Ndt & E International最新文献_第2页

Broadband acoustic resonance excitation method in gas pipelines via integrated frequency response compensation and spider wasp optimizer 基于集成频响补偿和黄蜂优化的输气管道宽带声共振激励方法

IF 4.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Ndt & E International

Pub Date : 2026-05-01 Epub Date: 2026-02-09 DOI: 10.1016/j.ndteint.2026.103671

Rongxue Li, Lijian Yang, Zheng Lian, Hao Geng, Feiyun Liu

Ultrasonic testing (UT) offers high precision for pipeline integrity assessment, but its reliance on liquid couplants prevents its application in gas pipelines. Air-coupled acoustic resonance technology offers a promising couplant-free alternative, enabling practical in-service inspection. However, the narrow bandwidth and limited efficiency of air-coupled transducers (ACTs) constrain broadband excitation and precise resonance identification, thereby reducing detection sensitivity and resolution. To overcome these limitations, a novel adaptive broadband excitation method is developed. Its core is a newly designed frequency-response-compensated linear frequency modulation (LFM) signal, which dynamically counteracts ACT frequency-dependent attenuation and effectively broadens the useable excitation bandwidth. Furthermore, to automate the selection of the three key parameters for this excitation signal, an adaptive optimization framework is introduced that integrates the spider wasp optimizer (SWO) with a newly proposed spectral equilibrium consistency metric (SECM), thereby eliminating subjective empirical tuning. Experimental results demonstrate that the proposed method suppresses interference from the transducer's central frequency band, enhances higher-order resonance amplitudes, and delivers high-precision thickness measurement along with reliable defect-induced resonance identification. This integrated methodology significantly improves the sensitivity and reliability of air-coupled resonance detection, offering a robust solution for in-service pipeline integrity monitoring.

超声检测为管道完整性评估提供了高精度的方法，但其对液体耦合剂的依赖阻碍了其在天然气管道中的应用。空气耦合声共振技术提供了一种很有前途的无耦合剂替代方案，使实际的在役检测成为可能。然而，空气耦合换能器（ACTs）的窄带带宽和有限的效率限制了宽带激励和精确的谐振识别，从而降低了检测灵敏度和分辨率。为了克服这些限制，开发了一种新的自适应宽带激励方法。其核心是新设计的频率响应补偿线性调频（LFM）信号，动态抵消ACT频率相关衰减，有效拓宽可用激励带宽。此外，为了自动选择该激励信号的三个关键参数，引入了一个自适应优化框架，该框架将黄蜂优化器（SWO）与新提出的光谱平衡一致性度量（SECM）相结合，从而消除了主观经验调谐。实验结果表明，该方法抑制了换能器中心频段的干扰，提高了高阶共振幅度，实现了高精度的厚度测量和可靠的缺陷共振识别。这种集成方法显著提高了空气耦合共振检测的灵敏度和可靠性，为在役管道完整性监测提供了一个强大的解决方案。

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引用次数: 0

A fast numerical method for low-power vibrothermography nondestructive testing of fatigue cracks 疲劳裂纹小功率振动热成像无损检测的快速数值方法

IF 4.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Ndt & E International

Pub Date : 2026-05-01 Epub Date: 2026-01-08 DOI: 10.1016/j.ndteint.2026.103642

Yang Yang , Bofan Liu , Zongfei Tong , Hong-En Chen , Jianguo Zhu , Cuixiang Pei , Shejuan Xie , Hao Su , Zhenmao Chen

Fatigue crack is a typical defect initiated in key engineering structures under dynamic loads. The propagation of fatigue cracks would significantly shorten the structural service life and even cause serious accidents. The vibrothermography (VT), as a promising non-destructive testing (NDT) technique, presents great potential for fatigue crack inspection due to its internal heating mode and applicable for both metallic and nonmetallic materials. However, the multi-parameters optimization and agent model building of VT system put forward higher requirements of an efficient numerical simulation technique for VT signals. In this paper, a fast numerical method for low-power VT under high frequency excitation is proposed and validated. For efficient simulation of dynamic displacement, the element birth and death method is utilized to adjust the coefficient matrix of finite element based on the contact or separation state of crack surface. This method can cope with the complex nonlinear phenomenon of crack closing properly while maintaining computational feasibility during vibration analysis. For the simulation of temperature field of VT, the energy equivalent method proposed by authors is employed to address the efficiency problem of the direct time domain integration for the high-frequency excitation. By linearizing the heat source, the present method can reduce computational burden while preserving numerical accuracy, enabling efficient simulation of the thermal field during VT process. Finally, the proposed method is validated via numerical simulations and experiments which show that the method is over six times faster than the commercial software but with a comparablenumerical precision.

