scholarly journals EXPERIMENTAL VERIFICATION OF TWO STAGE ALGORITHM FOR HEALTH MONITORING OF AEROSPACE STRUCTURES

2007 ◽  
Vol 12 (ASAT CONFERENCE) ◽  
pp. 1-18
Author(s):  
Amin, S. ◽  
Abdelkhalik, M.
2019 ◽  
Vol 18 (5-6) ◽  
pp. 1789-1802 ◽  
Author(s):  
Subir Patra ◽  
Hossain Ahmed ◽  
Mohammadsadegh Saadatzi ◽  
Sourav Banerjee

In this article, experimental verification and validation of a peridynamics-based simulation technique, called peri-elastodynamics, are presented while simulating the guided Lamb wave propagation and wave–damage interaction for ultrasonic nondestructive evaluation and structural health monitoring applications. Peri-elastodynamics is a recently developed elastodynamic computation tool where material particles are assumed to interact with the neighboring particles nonlocally, distributed within an influence zone. First, in this article, peri-elastodynamics was used to simulate the Lamb wave modes and their interactions with the damages in a three-dimensional plate-like structure, while the accuracy and the efficacy of the method were verified using the finite element simulation method (FEM). Next, the peri-elastodynamics results were validated with the experimental results, which showed that the newly developed method is more accurate and computationally cheaper than the FEM to be used for computational nondestructive evaluation and structural health monitoring. Specifically, in this work, peri-elastodynamics was used to accurately simulate the in-plane and out-of-plane symmetric and anti-symmetric guided Lamb wave modes in a pristine plate and was extended to investigate the wave–damage interaction with damage (e.g. a crack) in the plate. Experiments were designed keeping all the simulation parameters consistent. The accuracy of the proposed technique is confirmed by performing error analysis on symmetric and anti-symmetric Lamb wave modes compared to the experimental results for pristine and damaged plates.


Author(s):  
Mohammad Mehdizadeh ◽  
Sabu John ◽  
Chun Wang ◽  
Michael Bannister ◽  
Viktor Verijenko

Structural health monitoring (SHM) systems are increasingly being considered for implementation in aerospace structures. As the application of SHM systems increase, it will be important to define standardized procedures to test durability, reliability, and longevity of the systems. The work presented in this paper is some preliminary work on the integrity of Piezoelectric sensors itself when used to monitor the strains in structures. This study involved the measurements of pertinent electrical properties of these sensors over 100,000 cycles of fatigue loading. Marked changes in the capacitance and inductance of these sensors highlighted deleterious structural changes in the sensor itself without any discernible change in the structure it is supposed to monitor. This might have significant implications in the reliability assessment of sensory data from SHM systems.


Author(s):  
Mohammad Jalalpour ◽  
Mahmoud Reda Taha ◽  
Eric Austin

Bolted joints are critical components in aerospace structures. Checking the integrity of these connections, although time consuming, is a necessary step before launching aerospace vehicles and satellites. Recent advances in structural health monitoring (SHM) suggest the possible use of SHM technologies to assess the integrity of these joints. Moreover, there exists a need for continuous monitoring of aerospace structures after launching. This continuous monitoring requires relating damage features that can be extracted using sensing techniques (e.g. ultrasonic methods) to physical quantities representing the structural integrity of bolted joints typically related to contact pressure. This paper describes an experimental effort to correlate shear slip measurements of a bolted connection to contact pressure. The contact pressure map (spatial distribution of contact pressure) is calibrated to the torque applied to the bolted connection. Loading and unloading experiments on the joint allowed separating elastic and shear slip displacements. Shear slip is then correlated to contact pressure maps. Further efforts are underway to connect these measures to SHM metrics.


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