Simulation and experimental research on nonlinear ultrasonic testing of composite material porosity

Abstract Nonlinear ultrasonic testing is considered a more promising technique for evaluating closed cracks than conventional ultrasonic testing. However, the mechanism of the generation of nonlinear ultrasonic waves has not been sufficiently explained. We first set up a system to measure the frequency–response characteristics of ultrasonic waves and experimentally investigated the mechanism of second higher-harmonic (HH) wave generation for a fatigue crack. Sweeping the frequencies of incident waves impinging on a fatigue crack introduced to a specimen, we obtained a frequency–response characteristic curve for the crack. From the curve, resonance phenomena resulting from local defect resonance were observed. We then measured the frequency response characteristics of second HH waves using the same system and consequently confirmed that second HH waves resonated when their frequencies corresponded to the eigenfrequencies of the crack. Finally, we theoretically showed that the resonant second HH waves were generated by local defect resonance and nonlinearity.

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Nonlinear Ultrasonic Testing with Resonant and Pulse Velocity Parameters for Early Damage in Concrete

ACI Materials Journal ◽

10.14359/14305 ◽

2005 ◽

Vol 102 (2) ◽

Cited By ~ 4

Keyword(s):

Ultrasonic Testing ◽

Pulse Velocity ◽

Nonlinear Ultrasonic ◽

Damage In Concrete ◽

Early Damage

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Experimental Research on Calculation Parameters of GFRP Bars Tensile Strength

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1049-1050.272 ◽

2014 ◽

Vol 1049-1050 ◽

pp. 272-275

Author(s):

Qing Ping Jin ◽

Zu Jia Zheng ◽

Liang Li Xiao

Keyword(s):

Tensile Strength ◽

Composite Material ◽

Tensile Test ◽

Experimental Research ◽

Intensity Distribution ◽

Distribution Model ◽

Theoretical Formula ◽

Failure Strength ◽

Gfrp Bars ◽

Fiber Materials

A tensile test on the 18mm diameter (φ18) and 25mm (φ25) GFRP bars was conducted to observe the tensile apparent characteristics and failure strength. The value calculated by failure strength fomula and the experimental value were ,contrasted to study the parameters and value of the strength calculating formula,, and drawn the conclusions as follows: The φ18 and φ25 GFRP bars' failure strength is effected by fiber materials, enhance materials itself and interface performance. The φ18 bars’ failure strength is about 10% higher than φ25 bars’. The deviation between the calculated value and the actual value is more than 30%. k is the correction parameter in theoretical formula, kφ18=0.76, kφ25 = 0.68 is appropriate. Based on statistical intensity distribution model of GFRP bars’ failure strength, reference stresses value of the φ18 and φ25 GFRP bars are different and the diameters of GFRP bars increases to weaken the strength of the composite material. The reducing rate of the reference stresses is significantly affected by the diameters. The diameters effect is greater than the fiber content effect.

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Lock-In Thermography and Ultrasonic Testing of Impacted Basalt Fibers Reinforced Thermoplastic Matrix Composites

Applied Sciences ◽

10.3390/app9153025 ◽

2019 ◽

Vol 9 (15) ◽

pp. 3025 ◽

Cited By ~ 3

Author(s):

Boccardi ◽

Boffa ◽

Carlomagno ◽

Core ◽

Meola ◽

...

Keyword(s):

