Figure 6 - uploaded by Neil Hankinson
Content may be subject to copyright.
Typical wing skin joint configuration showing sealant and fastener locations. Possible crack locations are shown in black to the left and right of the fastener.
Source publication
There has been an increase in the use of composite materials in the aerospace industry which is driving a need for new NDT techniques that can rapidly scan large structures and provide quantitative data on the material integrity. In many applications there are common requirements for the ultrasonic inspection of composites for porosity, delaminatio...
Similar publications
The prerequisite for more competent and cost effective aircraft has led to the evolution of innovative testing and evaluation procedures. Non-destructive testing and evaluation (NDT & E) techniques for assessing the integrity of an aircraft structure are essential to both reduce manufacturing costs and out of service time of aircraft due to mainten...
This paper investigates the potential of a novel vibration-based thermal health monitoring method for continuous and on-board damage detection in fiber reinforced polymer sandwich structures, as typically used in aerospace applications. This novel structural health monitoring method uses the same principles, which are used for vibration-based therm...
The ability to accurately locate damage in any given structure is a highly desirable attribute for an effective structural health monitoring system and could help to reduce operating costs and improve safety. This becomes a far greater challenge in complex geometries and materials, such as modern composite airframes. The poor translation of promisi...
Due to the development of lighter aerospace structures and the increasing use of composite parts, the need of non-destructive testing (NDT) for adhesive bonding raised in the last years. Some NDT techniques are already used for the inspection of bonded structures: for instance for detection of defects like pores, delamination or debonding within ad...
![Fig. 4 -Visual inspection for composite [10]](profile/Lijalem-Gebrehiwet/publication/373439134/figure/fig1/AS:11431281183981136@1693208485940/Visual-inspection-for-composite-10_Q320.jpg)
![Fig. 6-Aviation Tap Testing at Maintenance Depot [36]](profile/Lijalem-Gebrehiwet/publication/373439134/figure/fig2/AS:11431281184042776@1693208486023/Aviation-Tap-Testing-at-Maintenance-Depot-36_Q320.jpg)
![Fig. 7 -Eddy current testing [36]](profile/Lijalem-Gebrehiwet/publication/373439134/figure/fig3/AS:11431281184010685@1693208486185/Eddy-current-testing-36_Q320.jpg)
![Fig. 9 -Schematic Ultrasonic Testing [38]](profile/Lijalem-Gebrehiwet/publication/373439134/figure/fig4/AS:11431281184001212@1693208486833/Schematic-Ultrasonic-Testing-38_Q320.jpg)
![Fig. 11 -Pulse echo test equipment [43]](profile/Lijalem-Gebrehiwet/publication/373439134/figure/fig5/AS:11431281184001213@1693208487911/Pulse-echo-test-equipment-43_Q320.jpg)
There are different aerospace composite defects detection methodologies nowadays. In this paper it is clearly defined the common damage identification
techniques namely damage detection, damage assessment techniques and NDT modeling softwares. The main sources of composite defects occurred at aerospace
structures are clearly reviewed. Delivering de...
Citations
... It implements multiple ultrasonic transducers, adjusting the timing and amplitude, and combines the resulting waves. It provides high resolution and high efficiency; with the newly developed methods like the time reversal technique [10] and wheel probe [11], it can compensate for the misalignment between the probe and composite or detect curved edges and narrow components. ...
The application of carbon fiber in aerospace requires more advanced non-destructive testing methods due to its unique properties such as anisotropy. In this paper, mainstream non-destructive testing methods are introduced, including visual inspection, resonance test, acoustic emission, eddy current test, ultrasonic test, laser shearography, infra-red thermography, and X-ray. Their strengths and weaknesses are compared, and the common challenges are exposed. To solve those problems, some developing techniques such as hybrid methods and deep-learning-based automated inspection are proposed.
... They also successfully developed a curved-surface transducer with a radius of curvature of 15 mm [116]. To inspect large-area aerospace composite components, Freemantle et al. [117] installed a phased array in rubber wheels to effectively detect delamination and wrinkles in aerospace composite components. Research on the application of phased arrays for damage detection in composite materials is summarized in Table 3. Owing to the complexity of wave propagation in composite materials, phased-array detection with delayed transmission, in which all the elements are fired to form a beam with a fixed focus, is rarely utilized. ...
... Pulse-Echo technique utilizes a single transducer placed along the surface which acts as a transmitter as well as a receiver. It is applicable where inspection scan is limited to as single surface [5]. A review of studies in this area confirmed that this technique is most sensitive to imperfections such as delamination which lies parallel to the surface whereas imperfections that lie perpendicular to surface such as matrix cracks and fibre fractures are hard to detect [4]. ...
... It has higher resolution and reliability compared to the traditional NDT methods and holds notable capabilities in case of aircraft components. In [5], a wheel probe is developed using this technique which scans curved edges and narrow components with high efficiency. It is used to detect impact damage, fibre lay-up and porosity in the structures. ...
