Acoustic Stress Research Articles

Early detection of structural damage in UHPFRC structures through the combination of acoustic emission and ultrasonic stress wave monitoring

Ultra-High-Performance Fiber-Reinforced Cementitious Composite (UHPFRC) offers several advantages compared to concrete, notably due to the strain hardening behavior under tensile actions. Structures made of this composite material are lightweight and highly durable, thanks to the UHPFRC waterproofing quality. Nonetheless, the tensile behavior leads to a different cracking pattern than conventional concrete that is not fully understood yet. This paper presents an innovative monitoring approach that combines passive acoustic emission and active ultrasonic stress wave to localize and quantify damage on a full-scale UHPFRC beam during the loading protocol. This monitoring technique involves 24 transducers that are embedded throughout a UHPFRC t-shape beam of 4.2 meters. Continuous monitoring using this unique passive and active approach enables accurate location events, such as micro-cracking within the beam. Moreover, this sensor network is able to determine the location of the macro-crack that is linked to the structural collapse just after the end of the elastic domain. This novel sensor network opens new possibilities to monitor the structural behavior and detect damage on UHPFRC structures before they affect the structural behavior in terms of deflection and strain.

Contact stress ultrasonic detection method based on contact acoustic resistance model

The size and distribution of the contact stress at the assembly interface will directly affect the connection performance of the mechanical joint. However, the rough assembly interface presents strong dielectric discontinuity and material nonlinearity, which become the bottleneck restricting the development of contact stress detection. How to obtain contact stress by nondestructive testing means has become an urgent problem to be solved. In this paper, a multi-layer interface contact stress detection method based on contact acoustic resistance model is proposed to solve the difficult problem of rough interface contact stress detection. Firstly, based on the formation mechanism of contact acoustic resistance of rough assembly interface, the equivalent contact acoustic resistance expression of contact layer is derived. Secondly, the contact mechanism of rough assembly interface is clarified, and the mapping relationship model between contact acoustic resistance and contact stress is constructed. On this basis, according to the transmission law of ultrasonic wave at different interfaces of multilayer acoustic impedance, the expression of acoustic transmission coefficient at the interface of variable acoustic impedance is obtained. A contact stress detection method based on contact stress-contact acoustic resistance coefficient and acoustic transmission coefficient is proposed. The correctness of the theoretical model is verified by the tensile testing machine, and the maximum error is 15.52 %. This method will provide powerful data support for the evaluation of assembly interface connection state.

Method for rock fracture prediction and early warning: Insight from fusion of multi-physics field information

Understanding the precursors leading to rock fracture is crucial for ensuring safety in mining and geotechnical engineering projects. To effectively discern these precursors, a collaborative monitoring approach that integrates multiple sources of information is imperative. This paper considered a rock multi-parameter monitoring loading system, incorporating infrared radiation and acoustic emission monitoring technologies to simultaneously track the rock fracture process. The study delves into the spatiotemporal evolution patterns of infrared radiation and acoustic emission in rock under loading. Utilizing stress, cumulative acoustic emission count, and average infrared radiation temperature (AIRT), the paper establishes a comprehensive evaluation model termed “acoustic-thermal-stress” fusion information, employing principal component analysis (PCA). The research reveals that the sensitivity to rock sample damage response follows the sequence of cumulative acoustic emission count, AIRT, and stress. Furthermore, a novel method for identifying rock fracture precursors is proposed, based on the first derivative of the comprehensive evaluation model. This method addresses the limitations of single physical field information, enhancing the robustness of monitoring data. It determines the average stress level of fracture precursors to be 0.77σmax. Subsequently, the study defines the probability function of rock damage during loading and fracture, enabling the realization of probability-based warnings for rock fracture. This approach introduces a new perspective on rock fracture prediction, significantly contributing to safety monitoring and warning systems in mine safety and geotechnical engineering. The findings of this research hold paramount engineering significance, offering valuable insights for enhancing safety measures in such projects.

Metabolomics responses and tolerance of Pseudomonas aeruginosa under acoustic vibration stress.

