Recent 2015 earthquake that had strike Katmandu region in Nepal have clearly indicated the negligence of the Government, engineers and the dwellers in following the Building code during its construction and use. If those buildings were evaluated structurally as per the norms, the picture would not have been so devastating. The structural engineers should have assessed the health and condition of old buildings. But the main problem here was lack of documents for conducting the survey. The whole survey was done in favor of client. It's a need to create awareness and impose the building byelaws so that it will be followed strictly, at least when it comes to the part of human life. Loss of human life is a great loss to nation which cannot be recovered in terms of any compensation.
Although bridges were among the first civil engineering structures to use structural health monitoring (SHM) technologies, research is now expanding to explore other types of applications, including Manitoba's famous Golden Boy statue. Global research is identifying the value of using SHM technologies for civil engineering applications. Structural health monitoring uses a variety of sensors to gather information about the behaviour of a structure. The information creates a valuable knowledge base that can be analyzed to help identify potential structural risks, develop safer and more efficient new structures, and determine more effective ways to rehabilitate existing structures. This paper briefly describes the history of the Manitoba Legislative Building and the Golden Boy and also the use of SHM technologies to help preserve the Golden Boy statue, an icon of provincial heritage.
Structural health monitoring (SHM) is an automated approach to determine any changes in the integrity of mechanical system. The SHM system gives information in real time and online. Hence it provides advantages in damage detection, damage localization, damage assessment, and life prediction as well compare to Non-destructive test (NDT) which is conducted offline
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The M1114 High Mobility Multipurpose Wheeled Vehicle (HMMWV) has been the workhorse vehicle of the U.S. Armed Forces in Afghanistan and Iraq. Donald Rumsfeld, Secretary of Defense, was faced with massive public criticism in 2004 for not equipping our military personnel in Afghanistan and Iraq with M1114s that had the proper ballistic armor. In May 2004, a $618M Senate Bill was passed to increase the production level of HMMWVs and improve their ballistic protection capabilities while minimizing additional weight. While the military is taking advantage of using composite armor on the HMMWV, it does not have a rigorous method to detect, locate, and quantify damage on a two-layer composite armor system. Structural Health Monitoring (SHM) is the process of implementing a damage detection and characterization strategy for engineering structures. Damage is defined as changes to the material and geometric properties of a structural system, including changes to boundary conditions and system connectivity, which adversely affect the system's performance. An active SHM system was developed to detect, locate, and quantify damage on a two-layer composite armor (HJ1 composite with ceramic frontal plates) that encounters impact from a 0.30 caliber armor piercing projectile. An adaptive version of a one-at-a-time experiment was used during this research. Base line testing was performed to provide information on the structural properties and wave propagation characteristics of the material. Ballistic testing was completed to replicate David Fecko's experiment of maximum V50 velocity of 947 meters per second and a ceramic-to-composite ratio of 60/40%
This is the final version of the article. Available from the publisher via the DOI in this record. ; This paper presents an envisaged autonomous strain sensor device, which is dedicated to structural health monitoring applications. The paper introduces the ASIC approach that replaces the discrete approach of some of the main modules ; The SMARTER project is supported by European Union under the ERA-Net funding scheme of the FP7 (CHIST-ERA), and in the case of the spaniard partner through MINECO, reference PCIN-2013- 069.