疲劳裂纹是关键工程结构在动荷载作用下产生的一种典型缺陷。疲劳裂纹的扩展会大大缩短结构的使用寿命，甚至造成严重的事故。振动热像仪（VT）作为一种很有前途的无损检测技术，由于其内部加热的方式，在检测金属和非金属材料的疲劳裂纹方面具有很大的潜力。然而，VT系统的多参数优化和智能体模型的建立对VT信号的高效数值仿真技术提出了更高的要求。本文提出并验证了高频激励下小功率VT的快速数值计算方法。为了有效地模拟动态位移，采用单元生死法根据裂纹表面的接触或分离状态调整有限元系数矩阵。该方法能较好地处理复杂的非线性裂纹闭合现象，同时保持振动分析的计算可行性。对于VT温度场的仿真，采用了作者提出的能量等效法解决了高频激励直接时域积分的效率问题。该方法通过对热源进行线性化处理，在保证数值精度的同时减少了计算量，实现了VT过程热场的高效模拟。最后，通过数值模拟和实验验证了该方法的有效性，结果表明，该方法的计算速度比商业软件快6倍以上，且具有相当的数值精度。

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引用次数: 0

Velocity field inversion for heterogeneous concrete and recognition of near-surface rebar using ultrasonic waves 非均质混凝土的速度场反演及近表面钢筋的超声识别

IF 4.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Ndt & E International

Pub Date : 2026-05-01 Epub Date: 2026-01-29 DOI: 10.1016/j.ndteint.2026.103657

Yunfei Zou , Zhiyong Xu , Zijian Wang , Zhishen Wu

The Total Focusing Method (TFM) is widely used for imaging and recognizing the interior of underwater concrete. However, the TFM relies on known wave velocities and cannot invert material properties, resulting in resolution limitations. To this end, this study presents an improved Full Waveform Inversion (FWI) approach that can invert the velocity field characterizing heterogeneous concrete, enabling accurate recognition of rebars near the surface. First, the polarization characteristics of shear horizontal waves are used to suppress the mode conversion of ultrasounds, thereby simplifying the wavefield. Second, source signal estimation combined with a parabolic search algorithm is implemented to iteratively update the optimal source wavelet and step size, improving inversion stability. Third, a weighting function is introduced to suppress interference from interfacial waves, thereby enabling the inversion of high-resolution velocity fields. Additionally, a detection method is proposed for accurate recognition of rebars and structural interfaces. Experimental results demonstrate that the improved FWI method outperforms traditional TFM in both localization and diameter accuracy. Specifically, the mean error of rebar localization is reduced from 1.76 cm to 0.27 cm, while the mean error of diameter decreases from 0.94 cm to 0.36 cm. These advancements extend the application of FWI from seismic wavefield to underwater concrete, advancing the fields of non-destructive testing and structural health monitoring.

全聚焦法（TFM）广泛用于水下混凝土内部的成像和识别。然而，TFM依赖于已知的波速，不能反转材料特性，导致分辨率限制。为此，本研究提出了一种改进的全波形反演（FWI）方法，该方法可以反演表征非均质混凝土的速度场，从而准确识别地表附近的钢筋。首先，利用剪切水平波的偏振特性抑制超声波的模式转换，从而简化波场；其次，将源信号估计与抛物线搜索算法相结合，迭代更新最优源小波和步长，提高反演稳定性；第三，引入加权函数抑制界面波的干扰，从而实现高分辨率速度场的反演。此外，提出了一种准确识别钢筋和结构界面的检测方法。实验结果表明，改进的FWI方法在定位和直径精度上都优于传统的TFM方法。其中，钢筋定位的平均误差从1.76 cm减小到0.27 cm，直径的平均误差从0.94 cm减小到0.36 cm。这些进展将FWI的应用从地震波场扩展到水下混凝土，推动了无损检测和结构健康监测领域的发展。

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引用次数: 0

Remote field eddy current monitoring of hole-edge cracks in bolted joints: Theoretical modeling and experimental validation 螺栓连接孔边裂纹远场涡流监测：理论建模与实验验证