Sound has been shown to impact microbial behaviors. However, our understanding of the chemical and molecular mechanisms underlying these microbial responses to acoustic vibration is limited. In this study, we used untargeted metabolomics analysis to investigate the effects of 100-Hz acoustic vibration on the intra- and extracellular hydrophobic metabolites of P. aeruginosa PAO1. Our findings revealed increased levels of fatty acids and their derivatives, quinolones, and N-acylethanolamines upon sound exposure, while rhamnolipids (RLs) showed decreased levels. Further quantitative real-time polymerase chain reaction experiments showed slight downregulation of the rhlA gene (1.3-fold) and upregulation of fabY (1.5-fold), fadE (1.7-fold), and pqsA (1.4-fold) genes, which are associated with RL, fatty acid, and quinolone biosynthesis. However, no alterations in the genes related to the rpoS regulators or quorum-sensing networks were observed. Supplementing sodium oleate to P. aeruginosa cultures to simulate the effects of sound resulted in increased tolerance of P. aeruginosa in the presence of sound at 48 h, suggesting a potential novel response-tolerance correlation. In contrast, adding RL, which went against the response direction, did not affect its growth. Overall, these findings provide potential implications for the control and manipulation of virulence and bacterial characteristics for medical and industrial applications.

Birefringence Technique for Evaluating Thermal Stresses in Railroad Rails

This paper discusses the development of an in situ noncontact electromagnetic acoustic transducer (EMAT) nondestructive evaluation technology to determine rail neutral temperature and estimate rail stress in continuous welded rail (CWR). Stresses develop in CWR due to a lack of expansion joints to accommodate thermal expansion and contraction of the rail when ambient temperatures vary over time. The novelty of the work presented is the usage of ultrasonic birefringence properties using EMATs to estimate thermally induced stresses in rails. EMATs produce polarized shear waves propagating through the rail web in the pulse-echo mode. Experimental tests were performed on machined 136RE and 141RE rail material with applied compressive and tensile stresses to explore the stress-birefringence behavior. Two additional sets of experimental tests were conducted on full-size rail sections with in situ surface conditions to study variations in the in situ birefringence and the acoustic stress constant in different rail materials including 115RE rail, 119RE rail, two different 136RE rails, and 141RE rail. The results show a highly linear relationship between the stresses applied and the measured acoustic birefringence.

Evaluation of the anxiolytic activity of dry extract of Patrinia scabiosifolia under acoustic stress.

Patrinia scabiosifolia has been used in traditional medicine in East Asia, Africa, and South America for a variety of diseases for more than 2000 years. The purpose of the article is to evaluate the anxiolytic properties of dry extract of P. scabiosifolia. In vivo experiments were performed on outbred white male mice. The psychotropic effect of P. scabiosifolia dry extract was assessed using behavioral test systems aimed at identifying changes in the psycho-emotional state of animals under the influence of acoustic stress. In addition, the preparation toxicity was also assessed. HPLC-MS analysis was carried out to confirm the presence of active components in local raw materials. The article describes the possibility of using dry extract of P. scabiosifolia as an anxiolytic and sedative for psycho-emotional stress in experimental animals. Based on comprehensive research results, the effectiveness and safety of the studied herbal preparation have been proven. In this study, a dry extract of P. scabiosifolia has been proposed as a novel means of combating neuropsychiatric disorders. P. scabiosifolia showed efficacy comparable to the reference drug (Mebicar), reducing sleep time and increasing sleep duration. The results obtained can subsequently serve as the basis for clinical trials.

Does Soundpeaking Affect the Behavior of Chub (Squalius cephalus) and Brown Trout (Salmo trutta)? An Experimental Approach

Increased turbulent flow and sediment transport during flood or hydropeaking events often induces rapid changes in underwater sound pressure levels, which is here referred to as soundpeaking. This study is the first to investigate such a change in the underwater soundscape in relation to fish behavior using an experimental approach. Trials were conducted in an experimental channel stocked with either adult chub (Squalius cephalus) or brown trout (Salmo trutta). To mimic soundpeaking, the underwater soundscape of a small alpine river was recorded during a flood event and later played back through an underwater speaker during treatment trials. Furthermore, trials were recorded with a video camera, and based on the fish position, movement variables (swimming distance, number of movement direction changes, variance of the acceleration), the aggregation of individuals, the longitudinal and the lateral position in the experimental area were compared between control (no sound played) and treatment trials. During treatment trials, brown trout changed their movement direction significantly more often, chub showed a significantly higher variation of the acceleration, and individuals from both species were significantly more aggregated. Furthermore, the soundpeaking treatment had a significant effect on the longitudinal position of brown trout in the experimental area. However, the overall results did not provide any indication for a stronger soundpeaking effect in chub despite being equipped with much more refined hearing abilities in comparison to brown trout. Based on these results and findings from other studies, soundpeaking is discussed as a behavioral trigger as well as a source of acoustic stress.

