Nuestros investigadores

Aitor Cazón Martín

Departamento de Ingeniería Mecánica y Materiales
Escuela de Ingeniería (TECNUN). Universidad de Navarra
Líneas de investigación
Fabricación Aditiva, Wearable
Índice H
5, (Scopus, 16/04/2019)
4, (WoS, 14/01/2020)

Publicaciones científicas más recientes (desde 2010)

Autores: Francés Morcillo, Leire; Morer Camo, María de la Paz; Rodríguez Ferradas, María Isabel; et al.
Revista: SENSORS
ISSN 1424-8220  Vol. 20  Nº 9  2020  págs. 2599
Wearable electronics make it possible to monitor human activity and behavior. Most of these devices have not taken into account human factors and they have instead focused on technological issues. This fact could not only affect human¿computer interaction and user experience but also the devices¿ use cycle. Firstly, this paper presents a classification of wearable design requirements that have been carried out by combining a quantitative and a qualitative methodology. Secondly, we present some evaluation procedures based on design methodologies and human¿computer interaction measurement tools. Thus, this contribution aims to provide a roadmap for wearable designers and researchers in order to help them to find more efficient processes by providing a classification of the design requirements and evaluation tools. These resources represent time and resource-saving contributions. Therefore designers and researchers do not have to review the literature. It will no be necessary to carry out exploratory studies for the purposes of identifying requirements or evaluation tools either.
Autores: Francés Morcillo, Leire (Autor de correspondencia); Morer Camo, María de la Paz; Rodríguez Ferradas, María Isabel; et al.
Revista: SENSORS
ISSN 1424-8220  Vol. 20  Nº 10  2020  págs. 2934
This paper presents a user-centered methodology to co-design and co-evaluate wearables that has been developed following a research-through design methodology. It has been based on the principles of human-computer interaction and on an empirical case entitled "Design and Development of a Low-Cost Wearable Glove to Track Forces Exerted by Workers in Car Assembly Lines" published in Sensors. Insights from both studies have been used to develop the wearable co-design domino presented in this study. The methodology consists of different design stages composed of an ideation stage, digital service development and test stages, hardware development and test stage, and a final test stage. The main conclusions state that it is necessary to maintain a close relationship between human factors and technical factors when designing wearable. Additionally, through the several studies, it has been concluded that there is need of different field experts that should co-design and co-evaluate wearable iteratively and involving users from the beginning of the process.
Autores: Francés Morcillo, Leire (Autor de correspondencia); Morer Camo, María de la Paz; Rodríguez Ferradas, María Isabel; et al.
Revista: SENSORS
ISSN 1424-8220  Vol. 19  Nº 2  2019 
Wearables are gaining widespread use and technologies are making it possible to monitor human physical activity and behaviour as part of connected infrastructures. Many companies see wearables as an opportunity to enhance worker safety since they can monitor their workers' activity in real life scenarios. One of the goals of this technology is to integrate existing electronic components, such as sensors or conductors, in order to create fully wearable systems. This integration is constrained not only by technical factors but also by user requirements and internal company standards. This paper considers such constraints and presents preliminary research for the design of a wearable glove as a new tool to track forces exerted by workers in car assembly lines. The objective of the glove is to measure forces and compare these to maximum forces already identified by the company. Thus, the main objectives are to: (1) integrate the components based on the requirements of the users and the context of application, and (2) provide a new tool that can be used in situ to track workers. This study was carried out in close collaboration with Volkswagen through a human-centred iterative design process. Thus, this paper presents the development of a wearable device glove based on a specific design methodology where both the human and technological aspects are considered.
Autores: Cazón Martín, Aitor; Iturrizaga Campelo, Macarena; Matey Muñoz, Luis Mariano; et al.
ISSN 1754-3371  Vol. 233  Nº 1  2019  págs. 160 - 169
Shin pads are part of the mandatory equipment footballers must wear so as to prevent lesions. Most players wear commercially available shin pads made from a variety of common materials (polypropylene or polyethylene) and high-resistance materials (glass fibre, carbon fibre or Kevlar) using traditional manufacturing techniques. Additive manufacturing was used years ago to deliver customised rigid shin pads, but they did not offer any significant advantage in terms of materials or design compared to traditional shin pads. This project analyses a novel approach to the design and manufacture of shin pads for football players that combines existing digitisation tools, lattice structures and a multi-material additive manufacturing device. A total of 24 different additive manufacturing geometries were evaluated using a customised rig where a 1-kg impactor was released from several heights (100-400 mm). The impact acceleration, the transmitted force to the leg and penetration were calculated. Results were compared against two commercially available shin pads. Results show that two of the additive manufacturing specimens tested at the highest drop height had lower impact accelerations than commercial shin pads. They had an acceleration reduction between 42% and 68% with respect to the commercial shin pads. Regarding the penetration, the improvement achieved with additive manufacturing specimens ranged from 13% to 32%, while the attenuation and the contact times were similar.
