Damage Index Comparison for a Composite Stiffened Panel Using Lamb Wave

2007 ◽  
pp. 1265-1268
Author(s):  
Chan Yik Park
Keyword(s):  
Lamb Wave ◽  
Damage Index ◽  
Stiffened Panel ◽  
Composite Stiffened Panel ◽  
Index Comparison

Damage Index Comparison for a Composite Stiffened Panel Using Lamb Wave

2007 ◽  
Vol 26-28 ◽  
pp. 1265-1268 ◽  
Author(s):  
Chan Yik Park
Keyword(s):  
Lead Zirconate Titanate ◽  
Lamb Waves ◽  
Impact Damage ◽  
Damage Index ◽  
Lead Zirconate ◽  
Low Velocity Impact ◽  
Stiffened Panel ◽  
Low Velocity ◽  
Composite Stiffened Panel ◽  
Index Comparison

Various damage index (DI) algorithms of detecting changes such as a loosen bolt and a delamination development in a composite structure were examined using ultrasonic Lamb waves generated by embedded piezoelectric active sensors. The DI is a single value that is a function of response signal’s attenuation due to any damage or changes in a structure. Various DI algorithms such as active damage interrogation (ADI), time domain root men square (RMS), short time Fourier Transform (STFT) and time reversal (TR) were discussed. For experimental validation, a composite stiffened panel was used, and loosen bolt damage and low-velocity- impact damage were tested. In order to pitch and catch Lamb waves, surface mounted PZTs (lead zirconate titanate) were used. According to the DI algorithms, appropriate ultrasonic guided Lamb waves were selected for actuators. Each set of DI algorithm and drive signal showed different characteristics to detect the damage.

scholarly journals Effects of plies orientations and initial geometric imperfections on buckling strength of a composite stiffened panel

2018 ◽  
Vol 191 ◽  
pp. 00008
Author(s):  
Ikram Feddal ◽  
Abdellatif Khamlichi ◽  
Koutaiba Ameziane
Keyword(s):  
Stiffened Panel ◽  
Buckling Mode ◽  
Element Analysis ◽  
Geometric Imperfections ◽  
Stiffened Panels ◽  
Specific Strength ◽  
Euler Buckling ◽  
Buckling Behavior ◽  
Composite Stiffened Panel ◽  
Strength And Stiffness

The use of composite stiffened panels is common in several activities such as aerospace, marine and civil engineering. The biggest advantage of the composite materials is their high specific strength and stiffness ratios, coupled with weight reduction compared to conventional materials. However, any structural system may reach its limit and buckle under extreme circumstances by a progressive local failure of components. Moreover, stiffened panels are usually assembled from elementary parts. This affects the geometric as well as the material properties resulting in a considerable sensitivity to buckling phenomenon. In this work, the buckling behavior of a composite stiffened panel made from carbon Epoxy Prepregs is studied by using the finite element analysis under Abaqus software package. Different plies orientations sets were considered. The initial distributed geometric imperfections were modeled by means of the first Euler buckling mode. The nonlinear Riks method of analysis provided by Abaqus was applied. This method enables to predict more consistently unstable geometrically nonlinear induced collapse of a structure by detecting potential limit points during the loading history. It was found that plies orientations of the composite and the presence of geometric imperfections have huge influence on the strength resistance.

scholarly journals An Aircraft Pallet Damage Monitoring Method Based on Damage Subarea Identification and Probability-Based Diagnostic Imaging

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Bin Liu ◽  
Tingzhang Liu ◽  
Yue Lin ◽  
Jianfei Zhao
Keyword(s):  
Diagnostic Imaging ◽  
Lamb Wave ◽  
Damage Index ◽  
Imaging Method ◽  
Monitoring Method ◽  
Study Results ◽  
Damage Monitoring ◽  
Weighted Algorithm ◽  
Damage Simulation ◽  
Monitoring Area

To improve the safety and economy of aircraft pallet use, an aircraft pallet damage monitoring method based on damage subarea identification and probability-based diagnostic imaging is proposed. In the proposed method, first, the large aircraft pallet monitoring area is divided into rectangular subareas, and a piezoelectric transducer sensor is pasted on each vertex of the rectangular subarea that is used to excitation and sensing the Lamb wave. Second, the damage subarea is identified according to the diagonal damage indexes. Third, the damage position in the damage subarea is calculated using the probability-based diagnostic imaging method and coordinate probability weighted algorithm. Finally, the aircraft pallet damage can be localized based on the damage subarea position. Frequency selection and damage simulation study results show that the Lamb wave is sensitive to aircraft pallet damage whose centre frequency ranges from 50 kHz to 150 kHz, and the damage index of a steel ball is less than that of all real aircraft pallet damage from 95 kHz to 125 kHz. The verification results show that the proposed method can locate aircraft pallet damage with an error of less than 2 cm.

