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Prof. Armando Ramalho
Polytechnic Institute of Castelo Branco, School of Technology

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Research Keywords & Expertise

0 Fatigue and Fracture Analysis
0 weld modeling
0 Residual stresses in welding joint
0 Finite element analysis and simulation
0 Biomechanical analysis

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Journal article
Published: 12 March 2021 in Journal of Sensor and Actuator Networks
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This experimental study focuses on the comparison between two different sensors for vibration signals: a magnetoresistive sensor and an accelerometer as a calibrated reference. The vibrations are collected from a variable speed inductor motor setup, coupled to a ball bearing load with adjustable misalignments. To evaluate the performance of the magnetoresistive sensor against the accelerometer, several vibration measurements are performed in three different axes: axial, horizontal and vertical. Vibration velocity measurements from both sensors were collected and analyzed based on spectral decomposition of the signals. The high cross-correlation coefficient between spectrum vibration signatures in all experimental measurements shows good agreement between the proposed magnetoresistive sensor and the reference accelerometer performances. The results demonstrate the potential of this type of innovative and non-contact approach to vibration data collection and a prospective use of magnetoresistive sensors for predictive maintenance models for inductive motors in Industry 4.0 applications.

ACS Style

Rogerio Dionisio; Pedro Torres; Armando Ramalho; Ricardo Ferreira. Magnetoresistive Sensors and Piezoresistive Accelerometers for Vibration Measurements: A Comparative Study. Journal of Sensor and Actuator Networks 2021, 10, 22 .

AMA Style

Rogerio Dionisio, Pedro Torres, Armando Ramalho, Ricardo Ferreira. Magnetoresistive Sensors and Piezoresistive Accelerometers for Vibration Measurements: A Comparative Study. Journal of Sensor and Actuator Networks. 2021; 10 (1):22.

Chicago/Turabian Style

Rogerio Dionisio; Pedro Torres; Armando Ramalho; Ricardo Ferreira. 2021. "Magnetoresistive Sensors and Piezoresistive Accelerometers for Vibration Measurements: A Comparative Study." Journal of Sensor and Actuator Networks 10, no. 1: 22.

Conference paper
Published: 06 June 2020 in Materials Today: Proceedings
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The use of numerical modelling tools allows optimizing the development of complex anatomical artefacts, such as customized prostheses for lower limb amputees. These numerical tools make it possible to characterize the interfacial interactions taking place between different parts of the prosthesis and the residual limb. This allows for understanding which rectifications and fittings having to be made on the custom design of the artificial body part without the need for manufacturing and donning prostheses. To such end, current research focused on the development of a preliminary Finite Element Model to assess the effects of friction on the residual limb of a transfemoral amputee, as the friction on the contact between the soft tissues, the liner and the prosthesis of the amputee is of major importance for his/her health and comfort.

ACS Style

Armando Ramalho; Miguel Ferraz; Marcelo Gaspar; Carlos Capela. Development of a preliminary finite element model to assess the effects of friction on the residual limb of a transfemoral amputee. Materials Today: Proceedings 2020, 33, 1859 -1863.

AMA Style

Armando Ramalho, Miguel Ferraz, Marcelo Gaspar, Carlos Capela. Development of a preliminary finite element model to assess the effects of friction on the residual limb of a transfemoral amputee. Materials Today: Proceedings. 2020; 33 ():1859-1863.

Chicago/Turabian Style

Armando Ramalho; Miguel Ferraz; Marcelo Gaspar; Carlos Capela. 2020. "Development of a preliminary finite element model to assess the effects of friction on the residual limb of a transfemoral amputee." Materials Today: Proceedings 33, no. : 1859-1863.

Journal article
Published: 22 March 2016 in Multidisciplinary Journal for Education, Social and Technological Sciences
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This paper describes the collaborative learning task carried out in the framework of a Strength of Materials course in an undergraduate degree program in Industrial Engineering using a wiki platform as a support tool. Stages of the teaching/learning process are described. These are: organization of the wiki to host the work of student groups, creation of working groups and assignation of projects, delivery of guidance material and model, editing the project and publishing pages on the wiki, assessments performed using rubrics, and the results obtained. The wiki platform provides interesting statistics for evaluating cooperation between students and time variation of students’ effort. The final quality of the projects is very high because a midterm evaluation in the form of a “peer review rubric” is carried out. Then, students improve their projects. The paper concludes by gathering the opinions made by students; the benefits provided by this teaching experience are then analyzed.

