José Machado

• PhD Mechanical Engineering
• Assistant Professor at University of Porto

Composite structures currently used in the automotive industry must meet strict requirements for safety reasons. They need to maintain strength under varied temperatures and strain rates, including impact. It is therefore critical to fully understand the impact behaviour of composites. This work presents experimental results regarding the influence...

The study of the behaviour of adhesive joints under impact loading is a very active field of research, driven by significant industrial interest. Many industries, such as the automotive industry, are currently employing adhesive joints extensively, making use of the inherent properties of adhesive joints to improve the mechanical behaviour, reduce...

Knowledge of the fracture properties of composite materials is fundamental to predict the impact behaviour of the lightweight structures currently used in the automotive industry. Although there is substantial research on mode I fracture behaviour of composites, limited information exists on mode II behaviour. This work aims to fulfil this gap, pre...

The automotive industry has significantly increased the use of adhesive joints in vehicle construction, which can be explained in part by the widespread adoption of composite materials and structures. The combined use of composites and bonding allows the manufacture of structures with high mechanical strength and reduced weight. However, to ensure...

The increasing use of composite structures in the automotive industry is due to strict regulations regarding both fuel efficiency and safety standards, since this kind of structures allow to produce strong yet light vehicles. The main advantage of the use of adhesives is the possibility of joining dissimilar materials, particularly composite materi...

Renewable energy sources are particularly significant in global energy production, with wind and solar being the most prevalent sources. Managing the simultaneous connection of wind and solar energy generators to the smart grid as distributed generators involves complex control and stabilization due to their inherent uncertainties, making their man...

This study outlines a comprehensive methodology for the design and 3D printing of personalized wrist-hand orthoses. The novelty of this work consists in using a comprehensive methodology that combines 3D scanning, CAD modelling, FEM simulation, and FDM 3D printing to create a personalized wrist-hand orthosis (RO) that fits the patient’s hand geomet...

Many text mining methods use statistical information as a text- and language-independent approach for sentiment analysis. However, text mining methods based on stochastic patterns and rules require many samples for training. On the other hand, deterministic and non-probabilistic methods are easier and faster to solve than other methods, but they ar...

The detection of sound events has become increasingly important due to the development of signal processing methods, social media, and the need for automatic labeling methods in applications such as smart cities, navigation, and security systems. For example, in such applications, it is often important to detect sound events at different levels, su...

Acoustic event detection (AED) systems, combined with video surveillance systems, can enhance urban security and safety by automatically detecting incidents, supporting the smart city concept. AED systems mostly use mel spectrograms as a well-known effective acoustic feature. The spectrogram is a combination of frequency bands. A big challenge is t...

Kidney disease remains one of the most common ailments worldwide, with cancer being one of its most common forms. Early diagnosis can significantly increase the good prognosis for the patient. The development of an artificial intelligence-based system to assist in kidney cancer diagnosis is crucial because kidney illness is a global health concern,...

Audio event detection (AED) systems have various applications in modern world. Examples of applications include security systems, urban management and automatic monitoring in smart cities, and online multimedia processing. The noise and background sound vary in an urban environment, so frequency domain and normalized features usually show better ef...

One of the interesting fields in video processing is motion detection and human action detection (HAR) in video. In some applications where both objects in the scene and the camera may be moving, camera movement cancellation is very important to increase accuracy in extracting motion features. HAR systems usually use image matching/registration alg...

Since digital media has become increasingly popular, video processing has expanded in recent years. Video processing systems require high levels of processing, which is one of the challenges in this field. Various approaches, such as hardware upgrades, algorithmic optimizations, and removing unnecessary information, have been suggested to solve thi...

The rapid population growth, insecure lifestyle, wastage of natural resources, indiscipline behavior of human beings, urgency in the medical field, security of patient information, agricultural-related problems, and automation requirements in industries are the reasons for invention of technologies. Smart cities aim to address these challenges thro...