Vocalization behavior response of captive bottlenose dolphins (Tursiops truncatus) to playbacks of pile driving noise

Anthropogenic noises in the ocean may cause significant impacts on the behavior of marine mammals, including stress, hearing impairment, and disruptions in social interactions. To investigate the potential effects of off-shore wind farm pile driving noise on dolphins, we conducted controlled experiments to 3 captive bottlenose dolphins (Tursiops truncatus) exposed to pile driving noise playbacks at four different sound pressure levels (Mean Lpeak 0,127,147,160 dB re 1 μPa) with a Lubell LL1424HP underwater transducer. Several vocalizational parameters of the underwater video recordings during the exposure were analyzed to assess the quantity of vocalizations and frequency modulations. Our findings revealed a notable increase in frequency modulation within whistle calls as the sound levels of pile driving noises increased. Changes in the number of calls at different noise levels can also be noticed. Additionally, we observed time-matching jaw claps to the pile driving sounds. These results suggest that pile driving activity several kilometres away from the habitat may still cause frequency masking, leading to altered behaviors of dolphins and potentially inducing population-level stress. Understanding the impact of anthropogenic noise including behavioral and acoustic responses, auditory masking, and stress on marine species is crucial for effective conservation and mitigation strategies.

Examination of combustion behaviors and emissions of hydrogen enriched propane/methane fuel under external acoustic application

In this study, the instability and emission changes of hydrogen-enriched methane-propane fuel under external acoustic application in a premixed and vortex assisted system were investigated. In the experiment, 67% -33% and 63,5% -31,5% -5% were studied under different acoustic stresses as fuel mixtures. It is known that hydrogen can reduce the emission parameters polluting the environment and its effect on combustion stability. For this reason, interest in the use of hydrogen fuel with other fuels has increased. It may be possible to improve the combustive performance properties of compatible methane and propane mixtures by adding hydrogen. Also, the effects of acoustic applications were examined. Addition of hydrogen to the methane/propane flame increased the heating value of the mixture and caused flame instability due to the increase in laminar flame velocity. There was an increase of 12.2% in light intensity. When the amount of hydrogen increased, the flame was more resistant to acoustic stress. High dynamic pressure fluctuations occurred with 90 Hz acoustic forcing. The emission capacity of the mixture to which hydrogen is added by acoustic forcing has consistently higher values. This was attributed to the change in reaction kinetics due to the increased content.

Deformation of nucleated cells driven by ultrasonic standing waves

The deformation of nucleated cells driven by ultrasonic standing waves in fluid environment is investigated by theoretical analysis and numerical simulation. The nucleated cells are considered to consist of cell membrane, cytoplasm and nucleus The cell membrane is assumed to have in-plane deformation and bending resistances, in which the in-plane deformation is modeled by the generalized Hooke's law, and the bending resistance is modeled by the Helfrich bending energy formula. Due to the acoustic mismatch between the media inside and outside the cell, the generated acoustic radiation stress on the cell membrane causes the nucleated cell to deform. Considering the acoustic scattering of the nucleus, the acoustic radiation stress is formulated by applying the acoustic radiation stress tensor theory. Based on the proposed theoretical model, a finite element model is established to solve the coupling problem of ultrasonic propagation and cell deformation. The analytical solution for the acoustic induced deformation of nucleated cells in the limits of long wavelength and small deformation is given and successfully verifies the finite element model. The results show that the deformation of nucleated cells is much larger than that of enucleated cells due to the effect of the nucleus on wave propagation. The deformation of nucleated cells is significantly affected by nuclear size and nuclear density. This study is helpful to accurately extract the mechanical properties of nucleated cells and further promote the detection of cell-related diseases by acoustic deformation technology.