ACS Style

L. Celorrio-Barragué; A. Lopes-Ramalho; M.R. Calvete Gaspar. Development of generic and strategic skills through a wiki platform in industrial engineering programs. Multidisciplinary Journal for Education, Social and Technological Sciences 2016, 3, 152 .

AMA Style

L. Celorrio-Barragué, A. Lopes-Ramalho, M.R. Calvete Gaspar. Development of generic and strategic skills through a wiki platform in industrial engineering programs. Multidisciplinary Journal for Education, Social and Technological Sciences. 2016; 3 (1):152.

Chicago/Turabian Style

L. Celorrio-Barragué; A. Lopes-Ramalho; M.R. Calvete Gaspar. 2016. "Development of generic and strategic skills through a wiki platform in industrial engineering programs." Multidisciplinary Journal for Education, Social and Technological Sciences 3, no. 1: 152.

Journal article
Published: 01 January 2016 in Procedia Structural Integrity
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Crack closure concept has been widely used to explain different issues of fatigue crack propagation. However, some authors have questioned the relevance of crack closure and have proposed alternative concepts. The main objective here is to check the effectiveness of crack closure concept by linking the contact of crack flanks with non-linear crack tip parameters. Numerical models with and without contact of crack flanks were built for a wide range of loading parameters. The non-linear crack tip parameters studied were the range of cyclic plastic strain, the crack tip opening displacement (CTOD) and the size of reversed plastic zone. Well defined relations between non linear parameters and K were obtained without contact of crack flanks which reinforces the validity of linear elastic fracture mechanics. When the CTOD with contact is plotted versus ΔKeff the values are coincident with those obtained without contact, which shows that the crack closure concept is valid and able to explain the influence of mean stress. The analysis of overloads and high-low load blocks demonstrated the validity of crack closure concept for variable amplitude loading.

ACS Style

Fv Antunes; Ricardo Branco; L Correia; Al Ramalho; S Mesquita. Numerical validation of crack closure concept using non-linear crack tip parameters. Procedia Structural Integrity 2016, 1, 90 -97.

AMA Style

Fv Antunes, Ricardo Branco, L Correia, Al Ramalho, S Mesquita. Numerical validation of crack closure concept using non-linear crack tip parameters. Procedia Structural Integrity. 2016; 1 ():90-97.

Chicago/Turabian Style

Fv Antunes; Ricardo Branco; L Correia; Al Ramalho; S Mesquita. 2016. "Numerical validation of crack closure concept using non-linear crack tip parameters." Procedia Structural Integrity 1, no. : 90-97.

Journal article
Published: 19 June 2015 in Frattura ed Integrità Strutturale
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ACS Style

F.V. Antunes; R. Branco; L. Correia; Armando Ramalho. A numerical study of non-linear crack tip parameters. Frattura ed Integrità Strutturale 2015, 9, 199 -208.

AMA Style

F.V. Antunes, R. Branco, L. Correia, Armando Ramalho. A numerical study of non-linear crack tip parameters. Frattura ed Integrità Strutturale. 2015; 9 (33):199-208.

Chicago/Turabian Style

F.V. Antunes; R. Branco; L. Correia; Armando Ramalho. 2015. "A numerical study of non-linear crack tip parameters." Frattura ed Integrità Strutturale 9, no. 33: 199-208.

Journal article
Published: 10 September 2013 in International Journal of Fatigue
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Numerical models have been successfully developed to predict plasticity induced crack closure (PICC). However, despite the large research effort a full understanding of the links between physical parameters, residual plastic wake and PICC has not been achieved yet. The plastic extension of material behind crack tip, Δyp, obtained by the integration of vertical plastic deformation perpendicularly to crack flank, is proposed here to quantify the residual plastic field. The values of Δyp and PICC were obtained numerically in a M(T) specimen using the finite element method. An excellent correlation was found between PICC and Δyp which indicates that this parameter controls the phenomenon, and can be used to quantify the effect of physical parameters. An empirical model was developed to predict PICC assuming that the residual plastic field is a set of vertical plastic wedges, that the linear superposition principle applies and that the influence of a particular wedge exponentially decreases with distance to crack tip. The model was applied successfully to predict PICC for different residual plastic fields which provided an additional validation of Δyp as the parameter controlling PICC.