In this article, a hierarchical method for action recognition based on temporal and spatial features is proposed. In current HAR methods, camera movement, sensor movement, sudden scene changes, and scene movement can increase motion feature errors and decrease accuracy. Another important aspect to take into account in a HAR method is the required c...

Fracture toughness determination is crucial for the design phase of pressure vessels, and, although ASTM E1820 and ISO 12135 fracture toughness standards have existed for some time, some differences have been reported in the determination of this property. This study investigates the ductile fracture behavior of ASTM A516 Gr.70 pressure vessel stee...

An autonomous vehicle can sense its environment and operate without human involvement. Its adequate management in an intelligent transportation system could significantly reduce traffic congestion and overall travel time in a network. Adaptive traffic signal controller (ATSC) based on multi‐agent systems using state‐action‐reward‐state‐action (SARS...

Machine learning is extensively used in material research and development, including adhesion technology. However, it requires a large dataset to train the models for optimizing, developing, and designing new adhesives. This study proposes a novel testing machine that enables quick high-throughput measurements of the shear strength of adhesively bo...

Heart sounds convey important information regarding potential heart diseases. Currently, heart sound classification attracts many researchers from the fields of telemedicine, digital signal processing, and machine learning—among others—mainly to identify cardiac pathology as quickly as possible. This article proposes chaogram as a new transform to...

Many relevant sound events occur in urban scenarios, and robust classification models are required to identify abnormal and relevant events correctly. These models need to identify such events within valuable time, being effective and prompt. It is also essential to determine for how much time these events prevail. This article presents an extensiv...

Audio recognition can be used in smart cities for security, surveillance, manufacturing, autonomous vehicles, and noise mitigation, just to name a few. However, urban sounds are everyday audio events that occur daily, presenting unstructured characteristics containing different genres of noise and sounds unrelated to the sound event under study, ma...

Speech recognition aims to convert human speech into text and has applications in security, healthcare, commerce, automobiles, and technology, just to name a few. Inserting residual neural networks before recurrent neural network cells improves accuracy and cuts training time by a good margin. Furthermore, layer normalization instead of batch norma...

Road network studies attracted unprecedented and overwhelming interest in recent years due to the clear relationship between human existence and city evolution. Current studies cover many aspects of a road network , for example, road feature extraction from video/image data, road map generalisation, traffic simulation, optimisation of optimal route...

Traffic flow forecasting is an essential component of an intelligent transportation system to mitigate congestion. Recurrent neural networks, particularly gated recurrent units and long short-term memory, have been the state-of-the-art traffic flow forecasting models for the last few years. However, a more sophisticated and resilient model is neces...

The crowd counting task has become a pillar for crowd control as it provides information concerning the number of people in a scene. It is helpful in many scenarios such as video surveillance, public safety, and future event planning. To solve such tasks, researchers have proposed different solutions. In the beginning, researchers went with more tr...

Requests for caring for and monitoring the health and safety of older adults are increasing nowadays and form a topic of great social interest. One of the issues that lead to serious concerns is human falls, especially among aged people. Computer vision techniques can be used to identify fall events, and Deep Learning methods can detect them with o...

Traffic state prediction is a vitally important keystone of an intelligent transportation system (ITS). It aims to improve better travel route selection, comply with the reduction of overall carbon emissions, mitigate congestion, and enhance the safety of inhabitants. However, modelling efficiently traffic flow is challenging due to its dynamic and...

The attitude and heading reference system (AHRS) is an important concept in the area of navigation, image stabilization, and object detection and tracking. Many studies and works have been conducted in this regard to estimate the accurate orientation of rigid bodies. In most research in this area, low-cost MEMS sensors are employed, but since the s...

In recent years, with the growth of digital media and modern imaging equipment, the use of video processing algorithms and semantic film and image management has expanded. The usage of different video datasets in training artificial intelligence algorithms is also rapidly expanding in various fields. Due to the high volume of information in a video...

