scholarly journals Ultrasound Phased Array for High Acoustic Attenuation Thick Composite Materials

2015 ◽  
Author(s):  
Jikai Du ◽  
Ali Rajhi
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Composite Structures ◽  
Phased Array ◽  
Fiber Direction ◽  
Single Element ◽  
Acoustic Attenuation ◽  
Ultrasound Beam ◽  
High Attenuation ◽  
Beam Focusing

Composite materials and structures are increasingly being applied in aerospace, marine, and wind power industries, as well as in commercial products. One main reason for the scientific interest in composite materials is their tailorable mechanical properties. However, because of the fiber-direction-dependent nature of its physical and mechanical properties, composite material’s property and failure behaviors are usually complex, typically involving various mechanisms depending on applications. Nondestructive testing plays a key role during composite fabrication and maintenance in service. Among the variety of nondestructive techniques available, ultrasound phased array technique has emerged as a promising new approach. Unlike a conventional ultrasound single element transducer, an ultrasound phased array sensor can control and focus acoustic energy to the desired directions and locations. This heightened flexibility and sensitivity is essential given complex shape of modern composite structures. Despite such promise, understanding and application of ultrasound phased array technique is limited due to the anisotropic nature of composite materials, as well as its high acoustic attenuation. Attenuation and velocity dispersion are the two major challenges to the ultrasound evaluation of composite structures; these two factors complicate the control of phased array ultrasound propagation both theoretically and experimentally. This is especially true for thick high attenuation carbon fiber or glass fiber composite materials that have been widely applied in aerospace and wind turbine industries. In our study, ultrasound phased array technique was applied to increase the acoustic penetration power in high acoustic attenuation composite materials. First, ultrasound phased array signal in isotropic materials was studied to calibrate the probe parameters. Then for composite materials, the dependence of ultrasound field on the number of active elements, steering angles, beam focusing laws and on the characteristics of materials was analyzed and optimized through theoretical simulations and experimental evaluations. Results showed that the steering angles and the parameters of beam focusing laws might change the ultrasound beam intensity and uniformity, which had a significant influence on the sensitivity and resolution of the technique; the anisotropic properties of composite materials could distort the ultrasound beam, which made the calibration a necessary and important procedure during practical inspections. The influence of ultrasound frequency and beam angle were also quantitatively evaluated. The proposed research has the potential to apply ultrasound phased array technique to the detection of defects in composite materials and the evaluation of composite structural health. The study of the interaction between ultrasound and composite structures will open the window for the successful application of ultrasound phased array technique.

Phased Array Ultrasonic Technique Parametric Evaluation for Composite Materials

2014 ◽  
Author(s):  
Hossein Taheri ◽  
Katrina M. Ladd ◽  
Fereidoon Delfanian ◽  
Jikai Du
Keyword(s):  
Composite Materials ◽  
Phased Array ◽  
Composite Plates ◽  
Single Element ◽  
Bulk Wave ◽  
Plate Wave ◽  
High Attenuation ◽  
Array Transducer ◽  
General Improvement ◽  
Aluminum Plates

A series of ultrasonic elements arranged in a phased array transducer can provide the capability to activate each element separately but in a programmed sequence. This will help the acoustic signal to be generated at desired focusing distances and anticipated angles for specific materials and structures. In case of composite material inspection, this characteristic of the phased array method can improve the undesirable effects of the high attenuation and anisotropic structure of composite materials on response signals. In this study different phased array probes and wedges which are commercially available were evaluated for their response signals’ characteristics. First, the capability and resolution of bulk wave generation were studied for each set of probe and wedge, and the response signals were compared to that of the conventional single element ultrasonic transducers for different thicknesses composite plates. Then the resolution of the response signals and their sensitivity to defect size were evaluated and compared to the single element transducers as well. Next, each phased array probe and wedge set was used to generate plate waves in aluminum plates based on plate wave propagation theory, probe and wedge physical properties and the definition of delay law. Results show a general improvement in response signals’ strength and resolution for phased array method in comparison to the single element transducers. Also some plate wave modes could be generated with optimized signal generation parameters in phased array system.

