IMPACT DAMAGE DETECTION LIMITS OF MICROWAVE NDE TECHNIQUE FOR POLYMER COMPOSITES

2021 ◽  
Author(s):  
KATHERINE BERKOWITZ ◽  
RISHABH D. GUHA ◽  
OGHENEOVO IDOLOR ◽  
MARK PANKOW ◽  
LANDON GRACE
Keyword(s):  
Moisture Content ◽  
Damage Detection ◽  
Polymer Matrix ◽  
Early Stage ◽  
Impact Damage ◽  
Free Water ◽  
Moisture Level ◽  
Molecular Water ◽  
Preferential Diffusion ◽  
The Impact

Despite recent advances, the need for improved non-destructive evaluation (NDE) techniques to detect and quantify early-stage damage in polymer matrix composites remains critical. A recently developed microwave based NDE technique which capitalizes on the ubiquitous presence of moisture within a polymer matrix has yielded positive results. The chemical state of moisture directly affects dielectric properties of a polymer matrix composite. Thus, the preferential diffusion of ‘free’ water into microcracks and voids associated with physical damage allows for damage detection through spatial permittivity mapping using techniques that are sensitive to moisture content and molecular water state. While it has been demonstrated that the method can detect damage at low levels of moisture and impact damage, the specific parameters under which the technique will accurately and reliably capture damage within a composite are unknown. The three variables affecting the performance of the method to detect impact damage are moisture content, extent of damage, and resolution of the dielectric scanning technique. Here, we report on the impact of the latter as a function of the two environmental variables (moisture and damage extent). To understand limits and optimize execution of the technique, the interrelationships between each of the variables must be explored. This study investigates the relationship between moisture content and scan resolution. Two BMI/quartz laminates were impacted at 9 Joules to induce barely visible impact damage. The specimens were inspected at a variety of gravimetric moisture levels, and several variations of the spatial permittivity map were created for each moisture level. Detection standards for the technique were investigated based on moisture content and desired scan accuracy; findings showed at 0.05-0.4% moisture content (by wt.) the technique can detect damage location and size with a minimum of 88% accuracy. Pareto frontiers were generated at each moisture level to optimize scan speed and accuracy.

Experimental Investigation on Improving Electromechanical Impedance Based Damage Detection by Temperature Compensation

2013 ◽  
Vol 569-570 ◽  
pp. 1132-1139 ◽  
Author(s):  
Thomas Siebel ◽  
Mihail Lilov
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Temperature Compensation ◽  
Impact Damage ◽  
Correlation Coefficients ◽  
Electromechanical Impedance ◽  
Reinforced Plastic ◽  
Influence Of Temperature On ◽  
Compensation Approach ◽  
The Impact

The sensitivity of the electromechanical impedance to structural damage under varying temperature is investigated in this paper. An approach based on maximizing cross-correlation coefficients is used to compensate temperature effects. The experiments are carried out on an air plane conform carbon fiber reinforced plastic (CFRP) panel (500mm x 500mm x 5mm) instrumented with 26 piezoelectric transducers of two different sizes. In a first step, the panel is stepwise subjected to temperatures between-50 °C and 100 °C. The influence of varying temperatures on the measured impedances and the capability of the temperature compensation approach are analyzed. Next, the sensitivity to a 200 J impact damage is analyzed and it is set in relation to the influence of a temperature change. It becomes apparent the impact of the transducer size and location on the quality of the damage detection. The results further indicate a significant influence of temperature on the measured spectra. However, applying the temperature compensation algorithm can reduce the temperature effect at the same time increasing the transducer sensitivity within its measuring area. The paper concludes with a discussion about the trade-off between the sensing area, where damage should be detected, and the temperature range, in which damage within this area can reliably be detected.

scholarly journals Crushing Susceptibility of Vetch Seeds Under Impact Loading

2017 ◽  
Vol 50 (4) ◽  
pp. 5-16
Author(s):  
F. Shahbazi
Keyword(s):  
Moisture Content ◽  
Impact Energy ◽  
Impact Loading ◽  
Impact Damage ◽  
Mechanical Damage ◽  
Seed Moisture Content ◽  
Mean Values ◽  
Seed Moisture ◽  
Mathematical Relationships ◽  
The Impact