Autores: Calvo, J. O.; Cazón Martín, Aitor (Autor de correspondencia); Rodríguez Ferradas, María Isabel; et al.
Revista: DYNA
ISSN 0012-7361  Vol. 94  Nº 2  2019  págs. 221 - 225
Additive Manufacturing devices or 3D printers allow the possibility of creating almost anything. One of the most promising fields of application are wearable devices, which can be directly printed on textiles. This paper aims to study adhesion forces and warping effects when depositing a polymer onto a textile with a low-cost extrusion 3D printer. To achieve this, two different polymers (PLA and Filaflex) and six of the most common textile materials were selected. L-shaped specimens were printed by combining the two polymers and the six textiles. Most of the common printing settings were fixed for both materials, while the layer quality was 0.1 mm and 0.2 mm. Once printed, they were inspected with a Coordinate Measuring Machine and the deformation of each specimen was quantified by calculating their maximum and minimum displacements. Afterwards, each specimen was axially tested to evaluate the adhesion forces between the polymer and the textile. In terms of warping, flexible filament showed the lowest values independent of printing quality (0.56 mm and 0.3 mm) relative to the rigid filament (0.73 mm and 0.8 mm). In terms of adhesion, the combination of a porous textile and a flexible filament got the highest values, regardless of the layer height selected. The conclusion of this study is that polymer textile deposition can be a real manufacturing strategy that should be considered when thinking about the design of a wearable device to be worn on the body.
Autores: Chuan, C; Cazón Martín, Aitor (Autor de correspondencia); Rodríguez Ferradas, María Isabel; et al.
ISSN 1355-2546  Vol. 26  Nº 2  2019  págs. 349 - 359
Purpose The purpose of this study is to explore a methodology for connecting microelectromechanical system sensors - i.e. inertial measurement unit (IMU) - to an Arduino-based microcontroller, using graphene-based conductive filament and flexible thermoplastic polyurethane (FTPU) filament and low-cost dual material extrusion technology. Design/methodology/approach A series of electrical tests were carried out to determine the maximum resistance the conductive paths may take to connect printed circuit boards (PCB). To select the most suitable printing material, three types of conductive filaments were examined. Then an experiment was carried out to find the best printing parameters in terms of printing speed, printing temperature and layer height to minimise resistivity. The size of the conductive path was also analysed. A final prototype was designed and printed according to optimised printing settings and maximum allowable resistances for each line and considering different geometries and printing strategies to reduce cross-contamination among paths. Findings For the Black Magic 3D conductive filament, the printing speed and layer height played a significant role regarding resistivity, while the printing temperature was not very important. The infill pattern of the conductive paths had to be aligned with the expected current path, while using air gaps between two adjacent paths resulted in the best approach to reducing cross-contamination. Moreover, the cross-section size of
Autores: Francés Morcillo, Leire (Autor de correspondencia); Morer Camo, María de la Paz; Rodríguez Ferradas, María Isabel; et al.
Revista: DYNA
ISSN 0012-7361  Vol. 93  2018  págs. 421 - 427
Many industrial companies are now getting on board the new industrial revolution dominated by data acquisition, digitalization and other new technologies. Wearables combine the features of some of the most popular technologies of this revolution: they can monitor specific body regions by tracking information anywhere and anytime. Wearable systems for hands represent a special field of interest since they are the main body region involved in industrial tasks. This paper surveys such wearable systems based on the data from the last years. It collects information about the most important components they incorporate and analyses their features considering that they are devices aimed to be worn on the body. Thus, this paper is addressed to researchers who want to understand what a wearable is and which the main components and characteristics should incorporate, and also, those who want to explore new trends in this research field.
Autores: Ruiz de Galarreta Moriones, Sergio; Antón Remírez, Raúl; Cazón Martín, Aitor; et al.
