Articles publicats (D-EMCI)http://hdl.handle.net/10256/71432016-05-27T11:14:36Z2016-05-27T11:14:36ZModeling analysis of longitudinal thermoelectric energy harvester in low temperature waste heat recovery applicationsMassaguer Colomer, EduardMassaguer Colomer, AlbertMontoro Moreno, LinoGonzález Castro, Josep R.http://hdl.handle.net/10256/124362016-05-20T00:00:53Z2015-02-05T00:00:00ZModeling analysis of longitudinal thermoelectric energy harvester in low temperature waste heat recovery applications
Massaguer Colomer, Eduard; Massaguer Colomer, Albert; Montoro Moreno, Lino; González Castro, Josep R.
The worldwide interest in thermoelectric waste heat recovery is constantly growing, with a wide range of applications ranging from small harvesters integrated into wireless sensor networks all the way to larger harvesters such as the ones that can potentially be integrated into cars. The wide range of applications makes a requirement for studying the dynamic response of TEGs. The aim of this work is to develop a mathematical model to accurately simulate the thermal and electrical behaviours of a longitudinal thermoelectric energy harvester (LTEH). In order to implement the theoretical analysis, a new TRNSYS component has been developed so this new model can also be used as a design tool.The LTEH model presented in this paper is validated through the comparison of results between theoretical analysis and experimental data. Testing results and discussion show the reasonability of this new model and also their use as a simulation tool
2015-02-05T00:00:00ZDevelopment and validation of a new TRNSYS type for the simulation of thermoelectric generatorsMassaguer Colomer, EduardMassaguer Colomer, AlbertMontoro Moreno, LinoGonzález Castro, Josep R.http://hdl.handle.net/10256/124342016-05-20T00:00:51Z2014-12-01T00:00:00ZDevelopment and validation of a new TRNSYS type for the simulation of thermoelectric generators
Massaguer Colomer, Eduard; Massaguer Colomer, Albert; Montoro Moreno, Lino; González Castro, Josep R.
Thermoelectric generators (TEGs) make use of the Seebeck effect in semiconductors for the direct conversion of heat into electrical energy, being of particular interest for high reliability systems or for waste heat recovery. Although several TEG models can be found in the literature, many of them not offer a theoretical solution because they are based on steady-state solutions or they are assuming fixed parameters as boundary conditions. Consequently, to assess and optimize thermoelectric generators in real applications a numerical transient simulation tool, which takes into account the whole energy system, is mandatory. For that purpose, a new TRNSYS type is developed. This TEG component, which can be used as a design tool, is presented in this paper and validated using experimental data.The results show that the proposed component is able to cope with both thermal and electrical dynamics. The comparison between theoretic and experimental results has approved the reasonability of the new component. The normalized root mean square errors are 3.53% and 2.33% for temperature difference between hot and cold sides and electrical output power, respectively
2014-12-01T00:00:00ZGeometrical feature analysis of Co-Cr-Mo single tracks after selective laser melting processingMonroy, Karla P.Delgado Sanglas, JordiSerenó, LídiaCiurana, Quim deHendrichs, Nicolas J.http://hdl.handle.net/10256/123902016-05-06T00:00:54Z2015-01-01T00:00:00ZGeometrical feature analysis of Co-Cr-Mo single tracks after selective laser melting processing
Monroy, Karla P.; Delgado Sanglas, Jordi; Serenó, Lídia; Ciurana, Quim de; Hendrichs, Nicolas J.
