Monitoring damage in composite plates from crack initiation to macro-crack propagation combining linear and nonlinear ultrasonic techniques

2020 ◽  
pp. 147592172092292
Author(s):  
Hamad Alnuaimi ◽  
Umar Amjad ◽  
Pietro Russo ◽  
Valentina Lopresto ◽  
Tribikram Kundu
Keyword(s):  
Composite Plates ◽  
Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Damage Progression ◽  
Nonlinear Ultrasonic ◽  
Ultrasonic Techniques ◽  
Linear And Nonlinear ◽  
Ultrasonic Parameters ◽  
Peak Count ◽  
Ultrasonic Parameter

In this article, a holistic technique for sensing damage initiation, as well as damage progression in composite plates, is presented combining linear and nonlinear ultrasonic techniques. For this investigation, multiple sets of composite plate specimens made of two different composite materials were fabricated to check if the proposed technique works for different types of specimens. The specimens were damaged by impact loading and then inspected by propagating Lamb waves through them. Different failure mechanisms, such as fiber breaks, matrix cracking, debonding, and delamination, cause composite damage. Two groups of composite specimens that were fabricated and damaged were glass fiber–reinforced polymer composite and basalt fiber–reinforced polymer composite. A chirp signal excited by PZT (lead zirconate titanate) transducer was propagated through undamaged and damaged specimens to investigate the effects of varying degrees of damage on the recorded signals. Both linear and nonlinear ultrasonic parameters were extracted from the recorded signals and analyzed. The change in the linear ultrasonic parameters such as the wave speed and attenuation with damage progression were recorded. A new nonlinear ultrasonic parameter, the sideband peak count or sideband peak count-index, is also introduced and calculated from the recorded signals. It is observed that the nonlinear ultrasonic parameter can monitor the early stage of damage progression better than the linear ultrasonic parameters, while some linear ultrasonic parameters are more effective than the nonlinear ultrasonic parameter for monitoring the advanced stage of damage. Therefore, a combination of linear ultrasonic and nonlinear ultrasonic analyses is ideal for the holistic monitoring of the composite panels from the crack nucleation stage to the structural failure stage.

scholarly journals Effects of moisture absorption on damage progression and strength of unidirectional and cross-ply fiberglass–epoxy composites

2018 ◽  
Vol 3 (1) ◽  
pp. 427-438
Author(s):  
Jake D. Nunemaker ◽  
Michael M. Voth ◽  
David A. Miller ◽  
Daniel D. Samborsky ◽  
Paul Murdy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Moisture Absorption ◽  
Fiber Reinforced Polymer ◽  
Material System ◽  
Marine Environments ◽  
Reinforced Polymer ◽  
Damage Progression ◽  
Fiber Reinforced Polymer Composites ◽  
Superior Mechanical Properties ◽  
Marine Hydrokinetic

Abstract. Fiber-reinforced-polymer composites (FRPs) possess superior mechanical properties and formability, making them a desirable material for construction of large optimized mechanical structures, such as aircraft, wind turbines, and marine hydrokinetic (MHK) devices. However, exposure to harsh marine environments can result in moisture absorption into the microstructure of the FRPs comprising these structures and often degrading mechanical properties. Specifically, laminate static and fatigue strengths are often significantly reduced, which must be considered in design of FRP structures in marine environments. A study of fiberglass epoxy unidirectional and cross-ply laminates was conducted to investigate hygrothermal effects on the mechanical behavior of a common material system used in wind applications. Several laminates were aged in 50 ∘C distilled water until maximum saturation was reached. Unconditioned control and the saturated samples were tested in quasi-static tension with the accompaniment of acoustic emission (AE) monitoring. Cross-ply laminates experienced a 54 % reduction in strength due to moisture absorption, while unidirectional laminate strengths were reduced by 40 %. Stress–strain curves and AE activity of the samples were analyzed to identify changes in damage progression due to aging.

scholarly journals Vibration Characteristics of Carbon Fiber Reinforced Polymer Composites under Varying Fiber Orientation Composition

2019 ◽  
Vol 9 (2) ◽  
pp. 2905-2918
Keyword(s):  
Carbon Fiber ◽  
Natural Frequency ◽  
Mode Shape ◽  
Fiber Orientation ◽  
Composite Plates ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

Many engineering applications today are increasingly made of laminated composite plates. The properties of laminated composite plates can change as the laminate and fiber composition change, enabling the engineering structure and components to be customized according to the desired static or dynamic properties. Therefore, it is of interest to investigate variation in dynamic properties of composites under different fiber orientation composition to forecast their vibration response. In this study, the natural frequency and mode shape of carbon fiber-reinforced polymer composite plates were obtained numerically under varying composition of the 0°, ±45° and 90° fiber orientations. Sixteen different cases were simulated using finite element method, showing changes in the natural frequency and mode shape of carbon fiber-reinforced polymer composite plates with changes in the composition of the fiber orientation. The first five values of natural frequency and mode shape of the composite laminate were reported and analyzed using a surface regression method. In addition, the effect of the stacking sequence on the natural frequency of the composite plate having the same orientation composition was also analyzed. Comparison with previous studies showed good agreement of the present numerical modeling. Numerical results indicate potential to develop relationships to estimate modal properties based on composition of fiber orientation.