All areas of structural design are moving towards high performance structures which minimise material usage leading to desirable savings in cost and weight. However, doing so leads to proportionally lower safety margins. These margins would previously absorb weaknesses which developed through mechanisms such as impact, corrosion and fatigue. This shift is highlighted in the aerospace industry, especially in military applications. Consequently military aerospace structures will be the focus of this thesis. Currently, the lowered safety margins are combated by regular inspections with skilled staff specialised in non-destructive testing (NDT). This is a manual, time consuming job which may require disassembly of components. As a result the frequency of inspections is limited and many hard to reach areas cannot be inspected. An emerging solution to this problem is structural health monitoring (SHM). This approach relies on permanently attached sensors to the structures critical areas. By doing so different approaches (such as baseline comparison) can be utilised and the system can be automated. This increases the frequency of inspection (potentially as frequent as real time) as well as the confidence in the results. Out of the competing technologies ultrasonic Lamb waves have stood out. Their low weight, profile and cost combined with versatility (many capabilities) make them the most promising technology at this time. As such the thesis shall propose a strategy for the implementation of Lamb wave based SHM into future structures during the design stage. Therefore it will contribute validated modeling techniques, signal processing techniques and a design philosophy. In order to formulate a strategy for implementing Lamb waves a variety of methods were developed. A customised automated laser vibrometry (ALV) rig has been built to capture Lamb wave induced displacements across entire plate specimens. The optimisations detailed in this thesis enable the ALV to capture high resolutions at practical speeds making it one of the best in the world. A finite element (FE) model has been developed alongside. Using custom scripting displacements across entire plate has been extracted for direct comparison with high resolution ALV data. This has enabled validation of FE methodology. ALV and FE were used extensively to characterise Lamb waves and establish fundamental parameters such as excitation frequency and modal content. It also revealed subtle features such as modal interference, mode conversion and refraction. These features form the basis for ray trace modelling of Lamb waves, a concept inspired by the field of optics. The development of the ray tracing tool provided an alternative method for modelling Lamb waves with low solution times. Following the development of an array of tools, the calculation of scattered Lamb waves was pursued to enable damage detection and possible quantification. This method was applied to an idealised flat plate which has been widely reported on, followed by a realistic specimen based on a realistic aircraft lower wing skin. This revealed that variations in plate geometry have a substantial influence on scattered waves used in damage detection. To understand this influence, the ray tracing tool was applied to observe the effects of plate geometry. It was realised that this influence could be controlled to direct Lamb waves at the desired inspection areas thereby improving sensitivity and reliability. Both these traits are critical to the success of Lamb wave based SHM. Finally, two case studies were performed where strategies were developed to improve sensitivity and reliability as previously mentioned. The strategies incorporate all the tools and techniques developed here and demonstrate their intended application. In each case existing realistic structures were redesigned to enhance their SHM prospects. The design philosophy focused on directing Lamb wave energy towards the desired detection area. This design change was facilitated by the ray tracing tool. Its ability to solve the effects of plate geometry on Lamb wave propagation in seconds results in near instant feedback enabling iterative design. The proposed optimisations resulted in substantial (50-90%) increase to damage sensitivity of the Lamb wave based SHM system.
Structural health monitoring is today growing challenge. A good health structure allows to assure in real-time a good performance level, to keep a high level of safety and to plan maintenance. Why drone applications? Drones are very expansive aircrafts, also referred to as UVA (unmanned air vehicle), exposed to a harsh environment due to their frequent military usage. In this context, propellers are among the key components worth health monitoring. The purpose of our research is to develop for the drone propeller an integrated electronics combining accelerometers and signal processing, able to record damaging events for the drone: shocks, vibrations or overspeeds whereas strain gauges could not analyze all these criteria. These parameters allow concluding whether the blade is damaged or not. This paper will present our embedded microsystem on drone propellers. Then we will show through real experiments how it is possible to monitor and detect events like stone shocks, propeller overspeeds or too strong vibrations. Specific algorithm for diagnosis will be discussed and evaluated in different environment tests conditions. Moreover the use of a wireless synchronization between several propellers will be studied too.