AbstractMechanical damage of seeds due to harvest, handling and other process is an important factor that affects the quality and quaintly of seeds. The objective of this research was to determine the effects of moisture content and the impact energy on the breakage susceptibility of vetch seeds. The experiments were conducted at moisture contents of 7.57 to 25% (wet basis) and at the impact energies of 0.1, 0.2 and 0.3 J, using an impact damage assessment device. The results showed that impact energy, moisture content, and the interaction effects of these two variables significantly influenced the percentage breakage in vetch seeds (p<0.01). Increasing the impact energy from 0.1 to 0.3 J caused a significant increase in the mean values of seeds breakage from 41.69 to 78.67%. It was found that the relation between vetch seeds moisture content and seeds breakage was non-linear, and the extent of damaged seeds decreased significantlyas a polynomial (from 92.47 to 33.56%) with increasing moisture (from 7.57 to 17.5%) and reached a minimum at moisture level of about 17.5%. Further increase in seed moisture, however, caused an increase in the amount of seeds breakage. Mathematical relationships composed of seed moisture content and impact energy, were developed for accurately description the percentage breakage of vetch seeds under impact loading. It was found that the models have provided satisfactory results over the whole set of values for the dependent variable.

Mechanical Damage to Pinto Bean Seeds as Affected by Moisture Content, Impact Velocity and Seed Orientation

2012 ◽  
Vol 7 (6) ◽  
Author(s):  
Feizollah Shahbazi ◽  
Mohamad Analooei ◽  
Ali Saffar
Keyword(s):  
Moisture Content ◽  
Impact Velocity ◽  
Impact Damage ◽  
Quadratic Function ◽  
Physical Damage ◽  
Seed Moisture Content ◽  
Mean Values ◽  
Pinto Bean ◽  
The Mean ◽  
The Impact

The objective of this experiment was evaluate of the impact damage to pinto bean seeds where seed moisture content (9.25, 12.51, 15.01, 17.52, 20.01% wet basis), impact velocity (5.5, 8, 10, 12.5 and 15m/s) and seed orientation (end and side) were independent variables. The study was conducted under laboratory conditions, using an impact damage assessment device. The results showed that impact velocity, moisture content and seed orientation significantly influenced the physical damages of pinto beans at 1% level. Increasing the impact velocity from 5.5 to 15m/s caused an increase in the mean values of damage from 0.39 to 37.30%. With increase the moisture content from 9.25 to 17.52%, the mean values of percentage of damaged beans decreased significantly from 41.24 to 4.27%. However, by a higher increase in the moisture from 17.52 to 20.01%, the mean values of physically damaged beans showed a nonsignificant increasing trend. There was an optimum moisture level of 17.52% at which seed damage was minimized. The relationship between the percent of physical damage with impact velocity and beans moisture content was expressed mathematically. It was found that the percentage damage to seeds was a quadratic function of moisture content and impact velocity. Impact to the end of the seeds (18.62%) produced the higher damage than side orientation (13.12%).

Damage Classification in CFRP Laminates Using Principal Component Analysis (PCA) Approach

2012 ◽  
Vol 225 ◽  
pp. 189-194
Author(s):  
Mohamed Thariq Hameed Sultan ◽  
Azmin Shakrine M. Rafie ◽  
Noorfaizal Yidris ◽  
Faizal Mustapha ◽  
Dayang Laila Majid
Keyword(s):  
Signal Processing ◽  
Damage Detection ◽  
Impact Damage ◽  
Research Work ◽  
Principal Component ◽  
Damage Classification ◽  
Cfrp Laminates ◽  
Work Related ◽  
Detection And Identification ◽  
The Impact

Signal processing is an important element used for identifying damage in any SHM-related application. The method here is used to extract features from the use of different types of sensors, of which there are many. The responses from the sensors are also interpreted to classify the location and severity of the damage. This paper describes the signal processing approaches used for detecting the impact locations and monitoring the responses of impact damage. Further explanations are also given on the most widely-used software tools for damage detection and identification implemented throughout this research work. A brief introduction to these signal processing tools, together with some previous work related to impact damage detection, are presented and discussed in this paper.

