The new researches and progresses on nondestructive testing and evaluation (NDT & E) for aerocomposites have been reviewed in this paper, including three parts. In part 1, the progresses on researches of NDT & E methods for aero-composites were reviewed, giving a typical experimental research results. The practical applications and their feasibilities in aero-composites manufacturing, in-service, repair were summarized in part 2. In part 3, the new challenges in aero-composite NDT & E area were analyzed according to the new requirements from current and future material development, research and application. The review in this paper included the new progress on researches and applications of ultrasonic testing (UT), X-ray testing (RT), infrared ray (IR), electronic speckle pattern interferometry (ESPI), terahertz testing (THz), eddy current (ET), sonic testing etc.

    Full matrix is an A-Scan data set of all transmit and receive elements’ combinations. Array ultrasound nondestructive testing and evaluation technology based on full matrix uses specific post-processing algorithm to image and quantify defects inside the test pieces. Compared with traditional phased array methods, algorithms based on full matrix have much higher imaging resolution and quantitative accuracy. On the other hands, full matrix algorithms can be customized according to geometrical or material properties of testing pieces. It’s the next generation ultrasonic array testing and evaluation method. This paper systematically summarizes the fundamental, typical algorithms, key technologies, and applications of ultrasonic array technology based on the FMC, aiming to promote the technology and lower the application threshold, and to provide new ideas and new methods for the challenge of non-destructive testing and evaluation in highend manufacturing industry.

    The aero-engine blade with characteristics of complex curved surfaces and variable thickness is unable to be accurately and automatically detected by conventional inspection method. For this issue, an automatic and non-destructive inspection method based on the combination of ultrasonic testing and industrial robot is proposed. Firstly, according to the structural characteristics of the blade, the ultrasonic longitudinal waves are applied to detect the defeats and measure the thickness of blade body through vertical incidence and to inspect the LTE (the leading and the trailing edges) and roots of blade through oblique incidence, respectively. Secondly, the defeats and thickness of a test block of blade are also detected and measured respectively based on the manipulator scanning trajectory planned according to the CAD model of blade. The inspection results show that a flat bottom hole with a minimum diameter of 0.15mm and a crack with a width of 0.15mm can be identified, the accuracy of thickness is ±0.03mm, and the inspection period for whole blade is less than 20min. These results meet the requirements of inspection for blade and indicate that the robotic ultrasonic non-destructive testing technique is effective for automatic inspection of blade.

    X-ray computed laminography (CL) is an advanced non-contact nondestructive three-dimensional testing method. It can visualize the internal structure and defects of plate-shell products with high-resolution images and overcome the shortcomings of the traditional computed tomography (CT) technique. In the field of aerospace, there are many plateshell components such as solar panels, tails, engine turbine discs, blades and microelectronic chips. Effective nondestructive testing and evaluation of internal damage and defects is an important guarantee for flight safety of aerospace vehicles. Based on the applications of nondestructive testing for aerospace plate and shell structures and the author’s engineering practice in this field, this paper briefly describes the principle and characteristics of CL, summarizes its research progresses, analyses its key techniques and difficulties, and looks forward to its promising future.

    Complex-shaped composite components have been extensively utilized in the aerospace industry. This paper investigates the feasibility of using ultrasonic feature guided waves (FGW) for rapid screening of two representative long-range composite structures, i.e. laminated bends and adhesive composite joints. Such FGWs are capable of focusing the propagation energy along the structural feature, with limited leakage into the adjacent plate. They also exhibit littledispersive and low-attenuative characteristics. Modal studies of the anisotropic viscoelastic waveguide were carried out via the semi-analytical finite element (SAFE) method to reveal the existing FGW modes. Both 3D finite element (FE) simulations and experiments were performed to cross-validate the modal properties of identified FGW modes and to study their interaction with different defects occurring in the structural feature, such as interlaminar delamination, cracks, and adhesive debonding. The wave-defect resonance phenomenon and the reflection behaviour were investigated for localizing these defects. The potential of proposed FGW-based approach for efficient damage detection in complex-shaped composite components is well demonstrated.

    Radii structures with complex geometries are commonly encountered in carbon fiber reinforced plastic (CFRP) composites in aerospace components. How to improve the corresponding nondestructive testing quality on defects is one key issue for the assurance of load-bearing properties. In virtue of numerical modeling and wave propagation analysis, the difficulties of ultrasonic testing in CFRP radii were clarified. Due to the intrinsically elastic anisotropy of CFRP material, the layered structure and the curved surface, the normal incidence of ultrasonic wave could not be easily realized and the wave propagation path kinks seriously. Moreover, the structural noise is obvious and the acoustic coupling is difficult. In view of this problem, the research progress in study of phased array ultrasonic testing (PAUT) was summarized, especially for the radii with a varied cross-section in plate thickness, curvature and included angle. The development of PAUT probe, the ultrasonic imaging based on signal post-processing technique, and the research of solid flexible coupling medium and probe jig were emphasized, respectively. The remaining issues and the future development trend were analyzed.

    TR tomographic scanning can detect large-scale components beyond the beam range, and has important applications in the field of ICT. One of the current reconstruction methods is to directly rebinding TR scan sinogram into standard parallel-beam sinogram without considering the influence of sector angle, and then reconstruct them using parallel-beam reconstruction method, which results in some errors in the reconstructed images. In this paper, a new rebinding algorithm is proposed. Through the coordinate transformation and interpolation calculation, the coordinates and gray scale information of the corresponding mapping points of the sampling points in the parallel sinogram are obtained in the TR scan sinogram. In this way, a complete parallel beam sinogram is obtained. Through simulations and experiments, it is found that the edge smoothness and artifacts are eliminated in both the sinogram and the reconstructed image obtained by the improved algorithm. The new rebinding algorithm can eliminate the errors of the existing rebinding algorithm. The TR scanning method can also achieve correct CT reconstruction when the fan beam angle is large.

    Aimed to multifarious surface conditions of aircraft composites, a research was conducted to apply thermography technology to composites with common aeronautic surfaces. A surface condition reference specimen with simulated defects was designed and manufactured, which included 8 kinds of common aircraft composites surfaces. NDTherm® NT thermography system was applied to conduct tests. For the composites part with same material and different surface conditions, the defect test results have obvious differences. And the results had been discussed from aspects of the detection sensitivity, copper net, surface materials and surface roughness.

    To improve the hole-making quality for CFRP/Ti6Al4V stacks and optimize the helical milling process parameters, experiments were designed and implemented based on the Taguchi method. The spindle rotation speed, feed rate and pitch were taken as the design variables in the experiments. The hole diameter error, surface roughness and damage factor in the composite material layer were taken as the output indicators of the Taguchi model. Based on the Taguchi experimental results, the grey relational analysis and principal components analysis were adopted to optimize the helical milling process parameters. The influences of helical milling parameters on the signal noise ratios, principal components and the grey correlation degrees of output indicators were analyzed. The experiment results show that the optimal helical milling parameters are spindle speed 2000r/min, feed rate 0.02mm/r, and pitch 0.15mm.

    Machined surface integrity has an impact on fatigue behavior of specimens directly. Therefore, researchers have done a lot of studies and analyses. Based on summarizing the previous research achievements, research status and main achievements of influence mechanism of machined surface integrity on fatigue behavior of specimens were presented and analyzed. Moreover, it is pointed out clearly that several key theories of fatigue behavior of specimens influenced by surface roughness, surface micro-hardness and surface residual stress should be developed and completed in the further, which provides a corresponding reference for the subsequent research work in the field of anti-fatigue manufacturing.