ACS Style

F.V. Antunes; L. Correia; A.L. Ramalho. A parameter for quantitative analysis of plasticity induced crack closure. International Journal of Fatigue 2013, 71, 87 -97.

AMA Style

F.V. Antunes, L. Correia, A.L. Ramalho. A parameter for quantitative analysis of plasticity induced crack closure. International Journal of Fatigue. 2013; 71 ():87-97.

Chicago/Turabian Style

F.V. Antunes; L. Correia; A.L. Ramalho. 2013. "A parameter for quantitative analysis of plasticity induced crack closure." International Journal of Fatigue 71, no. : 87-97.

Journal article
Published: 11 April 2013 in Frattura ed Integrità Strutturale
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Crack closure influences fatigue crack growth rate and must be included in the design ofcomponents. Plasticity induced crack closure is intimately linked with the crack tip plastic deformation, whichbecomes residual as the crack propagates. The objective here is to study numerically the effect of crackpropagation on crack tip fields. The transient effect observed at the beginning of crack propagation is linked tothe hardening behavior of material. The effect of mesh refinement is studied, and a singular behavior is evident,which is explained by the sharp crack associated with mesh topology, composed of a regular pattern of squareelements. The plastic zone size measured perpendicularly to crack flank in the residual plastic wake is quantifiedand compared with literature models. Finally, the removal of material at the first node behind crack tip withload cycling was observed for plane strain state and some hardening models in plane stress state

ACS Style

Fernando Antunes; Amir Goodarzvand Chegini; L.M. Correia; Armando Ramalho. Effect of crack propagation on crack tip fields. Frattura ed Integrità Strutturale 2013, 7, 54 -60.

AMA Style

Fernando Antunes, Amir Goodarzvand Chegini, L.M. Correia, Armando Ramalho. Effect of crack propagation on crack tip fields. Frattura ed Integrità Strutturale. 2013; 7 (25):54-60.

Chicago/Turabian Style

Fernando Antunes; Amir Goodarzvand Chegini; L.M. Correia; Armando Ramalho. 2013. "Effect of crack propagation on crack tip fields." Frattura ed Integrità Strutturale 7, no. 25: 54-60.

Journal article
Published: 31 December 2011 in Materials & Design
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This paper concerns a fatigue study on the effect of tungsten inert gas (TIG) and plasma dressing in non-load-carrying fillet welds of structural steel with medium strength. The fatigue tests were performed in three point bending at the main plate under constant amplitude loading, with a stress ratio of R = 0.05 and a frequency of 7 Hz. Fatigue results are presented in the form of nominal stress range versus fatigue life (S–N) curves obtained from the as welded joints and the TIG dressing joints at the welded toe. These results were compared with the ones obtained in repaired joints, where TIG and plasma dressing were applied at the welded toes, containing fatigue cracks with a depth of 3–5 mm in the main plate and through the plate thickness. A deficient repair was obtained by TIG dressing, caused by the excessive depth of the crack. A reasonable fatigue life benefits were obtained with plasma dressing. Good results were obtained with the TIG dressing technique for specimens with shallower initial defects (depth lesser than 2.5 mm). The fatigue life benefits were presented in terms of a gain parameter assessed using both experimental data and life predictions based on the fatigue crack propagation law.

ACS Style

Armando L. Ramalho; José Ferreira; Carlos A.G.M. Branco. Fatigue behaviour of T welded joints rehabilitated by tungsten inert gas and plasma dressing. Materials & Design 2011, 32, 4705 -4713.

AMA Style

Armando L. Ramalho, José Ferreira, Carlos A.G.M. Branco. Fatigue behaviour of T welded joints rehabilitated by tungsten inert gas and plasma dressing. Materials & Design. 2011; 32 (10):4705-4713.

Chicago/Turabian Style

Armando L. Ramalho; José Ferreira; Carlos A.G.M. Branco. 2011. "Fatigue behaviour of T welded joints rehabilitated by tungsten inert gas and plasma dressing." Materials & Design 32, no. 10: 4705-4713.