Correlating the Data on the Mechanical Damage to Mung Bean Seeds under Impact Loading

2012 ◽  
Vol 7 (6) ◽  
Author(s):  
Feizollah Shahbazi ◽  
Saman Valizadeh ◽  
Ali Dolatshaie
Keyword(s):  
Moisture Content ◽  
Impact Velocity ◽  
Mung Bean ◽  
Impact Damage ◽  
Mechanical Damage ◽  
Physical Damage ◽  
Seed Moisture Content ◽  
Mean Values ◽  
The Mean ◽  
The Impact

Mechanical damage of seeds due to harvest, handling, and other processes is an important factor that affects the quality and quaintly of seeds. This study evaluated impact damage to the mung bean seeds with moisture contents of 9.54 to 25% wet basis and subject to impact velocities from 10 to 25 m/s using a laboratory impact damage assessment device. The results showed that impact velocity, moisture content, and the interaction effects of these two variables significantly influenced the percentage physical damage in mung ban seeds (p<0.01). Increasing the impact velocity from 10 to 25 m/s caused a significant (p < 0.05) increase in the mean values of damage from 0.53 to 31.78%. The mean values of physical damage decreased significantly (p < 0.05) by a factor about two (from 22.41 to 11.24%), with increase in the moisture content from 9.54 to 20%. However, by a higher increase in the moisture from 20 to 25%, the mean value of damage showed a non-significant increasing trend. There was an optimum moisture level of 20%, at which seed damage was minimized. An empirical model composed of seed moisture content and velocity of impact developed for accurately describing the percentage of physical damage to mung beans. It was found that the model has provided satisfactory results over the whole set of values for the dependent variable.

Characterization of Resin-Injection Repair of Impact Damage in Polymer Matrix Composite

2015 ◽  
Author(s):  
Ritwik Prashant Moghe ◽  
Raghu V. Prakash ◽  
Deepika Sudevan ◽  
Hema Katta Shambhayya
Keyword(s):  
Polymer Matrix ◽  
Impact Damage ◽  
Damage Zone ◽  
Injection Pressure ◽  
High Energy ◽  
Low Energy ◽  
Repair Method ◽  
Energy Impact ◽  
Resin Injection ◽  
The Impact

Resin injection repair of impact damage in polymer matrix composites is studied using an in-house developed repair methodology. Carbon fiber reinforced polymeric composite specimens were impacted for three levels of impact damage (23 J, 35 J and 51 J — typical of low energy, medium energy, high energy) using a drop tup test rig and the damage zone was characterized using ultrasonic C-scan technique. The impact damaged specimens were repaired using a resin infiltration method. The selection of low viscosity room temperature curing resin, and process parameters such as resin injection pressure and vacuum levels to be maintained were studied to arrive at optimum repair method. The tension, compression strength of laminates prior to impact and post-impact as well as post-repair was studied to assess the quality of repair method. The results indicate that the chosen resin injection repair is effective for the repair of low energy impact damage but not in the case of medium and high energy impact damage.

Damage Detection Using In-Situ Piezo Transducers on a Composite Laminate Using Lamb Wave

2011 ◽  
Vol 83 ◽  
pp. 267-273
Author(s):  
S. Saravanan ◽  
K.R. Natarajan ◽  
J.L. Yang ◽  
B. S. Wong ◽  
N. Q. Guo
Keyword(s):  
Damage Detection ◽  
Piezoelectric Transducer ◽  
Lamb Wave ◽  
Composite Laminate ◽  
Impact Damage ◽  
Fibre Composite ◽  
Low Velocity Impact ◽  
Active Monitoring ◽  
The Impact

This paper is aimed at experimentally developing an in-situ macro-fibre composite (MFCTM) piezoelectric transducer sparse array which functions as both actuator and sensor of Lamb wave for damage detection in composite laminate. Lamb waves which have been used in non-destructive evaluation (NDE) of plate-like structures, can be used for active monitoring and interrogating the health of the structures due to their long range propagation with less attenuation. MFC acting as a powerful actuator of Lamb wave as well as a sensitive sensor is highly conformable and anisotropic in behaviour compared to monolithic piezoelectric transducer. The surface bonded MFC transducer on woven carbon fibre reinforced plastic (CFRP) laminate shows directional Lamb wave generation and reception characteristics. Pitch catch approach is used for low velocity impact damage detection. The MFC sensor shows a drastic drop in signal amplitude with the growth of the impact damage.

