Search results for "Testing"
showing 10 items of 1769 documents
Effectiveness of Flax-TRM composites under traction
2023
The scientific research in the field of masonry structures is increasingly welcoming the adoption of innovative and sustainable rehabilitation techniques aimed at the safeguarding of the Built Cultural Heritage. Textile Reinforced Matrix (TRM) composites are the most widely investigated strengthening systems for ancient masonry structures, thanks to their high compatibility level with the material substrates in terms of fire resistance, chemical/physical aspects, reversibility property, little impact on dimensions, stiffness and weight. Nevertheless, in the last years, the growing concern on sustainability increased the interest in products with low environmental impact, for promoting circu…
Evaluation of Flat Jack Test Method Effectiveness for Masonry Structural Investigations
2019
Flat jack testing method is one of the most commonly used techniques for the structural assessment of existing masonry structures. Single and double flat jack are commonly adopted to evaluate the acting normal stress, or the compressive behaviour of masonry material. Test procedures are codified by international standards (e.g. A.S.T.M D4729-87; C1196-04; C1197-04, R.I.L.E.M TC 177–MDT D.4; R.I.L.E.M. TC 177–MDT D.5), which provide the preliminary calibration of an experimental coefficient (km), which determination influences significantly the reliability of the test. This paper presents the result of an experimental study on the calibration of km coefficient for flat jacks. The problem is …
Full scale tests of the base-isolation system for an emergency hospital
2019
The paper presents the results of some full-scale tests regarding the base-isolation system of the emergency room building of the polyclinic hospital in Palermo (Italy). This building has been recently realized and its base isolation system is characterized by double friction pendulum isolators. Static lateral pushing tests were aimed at identifying fundamental mechanical properties of the whole isolation level (e.g. friction forces and stiffness) in order to verify the agreement with the design hypotheses. Further dynamic tests provided different displacements of the isolated base followed by the instantaneous release (snap-back tests), in order to verify the effectiveness, the mechanical …
Integration of a structural features-based preclassifier and a man-machine interactive classifier for a fast multi-stroke character recognition
2003
A transputer-based parallel machine for handwritten character recognition is proposed. An algorithm based on structural features and on a tree classifier was used to accomplish the pre-classification of the unknown sample in order to speed up the recognition process. The algorithm for the final classification is based on the description of the strokes through Fourier descriptors. The learning phase is accomplished through a man-machine interactive process. The proposed system can expand its knowledge base. A special representation of this knowledge base is proposed in order to record a great amount of data in a suitable way. A fast multistroke handwritten isolated character recognition syst…
Development of “Design of Experiments” for modelling direct expansion air-conditioning systems under variable cooling loads and faulty operating cond…
2019
Air conditioning systems are widely adopted in the building sector and are generally responsible for high energy consumption. Part of this consumption is related to the poor maintenance adopted by plant owner over time, which causes energy performance degradation. Typical faults, such as fouling or improper refrigerant charge have been shown to heavily impact on energy consumption of these systems. In order to support cost-effective maintenance schedule, Fault Detection and Diagnosis Technique are under investigation in the world. However, in order to devise a diagnostic method a preliminary modelling of air conditioning system is due. To this aim, a test procedure which requires the least …
Autonomous Robotic Sensing for Simultaneous Geometric and Volumetric Inspection of Free-Form Parts
2022
Robotic sensing is used in many sectors to improve the inspection of large and/or complex parts, enhancing data acquisition speed, part coverage and inspection reliability. Several automated or semi-automated solutions have been proposed to enable the automated deployment of specific types of sensors. The trajectory to be followed by a robotic manipulator is typically obtained through the offline programmed tool paths for the inspection of a part. This method is acceptable for a part with known geometry in a well-structured and controlled environment. The part undergoing assessment needs to be precisely registered with respect to the robot reference system. It implies the need for a setup p…
Experimental and numerical method for nondestructive ultrasonic defect detection
2010
Ultrasonic methods are well known as powerful and reliable tool for defect detection. Conventional ultrasonic techniques rely generally on piezoelectric transducers where transmission of energy to the material is achieved with contact. In the last decades focus and interest have been directed to non-contact sensors and methods, showing many advantages over contact techniques where inspection depends on contact conditions (pressure, coupling medium, contact area). The growing interest is also due to the further development of air-coupled probes, thanks to new materials for acoustic devices and manufacturing technologies. The use of laser as tool for ultrasonic defect detection is also an eme…
Photovoltaic performance of amorphous silicon flexible solar modules under mechanical loading
2007
The applications of photovoltaic devices can be significantly expanded by directly integrating them into structures. Solar cells integrated into structures can help to power a variety of devices such as structural monitoring sensors and unmanned aerial vehicles (UAVs). However, little work has been reported in the literature on the performance of solar cells under deformation. Thus, a thorough investigation on the photovoltaic behavior of solar modules under mechanical loading is necessary in order to provide the optimal integration conditions for practical applications. The photovoltaic performance of commercially available amorphous silicon solar modules was tested under applied mechanica…
Assessment of performance degradation of hybrid flax-glass fiber reinforced epoxy composites during a salt spray fog/dry aging cycle
2022
The main goal of this paper is the evaluation of the performances reversibility of hybrid composites when they are dried after being aged in salt-fog environment. To this aim, epoxy composites reinforced with flax and glass fabrics respectively in the internal and external laminae were at first exposed to salt-fog (i.e., identified as wet phase) and then stored in controlled conditions (i.e., identified as dry phase). The flexural properties evolution of these composites as well as their water uptake and contact angle were monitored at varying time of both phases. The flexural strength and modulus of hybrid composites is 23.4% (17.9%) and 15.5% (12.9%) lower than unaged ones after 30 (15) d…