48 research outputs found
Novel Approaches for Structural Health Monitoring
The thirty-plus years of progress in the field of structural health monitoring (SHM) have left a paramount impact on our everyday lives. Be it for the monitoring of fixed- and rotary-wing aircrafts, for the preservation of the cultural and architectural heritage, or for the predictive maintenance of long-span bridges or wind farms, SHM has shaped the framework of many engineering fields. Given the current state of quantitative and principled methodologies, it is nowadays possible to rapidly and consistently evaluate the structural safety of industrial machines, modern concrete buildings, historical masonry complexes, etc., to test their capability and to serve their intended purpose. However, old unsolved problematics as well as new challenges exist. Furthermore, unprecedented conditions, such as stricter safety requirements and ageing civil infrastructure, pose new challenges for confrontation. Therefore, this Special Issue gathers the main contributions of academics and practitioners in civil, aerospace, and mechanical engineering to provide a common ground for structural health monitoring in dealing with old and new aspects of this ever-growing research field
Active thermography for the investigation of corrosion in steel surfaces
The present work aims at developing an experimental methodology for the analysis
of corrosion phenomena of steel surfaces by means of Active Thermography (AT), in
reflexion configuration (RC).
The peculiarity of this AT approach consists in exciting by means of a laser source the sound
surface of the specimens and acquiring the thermal signal on the same surface, instead of the
corroded one: the thermal signal is then composed by the reflection of the thermal wave
reflected by the corroded surface. This procedure aims at investigating internal corroded
surfaces like in vessels, piping, carters etc. Thermal tests were performed in Step Heating and
Lock-In conditions, by varying excitation parameters (power, time, number of pulse, ….) to
improve the experimental set up. Surface thermal profiles were acquired by an IR
thermocamera and means of salt spray testing; at set time intervals the specimens were
investigated by means of AT. Each duration corresponded to a surface damage entity and to a
variation in the thermal response. Thermal responses of corroded specimens were related to
the corresponding corrosion level, referring to a reference specimen without corrosion. The
entity of corrosion was also verified by a metallographic optical microscope to measure the
thickness variation of the specimens
Index to 1983 NASA Tech Briefs, volume 8, numbers 1-4
Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1983 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences
NASA Tech Briefs, September 1997
Topics include: Data Acquisition and Analysis; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Software; Mechanics; Machinery/Automation; Manufacturing/Fabrication; Mathematics and Information Sciences
International Conference on Civil Infrastructure and Construction (CIC 2020)
This is the proceedings of the CIC 2020 Conference, which was held under
the patronage of His Excellency Sheikh Khalid bin Khalifa bin Abdulaziz Al
Thani in Doha, Qatar from 2 to 5 February 2020. The goal of the conference
was to provide a platform to discuss next-generation infrastructure and its
construction among key players such as researchers, industry professionals
and leaders, local government agencies, clients, construction contractors and
policymakers.
The conference gathered industry and academia to disseminate their research
and field experiences in multiple areas of civil engineering. It was also a unique
opportunity for companies and organizations to show the most recent
advances in the field of civil infrastructure and construction.
The conference covered a wide range of timely topics that address the needs
of the construction industry all over the world and particularly in Qatar. All
papers were peer reviewed by experts in their field and edited for publication.
The conference accepted a total number of 127 papers submitted by authors
from five different continents under the following four themes:
Theme 1: Construction Management and Process
Theme 2: Materials and Transportation Engineering
Theme 3: Geotechnical, Environmental, and Geo-environmental Engineering
Theme 4: Sustainability, Renovation, and Monitoring of Civil InfrastructureThe list of the Sponsors are listed at page 1
Proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress
Published proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress, hosted by York University, 27-30 May 2018
Technology 2000, volume 1
The purpose of the conference was to increase awareness of existing NASA developed technologies that are available for immediate use in the development of new products and processes, and to lay the groundwork for the effective utilization of emerging technologies. There were sessions on the following: Computer technology and software engineering; Human factors engineering and life sciences; Information and data management; Material sciences; Manufacturing and fabrication technology; Power, energy, and control systems; Robotics; Sensors and measurement technology; Artificial intelligence; Environmental technology; Optics and communications; and Superconductivity
Fiber Bragg Grating Displacement Sensor with High Abrasion Resistance for a Steel Spring Floating Slab Damping Track
This paper presents a fiber Bragg grating (FBG) displacement sensor with high abrasion resistance for displacement monitoring of a steel spring floating slab damping track. A wedge-shaped sliding block and an equal-strength beam form a conversion mechanism to transfer displacement to the deflection of the beam, and the deflection-induced strain is exerted on two FBGs. A special linear guide rail-slider and a precision rolling bearing have been adopted onto the conversion mechanism, which turned sliding friction into rolling friction and thus significantly reduced the friction during frequent alternating displacement measuring. Sensing principle and the corresponding theoretical derivation have been demonstrated. Experiment results show that the sensor has a sensitivity of 34.32 pm/mm and a high resolution of 0.0029 mm within a measurement range of 0~90 mm. Besides, the sensor has also a good measurement capability for micro-displacement within a range of 0~3 mm. The repeatability error and hysteresis error are 1.416% and 0.323%, respectively. Good creep resistance and high abrasion resistance for alternating displacement measurement have also been presented by a performance test. These excellent performances satisfy the requirements of high precision and long-term stability in structural health monitoring for machinery equipment and civil engineering, especially in the displacement monitoring of a floating slab damping track
Fiber Bragg Grating Displacement Sensor with High Abrasion Resistance for a Steel Spring Floating Slab Damping Track
This paper presents a fiber Bragg grating (FBG) displacement sensor with high abrasion resistance for displacement monitoring of a steel spring floating slab damping track. A wedge-shaped sliding block and an equal-strength beam form a conversion mechanism to transfer displacement to the deflection of the beam, and the deflection-induced strain is exerted on two FBGs. A special linear guide rail-slider and a precision rolling bearing have been adopted onto the conversion mechanism, which turned sliding friction into rolling friction and thus significantly reduced the friction during frequent alternating displacement measuring. Sensing principle and the corresponding theoretical derivation have been demonstrated. Experiment results show that the sensor has a sensitivity of 34.32 pm/mm and a high resolution of 0.0029 mm within a measurement range of 0~90 mm. Besides, the sensor has also a good measurement capability for micro-displacement within a range of 0~3 mm. The repeatability error and hysteresis error are 1.416% and 0.323%, respectively. Good creep resistance and high abrasion resistance for alternating displacement measurement have also been presented by a performance test. These excellent performances satisfy the requirements of high precision and long-term stability in structural health monitoring for machinery equipment and civil engineering, especially in the displacement monitoring of a floating slab damping track