scholarly journals The Working Principles of a Multifunctional Bondline with Disbond Stopping and Health Monitoring Features for Composite Structures

2021 ◽  
Vol 5 (2) ◽  
pp. 51
Author(s):  
Julian Steinmetz ◽  
Thomas Löbel ◽  
Oliver Völkerink ◽  
Christian Hühne ◽  
Michael Sinapius ◽  
...  
Keyword(s):  
Health Monitoring ◽  
Composite Structures ◽  
Failure Mechanisms ◽  
Design Feature ◽  
Crack Arrest ◽  
Bolted Joints ◽  
Light Weight ◽  
Health Monitoring System ◽  
The Status ◽  
Safety Features

In comparison to bolted joints, structural bonds are the desirable joining method for light-weight composite structures. To achieve a broad implementation of this technology in safety critical structures, the issues of structural bonds due to their complex and often unpredictable failure mechanisms have to be overcome. The proposed multifunctional bondline approach aims at solving this by adding two safety mechanisms to structural bondlines. These are a design feature for limiting damages to a certain size and a structural health monitoring system for damage detection. The key question is whether or not the implementation of both safety features without deteriorating the strength in comparison to a healthy conventional bondline is possible. In previous studies on the hybrid bondline, a design feature for damage limitations in bondlines by means of disbond stopping features was already developed. Thus, the approach to evolve the hybrid bondline to a multifunctional one is followed. A thorough analysis of the shear stress and tensile strain distribution within the hybrid bondline demonstrates the feasibility to access the status of the bondline by monitoring either of these quantities. Moreover, the results indicate that it is sufficient to place sensors within the disbond stopping feature only and not throughout the entire bondline. Based on these findings, the three main working principles of the multifunctional are stated. Finally, two initial concepts for a novel multifunctional disbond arrest feature are derived for testing the fundamental hypothesis that the integration of micro sensors into the disbond stopping feature only enables the crack arrest and the health monitoring functions, while reaching the mechanical strength of a conventional healthy epoxy bondline. This work therefore provides the fundamentals for future investigations in the scope of the multifunctional bondline.

A Strain Sensing Structural Health Monitoring System for Delaminated Composite Structures

2012 ◽  
Vol 249-250 ◽  
pp. 849-855 ◽  
Author(s):  
Andrea Alaimo ◽  
Alberto Milazzo ◽  
Calogero Orlando
Keyword(s):  
Structural Health Monitoring ◽  
Fiber Optics ◽  
Health Monitoring ◽  
Composite Structures ◽  
Piezoelectric Sensors ◽  
Strain Sensing ◽  
Health Monitoring System ◽  
Structural Health ◽  
Monitoring Model ◽  
Element Approach

Structural Health Monitoring (SHM) for composite materials is becoming a primary task due to their extended use in safety critical applications. Different methods, based on the use of piezoelectric transducers as well as of fiber optics, has been successfully proposed to detect and monitor damage in composite structural components with particular attention focused on delamination cracks.In the present paper a Structural Health Monitoring model, based on the use of piezoelectric sensors, already proposed by the authors for isotropic damaged components, is extended to delaminated composite structures. The dynamic behavior of the host damaged structure and the bonded piezoelectric sensors is modeled by means of a boundary element approach based on the Dual Reciprocity BEM. The sensitivity of the piezoelectric sensors has been studied by varying the delamination length characterizing the skin/stiffener debonding phenomenon of composite structures undergoing dynamic loads.

Design and Analysis of the Health Monitoring System for the Steel Arch of the Main Stadium Roof in Nanjing Olympic Sports Center

2016 ◽  
Vol 858 ◽  
pp. 3-9
Author(s):  
Guang Pan Zhou ◽  
Ai Qun Li ◽  
Na Li ◽  
Jian Hui Li
Keyword(s):  
Stress State ◽  
Monitoring System ◽  
Health Monitoring ◽  
Safety Evaluation ◽  
Small Range ◽  
Seasonal Temperature ◽  
Health Monitoring System ◽  
Finite Element Software ◽  
The Status ◽  
Main Support

For the purpose of grasping the stress state, vibration characteristics and safety of the steel arch in Nanjing Olympic Sports Center, which is the main support among the stadium roof system as well as the world's largest oblique arch structure, a real-time health monitoring system was established and the main achievements including the system constitution, monitoring items and layouts of measuring points were described. The monitoring data measured during the 2 years period from 2014 to 2016 as well as the SAP2000 finite element software were combined to conduct the status identification and safety evaluation. The results show that the simulation results are consistent with the measured date; The measured alignment of the large arch is relatively stable, although the structural stiffness of arch has weakened compared with the designed state, the low order vibration frequencies are stable during the 2 years period; The stress state of each monitoring component is at safe levels, and fluctuates within a small range affected by the extreme seasonal temperature changes.

