scholarly journals Delamination Detection in Polymeric Ablative Materials Using Pulse-Compression Thermography and Air-Coupled Ultrasound

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2198 ◽  
Author(s):  
Stefano Laureti ◽  
Muhammad Khalid Rizwan ◽  
Hamed Malekmohammadi ◽  
Pietro Burrascano ◽  
Maurizio Natali ◽  
...  
Keyword(s):  
Pulse Compression ◽  
Thermal Stresses ◽  
High Tech ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Active Thermography ◽  
Testing Techniques ◽  
The Cost ◽  
Non Destructive ◽  
Operating Stage

Ablative materials are used extensively in the aerospace industry for protection against high thermal stresses and temperatures, an example being glass/silicone composites. The extreme conditions faced and the cost-risk related to the production/operating stage of such high-tech materials indicate the importance of detecting any anomaly or defect arising from the manufacturing process. In this paper, two different non-destructive testing techniques, namely active thermography and ultrasonic testing, have been used to detect a delamination in a glass/silicone composite. It is shown that a frequency modulated chirp signal and pulse-compression can successfully be used in active thermography for detecting such a delamination. Moreover, the same type of input signal and post-processing can be used to generate an image using air-coupled ultrasound, and an interesting comparison between the two can be made to further characterise the defect.

Acoustic and Photoacoustic Inspection of Through-Silicon Vias in the GHz-Frequency Band

2017 ◽  
Author(s):  
Sebastian Brand ◽  
Michael Kögel ◽  
Frank Altmann ◽  
Ingrid DeWolf ◽  
Ahmad Khaled ◽  
...  
Keyword(s):  
Quality Assessment ◽  
Frequency Band ◽  
Process Development ◽  
Three Dimensional ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Vertical Interconnection ◽  
Testing Techniques ◽  
Silicon Vias ◽  
Non Destructive

Abstract Through Silicon Via (TSV) is the most promising technology for vertical interconnection in novel three-dimensional chip architectures. Reliability and quality assessment necessary for process development and manufacturing require appropriate non-destructive testing techniques to detect cracks and delamination defects with sufficient penetration and imaging capabilities. The current paper presents the application of two acoustically based methods operating in the GHz-frequency band for the assessment of the integrity of TSV structures.

scholarly journals Porosity and Inclusion Detection in CFRP by Infrared Thermography

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
C. Toscano ◽  
C. Meola ◽  
M. C. Iorio ◽  
G. M. Carlomagno
Keyword(s):  
Infrared Thermography ◽  
Production Costs ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Evaluation Methodologies ◽  
Slag Inclusions ◽  
Aeronautical Industry ◽  
Testing Techniques ◽  
Lock In ◽  
Non Destructive

The ever wide use of composite materials in the aeronautical industry has evidenced the need for development of ever more effective nondestructive evaluation methodologies in order to reduce rejected parts and to optimize production costs. Infrared thermography has been recently enclosed amongst the standardized non destructive testing techniques, but its usefulness needs still complete assessment since it can be employed in several different arrangements and for many purposes. In this work, the possibility to detect slag inclusions and porosity is analyzed with both lock-in themography and pulse thermography in the transmission mode. To this end, carbon-fiber-peinforced polymers different specimens are specifically fabricated of several different stacking sequences and with embedded slag inclusions and porosity percentages. As main results, both of the techniques are found definitely able to reveal the presence of the defects above mentioned. Moreover, these techniques could be considered complementary in order to better characterize the nature of the detected defects.

Three Non-Destructive Methods for the Modulus of Elasticity of the Trachea

2004 ◽  
Author(s):  
V. Hermawan ◽  
A. M. Al-Jumaily ◽  
M. Fatemi
Keyword(s):  
Modulus Of Elasticity ◽  
Radial Strain ◽  
Propagation Path ◽  
Non Destructive Testing ◽  
Thin Cylindrical Shell ◽  
Destructive Testing ◽  
Pros And Cons ◽  
Testing Techniques ◽  
Non Destructive ◽  
Practical Recommendations

Three non-destructive testing techniques are developed and investigated to determine the Young’s modulus of elasticity of the trachea and the results are compared with the standard uniaxial state of stress method. These techniques are based on: (1) simulating the trachea as a pressurized vessel and deducing a special relationship between the pressure and the radial strain; (2) using two hydrophones and determining the variation in acoustic transmittance caused by the presence of the trachea in a propagation path within a water-bath; (3) considering the trachea as a thin cylindrical shell and determining the resonance radial vibration response. Discussion is presented to identify the “pros” and “cons” of each technique and final practical recommendations are made.

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