Purpose - Therefore, the purpose of this study is to understand the relationships between the processing parameters and the geometric form of the produced single tracks, in order to control dimensional quality in future experimentations. The quality of the deposited single track and layer is of prime importance in the selective laser melting (SLM) process, as it affects the product quality in terms of dimensional precision and product performance. Design/methodology/approach - In this paper, a vertical milling machining center equipped with an Ytterbium-fiber laser was used in the SLM experimentation to form single cobalt-chromium-molybdenum (CoCrMo) tracks. The different geometric features and the influence of the scanning parameters on these morphologic characteristics were studied statistically by means of ANOVA. Findings - Evidently, track height (h1) inaccuracy reduced in layer thicknesses between 100 and 200 μm. The re-melt depth (h2) was determined by the energy parameters, with laser power of 325-350 W and scanning speed (SS) of 66.6-83.3 mm/s being the most favorable parameters to obtain the required anchoring. Moreover, a contact angle of 117° was proposed as optimal, as it permitted an adequate overlapping region and a full densification, and, finally, an SS of 50 mm/s and a layer thickness of 250 were suggested for its development. Originality/value - The comprehension of the phenomena inherent to the process is related to the single track geometrical characteristics, which allow the definition of an optimal value for each factor for a further proposal of processing conditions that can finally derive a higher precision, wetting, density and mechanical properties
2015-01-01T00:00:00ZA non-linear hyperelastic foundation beam theory model for double cantilever beam tests with thick flexible adhesiveCabello Ulloa, MarioZurbitu Gonzalez, JavierRenart Canalias, JordiTuron Blasco, AlbertMartínez, Félixhttp://hdl.handle.net/10256/123772016-05-04T00:00:51Z2016-01-01T00:00:00ZA non-linear hyperelastic foundation beam theory model for double cantilever beam tests with thick flexible adhesive
Cabello Ulloa, Mario; Zurbitu Gonzalez, Javier; Renart Canalias, Jordi; Turon Blasco, Albert; Martínez, Félix
Flexible adhesive joints, with adhesives of very low elastic modulus and very large failure deformation, are of special interest in industrial applications. Nevertheless, there is a lack of effective models for predicting their behaviour for structural applications. Existing methods developed for stiff compressible adhesives are not able to accurately capture the nonlinearities present on a thick flexible bondline. This paper presents a new analytical model for the simulation of a flexible adhesive bonded joint in a double cantilever beam (DCB) setup. Using the concepts of elastic foundation beam theory and developing them for a more general non-linear hyperelastic foundation case, a semi-analytical model is proposed. The effectiveness of the model, with respect to other approaches shown in the literature, is compared against experimental results for Krafft's flexible adhesive SILKRON POLYMER H-100. The hyperelastic foundation model accurately predicts the load-displacement response of the adhesive
2016-01-01T00:00:00ZAn automated methodology for mode II delamination tests under fatigue loading based on the real time monitoring of the specimen's complianceRenart Canalias, JordiVicens Cuyàs, JosepBudhe, Sandip RudhaRodríguez Bellido, Ana TeresaComas Baron, JordiMayugo Majó, Joan AndreuCosta i Balanzat, Josephttp://hdl.handle.net/10256/123762016-05-04T00:00:59Z2016-01-01T00:00:00ZAn automated methodology for mode II delamination tests under fatigue loading based on the real time monitoring of the specimen's compliance
Renart Canalias, Jordi; Vicens Cuyàs, Josep; Budhe, Sandip Rudha; Rodríguez Bellido, Ana Teresa; Comas Baron, Jordi; Mayugo Majó, Joan Andreu; Costa i Balanzat, Josep
This work introduces a procedure based on the real time monitoring of the specimen's compliance for the experimental characterization of the fatigue behaviour of interlaminar cracks in composites. The methodology was applied to a mode II loading in a three-point end notch flexure test. The onset point for fatigue damage was determined with a precision of one cycle by establishing a threshold on the compliance variation from its initial value. On the other hand, the crack growth rate curve was derived from the continuous monitoring of the compliance and an experimental calibration of said compliance. The precision of this methodology allowed the effect of commonly neglected phenomena such as the thermal expansion of the testing system or the friction between the specimen and the fixture, to be unveiled
2016-01-01T00:00:00ZA quasi-static indentation test to elucidate the sequence of damage events in low velocity impacts on composite laminatesWagih, A.Costa, J.Maimí Vert, PereBlanco Villaverde, NorbertCosta i Balanzat, Josephttp://hdl.handle.net/10256/123692016-05-04T00:00:53Z2016-01-01T00:00:00ZA quasi-static indentation test to elucidate the sequence of damage events in low velocity impacts on composite laminates
Wagih, A.; Costa, J.; Maimí Vert, Pere; Blanco Villaverde, Norbert; Costa i Balanzat, Josep
Any attempt to achieve composite laminates with improved damage tolerance to low velocity impacts must depart from the understanding of the sequence of damage mechanisms taking place. To this purpose, a series of quasi-static indentation experiments was conducted on AS4D/TC350 carbon/epoxy specimens. The induced damage at different indenter displacements was characterized using electron microscopy and C-scan, while the residual indentation profiles were captured with a 3D surface roughness machine. The indentation depth was shown to have relaxed after the test, reaching a steady value after 14 days. For the conditions explored, the relaxation was not dependent on the damage extent. The results showed that matrix cracking is in fact the crucial damage mechanism as it is responsible for the first sudden loss of load capacity and triggers the progressive growth of delaminations