ISSN 0021-9290  Vol. 57  2017  págs. 161 - 166
An Abdominal Aortic Aneurysm (AAA) is a permanent focal dilatation of the abdominal aorta at least 1.5 times its normal diameter. The criterion of maximum diameter is still used in clinical practice, although numerical studies have demonstrated the importance of biomechanical factors for rupture risk assessment. AAA phantoms could be used for experimental validation of the numerical studies and for pre intervention testing of endovascular grafts. We have applied multi-material 3D printing technology to manufacture idealized AAA phantoms with anisotropic mechanical behavior. Different composites were fabricated and the phantom specimens were characterized by biaxial tensile tests while using a constitutive model to fit the experimental data. One composite was chosen to manufacture the phantom based on having the same mechanical properties as those reported in the literature for human AAA tissue; the strain energy and anisotropic index were compared to make this choice. The materials for the matrix and fibers of the selected composite are, respectively, the digital materials FLX9940 and FLX9960 developed by Stratasys. The fiber proportion for the composite is equal to 0.15. The differences between the composite behavior and the AAA tissue are small, with a small difference in the strain energy (0.4%) and a maximum difference of 12.4% in the peak Green strain ratio. This work represents a step forward in the application of 3D printing technology for the manufacturing of AAA phantoms with anisotropic mechanical behavior. (C) 2017 Elsevier Ltd. All rights reserved.
Autores: Cazón Martín, Aitor; Kelly, S.; Paterson, A. M.; et al.
ISSN 0954-4119  Vol. 231  Nº 9  2017  págs. 881 - 897
Rheumatoid arthritis is a chronic disease affecting the joints. Treatment can include immobilisation of the affected joint with a custom-fitting splint, which is typically fabricated by hand from low temperature thermoplastic, but the approach poses several limitations. This study focused on the evaluation, by finite element analysis, of additive manufacturing techniques for wrist splints in order to improve upon the typical splinting approach. An additive manufactured/3D printed splint, specifically designed to be built using Objet Connex multi-material technology and a virtual model of a typical splint, digitised from a real patient-specific splint using three-dimensional scanning, were modelled in computer-aided design software. Forty finite element analysis simulations were performed in flexion-extension and radial-ulnar wrist movements to compare the displacements and the stresses. Simulations have shown that for low severity loads, the additive manufacturing splint has 25%, 76% and 27% less displacement in the main loading direction than the typical splint in flexion, extension and radial, respectively, while ulnar values were 75% lower in the traditional splint. For higher severity loads, the flexion and extension movements resulted in deflections that were 24% and 60%, respectively, lower in the additive manufacturing splint. However, for higher severity loading, the radial defection values were very similar in both splints and ulnar movement deflection was higher in the additive manufacturing splint. A physical prototype of the additive manufacturing splint was also manufactured and was tested under normal conditions to validate the finite element analysis data. Results from static tests showed maximum displacements of 3.46, 0.97, 3.53 and 2.51mm flexion, extension, radial and ulnar directions, respectively. According to these results, the present research argues that from a technical point of view, the additive manufacturing splint design stands at the same or even better level of performance in displacements and stress values in comparison to the typical low temperature thermoplastic approach and is therefore a feasible approach to splint design and manufacture.
Autores: Ruiz de Galarreta Moriones, Sergio; Cazón Martín, Aitor; Antón Remírez, Raúl; et al.
ISSN 0148-0731  Vol. 139  Nº 1  2017 
An abdominal aortic aneurysm (AAA) is a permanent focal dilatation of the abdominal aorta of at least 1.5 times its normal diameter. Although the criterion of maximum diameter is still used in clinical practice to decide on a timely intervention, numerical studies have demonstrated the importance of other geometric factors. However, the major drawback of numerical studies is that they must be validated experimentally before clinical implementation. This work presents a new methodology to verify wall stress predicted from the numerical studies against the experimental testing. To this end, four AAA phantoms were manufactured using vacuum casting. The geometry of each phantom was subject to microcomputed tomography (lCT) scanning at zero and three other intraluminal pressures: 80, 100, and 120 mm Hg. A zero-pressure geometry algorithm was used to calculate the wall stress in the phantom, while the numerical wall stress was calculated with a finite-element analysis (FEA) solver based on the actual zero-pressure geometry subjected to 80, 100, and 120 mm Hg intraluminal pressure loading. Results demonstrate the moderate accuracy of this methodology with small relative differences in the average wall stress (1.14%). Additionally, the contribution of geometric factors to the wall stress distribution was statistically analyzed for the four phantoms. The results showed a significant correlation between wall thickness and mean curvature (MC) with wall stress.