Structural health monitoring is today growing challenge. A good health structure allows to assure in real-time a good performance level, to keep a high level of safety and to plan maintenance. Why drone applications? Drones are very expansive aircrafts, also referred to as UVA (unmanned air vehicle), exposed to a harsh environment due to their frequent military usage. In this context, propellers are among the key components worth health monitoring. The purpose of our research is to develop for the drone propeller an integrated electronics combining accelerometers and signal processing, able to record damaging events for the drone: shocks, vibrations or overspeeds whereas strain gauges could not analyze all these criteria. These parameters allow concluding whether the blade is damaged or not. This paper will present our embedded microsystem on drone propellers. Then we will show through real experiments how it is possible to monitor and detect events like stone shocks, propeller overspeeds or too strong vibrations. Specific algorithm for diagnosis will be discussed and evaluated in different environment tests conditions. Moreover the use of a wireless synchronization between several propellers will be studied too.
Structural health monitoring is today growing challenge. A good health structure allows to assure in real-time a good performance level, to keep a high level of safety and to plan maintenance. Why drone applications? Drones are very expansive aircrafts, also referred to as UVA (unmanned air vehicle), exposed to a harsh environment due to their frequent military usage. In this context, propellers are among the key components worth health monitoring. The purpose of our research is to develop for the drone propeller an integrated electronics combining accelerometers and signal processing, able to record damaging events for the drone: shocks, vibrations or overspeeds whereas strain gauges could not analyze all these criteria. These parameters allow concluding whether the blade is damaged or not. This paper will present our embedded microsystem on drone propellers. Then we will show through real experiments how it is possible to monitor and detect events like stone shocks, propeller overspeeds or too strong vibrations. Specific algorithm for diagnosis will be discussed and evaluated in different environment tests conditions. Moreover the use of a wireless synchronization between several propellers will be studied too.
This is the peer reviewed version of the following article: [Makoond, N, Pelà, L, Molins, C, Roca, P, Alarcón, D. Automated data analysis for static structural health monitoring of masonry heritage structures. Struct Control Health Monit. 2020; 27:e2581. https://doi.org/10.1002/stc.2581], which has been published in final form at https://onlinelibrary.wiley.com/doi/epdf/10.1002/stc.2581. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. ; Masonry heritage structures are often affected by slow irreversible deterioration mechanisms that can jeopardise structural stability in the foreseeable future. Static structural health monitoring (SHM), aimed at the continuous measurement of key slow-varying parameters, has the potential to identify such mechanisms at a very early stage. This can greatly facilitate the implementation of adequate preventive and remedial measures, which can be critical to ensure that such structures are preserved for generations to come. However, because monitored parameters usually experience reversible seasonal variations of the same order of magnitude as changes caused by active mechanisms, identification of the latter is often a difficult task. This paper presents a fully integrated automated data analysis procedure for complete static SHM systems utilising dynamic linear regression models to filter out the effects caused by environmental variations. The method does not only produce estimated evolution rates but also classifies monitored responses in predefined evolution states. The procedure has successfully been used to identify vulnerable areas in two important medieval heritage structures in Spain, namely, the cathedral of Mallorca and the church of the monastery of Sant Cugat. ; Ajuntament de Sant Cugat through a project aimed at monitoring the Monastery of Sant Cugat, ref. num. C-10764. Ministry of Education, Culture and Sports of the Spanish Government through a project aimed at studying the structural condition of Mallorca Cathedral, ref. num. 2/131400106ca - 5/030300592 EF. AGAUR agency of the Generalitat de Catalunya and European Social Fund, through a predoctoral grant awarded to the corresponding author. Ministry of Science, Innovation and Universities of the Spanish Government and European Regional Development Fund through the SEVERUS project, ref. num. RTI2018-099589-B-100. ; Peer Reviewed ; Postprint (author's final draft)
The United States Air Force and many of its Coalition partners have extended the original service life of some of their aging aircraft due to fiscal constraints. This life extension often requires increased periodic and in-depth inspections; increasing maintenance costs and resulting in longer periods of aircraft downtime. A structural health monitoring system for aging aircraft could reduce the current inspection burden, and thus decrease costs and system downtime. This presentation describes a baseline systems engineering methodology for system definition of an aging aircraft structural health monitoring system. Analysis was performed to quantify the potential benefit a structural health monitoring affords.