Acoustic Emission and Ultrasound Phased Array Technique for Composite Material Evaluation

2013 ◽  
Author(s):  
Hossein Taheri ◽  
Fereidoon Delfanian ◽  
Jikai Du
Keyword(s):  
Acoustic Emission ◽  
Composite Materials ◽  
Composite Structures ◽  
Phased Array ◽  
Failure Modes ◽  
Acoustic Energy ◽  
Single Element ◽  
Signal Velocity ◽  
Acoustic Evaluation ◽  
Conventional Ultrasound

The successful application of various acoustic evaluation techniques to composite materials and structures depends on the understanding of the acoustic wave propagation mechanisms. However, due to the anisotropic nature of composite materials, where the acoustic signal velocity and attenuation depend on its traveling direction, the correlation of the different material failure modes to the recorded acoustic signals, such as during of an acoustic emission (AE) inspection, is difficult to be defined. This issue becomes even more challenging for ultrasound phased array technique, where unlike a conventional ultrasound single element transducer, an ultrasound phased array of sensors will generate and receive acoustic energy at various desired directions and locations. Such heightened flexibility and sensitivity is essential for the complex shape of modern composite structures. In this paper, the influence of fiber orientation on AE signal was first studied. AE parameters such as counts, duration, energy, rise time and amplitude for aluminum and composite plate were analyzed in MS-Excel and results were compared to AE software. Acoustic velocities along various fiber directions were also theoretically studied and experimentally measured. Then ultrasound phased array technique and related parameters such as ultrasound beam angle and focusing, frequency and material attenuation factors were quantitatively analyzed, and the optimization and limitation of ultrasound phased array inspection procedure were summarized.

scholarly journals Nondestructive Ultrasonic Inspection of Composite Materials: A Comparative Advantage of Phased Array Ultrasonic

2019 ◽  
Vol 9 (8) ◽  
pp. 1628 ◽  
Author(s):  
Hossein Taheri ◽  
Ahmed Arabi Hassen
Keyword(s):  
Composite Materials ◽  
Guided Waves ◽  
Phased Array ◽  
Ultrasonic Inspection ◽  
Flaw Detection ◽  
Weight Ratio ◽  
Guided Wave ◽  
Single Element ◽  
High Attenuation ◽  
Ultrasonic Ndt

Carbon- and glass fiber-reinforced polymer (CFRP and GFRP) composite materials have been used in many industries such as aerospace and automobile because of their outstanding strength-to-weight ratio and corrosion resistance. The quality of these materials is important for safe operation. Nondestructive testing (NDT) techniques are an effective way to inspect these composites. While ultrasonic NDT has previously been used for inspection of composites, conventional ultrasonic NDT, using single element transducers, has limitations such as high attenuation and low signal-to-noise ratio (SNR). Using phased array ultrasonic testing (PAUT) techniques, signals can be generated at desired distances and angles. These capabilities provide promising results for composites where the anisotropic structure makes signal evaluation challenging. Defect detection in composites based on bulk and guided waves are studied. The capability of the PAUT and its sensitivity to flaws were evaluated by comparing the signal characteristics to the conventional method. The results show that flaw sizes as small as 0.8 mm with penetration depth up to 25 mm can be detected using PAUT, and the result signals have better characteristics than the conventional ultrasonic technique. In addition, it has been shown that guided wave generated by PAUT also has outstanding capability of flaw detection in composite materials.

Joining of Zirconia Reinforced Metal-Matrix Composites

2015 ◽  
Vol 825-826 ◽  
pp. 498-505 ◽  
Author(s):  
Christian Weigelt ◽  
Harry Berek ◽  
Christos G. Aneziris ◽  
Ralf Eckner ◽  
Lutz Krüger
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Composite Structures ◽  
Room Temperature ◽  
Heat Exposure ◽  
Base Materials ◽  
Metastable Austenitic Stainless Steel

Metal-matrix composite materials, based on a metastable austenitic stainless steel reinforced with a magnesia partially stabilised zirconia have been prepared by a ceramics-derived extrusion technology. Using this powder metallurgical method enables the shaping of lightweight cellular structures as well as bulk specimens with a variety of steel/ceramic ratios at room temperature. However, the extrusion of composite structures is limited by the uniform cross section throughout its entire length. Joining of these metal-matrix composite preforms after sintering by conventional welding techniques is a challenging task. The presence of ceramic fractions may lead to several complications and the subsequent heat exposure during joining may initiate phase transformations in both metastable components resulting in a deterioration of the mechanical properties of the composite material. An adapted ceramics-derived joining technology allows the combination of varying TRIP-steel/zirconia composite materials. The main features are the machining and joining of the parts in their dry green state at room temperature before their thermal treatment. Thus, the material’s consolidation and the formation of the joint take place simultaneously. The ability of joining different parts offers the possibility to create structures for complex applications and testing conditions. The key to advanced properties of the joining zone are the base materials, the surface treatment of the parts, and the paste used for joining. The joining process of different base materials, the mechanical properties, and the microstructure of sinter-joint samples are presented.