IF 4.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Ndt & E International

Pub Date : 2026-05-01 Epub Date: 2026-01-27 DOI: 10.1016/j.ndteint.2026.103660

Jun Hou, Hu Sun, Xinlin Qing

Remote field eddy current (RFEC) testing offers deep-penetration capability for subsurface inspection, but its application to confined multi-layer geometries such as bolted joints remains unexplored. This study proposes an embedded RFEC method that combines flexible eddy current sensor integration with analytical and finite element modeling to elucidate the formation mechanism of the remote field within bolted joints. The effects of excitation frequency, material properties, and bolt geometry on RFEC coupling are systematically analyzed. Experimental validation on aluminum bolted joints demonstrates that under 3 kHz excitation, crack depths up to 10 mm can be monitored by the sensor, corresponding to amplitude and phase changes of 53 μV and 0.55°, respectively. The location, length, and depth of cracks can be monitored based on sensor signal characteristics. The research results validate the feasibility and high sensitivity of the embedded RFEC method, extending the application of RFEC to complex structural health monitoring scenarios.

远程场涡流（RFEC）测试为地下检测提供了深穿透能力，但其在受限多层几何结构（如螺栓连接）中的应用仍未开发。本研究提出了一种将柔性涡流传感器集成与解析和有限元建模相结合的嵌入式RFEC方法，以阐明螺栓连接内远程场的形成机制。系统分析了激励频率、材料性能和螺栓几何形状对RFEC耦合的影响。对铝合金螺栓连接的实验验证表明，在3 kHz激励下，该传感器可监测裂纹深度达10 mm，对应的振幅和相位变化分别为53 μV和0.55°。根据传感器信号特征，可以监测裂缝的位置、长度和深度。研究结果验证了嵌入式RFEC方法的可行性和高灵敏度，将RFEC应用于复杂的结构健康监测场景。

引用次数: 0

Characterization of localized porosity in laminated composites using ultrasonic interferometry 用超声干涉测量法表征层合复合材料的局部孔隙度

IF 4.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Ndt & E International

Pub Date : 2026-05-01 Epub Date: 2026-01-28 DOI: 10.1016/j.ndteint.2026.103658

William Lucas , Florence Saffar , Tony Valier-Brasier , Alverède Simon

Localized porosity in stratified carbon fiber–reinforced polymer (CFRP) composites can severely affect mechanical performance and structural integrity. Conventional ultrasonic attenuation methods can quantify residual porosity but cannot characterize clusters of voids. This work presents an ultrasonic interferometric approach for the quantitative assessment of localized porosity in laminated composites. CFRP specimens are manufactured in an autoclave under controlled conditions to introduce defined porosity levels. Through-transmission ultrasonic measurements are compared with an analytical multilayer propagation model including a degraded layer described by multiple scattering theory. Solving the inverse problem enabled estimation of both the location and concentration of void clusters.

Results show good agreement with X-ray tomographies, confirming the capability of ultrasonic interferometry for accurate detection of localized porosity and its potential for non-destructive evaluation of laminated composites.

层状碳纤维增强聚合物（CFRP）复合材料的局部孔隙严重影响其力学性能和结构完整性。传统的超声衰减方法可以量化残余孔隙度，但不能表征孔隙簇。本文提出了一种超声干涉法定量评价层合复合材料局部孔隙度的方法。CFRP试样在受控条件下在高压灭菌器中制造，以引入定义的孔隙率水平。将透射超声测量结果与包含退化层的多层解析传播模型进行了比较。通过求解逆问题，可以估计空穴团的位置和浓度。结果与x射线层析成像结果吻合良好，证实了超声干涉测量法精确检测局部孔隙的能力，以及其对层合复合材料无损评价的潜力。

引用次数: 0

The methodology of defect thermal characterization in pulsed thermal NDT based on 3D numerical solutions and polynomial approximation 基于三维数值解和多项式近似的脉冲热无损检测缺陷热表征方法

IF 4.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Ndt & E International

Pub Date : 2026-05-01 Epub Date: 2026-01-14 DOI: 10.1016/j.ndteint.2026.103639

Vladimir Vavilov, Arsenii Chulkov, Olesia Ganina, Marina Kuimova, Oleg Makushev

This study presents a comprehensive methodology for characterizing air-filled finite-size defects in materials with varying thermal properties using pulsed thermal nondestructive testing (TNDT). We numerically solve the three-dimensional heat transfer problem for 729 test cases encompassing defects with different lateral dimensions, depths, and thicknesses in both metallic and non-metallic materials. The analysis yields maximum temperature contrasts and their corresponding observation times, while investigating the influence of defect geometry on thermal signatures. An analytical expression for predicting observation times is derived to complement the numerical results.

