The response of composite structures with pre-stress subject to low velocity impact damage

2004 ◽  
Vol 66 (1-4) ◽  
pp. 685-698 ◽  
Author(s):  
B. Whittingham ◽  
I.H. Marshall ◽  
T. Mitrevski ◽  
R. Jones
2018 ◽  
Vol 18 (2) ◽  
pp. 454-465 ◽  
Author(s):  
Shaowei Lu ◽  
Kai Du ◽  
Xiaoqiang Wang ◽  
Caijiao Tian ◽  
Duo Chen ◽  
...  

A novel, omnidirectional, nanomaterial-based sensor technology which can provide wide area damage detection of composite structures was proposed in this work. The behaviors of the buckypaper sensors subjected to both tensile and low-velocity impact were investigated. The experimental results showed that the rectangle buckypaper sensor has a large range of sensing coefficients from 21.40 to 35.83 at different directions under tensile. However, the circular buckypaper sensor has a steady sensing coefficient of about 155.63. Thus, the circular buckypaper sensor as a kind of omnidirectional sensor was chosen to monitor the impact damage. The low-velocity impact damage of composite structures is characterized by the gauge factor of omnidirectional buckypaper sensors and the results of C-scanning. Omnidirectional buckypaper sensors’ electrical resistance increases with repeated impact loading; composite structure elastic deformation and damage evolution can be identified from resistance change. Experiment results show that structure monitoring based on the omnidirectional buckypaper sensor not only can detect small barely visible impact damage flaws and the damage evaluation of composite structures subjected to impact but also can determine the location of low-velocity impact damage through the analysis of results. Through comparison with C-scan, the results have preliminarily demonstrated that the omnidirectional carbon nanotubes’ buckypaper sensor can serve as an efficient tool for sensing the evolution of impact damage as well as serve structural health monitoring of composite structures.


2006 ◽  
Vol 306-308 ◽  
pp. 285-290
Author(s):  
Young Shin Lee ◽  
Hyun Soo Kim ◽  
Young Jin Choi ◽  
Jae Hoon Kim

The laminated composite structures applied to the wing and the speed brake of an aircraft or the turbine blade of a compressor. These structures may be impacted by birds and hails during operation. They may also be impacted by drop of a tool during manufacture or repair. Unlike high velocity impact damage, which can be easily found by the naked eye, the damage due to low velocity impact may be difficult to detect. Damage which is not detected may cause failure of a structure and result in damage propagation. Growth of damage means reduction of stiffness on the structure. So, exact prediction of damage caused by a low velocity impact is very important in order to guard against sudden failure of the structure. In this study, modified delamination failure criterion has suggested in order to predict the failure behavior of a composite plate subjected to low-velocity impact. The criterion includes the assumption which is matrix cracking mode causes delamination failure. Predicted damage using supposed delamination criterion is similar to experiment results.


Author(s):  
Yingtao Liu ◽  
Masoud Yekani Fard ◽  
Aditi Chattopadhyay

Impact damage has been identified as a critical form of defect that constantly threatens the reliability of composite structures, such as those used in aircrafts and naval vessels. Low energy impacts can introduce barely visible damage and cause structural degradation. Therefore, efficient structural health monitoring methods, which can accurately detect, quantify, and localize impact damage in complex composite structures, are required. In this paper a novel damage detection methodology is demonstrated for monitoring and quantifying the impact damage propagation. Statistical feature matrices, composed of features extracted from the time and frequency domains, are developed. Kernel Principal Component Analysis (KPCA) is used to compress and classify the statistical feature matrices. Compared with traditional PCA algorithm, KPCA method shows better feature clustering and damage quantification capabilities. A new damage index, formulated using Mahalanobis distance, is defined to quantify impact damage. The developed methodology has been validated using low velocity impact experiments with a sandwich composite wing.


Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8342
Author(s):  
Angelika Wronkowicz-Katunin ◽  
Andrzej Katunin ◽  
Marko Nagode ◽  
Jernej Klemenc

The problem of characterizing the structural residual life is one of the most challenging issues of the damage tolerance concept currently applied in modern aviation. Considering the complexity of the internal architecture of composite structures widely applied for aircraft components nowadays, as well as the additional complexity related to the appearance of barely visible impact damage, prediction of the structural residual life is a demanding task. In this paper, the authors proposed a method based on detection of structural damage after low-velocity impact loading and its classification with respect to types of acting stress on constituents of composite structures using the developed processing algorithm based on segmentation of 3D X-ray computed tomograms using the rebmix package, real-oriented dual-tree wavelet transform and supporting image processing procedures. The presented algorithm allowed for accurate distinguishing of defined types of damage from X-ray computed tomograms with strong robustness to noise and measurement artifacts. The processing was performed on experimental data obtained from X-ray computed tomography of a composite structure with barely visible impact damage, which allowed better understanding of fracture mechanisms in such conditions. The gained knowledge will allow for a more accurate simulation of structural damage in composite structures, which will provide higher accuracy in predicting structural residual life.


2010 ◽  
Vol 92 (8) ◽  
pp. 1913-1919 ◽  
Author(s):  
F. Capezzuto ◽  
F. Ciampa ◽  
G. Carotenuto ◽  
M. Meo ◽  
Eva Milella ◽  
...  

Author(s):  
Venkata M. K. Akula

The layered architecture of composite material allows for designing light-weight structural components. However, one of the challenges associated with composite structures is design and analysis considering impact damage. Although the damage associated with high-velocity impact events is often readily observed in a structure, by loss of material, for example, low-velocity impact damage is not always visible. However, low-velocity impact damage can undermine the strength capacity of a composite component. To ensure the structural integrity of components, predicting the residual strength after impact damage is critical. In this paper, a methodology for analysis of low-velocity impact on a curved composite panel is discussed. First, impact analysis of the panel utilizing Abaqus\Explicit is presented. A metallic projectile is utilized to simulate a tool drop event. Thereafter, a simulation technique for predicting the residual strength of the panel is discussed. The residual strength is measured in terms of collapse load when the panel is subjected to axial compression. Finally, parameter sensitivity analysis is performed to understand the influence of the various design parameters on the residual strength of the component after impact. This procedure requires automating the entire simulation workflow. The results of the simulation are presented along with the important observations.


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