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- 实验方案
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A method for experimental thermo-mechanical aging of materials submitted to concentrated solar irradiation
摘要： Concentrated Solar Technology can produce process heat, power and fuels from solar energy in the temperature range 150–1500 °C, bringing the question of the receiver ability to reliably perform over the expected lifetime. Conventional methods commonly used to assess the mechanical stability and lifetime involve in-door laboratory testing, which suffers from the fundamental inability to reproduce the real operating conditions. A previous work introduced an original experimental setup based on acoustic emission named IMPACT (In situ thermo-Mechanical Probe by ACoustic Tracking), designed for an in situ and passive characterization of receiver materials under harsh thermo-mechanical stresses. This paper proposes an original method, based on a modelling approach, to control the sample damage amplification with IMPACT, and assess its relevance through an experimental campaign on two selected materials (SiC and Inconel 625).
关键词： Central receiver,Thermo-mechanical behaviour,Concentrated Solar Power (CSP),Acoustic Emission
更新于2025-09-23 15:23:52
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Detecting the Burns temperature in Na <sub/>0.5</sub> Bi <sub/>0.5</sub> TiO <sub/>3</sub> -xBaTiO <sub/>3</sub> lead-free relaxor ferroelectrics by means of acoustic emission
摘要： Na0.5Bi0.5TiO3-xBaTiO3 ceramics samples (0 < x < 0.8) were studied by means of an acoustic emission method. The characteristic temperatures such as the Burns temperature, TB, the transition to paraelectric phase, Tp, the temperature maximum of the dielectric constant, Tm, and the intermediate temperature, T ? were detected and their dependences on x were plotted. Based on the comparison of the obtained data with the previously published ones, it is shown that the Burns temperature, TB, cannot be reliably determined by the deviation of the reverse dielectric constant, 1/ε(cid:3), from a straight line.
关键词： phase transitions,relaxor ferroelectrics,Na0.5Bi0.5TiO3-xBaTiO3,Burns temperature,acoustic emission
更新于2025-09-23 15:23:52
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Multichannel fiber laser acoustic emission sensor system for crack detection and location in accelerated fatigue testing of aluminum panels
摘要： Detection and location of the source of acoustic emission in a thin aluminum panel is demonstrated using a multichannel fiber laser sensor system. Acoustic emission generated by a crack in an aluminum panel used as a test coupon in an accelerated fatigue experiment is detected and the location of the crack identified. Acoustic emission is detected over a bandwidth of around 0.5 MHz from a serially multiplexed array of four laser sensors and compared with measurements taken from four piezo-electric sensors co-located with the fiber laser sensors. The location of the crack is determined by first estimating time difference of arrival of signals at each sensor using a novel algorithm based on the cumulative distribution transform method with hyperbolic positioning. The fiber laser sensor is shown to match the signal-to-noise ratio of the industry standard (Mistras S9225) piezo-electric acoustic emission sensor.
关键词： location,crack detection,fiber laser,acoustic emission,accelerated fatigue testing
更新于2025-09-23 15:21:01
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Monitoring of type IV composite pressure vessels with multilayer fully integrated optical fiber based distributed strain sensing
摘要： We present the results of distributed fiber optic strain sensing for condition monitoring of a hybrid type IV composite fully wrapped pressure vessel using multilayer integrated optical fibers. Distributed strain sensing was performed for a total number of 252,000 load cycles until burst of the vessel. During this ageing test material fatigue could be monitored and spatially localized. Critical material changes were detected 17,000 cycles before material failure. Results have been validated by acoustic emission analysis.
关键词： Hybrid composite pressure vessel,Acoustic emission analysis,Structural health monitoring,Distributed fiber optic sensing
更新于2025-09-23 15:19:57
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Application of acoustic emission and laser optoacoustics at various stages of defect formation during friction stir welding
摘要： This paper covers basic aspects of laser ultrasound and acoustic emission non-destructive testing methods in application of monitoring friction stir welds during its deformation and fracture. Stress-strain curves for such welds were obtained and the mechanical characteristics of welded joints of aluminum-magnesium alloy were determined. Using acoustic elastic effect levels of mechanical stresses were measured. Signals of acoustic emission, stimulated by one-axis loading, were registered and analyzed. It was established that acoustic emission during deformation and fracture of samples of welded joints is associated with the course of the process of plastic flow of the material. The nature of the distribution of acoustic emission parameters in the destruction of welded joints with defects has distinctive features. In conditions of one axis quasi static loading rate event count acoustic emission is the most informative parameter.