The computational results are fitted with polynomial functions to enable rapid estimation of optimal TNDT parameters. This approach provides a practical framework for evaluating detection limits across a wide range of material properties and defect geometries. System-wide analysis reveals mean errors of 60 % for temperature contrast evaluation and 36 % for determination of observation times. Experimental validation using reference samples demonstrates measurement accuracies of 14–35 % for temperature contrasts and 2–8 % for observation times. The proposed inverse solution achieves particularly accurate depth characterization (<14 % error), though thickness estimation shows greater variability (up to 61 % error).

本研究提出了一种综合的方法，用于表征具有不同热性能的材料中的充气有限尺寸缺陷，使用脉冲热无损检测（TNDT）。我们对729个测试用例的三维传热问题进行了数值求解，这些测试用例包括金属和非金属材料中具有不同横向尺寸、深度和厚度的缺陷。分析得出了最大温度对比和相应的观察时间，同时研究了缺陷几何形状对热特征的影响。推导了预测观测次数的解析表达式，以补充数值结果。计算结果用多项式函数拟合，以便快速估计最优TNDT参数。这种方法为评估各种材料特性和缺陷几何形状的检测极限提供了一个实用的框架。全系统分析显示，温度对比评估的平均误差为60%，确定观测时间的平均误差为36%。使用参考样品的实验验证表明，温度对比的测量精度为14 - 35%，观察时间的测量精度为2 - 8%。所提出的反解实现了特别精确的深度表征（误差为14%），尽管厚度估计显示出更大的可变性（误差高达61%）。

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引用次数: 0

Delamination detection in composite laminates using Lamb wave tomographic method based on sparse and probabilistic reconstruction 基于稀疏重建和概率重建的Lamb波层析检测复合材料层合板的分层检测

IF 4.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Ndt & E International

Pub Date : 2026-05-01 Epub Date: 2026-01-16 DOI: 10.1016/j.ndteint.2026.103650

Tong Tong , Wan Qu , Jiadong Hua , Daogui Chen , Jinghan Tan , Jing Lin

Composite materials are widely employed in many industrial fields, and transmitted Lamb wave-based methods, represented by tomography, have been widely utilized for delamination detection in composite laminates. Nevertheless, conventional Lamb wave tomography may suffer from large artifacts and other problems. To break these limitations, a Lamb wave tomographic method based on sparse and probabilistic reconstruction for delamination detection in composite laminates is proposed in this study. Firstly, Lamb wave propagation in delaminated laminates is analyzed, from which it can be derived that delamination can cause the time-of-flight (ToF) delay of A0 mode. Then, differences in ToF between intact and delaminated laminates are calculated and constitute the time difference vector, which can be represented by the product of the length matrix and the slowness difference vector. Since the delamination distribution is sparse, the slowness difference vector satisfies the sparse assumption, which indicates that it can be solved with sparse reconstruction techniques. Furthermore, to improve the quality of sparse reconstruction, the probability distribution is introduced as a prior weight during the solving procedure. Finally, numerical and experimental investigations are implemented. The imaging results can provide a more precise estimation of delamination size and location, which demonstrates the performance improvement of the presented approach.

复合材料广泛应用于许多工业领域，以层析成像为代表的基于透射兰姆波的方法已广泛用于复合材料层合板的分层检测。然而，传统的兰姆波断层扫描可能存在较大的伪影和其他问题。为了突破这些局限性，本文提出了一种基于稀疏重建和概率重建的Lamb波层析检测方法。首先，分析了Lamb波在分层层压板中的传播，推导出分层会导致A0模式的飞行时间延迟。然后，计算完整层合板和分层层合板之间的ToF差，并构成时间差向量，该时间差向量可以用长度矩阵和慢度差向量的乘积表示。由于分层分布是稀疏的，因此慢度差向量满足稀疏假设，可以用稀疏重建技术求解。此外，为了提高稀疏重建的质量，在求解过程中引入了概率分布作为先验权值。最后，进行了数值和实验研究。成像结果可以更精确地估计分层的大小和位置，这表明了该方法的性能改进。