Autores: Ruiz de Galarreta Moriones, Sergio; Cazón Martín, Aitor (Autor de correspondencia); Antón Remírez, Raúl; et al.
ISSN 0148-0731  Vol. 139  Nº 8  2017  págs. 081006 - 081006-7
The maximum diameter (MD) criterion is the most important factor when predicting risk of rupture of abdominal aortic aneurysms (AAAs). An elevated wall stress has also been linked to a high risk of aneurysm rupture, yet is an uncommon clinical practice to compute AAA wall stress. The purpose of this study is to assess whether other characteristics of the AAA geometry are statistically correlated with wall stress. Using in-house segmentation and meshing algorithms, 30 patient-specific AAA models were generated for finite element analysis (FEA). These models were subsequently used to estimate wall stress and maximum diameter and to evaluate the spatial distributions of wall thickness, cross-sectional diameter, mean curvature, and Gaussian curvature. Data analysis consisted of statistical correlations of the aforementioned geometry metrics with wall stress for the 30 AAA inner and outer wall surfaces. In addition, a linear regression analysis was performed with all the AAA wall surfaces to quantify the relationship of the geometric indices with wall stress. These analyses indicated that while all the geometry metrics have statistically significant correlations with wall stress, the local mean curvature (LMC) exhibits the highest average Pearson's correlation coefficient for both inner and outer wall surfaces. The linear regression analysis revealed coefficients of determination for the outer and inner wall surfaces of 0.712 and 0.516, respectively, with LMC having the largest effect on the linear regression equation with wall stress. This work underscores the importance of evaluating AAA mean wall curvature as a potential surrogate for wall stress.
Autores: Ruiz de Galarreta Moriones, Sergio; Antón Remírez, Raúl (Autor de correspondencia); Cazón Martín, Aitor; et al.
ISSN 0219-5194  Vol. 17  Nº 8  2017 
Autores: González Prada, Jorge; Cazón Martín, Aitor; Carda, J.; et al.
ISSN 1355-2546  Vol. 22  Nº 2  2016  págs. 311 - 321
Purpose - This paper aims to focus on the design, analysis and additive manufacturing (AM) with two different technologies of an accelerator pedal for the Formula Student 2014 edition to reduce the weight of the original pedal in aluminium and maintain a reasonable level of performance. Design/methodology/approach - The new and the original accelerator pedals were modelled in a computer-aided design application, and three finite element simulations were performed for each manufacturing technology to evaluate three different driving scenarios. Later on, two physical prototypes were manufactured using two AM technologies: poly-jet and fused deposition modelling (FDM). With these physical prototypes, static tests were carried out to verify the computational simulations and to determine the fracture load, while dynamic tests, based on an input signal from a real racing scenario, were performed to ensure their technical viability. Findings - Simulations with poly-jet and FDM printing material show that the new design presents a maximum deformation of 4.8 and 4.09 mm, respectively, under a nominal load of 150N. The results of the static tests with the poly-jet physical prototype showed a maximum displacement of 4.05 mm under a nominal load of 150N, while the ultimate load before fracture was 450N. The FDM prototype reached 3.98 mm under 150N and the ultimate load was 350N. Dynamic tests showed that both pedals were able to withstand four Formula Student "Endurance" events without failure. Originality/value - This paper states that AM approach is a feasible and economically affordable solution in comparison to exiting solutions with metallic alloys and composite materials when designing and manufacturing accelerator pedal arms for Formula Student competition cars. According to these results, the present research argues that, from a technical point of view, the AM pedals stand at a reasonable level of performance in displacements and stresses. This study suggests that AM pedals could be a viable option that must be considered in professional competitive automobiles.
Autores: Ruiz de Galarreta Moriones, Sergio; Antón Remírez, Raúl; Cazón Martín, Aitor; et al.