Detection of Impact Damages in CFRP Composites Using Ultrasonic Burst Phase Thermography

2011 ◽  
Vol 689 ◽  
pp. 282-288 ◽  
Author(s):  
Da Peng Chen ◽  
Nai Ming Wu ◽  
Zheng Zhang ◽  
Yue Li ◽  
Xiao Xia Li ◽  
...  
Keyword(s):  
Damage Detection ◽  
Impact Damage ◽  
Imaging Tool ◽  
Cfrp Composites ◽  
Phase Images ◽  
Control And Prevention ◽  
Burst Phase ◽  
The Impact ◽  
The Relationship ◽  
Impact Damages

Carbon fiber reinforced polymer (CFRP) composites have been used extensively because of their excellent performance, but they are susceptible to the impact damages, such as the impact of birds, runway stones and tools off can cause the failure of CFRP composites. Therefore, nondestructive testing of CFRP composites is necessary to promote the failure control and prevention. Ultrasonic burst phase thermography (UBP) developed a few years ago is a defect-selective and fast imaging tool for damage detection. This paper describes the principle of UBP, gives some UBP testing results of impact damages in five CFRP laminated boards. The shape and position of the damages are shown in the phase images visualized and the relationship between the damage areas and impact energy is discussed. The flash pulse thermography (PT) results and ultrasonic C-scan results are also shown as comparison. It is concluded that all of the three NDT methods have their own characteristics and the comparison verifies the feasibility of CFRP impact damage detection using ultrasonic burst phase thermography.

Localization of Barely Visible Impact Damage (BVID) in Composite Plates

2014 ◽  
Vol 627 ◽  
pp. 217-220 ◽  
Author(s):  
Shi Yang Meng ◽  
Zahra Sharif Khodaei ◽  
M.H. Aliabadi
Keyword(s):  
Damage Detection ◽  
Impact Damage ◽  
Composite Plates ◽  
Structural Features ◽  
Detection Technique ◽  
Stiffened Panel ◽  
Imaging Method ◽  
Flat Panel ◽  
Isotropic Composite ◽  
The Impact

This paper exploits the implementation of a delay-and-sum imaging method using Lamb wave signals to localise barely visible impact damage (BVID) in quasi-isotropic composite panels. The structural discontinuities, such as opening and stiffener, has also been tested to reflect the common structural features of an aircraft and to examine the feasibility of the proposed detection technique. The prediction results are compared with ultrasonic C-scan images, which indicate location error for three different panels –flat panel, flat panel with an opening and stiffened panel. The accuracy is believed to be improved by increasing the number of transducers. Overall the proposed damage detection technique, with the use of only four transducers, demonstrated sufficient accuracy and efficiency in impact damage detection and can be applied alongside the traditional NDT inspections for providing a priori information of the impact damage location.

Mechanical Damage to Corn Seeds

2018 ◽  
Vol 51 (3) ◽  
pp. 1-12 ◽  
Author(s):  
F. Shahbazi ◽  
R. Shahbazi
Keyword(s):  
Moisture Content ◽  
Impact Damage ◽  
Mechanical Damage ◽  
Mean Value ◽  
Physical Damage ◽  
Seed Moisture Content ◽  
Mean Values ◽  
Energy Impact ◽  
The Mean ◽  
The Impact

Abstract The objective of this research was to evaluate and model the mechanical damage to corn seeds under impact loading. The experiments were conducted at moisture contents of 7.60 to 25% (wet basis) and at the impact energies of 0.1, 0.2 and 0.3 J, using an impact damage assessment device. The results showed that impact energy, moisture content, and the interaction effects of these two variables significantly influenced the percentage of physical damage in corn seeds (p<0.01). Increasing the impact of the energy from 0.1 to 0.3 J caused a significant increase in the mean values of damage from 23.73 to 83.49%. The mean values of physical damage decreased significantly by a factor of 1.92 (from 83.75 to 43.56%), with an increase in the moisture content from 7.6 to 20%. However, by a higher increase in the moisture from 20 to 25%, the mean value of damage showed a non-significant increasing trend. There was an optimum moisture level of about 17 to 20%, at which seed damage was minimized. An empirical model composed of seed moisture content and energy impact was developed for accurately describing the percentage of physical damage to corn seeds. It was found that the model has provided satisfactory results over the whole set of values for the dependent variable.

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