The Effect of Ply Orientation and Damage Detection in Composite Stiffened Panel Using Lamb Waves

2019 ◽  
Vol 298 ◽  
pp. 161-166
Author(s):  
Ouadia Mouhat ◽  
Abdelmajid Bybi ◽  
Ahmed El Bouhmidi ◽  
Hasnae Boubel ◽  
Omaima Elmrabet ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Composite Structures ◽  
Laminate Composite ◽  
Lamb Waves ◽  
Stiffened Panel ◽  
Signal Acquisition ◽  
Frequency Increase ◽  
Stiffened Panels ◽  
Composite Stiffened Panel ◽  
Ply Orientation

The present work proposes a vibration study with different surface and layers orientations at 0°, 15°, 30°, 45°, 60°, 75° and 90°using the Abaqus finite element code, the frequencies Stratified laminate composite panels were studied and the comparison between damaged structures and perfect structures we used stiffened panels based on T-shaped reinforced fibers. Lamb waves (LW) were widely proposed for the long-range inspection of Structural Structural Health Monitoring (SHM) oriented composite structures, the obtained results show the angle effects on the natural frequency increase at a peak then decrease in the form of a sinusoidal half-curve and the numerical results found in this work can be compared to those of other authors in the same area of ​​research, A piezoelectric actuator is used to design acoustic waves and a sensor is used for signal acquisition.

Detection of Impact Location for Composite Stiffened Panel Using FBG Sensors

2010 ◽  
Vol 123-125 ◽  
pp. 895-898 ◽  
Author(s):  
Sang Oh Park ◽  
Byeong Wook Jang ◽  
Yeon Gwan Lee ◽  
Yoon Young Kim ◽  
Chun Gon Kim ◽  
...  
Keyword(s):  
Signal Processing ◽  
Noise Level ◽  
Composite Plate ◽  
Composite Plates ◽  
Stiffened Panel ◽  
Arrival Times ◽  
Fbg Sensor ◽  
Composite Stiffened Panel ◽  
Fbg Sensors ◽  
The Impact

We carried out experiments to detect impact locations on a composite plate using two types of composite plates, a composite flat plate with a constant thickness of 5 mm and a composite stiffened panel with stringers. Four multiplexed FBG sensors were attached to the bottom surface of the composite plates to acquire impact signals. The FBG sensor wavelength shift data were collected at a sampling frequency of 40 kHz using a high-speed FBG interrogator (SFI-710, Fiberpro Inc., Korea). The arrival times of the impact signals at each FBG sensor were obtained using a signal processing procedure. The arrival times were affected by noise level and signal-to-noise ratio. In order to overcome this weakness, signal processing techniques such as wavelet decomposition, normalization using each noise level and filtering with a moving average were adopted. To calculate the impact locations of the composite plate, a neural network algorithm was applied.

Optimization Methodology for Composite Stiffened Panel Based on Genetic Algorithm

2014 ◽  
Vol 952 ◽  
pp. 34-37
Author(s):  
Da Feng Jin ◽  
Zhe Liu ◽  
Zhi Rui Fan
Keyword(s):  
Genetic Algorithm ◽  
Finite Element Method ◽  
Finite Element ◽  
Design Space ◽  
Design Guidelines ◽  
Stiffened Panel ◽  
Stacking Sequence ◽  
Design Variables ◽  
Composite Stiffened Panel ◽  
Optimization Methodology

A novel optimization methodology for stiffened panel is proposed in this paper. The purpose of the optimization methodology is to improve the first buckling load of the panel which is obtained by finite element method. The stacking sequence of the stiffeners is taken as design variables. In order to ensure the manufacturability of design, the design guidelines of stacking sequence are taken into account. A DOE based on Halton Sequence makes the initial points of genetic algorithm spread more evenly in the design space of laminate parameters and consequently accelerates the search to convergence. The numerical example verifies the efficiency of this method.

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