Revealing the acoustic effects on heat transfer and material flow in ultrasonic assisted friction stir welding of dissimilar Al/Mg alloys

Development of a reasonable constitutive equation is critical to realize accurate numerical prediction of ultrasonic vibration-assisted friction stir welding (UVaFSW) of dissimilar Al/Mg alloys and deepen the understanding of the synchronous interaction between the ultrasonic vibration exerted on the tool and the tool induced thermo-mechanical behavior. Considering the thermal activation and dislocation evolution mechanisms, the calculation method of acoustic stress work based on the change of dislocation strain energy is redefined, and a modified acoustic-plastic constitutive equation is developed. The modified constitutive equation was applied to the computational fluid dynamics (CFD) model combined with the volume of fluid (VOF) method and quantitative analysis was conducted on the acoustic effects on heat generation, material flow and intermixing in UVaFSW of Al/Mg alloys. The results indicate that the exerted ultrasonic vibration has a little effect on the total heat due to the multiple effects of acoustic softening, acoustic antifriction and additional acoustic heat, but can promote the material flow around the tool and expand the material intermixed region. The experimental research validates the calculated results, and it is indicated that the flow stress and temperature field calculated by the improved constitutive equation have higher accuracy in UVaFSW of Al/Mg alloys.

Artificial sound impact could put at risk hermit crabs and their symbiont anemones

The sea anemone Calliactis parasitica, which is found in the East Atlantic (Portugal to Senegal) and the Mediterranean Sea, forms a symbiotic relationship with the red hermit crab, Dardanus calidus, in which the anemone provides protection from predators such as the octopus while it gains mobility, and possibly food scraps, from the hermit crab. Acoustic pollution is recognised by the scientific community as a growing threat to ocean inhabitants. Recent findings on marine invertebrates showed that exposure to artificial sound had direct behavioural, physiological and ultrastructural consequences. In this study we assess the impact of artificial sound (received level 157 ± 5 dB re 1 μPa2 with peak levels up to 175 dB re 1 μPa2) on the red hermit crab and its symbiotic sea anemone. Scanning electron microscopy analyses revealed lesions in the statocyst of the red hermit crab and in the tentacle sensory epithelia of its anemone when exposed to low-intensity, low-frequency sounds. These ultrastructural changes under situations of acoustic stress in symbiotic partners belonging to different phyla is a new issue that may limit their survival capacity, and a new challenge in assessing the effects of acoustic disturbance in the oceanic ecosystem. Despite the lesions found in the red hermit crab, its righting reflex time was not as strongly affected showing only an increase in the range of righting times. Given that low-frequency sound levels in the ocean are increasing and that reliable bioacoustic data on invertebrates is very scarce, in light of the results of the present study, we argue that anthropogenic sound effects on invertebrates species may have direct consequences in the entire ecosystem.

Experimental Investigation of Acoustic Forcing on the Combustion Effect of Propane - Methane Mixtures

Today, the ever-increasing energy resource needs are of great importance for all countries in the global sense. Countries have recently been developing important policies to meet their energy needs and to use existing energy resources efficiently. In addition, in order to minimize the emissions that harm the nature as a result of the burning of energy sources, they have turned to alternative energy sources that are less harmful to the environment. In order to be an alternative energy source, in this study, the effect of enriching propane gas with methane gas on combustion in a Tubitak supported combustor was experimentally investigated. The enrichment of methane gas was determined at the rates of 10%, 20% and 30%, and the effects of acoustic stress on combustion, emission values and the effects on the flame were investigated. The thermal power was 7 kW and the equivalence ratio (Փ) was 1.2, and the experiment was carried out with a constant eddy value (1.0). When the experiment was carried out without acoustic stress, it was determined that the temperature, flame brightness and light intensity increased as the methane ratio increased, the dynamic pressure value almost did not change, the NOx value was negligibly small, and the CO value decreased depending on the oxygen amount as the methane ratio increased. In the experiments carried out under 90 Hz, 185 Hz and 330 Hz acoustic stress, as the forcing value increases, the temperature and flame brightness increase; It was observed that the NOx value was negligibly small, and the CO value decreased compared to the experiment performed without acoustic stress.

