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 Effect of Temperature and Water Absorption on Low-Velocity Impact Damage of Composites with Multi-Layer Structured Flax Fiber

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 453 ◽  
Author(s):  
Yiou Shen ◽  
Junjie Zhong ◽  
Shenming Cai ◽  
Hao Ma ◽  
Zehua Qu ◽  
...  
Keyword(s):  
Water Absorption ◽  
Structural Damage ◽  
Impact Damage ◽  
Damage Threshold ◽  
Flax Fiber ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Damage Resistance ◽  
The Impact

Temperature and moisture can cause degradation to the impact properties of plant fiber-based composites owing to their complex chemical composition and multi-layer microstructure. This study focused on experimental characterization of the effect of important influencing factors, including manufacturing process temperature, exposure temperature, and water absorption, on the impact damage threshold and damage mechanisms of flax fiber reinforced composites. Firstly, serious reduction on the impact damage threshold and damage resistance was observed, this indicated excessive temperature can cause chemical decomposition and structural damage to flax fiber. It was also shown that a moderate high temperature resulted in lower impact damage threshold. Moreover, a small amount of water absorption could slightly improve the damage threshold load and the damage resistance. However, more water uptake caused severe degradation on the composite interface and structural damage of flax fiber, which reduced the impact performance of flax fiber reinforced composites.

Structural Damage Survey Using Nondestructive Tests Based on Stress Waves

2007 ◽  
Vol 348-349 ◽  
pp. 389-392
Author(s):  
Young Sang Cho ◽  
Seong Uk Hong
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Flaw Detection ◽  
Concrete Structures ◽  
Stress Waves ◽  
Stress Wave Propagation ◽  
Impact Echo ◽  
Nondestructive Tests ◽  
The Impact ◽  
Impact Echo Method

The impact echo method has been widely used to evaluate the integrity of concrete structures. This paper is to study damage detection technique of concrete members using impact echo method, one of the nondestructive tests based on stress waves. Stress wave propagation behavior is to be studied based on wave mechanics in concrete media. Based on the theoretical study, nondestructive tests using stress waves will be conducted to observe the wave behavior on structural damages. For the damage detection of concrete structures, a mock-up specimen was prepared, and various tests were conducted for the study of the behavior of stress waves. The concrete slab of the flaw detection consist of 5 types; the first group for the thickness presumption, the second group for the position of the voids, the third group for the position of the re-bars, the fourth group for the position conduit, and the fifth group for the position of the crack. Test results are evaluated and summarized to verify if the nondestructive tests can survey damages in the concrete structures in this paper.

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.

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.

scholarly journals Experimental Study on Damage Detection in ECC-Concrete Composite Beams Using Piezoelectric Transducers

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2799
Author(s):  
Fengjiang Qin ◽  
Zhigang Zhang ◽  
Bo Xie ◽  
Rui Sun
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Structural Integrity ◽  
Damage Index ◽  
Composite Beams ◽  
Damage State ◽  
Damage Scenarios ◽  
Electromechanical Impedance ◽  
Externally Bonded ◽  
Unique Strain

The use of engineered cementitious composite (ECC) has attracted extensive attention in recent years because of the highly enhanced ductility owing to its unique strain-hardening behavior. In this paper, an electromechanical impedance-based technique is used to monitor the structural damage of RC beams strengthened with an ECC layer at the tensile zone. To achieve this purpose, three specimens are tested under bending loads to evaluate the proposed damage detection methodology. Five externally bonded PZT transducers are uniformly distributed at the surface of the ECC layer of the beams to measure the output conductance signatures in a healthy state and in different damage scenarios induced by different load levels. Test results showed that discrepancies exist between the signals measured in the intact state and each damage state, which can be used to evaluate the structural integrity changes. To assess the damage of ECC-concrete composite beams quantitatively, the statistical scalar index-root mean square deviation (RMSD) is used as the index, which can be calculated from the variations of conductance measurements of PZT sensors. The damage index values of the uniformly distributed PZT sensors provided cogent evidence of damage and revealed the evolution of structural damage. The crack patterns of beams at different damage levels are compared with the damage index values, and it shows the damage location can be derived from the measured conductance signatures of an array of PZT transducers.

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.

scholarly journals Study of the Influence of Temperature on Boron Concentration Estimation in Desalinated Seawater for Agricultural Irrigation

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 322
Author(s):  
David Escarabajal-Henarejos ◽  
Dolores Parras-Burgos ◽  
Laura Ávila-Dávila ◽  
Francisco Javier Cánovas-Rodríguez ◽  
José Miguel Molina-Martínez
Keyword(s):  
Boron Concentration ◽  
Seawater Temperature ◽  
Correlation Coefficients ◽  
Production Costs ◽  
Limiting Factor ◽  
Reduction Techniques ◽  
Influence Of Temperature On ◽  
Scarce Water ◽  
Agricultural Areas ◽  
The Impact

After several decades, the incorporation of desalinated seawater into agricultural areas with scarce water resources has become one of the main water supply strategies. Compared to the several currently available desalination techniques, reverse osmosis (RO) is now the reference technology because it lowers energy uses and production costs. Nevertheless, its main limiting factor lies in the membranes used for this system not efficiently retaining boron, which is a problem because the concentration of this element in seawater is high. For 3 years, the present work analysed the impact of seawater temperature on the kinetic parameters of boron rejection in an RO system to establish their annual behaviour and the existing correlation between both parameters. A comparison was made using the values simulated in the projection software provided by the manufacturer of the membranes. The obtained results indicated a high correlation, and the R2 correlation coefficients came very close to the unity. Nonetheless, this correlation lowered with time due to typical membrane ageing and compaction because of the system’s continuous operation. Under the tested working conditions and by applying analysed temperature intervals, it was impossible to reach the 0.3 mg·L−1 boron concentration value that ensures lack of crop toxicity. Thus, incorporating other boron reduction techniques is necessary.

A Self-Repair Mode for Capillary Reinforced Polymer Composite

2013 ◽  
Vol 575-576 ◽  
pp. 147-150
Author(s):  
Xin Hua Yuan ◽  
Ji Ye Wu ◽  
Yong Qiang Liu ◽  
Jun Xia Mao ◽  
Xue Tao Ou ◽  
...  
Keyword(s):  
Impact Damage ◽  
The Self ◽  
Self Healing ◽  
Reinforced Polymer ◽  
Flexural Testing ◽  
Reinforced Plastic ◽  
Crack Morphology ◽  
Healing Agent ◽  
Self Repair ◽  
The Impact

The paper describes a novel capillary reinforced plastic which can self-repair the impact damage in polymer composites through employing a bio-mimetic approach. A epoxy resin E-51 and harder WSR706# was used as the healing agent, the two components being filled in to different directions (0°and 90° fibers). Impact test and tensile test were used as a measure of the self-healing effectiveness. The results of flexural testing have shown that strength lost after impact damage can be restored by the self-healing effect with healing agent stored in capillaries, and a significant fraction (about 79%) of lost mechanical strength is restored by this effect. At the same time, the paper also studied the morphology of fracture surface of no embedded and capillaries embedded sample. And micrographs of crack morphology which has been healed have been observed.

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