... Through conventional UT testing, ultrasound waves are sent into the material through a single transducer, while PA probes have multiple transducers. 4 Through a delay generation within the pulses sent out by each transducer, the beam angle, focal point, and focal spot of the produced wavefront are affected, making PA a versatile method for the inspection of complex geometries. 5 Titanium (Ti) and its alloys due to their high corrosion and wear resistance, 6 high strength, 7 biocompatibility, 8 high melting point, non-toxicity, 9,10 resistant to chemical attacks, low thermal expansion, and excellent machinability 11,12 are utilized extensively in the industrial applications. ...
Ultrasonic testing procedures are among the most extensively used techniques in non-destructive testing and non-destructive evaluation systems. Meanwhile, phased array inspection or phased-array ultrasonic testing techniques as a well-known type of ultrasonic testing in advanced non-destructive testing systems are utilized in numerous applications, including oil and gas, medical imaging applications, railway, automotive, marine, and aviation industries. Phased-array ultrasonic testing-based methods can also be used in a variety of weld inspections, bond testing, thickness profiling, flaw detections, corrosion inspections, and in-service crack detection. The rapidity, safety, easiness, affordable price, and accurate visualization of phased array in measuring the defect characteristics such as size, shape, depth, and orientation allow its wide usage and even as a substitute for other inspection methods like radiographic methods. In phased array methods, more than one sound wave is employed to enhance the reliability and flexibility of inspection through the operation of several transducer assemblies, involving 16 to 256 small individual elements. Titanium having many desirable properties like high strength to weight ratio found many industrial applications, which highly necessitates its persistent inspection. For this aim, the present study focuses on the application of the phased-array ultrasonic testing technique for inspecting Ti components specifically in additive manufacturing, welding inspections, and defect detection of complex geometries and composites. Moreover, modern applications and improved computation methods are discussed. The development of phased-array ultrasonic testing inspection systems, particularly high throughput and efficient in situ and mobile equipment, and new computation methods will open new horizons toward the highly sophisticated inspection procedures.
... Phased array and some special equipment are combined to achieve better testing effect or larger testing range. Habermehl et al. [76] and Freemantle et al. [77] have combined the ultrasonic phased array system to provide a new solution for defect detection of large CFRP components (see Figure 7). The ultrasonic array is placed on a rubber-coupled wheel, and the wheel can be manually applied or scanned by the structure and automatic scanning system, which can realize the inspection of a large composite structure. ...
... The ultrasonic array is placed on a rubber-coupled wheel, and the wheel can be manually applied or scanned by the structure and automatic scanning system, which can realize the inspection of a large composite structure. The glide scanner and phased array are combined [77]. [78]. ...
Composite materials have been extensively used in different fields due to their excellent properties, among which carbon fiber-reinforced polymer (CFRP) is the representative. Especially in high-precision fields, such as aerospace, CFRP has become the main structural material for some core components instead of metal. The particularity of such materials and their components in terms of structure, material properties, and required detection conditions puts forward more stringent and targeted detection requirements for detection technology. Ultrasonic testing technology as one of the important means of composite defect detection, which is derived from advanced nondestructive testing (NDT), has also been a rapid development. The propagation behavior and variation of ultrasonic waves in CFRP composites can reveal defects and damages in CFRP composites. Moreover, by constructing reasonable defect identification technology and detection technology, not only the qualitative and quantitative positioning analysis of defects and damages in CFRP composites can be realized but also the automatic, visual and intelligent NDT, and evaluation of CFRP composites can be realized. This paper mainly reviews the innovative nondestructive ultrasonic testing technology for CFRP composites and briefly introduces the research progress and application of this technology in CFRP defect detection. Finally, advanced nondestructive ultrasonic testing technology is summarized, and the problems and development direction of this kind of testing technology are put forward.
... To that end, an extreme effort is continuously invested towards the improvement of aircraft inspection worthiness and the development of reliable, automated, and synergistic techniques for capturing barely visible damage on aircraft. Currently, manual point-topoint inspection using conventional ultrasonic transducer and line-by-line Phased Array (PA) wheel probe [4] are used as a fundamental quantitative method, as per schedule-based maintenance for in-service inspections of composite skin surfaces. Such inspections are tactical and categorized in A-, C-, and D-checks, depending on the level of detail with respect to the aircraft age, hours in service, and the number of landing/take-off cycles. ...
... An ultrasonic inspection typically requires the use of free-flowing water, a film of water, local immersion, or ultrasonic gel as a coupling medium between the transducer and surface under inspection. The restriction of existing methods of couplant usage by VR platform requirements was addressed by developing a new wedge of elastomer material that is similar to a wheel probe roller material [4], which has low attenuation, low acoustic impedance, and lower couplant requirements. The wedge thickness was optimized for a 10 MHz PA transducer that is based on ultrasonic beam characteristics, near-field length, and attenuation in the elastomer material. ...