Smart Health Monitoring System

2020 ◽  
Vol 17 (5) ◽  
pp. 2261-2265
Author(s):  
P. Ezhilarasi ◽  
S. Rajeshkannan ◽  
P. Gokulaprasath
Keyword(s):  
Heart Rate ◽  
Monitoring System ◽  
Health Monitoring ◽  
Heart Attack ◽  
Death Rate ◽  
The Internet ◽  
Health Monitoring System ◽  
The Status ◽  
Smart Health ◽  
Growing Population

This paper proposes a Smart Health Monitoring System (SHMS) which monitors and takes care of patient's health. Nowadays in hospital, taking care of patient is a big task because of growing population and also regular check-ups are not at all possible. The percentage of death rate by only heart attack is 24.8%, which is not higher but these death rate can be reduced by monitoring the condition of patient's heart every second continuously. This can be achieved with the help of a technology called Internet of Things (IoT). The concept of IoT is that it can connect any device with the internet. Here the sensor can measure the heart rate and connects to the internet. Then it will update the status of the patient's heart to the person who wants to monitor the patient. Hence the prevention of death due to heart attack is being introduced. This idea can also be implemented for workers in industry

scholarly journals Microchip Health Monitoring System Using the FLL Circuit

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2285
Author(s):  
Emmanuel Bender ◽  
Joseph B. Bernstein
Keyword(s):  
Monitoring System ◽  
Health Monitoring ◽  
Failure Mechanisms ◽  
Ring Oscillator ◽  
Assessment Data ◽  
Health Monitoring System ◽  
Degradation Data ◽  
Operational Life ◽  
New Form ◽  
Steep Slopes

Here a solution for a Microchip Health Monitoring (MHM) system using MTOL (Multi-Temperature Operational Life) reliability testing assessment data is proposed. The module monitors frequency degradation over time compared to lab tested data. Since trends in performance degradation in recently developed devices have transitioned from multiple failure mechanisms to a single dominant failure mechanism, development of the monitor is greatly simplified. The monitor uses a novel circuit customized to deliver optimum accuracy by combining the concepts of ring oscillator (RO) and phase locked loop (PLL) circuits. The modified circuit proposed is a new form of the frequency locked loop (FLL) circuit. We demonstrate that the collection of frequency degradation data from the ring circuits of each test produces Weibull distributions with steep slopes. This implies that the monitor can predict accurate end-of-life (EOL) predictions at early stages of chip degradations. The design of the microchip health monitoring system projected in this work can have great benefit in all systems using FPGA and ASIC devices.

Application of structural health monitoring techniques to composite wing panels

2019 ◽  
Vol 53 (25) ◽  
pp. 3515-3533
Author(s):  
Fulvio Romano ◽  
Monica Ciminello ◽  
Assunta Sorrentino ◽  
Umberto Mercurio
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Composite Structures ◽  
Low Frequency ◽  
Controlled Environment ◽  
Stiffened Panels ◽  
Health Monitoring System ◽  
Structural Health ◽  
Measurement Analysis ◽  
Composite Wing

This detailed study proposes a structural health monitoring system which enables the identification, localisation, and correct measurement analysis, in relation to the damage and debonding induced by low energy impacts within aircraft composite wing panels. The said system has been envisaged as an offline system which aims to be considered as a valid alternative method in relation to the current first two maintenance approach levels: visual inspection, which is to be followed if necessary by ultrasonic scanning techniques. The architecture includes two different technologies which act at different frequency ranges: high-frequency sensors/actuators piezoceramics and low-frequency distributed fiber optic sensors. Experimental and numerical results on small stiffened panels are illustrated in this study, where technological verification and validation have been assessed within a laboratory-controlled environment. In addition, the potential benefit by utilising such techniques within the design of the aircraft composite structures has also been illustrated; in comparison with the current aircraft composite structures, a higher weight saving and better performing structures is foreseen.

scholarly journals A Hybrid Structural Health Monitoring System for the Detection and Localization of Damage in Composite Structures

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Darun Barazanchy ◽  
Marcias Martinez ◽  
Bruno Rocha ◽  
Marko Yanishevsky
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Composite Structures ◽  
Lamb Waves ◽  
Surface Damage ◽  
Fiber Reinforced Polymer ◽  
Health Monitoring System ◽  
Structural Health ◽  
Reinforced Polymer ◽  
Detection And Localization

A hybrid structural health monitoring (SHM) system, consisting of a piezoelectric transducer and fiber optic sensors (FOS) for generating and monitoring Lamb waves, was investigated to determine their potential for damage detection and localization in composite aerospace structures. As part of this study, the proposed hybrid SHM system, together with an in-house developed algorithm, was evaluated to detect and localize two types of damage: a through thickness damage (hole of 2 mm in diameter) and a surface damage (2 mm diameter bore hole with a depth of 0.65 mm) located on the backside of the plate. The experiments were performed using an aircraft representative composite plate skin, manufactured from carbon fiber reinforced polymer (CFRP).

scholarly journals Health monitoring system for composite structures

1996 ◽  
Author(s):  
S. Tang ◽  
P. Riccardella ◽  
R. Andrews ◽  
A. Mucciaradi ◽  
J. Grady
Keyword(s):  
Monitoring System ◽  
Health Monitoring ◽  
Composite Structures ◽  
Health Monitoring System
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