ISSN 1350-4533  Vol. 38  Nº 12  2016  págs. 1505 - 1512
An Abdominal Aortic Aneurysm (AAA) is a permanent focal dilatation of the abdominal aorta at least 1.5 times its normal diameter. The criterion of maximum diameter is still used in clinical practice, although numerical studies have demonstrated the importance of other biomechanical factors. Numerical studies, however, must be validated experimentally before they can be clinically implemented. We have developed a methodology for manufacturing anisotropic AAA replicas with non-uniform wall thickness. Different composites were fabricated and tested, and one was selected in order to manufacture a phantom with the same properties. The composites and the phantom were characterized by biaxial tensile tests and a material model was fit to the experimental data. The experimental results were compared with data from the literature, and similar responses were obtained. The anisotropic AAA replicas with non-uniform wall thickness can be used in benchtop experiments to validate deformations obtained with numerical simulations or for pre-intervention testing of endovascular grafts. This is a significant step forward considering the importance of anisotropy in numerical simulations.
Autores: Cazón Martín, Aitor; Matey Muñoz, Luis Mariano; Rodríguez Ferradas, María Isabel; et al.
Revista: DYNA
ISSN 0012-7361  Vol. 90  Nº 6  2015  págs. 621 - 627
Additive Manufacturing (AM), commonly called 3D printing, is the process of making objects layer upon layer from 3D model data in order to test design prototypes (called Rapid Prototyping), to obtain production tools (Rapid Tooling) or to build and then use that prototype as a final part in the final product (Direct Manufacturing). This paper aims to show new applications of the Direct Digital Manufacturing philosophy for sports and medical sciences. Particularly, the aim of the study is to present three case-studies that take advantage of AM so as to enable practitioners and professional players to manufacture customised 1) face masks to protect the face during sports or everyday activities, 2) foot insoles to treat foot problems and 3) shin pads to be worn by football players and shield them from shin injuries. In every case study, prior to fabrication, anthropometric features of volunteer patients were captured by a low-cost 3D scanner and a user-friendly semi-automatic modelling procedure was developed with Rhinoceros and Grasshopper in order to model and customise several features of the three products. The resulting virtual designs of the three products were manufactured with the help of four different AM devices while design workflow and the suitability of the physical prototypes were evaluated against volunteers and practitioners. Feedback results from practitioners and volunteers were satisfactory enough in order to consider the design tools provided as a good starting point for future developments. Further work is still necessary in terms of improvement to the design algorithm, inclusion of new materials and test procedures to verify the physical prototypes to the final user requirements. Nevertheless, this work confirmed that the combination of existing tools of three-dimensional digitisation, user-friendly semi-automatic algorithm within a Computer Aided Design (CAD) and Additive Manufacturing can lead to a technologically feasible and cost-effective solution to improve the traditional design and manufacturing process of customised orthotic and protective devices for sports and medical sciences.
Autores: Cazón Martín, Aitor; González Prada, Jorge (Autor de correspondencia); García, E.; et al.
ISSN 1745-2759  Vol. 10  Nº 3  2015  págs. 149 - 162
Formula Student is an international competition governed by the Society of Automotive Engineers (SAE) which challenges university students to design and build a racing car that will subsequently be compared against other cars from universities around the world on homologated racing circuits by non-professional drivers. This study focuses on the design, analysis and manufacturing process of a new oil sump for a Formula Student car - which involves combining a main ABS-plastic core created by an additive manufacturing (AM) printing process and a manual lay-up process with carbon fibre - in order to reduce the sloshing effect due to the movement of the oil during racing. The new oil sump and the original sump were modelled with computer-aided design (CAD) software and five computational fluid dynamics (CFD) simulations were performed to compare the sloshing effect in both designs in three driving scenarios: acceleration, braking and changing direction. The simulations showed that acceleration is not a critical situation since the new internal design of the sump was capable of delaying the immersion time of the oil pick-up pipe from 0.75 seconds to 2 seconds during braking and from 0.4 seconds to 0.8 seconds during lateral acceleration. The new design was physically manufactured and subsequently integrated into an internal combustion engine for testing for 45 minutes. During this test, the engine was started and put at 9600 RPM, so the oil worked under realistic temperature condi
Autores: Cazón Martín, Aitor; Morer Camo, María de la Paz; Matey Muñoz, Luis Mariano
ISSN 0954-4054  Vol. 228  Nº 12  2014  págs. 1664 - 1675
Design and manufacturing engineers are not fully aware of the different possibilities that PolyJet technology offers. The goal of this article is to provide the design and manufacturing engineers with greater knowledge about the final properties of parts printed with PolyJet rapid prototyping technology. This knowledge includes the effect of printing orientation and post-processing on the mechanical and surface properties of printed parts. Eighteen different samples considered all the possible printing orientations and the surface finishing treatments recommended by the manufacturer. These finishing properties include part printing using the matte/glossy option and removal of the support material using water pressure and/or a caustic soda bath. Tensile tests and surface roughness measurements were analysed for the printed samples using the statistical design of experiments in order to determinate the influence of the printing orientation and finishing properties on the results. These tests showed that the part orientation has a significant effect on elastic modulus and fracture stress while there is no statistical significance on ultimate tensile strength. With regard to the finish, none of the tensile test outputs showed significant differences. In terms of roughness, the analysis of variance indicated that position and finish presented statistically significant differences between the means of the three roughness directions. From all these experiences, it is possible to conclude that the glossy finish and the xy printing direction worked very well regarding roughness, whereas the critical load direction of the part should be placed along the x-axis when printing.
