose of validating the XFEM to predict the performance of T-peel hybrid joints between DIN C45E steel adherends under tensile loads. A comparison is made with spot-welded and adhesive joints. Three adhesives are tested (Araldite® AV138, Araldite® 2015 and Sikaforce® 7752). Different damage initiation and growth criteria, and also damage law shapes, were evaluated for strength and dissipated energy predictions. The joints’ performance was found to highly vary between adhesives and bonding method, and the XFEM analysis is accurate for specific modelling conditions.