Acoustic softening – investigation of the volume effect and introduction of amplitude strain parameter

Acoustic softening is a phenomenon where metals exhibit a lower flow stress when excited by a vibration at ultrasonic frequencies. This softening effect has been well documented in the literature, however, there are two areas that require further in-depth analysis. The first relates to the wide range of reported softening responses for the same alloy. The second relates to the use of coefficients and compensation factors when modeling the acoustic softening phenomenon in a complex forming processes. This study investigates the changes in softening response when altering specimen dimensions in ultrasonic assisted compression tests. Aluminum alloys (AA) 2024-O and AA7075-O were machined to different dimensions and compressed with ultrasonic assistance, to investigate the relationship between specimen volume and softening response. An inverse relationship between softening magnitude and sample volume was found. When relating this to acoustic energy density and stress, the values are invariant because the standard acoustic equations cannot account for changes in specimen height. The amplitude strain parameter, amplitude divided by the current specimen height, is introduced, and shown to account for changes in specimen dimensions. In addition, the softening effect diminishes relative to the state of strain. The results suggest acoustic softening is a function of the amplitude strain parameter and strain history.

Experimental study on acoustic emission stress memory function of rock-like specimens under uniaxial compression

The Kaiser effect in rock acoustic emission (AE) test is the most direct manifestation of rock memory function. This article focuses on the influence of different deformation stages and different historical stress conditions on stress memory function, and conducts AE testing of rock-like specimens. It explained the stress memory function in AE testing from the perspectives of crack propagation and damage accumulation. The crack initiation stress σci and crack damage stress σcd of specimens were obtained based on the stress-strain curve method, and the different deformation stages were divided. The damage evolution coefficient [Formula: see text] was proposed to measure the size of the stable development range of damage based on the normalized crack initiation and crack damage stress. The historical stress in the elastic stage could be easily identified from the Kaiser effect during the reloading process, even if the time interval reached 120 hours. The Felicity effect appeared during the reloading process when the historical stress was in the stage of stable crack propagation, and the FR value showed a decreasing trend with the extension of the time interval between loading tests. The loading history in the elastic stage was a training for the AE stress memory function under complex historical stress conditions, which restored the Kaiser effect in the stage of stable crack propagation. The distribution of AE events and CT scanning results were also analyzed in the article, and the damage accumulation information characterized by both are basically consistent. The double Kaiser effect phenomenon appeared in the AE test under complex historical stress conditions, although the criterion for discriminating the AE signal at the Kaiser effect point corresponding to the lower stress remained to be further studied and verified.

Study on the Acoustic Emission Characteristics and Failure Precursors of Water-Rich Frozen Sandstone under Different Lateral Unloading Rates

The artificial freezing method is used to cross the water-rich soft rock strata in order to exploit deep coal resources. At present, studies that consider both freezing effect and unloading rate are insufficient. To study the influences of the excavation rate using the artificial freezing method on the unloading deformation and failure of the water-rich surrounding rock, we carry out mechanical and synchronous acoustic emission (AE) tests on frozen (−10 °C) sandstone samples under different lateral unloading rates. Combined with the AE signals, the stress, strain and failure process are analysed to determine the mechanical behaviours of frozen rock samples under different lateral unloading rates. The damage difference between normal temperature rock and frozen rock during lateral unloading is studied. According to acoustic emission signals, the damage relationships among acoustic emission amplitude, energy, cumulative acoustic emission energy (CAEE), stress and strain were compared and analyzed. In this paper, acoustic emission 3D positioning system is used to monitor the fracture propagation trajectory in the process of unloading confining pressure of frozen sandstone. The results show that the peak stress of frozen sandstone during lateral unloading is about 2.5 times of that at 20 °C. More than 2 AE amplitudes per second are regarded as the precursor of failure (FP), and point FP is taken as the first level warning. The CAEE of rock samples at 20 °C and frozen rock samples shows the same change law over time, increasing slowly before the FP point and exponentially after the FP point. Peak stress increases and axial strain decreases with the increase of unloading rate of frozen rock sample. The CAEE at point FP and the peak acoustic emission energy (AEE) and the CAEE at the time of failure increase when the unloading rate of frozen rock sample increases. Principal component analysis method was used to extract key characteristic energy to obtain a clearer AEE concentration area, which was defined as second-level early warning. The research results can provide guidance for freezing shaft construction to reduce the occurrence of disasters.

Study protocol: how does parental stress measured by clinical scales and voice acoustic stress markers predict children’s response to PTSD trauma-focused therapies?