This paper presents an advanced methodology for the detection of damage in aircraft composite materials based on the sensor fusion of two image-based non-destructive evaluation techniques. Both of the techniques, phased-array ultrasonics and infra-red thermography, are benchmarked on an aircraft-grade painted composite material skin panel with stringers. The sensors systems for carrying out the inspections have been developed and miniaturized for being integrated on a vortex-robotic platform inspector, in the framework of a larger research initiative, the Horizon-2020 ‘CompInnova’ project.
... The ability of ultrasonic waves to propagate in composite materials enables detection of damage location and size [26]. Phased Array scanning is a handheld ultrasonic NDT technique, that can detect the presence of damage in composite structures, such as delamination and debonding [27,28]. This is achieved through the pulsing of ultrasonic waves from transducers in a linear array. ...
The use of Acoustic Emission (AE) to detect impacts is of interest within industries where vital components are prone to impact damage, in particular where Carbon Fibre Reinforced Polymers (CFRP) are used, as damage can often go un-noticed within them. For AE monitoring of impacts piezoelectric sensors are used to detect the ultrasonic wave produced by an impact. Classification is also possible of these waves enabling a distinction between damaging and non-damaging impacts. These sensors do however have resonance, so do not give an accurate picture of how the waves propagate, better knowledge would enable better selection of sensors. Laser Doppler Vibrometry is a non-contact and non-resonant method of analysing the surface displacement on a structure. In this study, a vibrometer was used to monitor CFRP plates during impact to assess its applicability for distinguishing between damaging and non-damaging impacts, compared with a surface mounted AE sensor. The vibrometer was able to detect both low frequency flexural modes due to the impact process and the higher frequency extensional modes, initiated by damage. When compared to the AE sensor the vibrometer was comparable in its results, and unlike the sensor, not susceptible to resonance or decoupling. For the tested material the vibrometer identified frequencies greater than 20 kHz to be associated with damaging impacts.
... On the basis of conventional UT, more advanced methods have been developed such as phased array ultrasonic testing [75,76]. Nowadays, phased array sensors can be integrated with time reversal techniques [77] that compensates for the misalignment between the probe and composite structure (due to complex geometry of aerospace composites), and increases the coverage area of sensor [78]. ...
Composite materials are increasingly used in the aerospace industry. To fully realise the weight saving potential along with superior mechanical properties that composites offer in safety critical applications, reliable Non-Destructive Testing (NDT) methods are required to prevent cata-strophic failures.This paper will review the state of the art in the field and point to highlight the success and challenges that different NDT methods are faced to evaluate the integrity of critical aerospace composites.The focus will be on advanced certificated NDT methods for damage detec-tion and characterization in composite laminates for use in the aircraft primary and secondary structures.
... Among the various nondestructive testing techniques, the ultrasonic nondestructive testing technology has good technical characteristics of sound beam controllability, imaging diversification, and detection automation and becomes an important means of quality monitoring of circular tube materials. It has outstanding performances in flaw detections for weld joint, composite material, and various components in the aerospace or nuclear industry [8][9][10][11]. ...
As ultrasonic wave field radiated by an ultrasonic transducer influences the results of ultrasonic nondestructive testing, simulation and emulation are widely used in nondestructive testing. In this paper, a simulation study is proposed to detect defects in a circular tube material. Firstly, the ultrasonic propagation behavior was analyzed, and a formulation of the Multi-Gaussian beam model (MGB) based on a superposition of Gaussian beams is described. The expression of the acoustic field from a linear phased-array ultrasonic transducer in the condition of a convex interface on the circular tube material is proposed. Secondly, in order to make the tapered probe wedge better fit the curved circular tube material and carry out the ultrasonic inspection of the curved surface, it was necessary to pare the angle probe wedge. Finally, acoustic field simulations in a circular tube were carried out and analyzed. The simulation results indicated that the method of ultrasonic phased-array inspection is feasible in circular tube testing. Tube materials with different curvatures need different array element lengths and widths to get the desired focused beam.
... High wave attenuation associated with the composite properties and high frequency transducers limits the inspection on large complex structures. Ultrasonic phased array [7] and tomography [8] have recently been utilized more in aircraft SHM as they can produce high resolution images. However the biggest problem with these methods is the requirement of good coupling and a constant angle of incidence for reproducible inspection results. ...
Low-velocity impact on composites typically produces a barely visible damage at the impacted surface. The internal defects can be complex, consisting of multimode damage and the extent of the impact damage normally spreads across the thickness under the impacted surface. The characterization of impact damage in composites can be very complicated and varies for every different composite structure. In this paper, independent characterization of the low-velocity impact damage on carbon-fiber/epoxy plates using three different non-destructive evaluation methods were used. The goal is to demonstrate the ability of guided ultrasonic waves imaging technique and compared to the more widely employed techniques such as X-ray imaging and ultrasonic immersion C-scan. It was demonstrated that the low frequency A0guided ultrasonic wave mode generated by a low-cost piezoelectric transducer can be successfully employed to detect impact damage in composite plates and managed to estimate the size and shape of the impact damage.