Evaluating the Mechanical Properties of 3D Woven Carbon-Epoxy Composite Materials Using Experimental Data and FEA Methods

2011 ◽  
Author(s):  
Mahdi Farahikia ◽  
Sunilbhai Macwan ◽  
Fereidoon Delfanian ◽  
Zhong Hu
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Composite Materials ◽  
Epoxy Composite ◽  
External Pressure ◽  
Fiber Direction ◽  
Strain Gages ◽  
Element Analysis ◽  
Test Specifications ◽  
Dog Bone

A series of tensile, compression and shear tests were carried out on carbon-epoxy composite materials to evaluate their mechanical properties. The experiments were set upin accordance with ASTM standards that best corresponded to the test specifications. Specimens were categorized into groups according to their dimensions and shape. Based on testing requirements, some were cut into rectangular and others into dog bone specimens to determine the effects of stress concentration. A number of specimens were reinforced at both ends by means of tabs which were bonded on both faces to reduce the effects of the external pressure exerted on them through the grips of the testing machines, and the rest of them were tested without any reinforcement tabs. All the specimens were tested until failure. Load, elongation (displacement) and strain data were recorded by means of strain gages and data acquisition systems. The experimental results obtained from similar tests on different groups are compared to examine the conformity of the results regardless of dimension and geometry, and are also verified by Finite Element Analysis (FEA). In addition, FEA is used to study different conditions, such as geometry, that could affect the final results. The experimental data are analyzed and effects of fiber direction on failure method are studied. It was concluded that shape and geometry factors as well as fiber direction influenced the failure method. The work, however, is still in progress and tests under conditions, such as elevated temperature, will be conducted to study other effects on the mechanical properties of 3D woven carbon-epoxy composites.

scholarly journals Manufacturing Technology of Some Impact Resistant Materials

2021 ◽  
Vol 44 (1) ◽  
pp. 54-58
Author(s):  
Iulian PĂDURARU ◽  
Vasile BRIA ◽  
Adrian CÎRCIUMARU
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Composite Structures ◽  
Impact Resistance ◽  
Polymeric Materials ◽  
Tensile Tests ◽  
Manufacturing Technology ◽  
Matrix Composites ◽  
Polymeric Matrix Composites ◽  
Key Parameter

In this paper impact resistance is a key parameter for composite materials. Composite structures can experience impact loads either accidentally in the designed life or in an anticipated hostile service environment. That is why the manufacturing technology is very important. For materials manufacture were established: the type of polymer matrix, the types of fabrics and additives which will be used to improve impact resistance and also analysis of mechanical properties of formed composite materials (bending and tensile tests). Knowledge of the mechanical properties of polymeric materials is necessary in all areas of their applicability. Thus, rigidity and mechanical strength are key properties for most applications in which polymeric matrix composites are used.

scholarly journals Computational Modeling of Polymer Matrix Composites

2018 ◽  
Author(s):  
DC Pham
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Composite Materials ◽  
Polymer Matrix ◽  
Composite Structures ◽  
Computational Models ◽  
Polymer Matrix Composites ◽  
Failure Criteria ◽  
Matrix Composites ◽  
Stiffness Reduction

Applications of polymer matrix composites are growing in aerospace and offshore industries due to the light-weight and good mechanical properties of composite materials. The design of composite materials can be made at macroscopic level in which the composite mechanical properties can be tailored to offer the most desired performance of composite structures. Understanding on mechanical behavior of the composite material may require detailed investigations at the microscopic level involving the behaviour of the composite constituents such as the fiber, the polymer matrix and the fiber/matrix interface under macroscopic loads. Composite failure criteria are often employed to evaluate the failure of composite material and its constituents. Computational damage models can be then developed to reflect the stiffness reduction of the material once damage at the macro- and micro- scales of the composite is indicated. The successful prediction of composite structures relies on consistent computational models which can capture the mechanical behaviour of composite materials at different length scales.