关键词： friction stir welding,laser optoacoustics,aluminum-magnesium alloy,acoustic emission,defect formation
更新于2025-09-16 10:30:52
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Why is in situ quality control of laser keyhole welding a real challenge?
摘要： In this work, we investigated keyhole welding including the pore dynamics (creation and collapse) of aluminium at the European Synchrotron Radiation Facility (ESRF, Grenoble, France). Optical back reflection and acoustic signals were simultaneously recorded during the welding process which was also visualized by high-speed X-ray imaging. This allows correlating the different momentary events with the signals recorded by the sensors. We demonstrate that keyhole welding is a highly dynamical and unstable process. In addition, to use either acoustic or optical sensors for pore detection, highly advance statistical methods such as machine learning are a requisite for signal processing.
关键词： in-situ monitoring,acoustic emission,X-ray imaging,Laser welding
更新于2025-09-12 10:27:22
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Acoustic emission-based characterization of focal position during ultra-short pulse laser ablation
摘要： Microstructures were ablated using an ultra-short pulse laser system in order to investigate the influence of focal position on the surface topography. In addition, acoustic emissions measured by a piezoelectric sensor adapted to the AISI 4140 workpiece were analyzed and correlated with the focal position and the resulting surface topography. Frequency ranges sensitive to variations of the z-axis position were determined by STFT analysis. Subsequently, significant signal components were processed to enable an inference about the focal position. The hypothesis of assessing the focal position in-process based on acoustic emissions to ensure high precision during laser ablation could be confirmed.
关键词： modulation,time-frequency analysis,acoustic emission,laser ablation,focal position
更新于2025-09-12 10:27:22
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A new acoustic emission on-line monitoring method of laser shock peening
摘要： Laser shock peening (LSP) is an advanced surface modification technology that can harden metallic materials by using plasma shock waves. It has significant technical advantages and has important application value in various fields like the aerospace, defense and military. In order to realize the large-scale industrial production of LSP, it is necessary to strengthen on-line monitoring of its working status. Acoustic emission (AE) is a dynamic non-destructive technique to evaluate the material performance change in real-time, which overcomes many shortcomings of traditional non-destructive testing methods and has been successfully applied to on-line monitoring of LSP. Generally the signal and characteristic parameters of AE are affected by sensor position, which is inconvenient to evaluate the quality of LSP in unified standard. The propagation characteristics of AE and the planar positioning function of AE were concerned in this work, the AE energy of material was obtained from detected waveforms and characteristic parameters of AE by calculation, which is helpful to realize the on-line monitoring of LSP.
关键词： AE energy,on-line monitoring,planar positioning,propagation characteristics,laser shock peening,acoustic emission
更新于2025-09-11 14:15:04
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Application of Fiber Bragg Grating Acoustic Emission Sensors in Thin Polymer-Bonded Explosives
摘要： Fiber Bragg grating (FBG) acoustic emission (AE) sensors have been used in many applications. In this paper, based on an FBG AE sensor, the sensing principle of the interaction between the AE wave and the sensor is introduced. Then, the directionality of the FBG AE sensor on the surface of a thin polymer-bonded explosive (PBX) material is studied. Finally, the time coefficient location method is proposed to correct the AE time detected by the FBG AE sensor, thereby improving the accuracy of location experiments.
关键词： directionality,polymer-bonded explosives,time coefficient location method,fiber Bragg grating acoustic emission sensor
更新于2025-09-10 09:29:36
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Fabrication and Characterization of a Magnetized Metal-Encapsulated FBG Sensor for Structural Health Monitoring
摘要： A novel means of metal packaging of a fiber Bragg grating (FBG) sensor using stainless steel and tin, together with high temperature resistant samarium cobalt (SmCo) magnet is proposed in this paper. The inclusion of high temperature-capable SmCo magnets enable the metal packaging of the FBG sensor with magnetic capabilities. This packaged sensor can be placed in direct contact with the substrate structures such as iron pipelines and other ferromagnetic components without any adhesives, making them easily detachable and reusable. This is a significant improvement compared with other commercial fiber optic sensors which are, surface attached using epoxies or welded to the substrate. The design parameters and characteristic properties such as load, temperature, and vibration sensitivity of the magnetic metal-packaged FBG sensor are studied numerically and validated experimentally to demonstrate the feasibility of using the encapsulated reusable FBGs for structural health monitoring of compatible structures.
关键词： fiber Bragg gratings,welding,Acoustic emission sensors,temperature,strain
更新于2025-09-10 09:29:36