Composite Material ◽

Ultrasonic Testing ◽

Impact Damage ◽

Low Velocity Impact ◽

Matrix Composites ◽

Basalt Fibers ◽

Low Velocity ◽

Destructive Testing ◽

Impact Tests ◽

Lock In

Basalt fibers are receiving increasing consideration because they seem to be adequate as reinforcement of composites and to comply with the environmental safeguard rules. However, many factors affect the performance of composite material, demanding specific testing; one may be performance assessment under impact tests. The attention of the present work is focused on the detection of impact damage in basalt-based composites with two non-destructive testing techniques: lock-in thermography (LT) and ultrasonic testing (UT). Two different types of materials are considered which both include basalt fibers as reinforcement but two different matrices: Polyamide and polypropylene. Polypropylene is used either pure or modified with the addition of a coupling agent; the latter improves the fiber/matrix interface strength, giving in practice, a material of different characteristics. Specimens are first subjected to low-velocity impact tests and then non-destructively examined with the two above mentioned techniques. The obtained results are analyzed and compared to highlight the advantages and limitations of the two techniques to detect impact damage in basalt-based composites. Both techniques seem effective for the inspection of polyamide/basalt composite; in particular, there is a general agreement between results. Conversely, UT seems not suitable for the inspection of polypropylene/basalt composites because of their superficial porosity, while lock-in thermography is effective also for this type of composite material.

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Enhancing the Robustness of Nonlinear Ultrasonic Testing by Implementing 1D Phononic Crystals

Structural Health Monitoring 2017 ◽

10.12783/shm2017/14114 ◽

2017 ◽

Cited By ~ 1

Author(s):

AMIR MOSTAVI ◽

MINOO KABIR ◽

DIDEM OZEVIN

Keyword(s):

Ultrasonic Testing ◽

Phononic Crystals ◽

Nonlinear Ultrasonic

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Research on Fatigue Damage of Compressor Blade Steel KMN-I Using Nonlinear Ultrasonic Testing

Shock and Vibration ◽

10.1155/2017/4568460 ◽

2017 ◽

Vol 2017 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Pengfei Wang ◽

Weiqiang Wang ◽

Jianfeng Li

Keyword(s):

Fatigue Life ◽

Fatigue Damage ◽

Ultrasonic Testing ◽

Early Stage ◽

Compressor Blade ◽

Nonlinearity Parameter ◽

Nonlinear Ultrasonic ◽

Blade Steel ◽

Scanning Electron ◽

Peak Value

The fatigue damage of compressor blade steel KMN-I was investigated using nonlinear ultrasonic testing and the relation curve between the material nonlinearity parameter β and the fatigue life was obtained. The results showed that the nonlinearity parameter increased first and then decreased with the increase of the fatigue cycles. The microstructures were observed by scanning electron microscopy (SEM). It was found that some small defects like holes and pits appeared in the material matrix with the increase of the fatigue cycles, and the nonlinearity parameter increased correspondingly. The nonlinearity parameter reached the peak value when the microcracks initiated, and the nonlinearity parameter began to decrease when the microcracks further propagated to macrocracks. Therefore, it is proved that the nonlinearity parameter can be used to characterize the initiation of microcracks at the early stage of fatigue, and a method of evaluating the fatigue life of materials by nonlinear ultrasonic testing is proposed.

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Assessment of Material Dislocation Damage by Nonlinear Ultrasound

MATEC Web of Conferences ◽

10.1051/matecconf/202031601001 ◽

2020 ◽

Vol 316 ◽

pp. 01001

Author(s):

Zaifu Zhan ◽

Shen Wang ◽

Songling Huang ◽

Yang Zheng ◽

Fuping Wang ◽

...

Keyword(s):

Mechanical Properties ◽

Ultrasonic Wave ◽

Ultrasonic Testing ◽

Harsh Environment ◽

Nonlinear Phenomenon ◽

Constitutive Behaviour ◽

Nonlinear Detection ◽

Nonlinear Ultrasonic ◽

Properties Of Materials ◽

Harmonic Components

Under harsh environment or during service, the mechanical properties of materials or structure will deteriorate. Most of the simulations exhibit the phenomenon of nonlinearity by introducing the actual small defects, without considering dislocation. In this manuscript, subroutines are written to change the mechanical constitutive behaviour of materials. When the mechanical constitutive behaviour of the material is not linear any more, it is found that the propagation of ultrasonic wave in the material will show more obvious nonlinear phenomenon. Furthermore, the nonlinear detection coefficient is used to characterize the increase of harmonic components. This work provides a new idea for nonlinear ultrasonic testing.

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