Autores: Pasciuto, I.; Ausejo Muñoz, Sergio; Celigüeta Lizarza, Juan Tomás; et al.
ISSN 1384-5640  Vol. 32  Nº 1  2014  págs. 27 - 53
In this paper, we present a novel method to predict human motion, seeking to combine the advantages of both data-based and knowledge-based motion prediction methods. Our method relies on a database of captured motions for reference and introduces knowledge in the prediction in the form of a motion control law, which is followed while resembling the actually performed reference motion. The prediction is carried out by solving an optimization problem in which the following conditions are imposed to the motion: must fulfill the goals of the task; resemble the reference motion selected from the database; follow a knowledge-based dynamic motion control law; and ensure the dynamic equilibrium of the human model, considering its interactions with the environment. In this work, we apply the proposed method to a database of clutch pedal depression motions, and we present the results for three predictions. The method is validated by comparing the results of the prediction to motions actually performed in similar conditions. The predicted motions closely resemble the motions in the validation database and no significant differences have been noted either in the motion's kinematics or in the motion's dynamics.
Autores: Pasciuto, I.; Ausejo Muñoz, Sergio; Celigüeta Lizarza, Juan Tomás; et al.
ISSN 1615-147X  Vol. 49  Nº 1  2014  págs. 169 - 183
In this paper an optimization-based hybrid dynamic motion prediction method is presented. The method is hybrid as the prediction relies both on actually performed motions for reference (following a data-based approach) and on the definition of appropriate performance measures (following a knowledge-based approach). The prediction is carried out through the definition of a constrained non-linear optimization problem, in which the objective function is composed of a weighted combination of data-based and knowledge-based contributions. The weights of each contribution are varied in order to generate a battery of hybrid predictions, which range from purely data-based to purely knowledge-based. The results of the predictions are analyzed and compared against actually performed motions both qualitatively and quantitatively, using a measure of realism defined as the distance of the predicted motions from the mean of the actually performed motions. The method is applied to clutch pedal depression motions and the comparison between the different approaches favors the hybrid solution, which seems to combine the strengths of both data- and knowledge-based approaches, enhancing the realism of the predicted motion.
Autores: Cazón Martín, Aitor; Aizpurua, J.; Paterson, A.; et al.
ISSN 1745-2759  Vol. 9  Nº 4  2014  págs. 251 - 256
This project analyses the viability of an efficient modelling approach using a semi-automatic algorithm within a Computer Aided Design (CAD) application in combination with low-cost digitising devices and low-cost Additive Manufacturing (AM) printers when designing and manufacturing patient-specific face masks. The aims of the study were to enable clinical practitioners to utilise the advantages of three-dimensional (3D) scanning, CAD and AM without having to be trained to use design/engineering software. Face features were captured using two 3D devices. The resulting meshes were compared via the Hausdorff Distance method. A semi-automatic modelling procedure was developed with `Rhinoceros¿ and `Grasshopper¿ to model the face mask and customise several features. With that procedure, volunteers modelled a face mask in less than 30 minutes in their first attempt. The resulting virtual mask was manufactured with two AM printers. An initial economic study indicated that the presented approach offers a feasible alternative to the current practices.
Autores: Ruiz de Galarreta Moriones, Sergio; Cazón Martín, Aitor; Antón Remírez, Raúl; et al.