2016-01-01T00:00:00ZModelling of tension-stiffening in bending RC elements based on equivalent stiffness of the rebarTorres Llinàs, LluísBarris Peña, CristinaKaklauskas, GintarisGribniak, Viktorhttp://hdl.handle.net/10256/123472016-04-30T00:00:54Z2015-01-01T00:00:00ZModelling of tension-stiffening in bending RC elements based on equivalent stiffness of the rebar
Torres Llinàs, Lluís; Barris Peña, Cristina; Kaklauskas, Gintaris; Gribniak, Viktor
The contribution of tensioned concrete between cracks (tension-stiffening) cannot be ignored when analysing deformation of reinforced concrete elements. The tension-stiffening effect is crucial when it comes to adequately estimating the load-deformation response of steel reinforced concrete and the more recently appeared fibre reinforced polymer (FRP) reinforced concrete. This paper presents a unified methodology for numerical modelling of the tension-stiffening effect in steel as well as FRP reinforced flexural members using the concept of equivalent deformation modulus and the smeared crack approach to obtain a modified stress-strain relation of the reinforcement. A closed-form solution for the equivalent secant modulus of deformation of the tensioned reinforcement is proposed for rectangular sections taking the Eurocode 2 curvature prediction technique as the reference. Using equations based on general principles of structural mechanics, the main influencing parameters are obtained. It is found that the ratio between the equivalent stiffness and the initial stiffness basically depends on the product of the modular ratio and reinforcement ratio (nρ), the effective-to-total depth ratio (d/h), and the level of loading. The proposed methodology is adequate for numerical modelling of tension-stiffening for different FRP and steel reinforcement, under both service and ultimate conditions. Comparison of the predicted and experimental data obtained by the authors indicates that the proposed methodology is capable to adequately model the tension-stiffening effect in beams reinforced with FRP or steel bars within wide range of loading
2015-01-01T00:00:00ZIncremental forming of polymers: Process parameters selection from the perspective of electric energy consumption and costBagudanch Frigolé, IsabelGarcia-Romeu, Maria LuisaSabater, M.http://hdl.handle.net/10256/122032016-03-09T13:09:46Z2015-01-01T00:00:00ZIncremental forming of polymers: Process parameters selection from the perspective of electric energy consumption and cost
Bagudanch Frigolé, Isabel; Garcia-Romeu, Maria Luisa; Sabater, M.
In recent years, environmental and sustainability concerns have attracted considerable attention in the field of mechanical engineering. A number of contributions have focused on the environmental footprint or life cycle analyses of typical manufacturing processes. However, for forming processes, this kind of analysis has just begun. To further the work in this area, this study assessed the influence of a number of process parameters on energy consumption in Single Point Incremental Forming (SPIF). Consequently, a campaign of experiments for two polymer materials (polycarbonate (PC) and polyvinylchloride (PVC)) was carried out. The results are used to identify the most suitable combination of process parameters in order to minimize energy consumption and costs
2015-01-01T00:00:00ZElectrically tunable thermal conductivity in thermoelectric materials: Active and passive controlMassaguer Colomer, AlbertMassaguer Colomer, EduardPujol i Sagaró, ToniComamala Laguna, MartíMontoro Moreno, LinoGonzález Castro, Josep R.http://hdl.handle.net/10256/122022016-03-04T01:00:50Z2015-01-01T00:00:00ZElectrically tunable thermal conductivity in thermoelectric materials: Active and passive control
Massaguer Colomer, Albert; Massaguer Colomer, Eduard; Pujol i Sagaró, Toni; Comamala Laguna, Martí; Montoro Moreno, Lino; González Castro, Josep R.
Applications involving the use of thermoelectric materials can be found in many different areas ranging from thermocouple sensors, portable coolers, to solar power generators. Generally, they can be subdivided by the direction of energy conversion. While the Peltier effect is used in solid-state refrigeration, the Seebeck effect is responsible for the conversion of temperature gradients into electrical voltage in energy harvesting systems. However, this paper proposes a novel approach to the use of thermoelectric couples, treating them as variable insulators in thermal systems. Here, we demonstrate that thermal conductivity in thermoelectric materials can be externally controlled by electrical parameters such as electrical load or DC voltage in passive and active systems, respectively. Active mode is a good solution when a complete insulation or a high control of thermal conductivity is needed. Passive mode permits a thermal conductivity increment of 1. +. ZTtimes with respect to semiconductor initial thermal conductivity. Results open new doors and new opportunities for thermoelectric materials
2015-01-01T00:00:00ZA quick procedure to predict free-edge delamination in thin-ply laminates under tensionGuillamet Busquets, GerardTuron Travesa, AlbertCosta i Balanzat, JosepLinde, Peterhttp://hdl.handle.net/10256/121252016-02-24T01:00:49Z2015-01-01T00:00:00ZA quick procedure to predict free-edge delamination in thin-ply laminates under tension
Guillamet Busquets, Gerard; Turon Travesa, Albert; Costa i Balanzat, Josep; Linde, Peter
Delaminations at the free-edges of a laminated composite under tension can be triggered by transverse cracks or by high interlaminar stresses. The capability for predicting these phenomena when the ply thickness is reduced (thin-ply laminates) is particularly challenging because damage mechanisms are delayed or even suppressed. In this work, an existing energy-based failure criterion and a simplified finite element model with cohesive elements are combined to develop a computationally inexpensive predictive tool. Its comparison with experimental data demonstrates that this approach captures the trends of the critical strain for delamination with respect to ply thickness and ply location and the quantitative agreement with the predictions is satisfactory
2015-01-01T00:00:00Z