Non-Destructive Inspection of Surface Defects in Cylindrical Structures

2017 ◽  
Author(s):  
Jikai Du
Keyword(s):  
Eddy Current ◽  
Phased Array ◽  
Surface Defects ◽  
Economic Benefits ◽  
Pressure Vessels ◽  
Cylindrical Structures ◽  
Ultrasound Beam ◽  
Beam Focusing ◽  
Test Cylinder ◽  
Non Destructive

Cylindrical structures have been applied in various pressure vessels and weapon systems, which may be subjected to harsh environmental conditions such as large mechanical stresses and thermal stresses. As a result, non-destructive evaluation of such structures is critical in quality control. Among the various defects that may be generated during fabrication, transportation, operation/firing, and so on, surface crack is a critical one and needs to be quantitatively and accurately evaluated. In this study, both ultrasound phased array technique and eddy current technique are applied for the inspection of 120 mm steel test cylinder. In the cylinder, a total of nine sets of surface defects of various size, depth and orientation are fabricated and quantitatively evaluated. In ultrasound phased array evaluation, simulations and experiments on standard aluminum block were carried out first to calibrate the system parameter setup. During this calibration, ultrasound propagation and its interaction with defects were simulated and studied. The dependence of ultrasound field on the ultrasound parameters and on the characteristics of defects was analyzed and optimized. Then simulations and experiments on steel test cylinder were carried out for the detection of the smallest detectable defects. Results showed that the optimization of the number of active elements can improve the distortion of defect images; the steering angles and the beam focusing laws may change the ultrasound beam intensity and uniformity, which has a significant influence on the sensitivity and resolution of the phased array technique; the geometry and material properties of cylindrical structures could distort the ultrasound beam, and as a result, calibration is necessary and important during practical inspections. Frequency is a key factor for phased array technique to improve its sensitivity. In eddy current evaluation, a prototype for wireless eddy current system was designed, and an eddy current probe interface and a main unit interface were developed. The main advantages of such wireless probe are safety, economic benefits and maneuverability when compared to conventional wired probe. During testing, the signal at the probe interface was activated, measured, digitized and transmitted wirelessly to the main unit interface. Experimental results showed that the eddy current signals can be wirelessly communicated with main unit, and the results are comparable with the wired eddy current tester. Testing results also showed that the wireless signal is about 8 dB lower compared to wired signals and phase difference exists between the wired and wireless signals.

Aging of polymer composite materials under loading. (See Beginning in #10-2020)

2020 ◽  
pp. 2-12
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Polymer Composite ◽  
Polymer Composite Materials ◽  
Cyclic Loads ◽  
Reinforced Plastics ◽  
Water Exposure ◽  
Laboratory Conditions ◽  
Bending Loads ◽  
Moisture Conditions

A study review of aging polymer composite materials (PCM) under different heat-moisture conditions or water exposure with the sequential or parallel influence of static or cyclic loads in laboratory conditions is presented. The influence of tension and bending loads is compared. Conditions of the different load influence on parameters of carbon-reinforced plastics and glass-reinforced plastics are discussed. Equipment and units for climatic tests of PCM under loading are described. Simulation examples of indices of mechanical properties of PCM under the influence of environment and loads are shown.

Aging of polymer composite materials under loading

2020 ◽  
pp. 7-18
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Polymer Composite ◽  
Polymer Composite Materials ◽  
Cyclic Loads ◽  
Reinforced Plastics ◽  
Water Exposure ◽  
Laboratory Conditions ◽  
Bending Loads ◽  
Moisture Conditions

A study review of aging polymer composite materials (PCM) under different heat-moisture conditions or water exposure with the sequential or parallel influence of static or cyclic loads in laboratory conditions is presented. The influence of tension and bending loads is compared. Conditions of the different load influence on parameters of carbon-reinforced plastics and glass-reinforced plastics are discussed. Equipment and units for climatic tests of PCM under loading are described. Simulation examples of indices of mechanical properties of PCM under the influence of environment and loads are shown.

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