The analysis of ambient sounds can be very useful when developing sound base intelligent systems. Acoustic scene classification (ASC) is defined as identifying the area of a recorded sound or clip among some predefined scenes. ASC has huge potential to be used in urban sound event classification systems. This research presents a hybrid method that...

Studies on road networks have received extraordinary and overwhelming attention during the last few years as it is closely related to human life and city evolution. Current studies cover many aspects of a road network, for example, road feature extraction from video/image data, road map generalization , traffic simulation, optimization of optimal r...

With the rapid growth and development of cities, Intelligent Traffic Management and Control (ITMC) is becoming a fundamental component to address the challenges of modern urban traffic management, where a wide range of daily problems need to be addressed in a prompt and expedited manner. Issues such as unpredictable traffic dynamics, resource const...

With the widespread use of surveillance image cameras and enhanced awareness of public security, objects, and persons Re-Identification (ReID), the task of recognizing objects in non-overlapping camera networks has attracted particular attention in computer vision and pattern recognition communities. Given an image or video of an object-of-interest...

Weakly supervised video anomaly detection is a recent focus of computer vision research thanks to the availability of large-scale weakly supervised video datasets. However, most existing research works are limited to the frame-level classification with emphasis on finding the presence of specific objects or activities. In this article, a new neural...

The use of composite adhesive joints increased in the last decades through structural applications, comprising the aeronautical and automotive industries. Contrary to the static loading case, in many real situations, adhesive joints are subjected to impact loads, such as in the event of vehicle crashes. Despite this fact, numerical modelling of thi...

Carbon fiber reinforced polymer–steel structural bonded joints are often subject to mixed-mode loading i.e. coupling action of normal and shear stress occurs in the joints. In this paper, an experimental approach based on fracture mechanics was adopted to obtain the fracture toughness (G ΙC and G ΙΙC ) of an adhesive currently employed in civil eng...

Based on economic and environmental factors related to energy efficiency, the automotive industry is being increasingly encouraged to design lighter structures, making use of adhesive bonding in vehicle body frames. To meet the standards of the automotive sector, adhesive joints must provide high strength and stiffness, low cost and good energy abs...

Composite structures currently used in the oil industry must meet strict requirements for design and safety reasons. They need to maintain strength under varied displacement rates throughout its lifetime. It is therefore critical to fully understand the fracture behavior of such composites. This work presents experimental results regarding the infl...

The use of adhesive to bond composites in vehicles continues to increase. Due to hygrothermal conditions, both adhesive and composite properties can be altered, making the mechanical behavior of a joint unpredictable. The novelty of this work is the assessment of the behavior of joints manufactured using composite and aluminum substrates tested und...

Industrial developments have led to an increasingly wide implementation of adhesive bonding. Due to the variability of adhesive bonding performance caused by different adhesive properties, it is necessary to validate Finite Element Method (FEM) tools. It is possible to increase the performance of adhesive joints when subjected to impact loadings, w...

Aiming to achieve the targets of reduction of fuel consumption and emissions, automotive manufacturers are increasingly using lightweight materials in the vehicle structures, namely, carbon fibre composites and aluminium alloys. The construction techniques for vehicle structures using this type of materials differ greatly from the techniques used f...

Aiming to predict the strength of bonded joints by techniques such as cohesive zone models (CZM), it is highly relevant to estimate the adhesive strength and fracture toughness (GC). Here, the tensile and shear fracture toughness (GIC and GIIC, respectively) and the corresponding mixed-mode behaviour acquire special relevancy. However, it is known...

The main objective of this work is, by using cohesive zone modelling, to compute the fracture toughness behaviour in mode I of unidirectional carbon-fibre-reinforced plastic subjected to an impact load at 4.7 m/s. To perform this task, double-cantilever beam specimens were simulated, with its opening displacement and crack propagation being assesse...

The use of adhesive joints has increased rapidly in the past decades. Driven by the growing demand for lightweight structures, composite adherends have increased in popularity, benefiting from their high specific mechanical properties and design tailorability. However, composites are typically weak in the transverse direction, which can cause prema...

