Application of Wave Propagation and Vibration-based Structural Health Monitoring Techniques to Friction Stir Welded Plate and Sandwich Honeycomb Panel

2007 ◽  
Author(s):  
S. Sundararaman ◽  
J. R. White ◽  
D. E. Adams ◽  
K. V. Jata
Keyword(s):  
Wave Propagation ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Friction Stir ◽  
Monitoring Techniques ◽  
Structural Health ◽  
Honeycomb Panel

Design, Development, and Assembly of Space Flight Structural Health Monitoring Experiment

2012 ◽  
Author(s):  
David Siler ◽  
Ben Cooper ◽  
Chris White ◽  
Stephen Marinsek ◽  
Andrei Zagrai ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Structural Health Monitoring ◽  
Data Acquisition ◽  
Health Monitoring ◽  
Space Flight ◽  
Design Development ◽  
Active Sensors ◽  
Electromechanical Impedance ◽  
Structural Health ◽  
Propagation Experiment

The paper presents the design, development, and assembly of Structural Health Monitoring (SHM) experiments intended to be launch in space on a sub-orbital rocket flight as well as a high altitude balloon flight. The experiments designed investigate the use of both piezoelectric sensing hardware in a wave propagation experiment and piezoelectric wafer active sensors (PWAS) in an electromechanical impedance experiment as active elements of spacecraft SHM systems. The list of PWAS experiments includes a bolted-joint test and an experiment to monitor PWAS condition during spaceflight. Electromechanical impedances of piezoelectric sensors will be recorded in-flight at varying input frequencies using an onboard data acquisition system. The wave propagation experiment will utilize the sensing hardware of the Metis Design MD7 Digital SHM system. The payload will employ a triggering system that will begin experiment data acquisition upon sufficient saturation of g-loading. The experiment designs must be able to withstand the harsh environment of space, intense vibrations from the rocket launch, and large shock loading upon re-entry. The paper discusses issues encountered during design, development, and assembly of the payload and aspects central to successful demonstration of the SHM system during both the sub-orbital space flight and balloon launch.

scholarly journals Analysis of Guided Wave Propagation in a Multi-Layered Structure in View of Structural Health Monitoring

2019 ◽  
Vol 9 (21) ◽  
pp. 4600 ◽  
Author(s):  
Yevgeniya Lugovtsova ◽  
Jannis Bulling ◽  
Christian Boller ◽  
Jens Prager
Keyword(s):  
Wave Propagation ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Guided Waves ◽  
Oil And Gas ◽  
Numerical Approach ◽  
Guided Wave ◽  
Mode Shapes ◽  
Engineering Structures ◽  
Structural Health

Guided waves (GW) are of great interest for non-destructive testing (NDT) and structural health monitoring (SHM) of engineering structures such as for oil and gas pipelines, rails, aircraft components, adhesive bonds and possibly much more. Development of a technique based on GWs requires careful understanding obtained through modelling and analysis of wave propagation and mode-damage interaction due to the dispersion and multimodal character of GWs. The Scaled Boundary Finite Element Method (SBFEM) is a suitable numerical approach for this purpose allowing calculation of dispersion curves, mode shapes and GW propagation analysis. In this article, the SBFEM is used to analyse wave propagation in a plate consisting of an isotropic aluminium layer bonded as a hybrid to an anisotropic carbon fibre reinforced plastics layer. This hybrid composite corresponds to one of those considered in a Type III composite pressure vessel used for storing gases, e.g., hydrogen in automotive and aerospace applications. The results show that most of the wave energy can be concentrated in a certain layer depending on the mode used, and by that damage present in this layer can be detected. The results obtained help to understand the wave propagation in multi-layered structures and are important for further development of NDT and SHM for engineering structures consisting of multiple layers.

scholarly journals POST-EVENT PLASTIC FAILURE ANALYSIS OF SHEAR FRAMES FROM THEIR PRE-EVENT ELASTIC RESPONSE

2019 ◽  
Author(s):  
Arzhang Alimoradi
Keyword(s):  
Structural Health Monitoring ◽  
Closed Form ◽  
Health Monitoring ◽  
Early Warning Systems ◽  
Closed Form Expression ◽  
Monitoring Techniques ◽  
Plastic Failure ◽  
Structural Health ◽  
Plastic Mechanism ◽  
Failure Loads

We demonstrate that plastic failure loads of shear frames can be inferred from their elastic ambient response. The interstory plastic mechanism force is derived for moment-resisting (rigid) frames as a function of two measured elastic (low-amplitude) frequencies. Structural health monitoring techniques are traditionally devised for “post-event” assessment of structures after exposure of a facility to a potentially damaging loading event such as strong earthquakes or blasts. The knowledge of induced damage, its location, and severity in an otherwise functioningstructure, as important as it is, may be too late for precautionary preparations. Naturally, one is interested in identification of potential failure mechanisms and indicators prior to damaging events when a structure is responding to environmental loads elastically. Are post-event plastic failure loads identifiable from the pre-event ambient response? We answer this question by first deriving interstory shear stiffness values from a set of measured ambient frequencies that are then incorporated into post-elastic equilibrium equations for a closed-form expression of failure loads as a function of measured frequencies. We test our procedure using a typical shear frame example as proof of concept. To extend the relevance and applicability of the proposed procedure we consider uncertainties associated with the measured and estimated quantities and assess their effects in our model output. The closed-form solutions presented allow study of fully-stressed designs and we present the optimal stiffness distribution for such designs as another example. It is anticipated that temporal relevance of structural health monitoring techniques to “pre-event” assessment will be extended in the near future to such promising technologies as earthquake early warning systems.

scholarly journals A Review of NDT/Structural Health Monitoring Techniques for Hot Gas Components in Gas Turbines

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 711 ◽  
Author(s):  
Frank Mevissen ◽  
Michele Meo
Keyword(s):  
Structural Health Monitoring ◽  
Gas Turbine ◽  
Health Monitoring ◽  
Gas Turbines ◽  
Failure Modes ◽  
Combustion Chambers ◽  
Monitoring Techniques ◽  
Structural Health ◽  
Advantages And Disadvantages ◽  
Turbine Vanes

The need for non-destructive testing/structural health monitoring (SHM) is becoming increasingly important for gas turbine manufacturers. Incipient cracks have to be detected before catastrophic events occur. With respect to condition-based maintenance, the complex and expensive parts should be used as long as their performance or integrity is not compromised. In this study, the main failure modes of turbines are reported. In particular, we focus on the turbine blades, turbine vanes and the transition ducts of the combustion chambers. The existing monitoring techniques for these components, with their own particular advantages and disadvantages, are summarised in this review. In addition to the vibrational approach, tip timing technology is the most used technique for blade monitoring. Several sensor types are appropriate for the extreme conditions in a gas turbine, but besides tip timing, other technologies are also very promising for future NDT/SHM applications. For static parts, like turbine vanes and the transition ducts of the combustion chambers, different monitoring possibilities are identified and discussed.

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