Monitoring Corrosion Fatigue Damage Process of LY12CZ Aluminum Alloy with and without Coating by Acoustic Emission

2014 ◽  
Vol 552 ◽  
pp. 145-148
Author(s):  
Hong Chang ◽  
Xiao Chao Pang ◽  
Zhi Jun Li ◽  
Wei Jie Tang ◽  
Fei Ming Chen
Keyword(s):  
Acoustic Emission ◽  
Aluminum Alloy ◽  
Corrosion Fatigue ◽  
Structural Damage ◽  
Peak Frequency ◽  
Nacl Solution ◽  
Damage Process ◽  
Parameters Analysis ◽  
Service Conditions ◽  
Important Form

Corrosion fatigue (CF) of aluminum alloy is an important form of aircraft structural damage. Considering the real service conditions, it is necessary to study the effects of the coating on the CF process. The CF lifetime tests were conducted in 3.5% NaCl solution. The coating could well protect specimens before it damaged and markedly improved the resistibility of CF. According to results of S-N fatigue curves, at σmax=250MPa, real-time detection of the CF process for LY12CZ aluminum alloy with and without coating was performed using digital acoustic emission (AE) technique. Three damage modes, namely, coating damage, corrosion and crack propagation, were determined using AE parameters analysis, that is the distribution of amplitude and peak frequency.

Corrosion Fatigue Behavior of 7A85 Aluminum Alloy Thick Plate in NaCl Solution

2015 ◽  
Vol 28 (8) ◽  
pp. 1047-1054 ◽  
Author(s):  
Zuo-Yan Ye ◽  
Dao-Xin Liu ◽  
Xiao-Hua Zhang ◽  
Xiao-Ming Zhang ◽  
Ming-Xia Lei ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Fatigue ◽  
Thick Plate ◽  
Fatigue Behavior ◽  
Nacl Solution ◽  
7A85 Aluminum Alloy

Effect of Sealing Treatments on the Corrosion Behavior of Micro-arc Oxidation Coating on Aluminum Alloy in Acid NaCl Solution

2015 ◽  
Vol 30 (6) ◽  
pp. 627
Author(s):  
YE Zuo-Yan ◽  
LIU Dao-Xin ◽  
LI Chong-Yang ◽  
ZHANG Xiao-Hua ◽  
ZANG Xiao-Ming ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
Nacl Solution ◽  
Micro Arc Oxidation

Tendency toward corrosion cracking of V93 p.ch. aluminum alloy in a 3.5% NaCl solution

1980 ◽  
Vol 16 (1) ◽  
pp. 20-23
Author(s):  
V. P. Batrakov ◽  
V. P. Zhilikov ◽  
V. V. Kafel'nikov ◽  
B. E. Kornaukhov
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Cracking ◽  
Nacl Solution

Random Critical Fracture Toughness Values of China Railway Grade B Cast Steel Wheel

2011 ◽  
Vol 480-481 ◽  
pp. 381-386
Author(s):  
Lei Chen ◽  
Yong Xiang Zhao ◽  
Guo Xiang Song
Keyword(s):  
Fracture Toughness ◽  
Structural Damage ◽  
Cast Steel ◽  
Comparison Method ◽  
Growth Direction ◽  
Steel Wheel ◽  
Quantitative Measurements ◽  
Critical Fracture ◽  
Plastic Dissipation ◽  
Damage Process

Fracture surface observations and statistical deriving are applied for investigating the random critical fracture toughness values of China grade B cast steel wheel. Results reveal that: the crack grows to show fabric like stripes along the growth direction with few of dimples. Cleavage flowers appear under higher magnification. Cracked structural damage process is verified with few of plastic dissipation. At the same time, code based evaluated results indicate that significant scatter exists for the toughness values. Lognormal modeling is constructed appropriately with a comprehensive statistical comparison method. It is verified that random characters and quantitative measurements have been well depicted for the present critical fracture toughness values.

Quantitative acoustic emission investigation on the crack evolution in concrete prisms by frequency analysis based on wavelet packet transform

2021 ◽  
pp. 147592172110188
Author(s):  
Zonglian Wang ◽  
Keqin Ding ◽  
Huilan Ren ◽  
Jianguo Ning
Keyword(s):  
Acoustic Emission ◽  
Frequency Band ◽  
Wavelet Packet ◽  
Strain Energy Release ◽  
Crack Size ◽  
Frequency Bands ◽  
Emission Signal ◽  
Damage Process ◽  
Concrete Materials ◽  
Stage 1

To gain an insight into the evolution of micro-cracks in concrete materials, a quantitative acoustic emission investigation on the damage process of concrete prisms subjected to three-point bending loading was performed. Each of the monitored acoustic emission signals was processed by a two-level wavelet packet decomposition into four different frequency bands (AA2, DA2, AD2, and DD2), and the energy coefficients R1, R2, R3, and R4 that parameterize their characteristic frequency bands were calculated. By analyzing variations in energy coefficients of the lowest frequency band (AA2), R1, and the energy coefficients of the highest frequency band (DD2), R4, the whole damage process was divided into three stages: crack initiation, crack growth, and crack coalescence. An inverse relationship between the frequency of the acoustic emission signal emitted by the propagating crack and the crack size in concrete materials was acquired based on the damage theory of brittle materials and the strain energy release theory. The statistical analysis results of the experimental data indicated that the average of R1 increased in turn, and the average of R4 correspondingly decreased in turn from Stage 1 to Stage 3. It revealed that the frequencies of acoustic emission signals decreased gradually with the evolution of the damage of concrete prisms, which is in a good agreement with the theoretical analysis result.

Acoustic emission waveforms for damage monitoring in composite materials: Shifting in spectral density, entropy and wavelet packet transform

2021 ◽  
pp. 147592172110446
Author(s):  
Claudia Barile ◽  
Caterina Casavola ◽  
Giovanni Pappalettera ◽  
Vimalathithan Paramsamy Kannan
Keyword(s):  
Acoustic Emission ◽  
Spectral Density ◽  
Flicker Noise ◽  
Wavelet Packet ◽  
Research Work ◽  
Wavelet Packet Transform ◽  
Spectral Energy ◽  
Emission Data ◽  
Cfrp Composites ◽  
Damage Process

Signal-based acoustic emission data are analysed in this research work for identifying the damage modes in carbon fibre–reinforced plastic (CFRP) composites. The research work is divided into three parts: analysis of the shifting in the spectral density of acoustic waveforms, use of waveform entropy for selecting the best wavelet and implementation of wavelet packet transform (WPT) for identifying the damage process. The first two methodologies introduced in this research work are novel. Shifting in the spectral density is introduced in analogous to ‘flicker noise’ which is popular in the field of waveform processing. The entropy-based wavelet selection is refined by using quadratic Renyi’s entropy and comparing the spectral energy of the dominating frequency band of the acoustic waveforms. Based on the method, ‘dmey’ wavelet is selected for analysing the waveforms using WPT. The slope values of the shifting in spectral density coincide with the results obtained from WPT in characterising the damage modes. The methodologies introduced in this research work are promising. They serve the purpose of identifying the damage process effectively in the CFRP composites.

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