ISSN 0148-0731  Vol. 136  Nº 1  2013  págs. 014502 - 014502-5
The goal of this work is to develop a framework for manufacturing nonuniform wall thickness replicas of abdominal aortic aneurysms (AAAs). The methodology was based on the use of computed tomography (CT) images for virtual modeling, additive manufacturing for the initial physical replica, and a vacuum casting process and range of polyurethane resins for the final rubberlike phantom. The average wall thickness of the resulting AAA phantom was compared with the average thickness of the corresponding patient-specific virtual model, obtaining an average dimensional mismatch of 180 lm (11.14%). The material characterization of the artery was determined from uniaxial tensile tests as various combinations of polyurethane resins were chosen due to their similarity with ex vivo AAA mechanical behavior in the physiological stress configuration. The proposed methodology yields AAA phantoms with nonuniform wall thickness using a fast and low-cost process. These replicas may be used in benchtop experiments to validate deformations obtained with numerical simulations using finite element analysis, or to validate optical methods developed to image ex vivo arterial deformations during pressure-inflation testing.
Autores: Cazón Martín, Aitor (Autor de correspondencia); Suescun Cruces, Ángel
ISSN 1358-8265  Vol. 15  Nº 1  2010  págs. 39 - 48
This paper evaluates the consequences of the impact of an unrestrained object against the head of vehicle occupant during a frontal crash by means of a computational head-neck biomechanical model. The correct positioning of head restraints can partially protect the rear side of the head, but there is still a significant probability of being injured. However, because head restraints are typically not properly adjusted as whiplash studies have shown, the probability of being impacted by an unrestrained object during a frontal crash is noticeably high and hence the risk of being injured is also high. In this work, head injury risk is evaluated through the Head Injury Criterion (HIC), by simulating a complete head-neck biomechanical model with realistic motion under frontal crash condition. The model developed includes all cervical vertebrae, intervertebral discs, ligaments and muscles. The model was validated against experimental data. Results have shown that the risk of severe head injury in frontal collision due to unrestrained objects cannot be neglected. The risk is directly related to the mass of the impact object, the relative velocity between the object and the head and the incorrect use of the head restraint.
Autores: Cao, Chuan; Rodríguez Ferradas, María Isabel; Cazón Martín, Aitor; et al.
Libro:  Advances on Mechanics, Design Engineering and Manufacturing II
2019  págs. 41 - 51
The increasing relevance of occupational injuries and illness related to lean manufacturing strategies in automotive assembly lines brings an increasing interest in this industry by the research and development of new tools and methods for the evaluation and prevention of work-related musculoskeletal disorders (WMSDs). However, few studies have focused on assessing the exposures to the hand region whereas disorder in this region remain at the primary tier of the prevalence ranking. Herein, this paper presents a low-cost, wearable inertial measurement unit (IMU) to measure workplace demands. This technology was selected after analysing an assessment scale composed of seven of the common ergonomic assessment tools and methods. After a brief verification through a laboratory goniometry experiment, eleven joint angles of a volunteer¿s hand were measured. The results indicated that the mean difference between the values measured by participants and the values obtained directly from the wearable is 2.44°, which has the same accuracy level of the commercial products. The proposed device is scalable enough to be iterated by further improvements, including conductive fabric 3D printing technology.



Prototipos (Ing.Gr.). 
Universidad de Navarra - Escuela de Ingeniería.

Diseño y ensayo de máquinas (MII). 
Universidad de Navarra - Escuela de Ingeniería.

Técnicas de Validación Experimental (Tecnun). 
Universidad de Navarra - Escuela de Ingeniería.

Ecodiseño (Tecnun). 
Universidad de Navarra - Escuela de Ingeniería.


Dr. Aitor Cazón, es Doctor Ingeniero (2009) por la Universidad de Navarra - Tecnun. Sus áreas de conocimiento se centran en el diseño para Fabricación Aditiva, incluyendo la parte de CAD/CAE y la fabricación final con equipos aditivos. Ha participado en más de 20 proyectos de investigación, tres de ellos europeos y tanto de financiación pública como privada, que han dado lugar a 23 artículos en revistas internacionales indexadas con revisión por pares, 15 comunicaciones en congresos y tres capítulos de libro en editorial internacional. Es profesor de las asignaturas de Prototipos, Ecodiseño, Técnicas de Validación y Tecnología de Materiales a nivel de Grado de Ingeniería y de Diseño y Ensayo de Maquinas en el Máster de Ingeniería Industrial. Esta docencia se ha completado con la publicación de 8 libros docentes. Además, ha dirigido más de 100 Proyectos Fin de Grado y Máster del Área de conocimiento de la Ingeniería Mecánica. Es Profesor Contratado Doctor por la ANECA desde mayo de 2014 y tiene un sexenio de investigación concedido en el periodo 2012-2017.