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引用次数: 0

Monitoring Tensile-Induced Subsurface Damages of Woven Glass Fiber Reinforced Polymer Using Terahertz Time-of-Flight Tomography 利用太赫兹飞行时间层析成像技术监测编织玻璃纤维增强聚合物拉伸引起的亚表面损伤

IF 4.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Ndt & E International

Pub Date : 2026-05-01 Epub Date: 2026-01-22 DOI: 10.1016/j.ndteint.2026.103645

Min Zhai , Haoyue Pan , Bin Xiao , Haolian Shi , Zhang Qu , Wenlong He , Cong Zhai , Yi Tang

Woven Glass Fiber Reinforced Polymer (GFRP) composites were studied using terahertz time-of-flight tomography to characterize failure modes in GFRP composite in a nondestructive and contactless fashion during in-situ tensile testing. The fracture morphologies of GFRP composite under different applied stresses were discussed by comparing terahertz C-and B-scan images to evaluate the dynamic evolution of tensile-induced microstructure. Our results show that significant THz-detectable damage initiation was observed at stress levels exceeding 60 MPa. In addition, tensile-induced damage can be observed not only on the surface, but also within the inner piles of GFRP composites. Finally, our work verifies the effectiveness of THz-based approach on three-dimensional dynamic monitoring the quality of GFRP composite in service and evaluating the influence of different loading conditions on structural properties and failure pattern of composite materials.

利用太赫兹飞行时间层析成像技术，研究了编织玻璃纤维增强聚合物（GFRP）复合材料在现场拉伸测试中的无损和无接触方式的失效模式。通过比较太赫兹c扫描和b扫描图像，探讨了GFRP复合材料在不同外加应力下的断裂形貌，以评估拉伸诱导微观结构的动态演变。我们的研究结果表明，在超过60 MPa的应力水平下，观察到明显的太赫兹可探测的损伤起裂。此外，GFRP复合材料不仅在表面存在拉伸损伤，而且在桩内也存在拉伸损伤。最后，验证了基于太赫兹的GFRP复合材料在役质量三维动态监测方法的有效性，并评估了不同载荷条件对复合材料结构性能和破坏模式的影响。

引用次数: 0

Ultrasonic characterisation of process-induced pores in selective laser melted TiB2/Al composites 选择性激光熔化TiB2/Al复合材料中工艺诱导气孔的超声表征

IF 4.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Ndt & E International

Pub Date : 2026-05-01 Epub Date: 2025-12-31 DOI: 10.1016/j.ndteint.2025.103629

Kaiwen Ni , Qiuyu Li , Ming Huang , Yuan Liu

Process-induced pores in metal additive manufacturing (AM) components critically compromise mechanical performance, necessitating reliable characterisation methods for quality assurance. While ultrasound offers promising advantages for rapid, non-destructive evaluation with deep penetration, existing studies struggle to isolate pore effects from confounding grain scattering. This work overcomes these limitations by investigating selective laser melted TiB

_{2}

/Al composites, whose ceramic-reinforced microstructure exhibits refined equiaxed grains and minimal texture, effectively suppressing grain scattering to reveal fundamental pore-ultrasound interactions. We systematically examined how porosity (0.22%–2.21%), morphology, and size distribution influence ultrasonic attenuation and velocity. This was achieved through integrated experimental measurements and three-dimensional pore-scale finite element simulations incorporating realistic pores derived from stereological transformation of microscopy data. Our findings reveal hierarchical pore effects: porosity exhibits strong linear correlations with both attenuation coefficient and phase velocity under the same pore morphology conditions; irregular morphologies amplify these effects, generating fivefold higher attenuation sensitivity and twofold higher velocity sensitivity compared to spherical pores; size variations primarily affect attenuation with minimal velocity impact. Additional, we demonstrated ultrasound’s spatial mapping capability for detecting subtle microstructural heterogeneities, with attenuation exhibiting superior porosity sensitivity. These quantitative pore-ultrasound relationships establish a robust framework for non-destructive evaluation in metal AM, enabling morphology-sensitive quality control and process optimisation for safety-critical applications.

