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The conservation of the civil and infrastructural building heritage is today an open challenge for any country. A well-preserved building heritage, in fact, on the one hand is able to cope with its own progressive and natural aging, on the other is capable of withstanding sudden calamitous events. Good conservation is achieved through careful structural health monitoring (SHM) that, in fact, allows to immediately detect any vulnerability point of the structure, and consequently to intervene promptly, before it completely loses its functionality or even collapses. In this work, we present a system for the SHM based on the study of the measurements of three nodes, each of which equipped with a triaxial accelerometer. The detected data are then sent to a master to be processed and correctly interpreted. Specifically, the focus will be placed on the description of a simple architecture based on a microcontroller system that can be easily used for the SHM.

In this paper an electronic sensory system for structural health monitoring applications is presented. The proposed system is composed of a master device and communication nodes placed on the monitored structure. Each node is made up of a digital triaxial accelerometer, an external memory and a microcontroller that acquires the values and stores them in the memory. The master device has the task of synchronizing the nodes with a general clock to acquire the samples at the same time. All the nodes collect the data taken from on-board memory through RS485 communication to the master device. Experimental results show that the system is able to monitor the structure with data synchronization from each node. The aim of this work is to develop a precise, reliable, but also inexpensive system that allows the structures to be monitored continuously.

In the last decades, the applications of structural monitoring are moving toward the field of civil engineering and infrastructures. Nevertheless, if the structures have damages, it does not mean that they have a complete loss of functionality, but rather that the system is no longer in an optimal condition so that, if the damage increases, the structure can collapse. Structural Health Monitoring (SHM), a process for the identification of damage, periodically collects data from suitable sensors that allow to characterize the damage and establishes the health status of the structure. Therefore, this monitoring will provide information on the structure condition, mostly about its integrity, in a short time, and, for infrastructures and civil structures, it is necessary to assess performance and health status. The aim of this work is to design an Internet of Things (IoT) system for Structural Health Monitoring to find possible damages and to see how the structure behaves over time. For this purpose, a customized datalogger and nodes have been designed. The datalogger is able to acquire the data coming from the nodes through RS485 communication and synchronize acquisitions. Furthermore, it has an internal memory to allow for the post-processing of the collected data. The nodes are composed of a digital triaxial accelerometer, a general-purpose microcontroller, and an external memory for storage measures. The microcontroller communicates with an accelerometer, acquires values, and then saves them in the memory. The system has been characterized and the damage indicator has been evaluated on a testing structure. Experimental results show that the estimated damage indicator increases when the structure is perturbed. In the present work, the damage indicator increased by a maximum value of 24.65 when the structure is perturbed by a 2.5 mm engraving.

The ability to work without supports is the most important factor of merit in additive manufacturing or 3D printing process. We here present a custom procedure and algorithm for 3D printing without using any support structure: this in order to avoid supports during the deposition phase the printer extruder must follows a detailed path that at the same time is part of the implemented 3D object and is also able to sustain the next deposited material. The proposed approach can be applied to any object, also long bridges and convex surfaces. Test objects implemented with the proposed method are reported and evaluated in order to show the method functionality and applicability in any condition.

The three-dimensional printing of complex shapes without using supporting structures is the most attractive factor of merit in current additive manufacturing because it allows to drastically reduce printing time, and ideally nullify postprocessing and waste material. In this work, we present an innovative procedure and algorithm (Print on Air, PoA) for additive manufacturing that, relying on sensing systems embedded into the three-dimensional (3D) printer (e.g., temperature and speed sensors), aims at generating a printing sequence capable of a self-sustaining bridge and overhang structures. This feature was achieved by splitting the actual floating area of the layer where the aforementioned structures are in many subsections. Each is generated with a negligible floating surface and printed in a well-determined sequence with accurate temperature and speed profiles. Therefore, each subsection is formed without the need for scaffolding, simultaneously acting as a supporting structure for the following subsection. The array of subsections constitutes the actual bridge or overhang structure. The proposed method can be used for any object, including very long bridges or convex surfaces. The revolutionary method is here reported and evaluated in order to show its applicability in any condition. Although the study was conducted in a Fused Deposition Material (FDM) environment, it can certainly be adapted to other manufacturing environments with adequate modifications.

This work deals on the design of a multisensorial anemometer able to provide an accurate measurement of both wind speed and direction. The system is based on thermal anemometry that is, probably, the preferable way to measure instantaneous wind velocity in any weather condition and surrounding. The application here proposed is based on a commercial flow probe, the IST FS5 that shows a robust design without moving parts, small dimensions and is suitable to operate up to 150 °C and a wind speed of 100 m/s. In addition, the sensor is organized as a pattern of probes. In this way, being the analysis based on differential measurements, analyzing the signal provided by each sensor is possible to perform an accurate evaluation of both the wind speed and direction. A microcontroller realizes the data management and wind flow identification process.

In this work, the authors propose a novel directional anemometric system, showing a compact design and the absence of external mechanical moving parts. The measuring principle is based on a dual channel spherical wind conveyor structure, combined with a pressure difference sensing technique of the conveyed air flows by the employment of electromagnetic inductive transducers.