Delamination Detection in Composite Plates Using Linear and Nonlinear Ultrasonic Guided Waves

2019 ◽  
Author(s):  
Yanfeng Shen ◽  
Mingjing Cen
Keyword(s):  
Wave Propagation ◽  
Guided Waves ◽  
Fiber Composite ◽  
Composite Plates ◽  
Ultrasonic Guided Waves ◽  
Carbon Fiber Composite ◽  
Laser Doppler Vibrometry ◽  
Delamination Detection ◽  
Nonlinear Ultrasonic ◽  
Linear And Nonlinear

Abstract This paper presents a delamination detection strategy for composite plates using linear and nonlinear ultrasonic guided waves via the wave field imaging and signal processing based on Scanning Laser Doppler Vibrometry (SLDV). The anisotropic elastodynamics in composite plates is first studied. Two numerical methods are deployed to analyze the wave mechanics within the composite plates. The Semi-analytical Finite Element (SAFE) method is utilized to obtain the dispersion curves and mode shapes for a carbon fiber composite plate by bonding two quasi-isotropic carbon fiber composite panels together. The Local Interaction Simulation Approach has been employed to investigate the wave propagation and interaction with the delamination. Contact Acoustic Nonlinearity (CAN) between the delamination interfaces during wave damage interaction is presented as a potential mechanism for delamination detection. After developing an in-depth understanding of the wave propagation and wave damage interaction mechanism, active sensing experiments are conducted using the Piezoelectric Wafer Active Sensors (PWAS) and the Scanning Laser Doppler Vibrometry (SLDV). Two delamination imaging methodologies are presented. The first one utilizes the total wave energy to detect the delamination, taking advantage of the trapped modes within the delaminated area. The second one adopts the nonlinear second harmonic imaging algorithm, highlighting the nonlinear interaction traces at the delamination region. The damage detection images are finally compared and fused to provide detailed diagnostic information of the delamination. The damage imaging technique presented in this paper possesses great potential in material evaluation and characterization applications. This paper finishes with summary, concluding remarks, and suggestions for future work.

scholarly journals Dynamic acousto-elastic testing of concrete with a coda-wave probe: comparison with standard linear and nonlinear ultrasonic techniques

Ultrasonics ◽  
2017 ◽  
Vol 81 ◽  
pp. 59-65 ◽  
Author(s):  
Parisa Shokouhi ◽  
Jacques Rivière ◽  
Colton R. Lake ◽  
Pierre-Yves Le Bas ◽  
T.J. Ulrich
Keyword(s):  
Coda Wave ◽  
Nonlinear Ultrasonic ◽  
Standard Linear ◽  
Ultrasonic Techniques ◽  
Linear And Nonlinear

scholarly journals Comparison of Linear and Nonlinear Ultrasonic Parameters in Characterizing Grain Size and Mechanical Properties of 304L Stainless Steel

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1279 ◽  
Author(s):  
Sungho Choi ◽  
Juyoung Ryu ◽  
Jae-Seung Kim ◽  
Kyung-Young Jhang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Attenuation Coefficient ◽  
Ultrasonic Velocity ◽  
Ultrasonic Attenuation ◽  
304L Stainless Steel ◽  
Ultrasonic Measurements ◽  
Nonlinear Ultrasonic ◽  
Ultrasonic Parameters ◽  
Ultrasonic Parameter

Ultrasonic nondestructive techniques can be used to characterize grain size and to evaluate mechanical properties of metals more practically than conventional destructive optical metallography and tensile tests. Typical ultrasonic parameters that can be correlated with material properties include ultrasonic velocity, ultrasonic attenuation coefficient, and nonlinear ultrasonic parameters. In this work, the abilities of these ultrasonic parameters to characterize the grain size and the mechanical properties of 304L stainless steel were evaluated and compared. Heat-treated specimens with different grain sizes were prepared and tested, where grain size ranged from approximately 40 to 300 μm. The measurements of ultrasonic velocity and ultrasonic attenuation coefficient were based on a pulse-echo mode, and the nonlinear ultrasonic parameter was measured based on a through-transmission mode. Grain size, elastic modulus, yield strength, and hardness were measured using conventional destructive methods, and their results were correlated with the results of ultrasonic measurements. The experimental results showed that all the measured ultrasonic parameters correlated well with the average grain size and the mechanical properties of the specimens. The nonlinear ultrasonic parameter provided better sensitivity than the ultrasonic velocity and the ultrasonic attenuation coefficient, which suggests that the nonlinear ultrasonic measurement would be more effective in characterizing grain size and mechanical properties than linear ultrasonic measurements.

scholarly journals Effects of moisture absorption on damage progression and strength of unidirectional and cross-ply fiberglass-epoxy composites

2018 ◽  
Author(s):  
Jake D. Nunemaker ◽  
Michael M. Voth ◽  
David A. Miller ◽  
Daniel D. Samborsky ◽  
Paul Murdy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Moisture Absorption ◽  
Fiber Reinforced Polymer ◽  
Material System ◽  
Marine Environments ◽  
Fiber Glass ◽  
Reinforced Polymer ◽  
Damage Progression ◽  
Fiber Reinforced Polymer Composites ◽  
Superior Mechanical Properties

Abstract. Fiber-Reinforced-Polymer composites (FRP's) possess superior mechanical properties and formability, making them a desirable material for construction of large optimized mechanical structures, such as aircraft, wind turbines, and marine hydro kinetic (MHK) devices. However, exposure to harsh marine environments can result in moisture absorption into the microstructure of the FRP's comprising these structures and often degrading mechanical properties. Specifically, laminate static and fatigue strengths are often significantly reduced, which must be considered in design of FRP structures in marine environments. A study of fiber-glass epoxy unidirectional and cross-ply laminates was conducted to investigate hygrothermal effects on the mechanical behavior of a common material system used in wind applications. Several laminates were aged in 50 °C distilled water until maximum saturation was reached. Unconditioned control and the saturated samples were tested in quasi-static tension with the accompaniment of Acoustic Emission (AE) monitoring. Cross-ply laminates experienced 54 % reduction in strengths from due to moisture absorption, while unidirectional laminates strengths were reduced by 40 %. Stress-strain curves and AE activity of the samples were analyzed to identify changes in damage progression due to aging.

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