金属增材制造（AM）部件中的工艺诱发孔隙严重影响机械性能，需要可靠的表征方法来保证质量。虽然超声在快速、无损的深穿透评估方面具有很好的优势，但现有的研究很难从混杂的颗粒散射中分离出孔隙效应。这项工作通过研究选择性激光熔化TiB2/Al复合材料克服了这些限制，其陶瓷增强微观结构表现出精致的等轴晶粒和最小的纹理，有效地抑制了晶粒散射，揭示了基本的孔-超声相互作用。我们系统地研究了孔隙度（0.22%-2.21%）、形貌和尺寸分布对超声衰减和速度的影响。这是通过综合实验测量和三维孔隙尺度的有限元模拟来实现的，其中包括来自显微镜数据的立体变换的真实孔隙。我们的研究结果揭示了分层孔隙效应：在相同孔隙形态条件下，孔隙度与衰减系数和相速度均表现出很强的线性相关性；不规则的孔隙形态放大了这些影响，与球形孔隙相比，衰减灵敏度提高了5倍，速度灵敏度提高了2倍；尺寸变化主要影响衰减，速度影响最小。此外，我们还证明了超声波的空间测绘能力，可以检测细微的微观结构非均质性，衰减显示出优越的孔隙度敏感性。这些定量的孔隙-超声关系为金属增材制造的无损评估建立了一个强大的框架，为安全关键应用实现了形态敏感的质量控制和工艺优化。

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引用次数: 0

Application of AI-based techniques for concrete air permeability classification 基于人工智能技术在混凝土透气性分类中的应用

IF 4.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Ndt & E International

Pub Date : 2026-05-01 Epub Date: 2026-01-27 DOI: 10.1016/j.ndteint.2026.103662

Jelena Bijeljić , Emina Petrović , Ernst Niederleithinger

Despite the growing interest in applying artificial intelligence (AI) in civil engineering, its use for evaluating concrete properties remains relatively underexplored. In particular, the assessment of air permeability, a key parameter for concrete durability and long-term performance, has not been extensively addressed using AI-based approaches.

Traditional methods, such as the Torrent test, provide reliable measurements but are time-consuming, labor-intensive, and require specialized equipment. In this study, an image-based deep learning framework was employed, where surface images of concrete specimens served as input data, and the air permeability coefficient kT, measured using the Torrent tester, was used as ground truth. Concrete mixtures were categorized into two classes: “Poor” (low quality) and “Very Poor” (very low quality). Nine batches of cement-based concrete mixtures were prepared, varying in maximum aggregate size and the dosage of air-entraining agents (LP). Deep learning models were developed to link visual surface features with the corresponding air permeability classes. Model performance was evaluated using a combination of statistical measures, including accuracy, precision, recall, F1-score, confusion matrices, ROC-AUC, and PR-AUC, computed across all folds of a 10-fold cross-validation procedure. One-way ANOVA and Tukey's HSD post-hoc test were applied to verify the statistical significance of performance differences. For models achieving the best performance, Gradient-weighted Class Activation Mapping (Grad-CAM) was used to highlight image regions that most strongly influenced the CNN predictions, providing visual insight into the learned feature representations. The results demonstrated that the ResNet50 architecture achieved the most reliable classification performance, highlighting the potential of image-based AI approaches for non-destructive, automated, and field-applicable assessment of concrete air permeability.

尽管人们对人工智能（AI）在土木工程中的应用越来越感兴趣，但它在评估混凝土性能方面的应用仍然相对不足。特别是，空气渗透性的评估，混凝土耐久性和长期性能的关键参数，尚未广泛解决使用基于人工智能的方法。传统的方法，如Torrent测试，提供了可靠的测量结果，但耗时，劳动密集，并且需要专门的设备。本研究采用基于图像的深度学习框架，以混凝土试件表面图像作为输入数据，以Torrent测试仪测量的空气渗透系数kT作为地面真值。混凝土混合物被分为两类：“差”（低质量）和“非常差”（非常低质量）。制备了9批水泥基混凝土混合料，其最大骨料粒径和引气剂（LP）的掺量不同。开发了深度学习模型，将视觉表面特征与相应的透气性类别联系起来。模型的性能使用统计测量的组合进行评估，包括准确性、精密度、召回率、f1得分、混淆矩阵、ROC-AUC和PR-AUC，在10次交叉验证程序的所有折叠中计算。采用单因素方差分析和Tukey’s HSD事后检验验证成绩差异的统计学意义。对于获得最佳性能的模型，使用梯度加权类激活映射（Gradient-weighted Class Activation Mapping, Grad-CAM）来突出显示对CNN预测影响最大的图像区域，提供对学习到的特征表示的视觉洞察。结果表明，ResNet50架构实现了最可靠的分类性能，突出了基于图像的人工智能方法在非破坏性、自动化和现场适用的混凝土透气性评估方面的潜力。

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引用次数: 0