Adhesive bonding has been extensively used to join composites and aluminium alloys in the automotive industry, but a deeper understanding of its fatigue behaviour is still required. This work presents a novel evaluation of the combined performance of joints manufactured with carbon fibre reinforced plastic (CFRP) and aluminium substrates subjected...

The use of bonding for joining composite materials in high-performance structures has increased significantly, as this joining method offers improved stress distributions and capability of joining dissimilar materials. However, the use of adhesive bonding for this purpose might lead to delamination failure, caused by peel stresses acting on the gen...

The aim of this work is to assess the influence of high strain rates and testing temperature on the fracture energy in mode I, GIC, of carbon fibre reinforced plastic (CFRP) plates. Double cantilever beam (DCB) specimens were tested to determine GIC as a function of temperature (24 and 80 °C) under an impact load of 4.7 m/s (using a falling-wedge i...

The use of bonded joints in industrial applications has been increasing in recent years, to the detriment of traditional bonding methods such as welding, brazing, and bolted and riveted joints. In many practical situations, such as vehicle crashes, adhesive joints are subjected to impact loads. However, the knowledge on the joint behaviour for this...

The wide and diverse application of adhesives in the automotive industry has increased over the last decades, driven by the need to produce efficient yet strong vehicles, able to meet both fuel economy and safety standards. This method allows to bond a variety of dissimilar materials used for structural parts, as well as to achieve lighter structur...

Adhesively bonded joints with composite substrates are crucial for the manufacture of lightweight structural components for the automotive industry. However, the safety of the vehicles must still be ensured after hygrothermal aging of both composite substrates and adhesive, as adverse conditions such as moisture and temperature will be a constant d...

The use of adhesives to bond metallic and composite structural components has increased substantially over the last decades. The aim of this work is to understand and predict the behaviour of dissimilar adhesive joints, using composite and aluminium substrates, under quasi-static and impact loads. Several testing temperatures (−30 to 80 °C) were co...

In this study the impact and quasi-static mechanical behaviour of single lap joints (SLJ) using a new crash resistant epoxy adhesive has been characterized as a function of temperature. Single lap adhesive joints were tested using a drop weight impact machine (impact tests) and using a universal test machine. Induction heating and nitrogen gas cool...

The use of adhesively bonded joints in structural components for the automotive industry has significantly increased over the last years, supported by the widespread integration of composite materials. This synergy allows vehicle manufacturers to offer a significant weight reduction of the vehicle allowing for fuel and emissions reduction and, at t...

To increase the confidence in the design of bonded structures, it is important to accurately predict their mechanical strength. In this context, Fracture and Damage Mechanics approaches have significant advantages over Continuum Mechanics. The Fracture Mechanics approach is often applied by an energetic analysis, where the main parameter to predict...

The increasing use of composite structures in the automotive industry is due to strict regulations regarding fuel efficiency and safety standards. The main advantage of the use of adhesives is the possibility of joining dissimilar materials, particularly composites. The technique studied was the mixed adhesive joints, as two or more adhesives can b...

The automotive industry is now extensively using multi-material structures to reduce vehicle weight. Joining these dissimilar materials effectively in a single structure demands the use of adhesive bonding, but the presence of stress concentrations leads to low mechanical performance. Mixed adhesive joints have been proposed as a solution for this...

The use of composite structures in the automotive industry aims to produce vehicles able to meet both fuel economy and safety standards. This work focused on the improvement of static and impact strength of composite adhesive joints, avoiding early delamination of the composite. The techniques applied are mixed adhesive combinations (use of two adh...

This work focus the potential of the ns pulsed Nd:YAG (1064 nm) fiber Laser for the micro texturing of Ti and its alloys, targeting its application for dental implants surfaces. The influence of Laser process parameters, such as pulse width and pulse overlap, on the surface morphology characteristics of TiCP GII and Ti-6Al-4V is analyzed, and its i...