IntroductionPost-traumatic stress disorder (PTSD) symptoms in youth are influenced by parental anxiety and stress. When parents have high levels of stress or have developed PTSD themselves, children tend to show...

Multiple exposure to thunderstorm sound in Nile tilapia (Oreochromis niloticus): physiological response and stress recovery

Abstract The present study investigated the impacts of multiple thunderstorm-sound exposures on growth and respiratory parameters in Nile tilapia (Oreochromis niloticus) in order to evaluate the acoustic stress response. Thunderstorm-sound exposure for 3 hours triggered respiration speed with an alarm reflex and rapid elevation of opercula beat rate (OBR) and pectoral wing rate (PWR), which increased two-fold over the control with no sound treatment, and peaked (OBR, 71.33±5.86 beat/min; PWR, 75.00±3.61 beat/min) in 10 hours after initiation of sound. Thereafter, respiration rates declined over the following days and returned to near-initial levels (45.33±4.04 beat/min OBR and 43.00±1.00 beat/min PWR) by day 3, an indication that fish recovered from thunderstorm-sound stress after 3 days of exposure. However, the same reaction course was observed each time of multiple sound exposures, repeated 20 times in a row with 4-day intervals, underlining that fish could not attune to repeated thunderstorm sound. Reduced voluntary feed intake as a result of anxiety and appetite loss was recorded in fish exposed to multiple thunderstorm sound, resulting in 50% less growth compared to those without sound treatment by the end of the 80-day experimentation. Therefore, it is advisable to monitor fish behavior during the 3-day stress period after a thunderstorm event in order to prevent waste from excess feeding, that in turn may contribute environment-friendly aquaculture for the future and sustainability of the oceans.

Acoustic Stress Induces Opposite Proliferative/Transformative Effects in Hippocampal Glia.

The hippocampus is a brain region crucially involved in regulating stress responses and highly sensitive to environmental changes, with elevated proliferative and adaptive activity of neurons and glial cells. Despite the prevalence of environmental noise as a stressor, its effects on hippocampal cytoarchitecture remain largely unknown. In this study, we aimed to investigate the impact of acoustic stress on hippocampal proliferation and glial cytoarchitecture in adult male rats, using environmental noise as a stress model. After 21 days of noise exposure, our results showed abnormal cellular proliferation in the hippocampus, with an inverse effect on the proliferation ratios of astrocytes and microglia. Both cell lineages also displayed atrophic morphologies with fewer processes and lower densities in the noise-stressed animals. Our findings suggest that, stress not only affects neurogenesis and neuronal death in the hippocampus, but also the proliferation ratio, cell density, and morphology of glial cells, potentially triggering an inflammatory-like response that compromises their homeostatic and repair functions.

Past strong experiences determine acute cardiovascular autonomic responses to acoustic stress

Stress is a major risk factor for cardiovascular (CV) disease. We hypothesized that past strong experiences might modulate acute CV autonomic responses to an unexpected acoustic stimulus. A i m: The study's aim was to compare acute CV autonomic responses to acoustic stress between students with and without a past strong experience associated with the acoustic stimulus. Twenty five healthy young volunteers - medical and non-medical students - were included in the study. CV hemodynamic parameters, heart rate (HR), and blood pressure (BP) variability were assessed for 10 min at rest and for 10 min after two different acoustic stimuli: a standard sound signal and a specific sound signal used during a practical anatomy exam (so-called "pins"). Both sounds stimulated the autonomic nervous system. The "pins" signal caused a stronger increase in HR in medical students (69 ± 10 vs. 73 ± 13 bpm, p = 0.004) when compared to non-medical students (69 ± 6 vs. 70 ± 10, p = 0.695). Rises in diastolic BP, observed 15 seconds after sound stressors, were more pronounced after the "pins" sound than after the standard sound signal only in medical students (3.1% and 1.4% vs. 3% and 4.4%), which was also reflected by low-frequency diastolic BP variability (medical students: 6.2 ± 1.6 vs. 4.1 ± 0.8 ms2, p = 0.04; non-medical students: 6.0 ± 4.3 vs. 4.1 ± 2.6 ms2, p = 0.06). The "pins" sound, which medical students remembered from their anatomy practical exam, provoked greater sympathetic activity in the medical student group than in their non-medical peers. Thus, past strong experiences modulate CV autonomic responses to acute acoustic stress.